JPWO2018154707A1 - Image composition display apparatus and method, program, and recording medium - Google Patents

Abstract

  A double buffer configuration higher than the layer of the single buffer configuration in which the image information is updated is used as a cover layer, and an image to be displayed next in the cover layer and lower layers is displayed in the writing buffer of the cover layer. Draw in order from the lowest layer, and set the drawn area to be opaque. Then, by replacing the cover layer buffer, the image stored in the buffer in which the opaque setting has been made shifts to a state where it is used for image composition. In this state, the image of the layer whose image information is updated is drawn in the buffer of the layer. When the drawing is completed, the cover layer buffer is replaced. As a result, the image stored in the new display buffer of the cover layer shifts to a state where it is used for image composition.

Description

  The present invention relates to an image composition display apparatus and method. In particular, the present invention relates to an image composition display apparatus and method for generating and displaying a composite image by temporarily storing a plurality of layers of images in a frame buffer and then superimposing them. The present invention also relates to a program for causing a computer to execute processing in the image composition display apparatus and method, and a computer-readable recording medium on which the program is recorded.

In a system that generates and displays a composite image by superimposing a plurality of layers of images, screen flicker during image rewriting becomes a problem. It is known to provide two buffers (storage areas) for images of each layer in order to prevent screen flicker during image rewriting. In such a configuration, one of the two buffers in each layer is assigned for display and the other is assigned for writing. An image read from the display buffer is used for composition. When an image needs to be rewritten in any layer, a new image is written in the writing buffer of the layer, and when the writing is completed, the role of the buffer is switched. That is, the buffer in which a new image is written is used as a new display buffer, and the role of the buffer that has been used for display is changed to writing.
In such a configuration, there is a problem that a large number of buffers are required.

  In order to reduce the number of buffers, one spare buffer is prepared for a plurality of layers, a new image of a layer that needs to be rewritten is written to the spare buffer. It has been proposed that a buffer used as a display buffer and used as a display buffer for the layer until then is allocated as a spare (Patent Document 1).

  Also, in a system that transparently synthesizes images of multiple layers, in order to prevent flickering of the screen when redrawing the image of the lower layer (back side), the redrawing area of the lower layer image before redrawing is set as the upper layer. In this state, the transparency setting is canceled, so that the redrawing area of the lower layer image is not output, the lower layer image is redrawn in that state, and when the redrawing is completed, the upper layer transparency setting is set. It has also been proposed to do this (Patent Document 2).

JP-A-5-83630 JP 2010-26297 A

  In the configuration of Patent Document 1, images of a plurality of layers cannot be rewritten at one time, and it is necessary to rewrite the images one layer at a time. Therefore, when image rewrite requests for multiple layers occur at the same time, the image before rewriting is stored in some buffers for the period until rewriting is completed in the buffers of all layers, The rewritten image is stored. As a result, the composite image may be inappropriate. For example, if a meaningful composite image is generated for the first time when the rewritten image is used in all of the multiple layers, the pre-rewritten image is used in some layers, so the composite image is meaningful. It may become something that is not.

In the configuration of Patent Document 2, when a translucent object exists in the upper layer, it is not possible to cope with only the process of fitting the lower layer image into the upper layer image.
Further, when the upper layer image is returned to the transparency setting, flicker may occur if the timing of the image transparency processing and the timing of memory reading overlap.

The image composition display device according to the first aspect of the present invention includes:
In an image composition display device for compositing by superimposing images of first to Nth layers (N is an integer of 2 or more) and displaying a composite image,
The image of the nth layer (n is any one from 1 to (N-1)) is a higher layer than the image of the (n + 1) th layer, and the higher layer image is Placed on the front side in the overlay for
A first to (N + 1) th storage area, a drawing processing unit, a memory control unit, a reading unit, and an image composition unit;
The first and (N + 1) storage areas are allocated to the first layer, the first layer is a double buffer configuration layer to which two storage areas are allocated, and the double buffer configuration layer , One of the two storage areas is assigned to the display buffer, the other is assigned to the write buffer,
The second to Nth storage areas are assigned to second to Nth layers, respectively, and the second to Nth layers are single buffer configuration layers to which a single storage area is assigned, and In each of the layers of the single buffer configuration, the allocated single storage area is allocated to the display and writing combined buffer,
The drawing processing unit performs drawing on the first layer writing buffer and the second to Nth layer display and writing combined buffers based on image information of each layer supplied from the outside. ,
The reading unit reads an image from the display buffer for the first layer and the display and write buffer for the second to Nth layers;
The image composition unit composes the read image,
When the image information of at least one of the second to Nth layers is updated, the drawing processing unit stores the first to Nth layers in the writing buffer of the first layer. , Draw the next image to be displayed in order from the lowest layer, set the rendered area to opaque,
When the drawing and the opacity setting are completed, the memory control unit allocates a storage area that has been used as a writing buffer in the first layer to a new display buffer and uses the storage area as a display buffer until then. Allocate the storage area that was used to a new writing buffer, so that the image stored in the storage area where the opaque setting has been made transitions to the opaque composition state used for image composition,
In the opaque composition state, the drawing processing unit is
Drawing each image of at least one layer of the second to Nth layers, in which image information is updated, in a display / write buffer for the layer;
Drawing an image to be displayed next to the first layer in the writing buffer of the first layer;
When the drawing in the opaque composition state is completed, the memory control unit allocates a storage area that has been used as a writing buffer in the first layer to a new display buffer, and uses it as a display buffer until then. The storage area used is allocated to a new writing buffer, whereby the image stored in the new display buffer of the first layer is shifted to a transparent composition state used for image composition. And

The image composition display device according to the second aspect of the present invention includes:
In an image composition display device that combines images by superimposing images of first to Nth layers (N is an integer of 3 or more) and displays a composite image.
The image of the nth layer (n is any one from 1 to (N-1)) is a higher layer than the image of the (n + 1) th layer, and the higher layer image is Placed on the front side in the overlay for
First to (N + M) storage areas (M is an integer greater than 1 and less than N), a drawing management unit, a drawing processing unit, a memory control unit, a reading unit, and an image composition unit;
The first to Nth storage areas are allocated to the first to Nth layers, respectively.
The (N + 1) th to (N + M) recording areas are assigned to M layers of the first to Nth layers, and the M layers are assigned with two storage areas. As a buffer configuration layer, in the double buffer configuration layer, one of the two storage areas is allocated to the display buffer, the other is allocated to the write buffer,
Of the first to Nth layers, (N−M) layers other than the M layers are layers of a single buffer configuration to which a single storage area is allocated, and the single buffer configuration In this layer, a single storage area is allocated to the display / write buffer,
The M layers include the first layer,
For each of the M double buffer layers, the drawing processing unit performs drawing in the writing buffer of the layer based on image information of the layer supplied from the outside,
For each of the (N−M) single buffer configuration layers, the rendering processing unit performs rendering in the display / write buffer for the layer based on image information of the layer supplied from the outside. Done
The reading unit reads an image from the M layer display buffer and the (NM) layer display and write buffer,
The image composition unit composes the read image,
When image information is updated for at least one layer of the single buffer configuration among the first to Nth layers,
The drawing management unit designates, as a cover layer, a layer of a double buffer configuration that is higher than any of the at least one single buffer configuration layer in which the image information is updated,
The drawing processing unit draws and draws the image to be displayed next to the cover layer and the layer lower than the cover layer on the writing buffer of the cover layer in order from the lowest layer. Make the area opaque,
When the drawing and the opacity setting are completed, the memory control unit allocates a storage area that has been used as a writing buffer in the cover layer to a new display buffer and is used as a display buffer until then. The storage area that has been allocated is assigned to a new writing buffer, whereby the image stored in the storage area in which the opaque setting has been made shifts to an opaque composition state used for image composition,
In the opaque composition state, the drawing processing unit is
Drawing each image of the layer of the at least one single buffer configuration in which the image information has been updated, in the display and writing combined buffer of the layer;
Draw an image to be displayed next to the cover layer in the writing buffer of the cover layer,
When the drawing in the opaque composite state is completed, the memory control unit allocates a storage area that has been used as a writing buffer in the cover layer to a new display buffer, and is allocated to the display buffer until then. The stored storage area is assigned to a new writing buffer, whereby the image stored in the new display buffer of the cover layer is shifted to a transparent composition state used for image composition.

The image composition display device according to the third aspect of the present invention is:
In an image composition display device that combines images by superimposing images of first to Nth layers (N is an integer of 3 or more) and displays a composite image.
The image of the nth layer (n is any one from 1 to (N-1)) is a higher layer than the image of the (n + 1) th layer, and the higher layer image is Placed on the front side in the overlay for
First to (N + S) storage areas (S is an integer greater than or equal to 1 and smaller than N), a drawing management unit, a drawing processing unit, a memory control unit, a reading unit, and an image composition unit ,
Of the first to (N + S) storage areas, N storage areas are normally allocated to the display and write combined buffers for the first to Nth layers, respectively.
Each of the S storage areas of the first to (N + S) storage areas is normally a spare buffer, and is allocated to a write buffer in any layer as necessary. By allocating a storage area of a layer that has been used as a display / write buffer to the display buffer, the layer is switched to a double buffer configuration layer to which two storage areas are allocated. In the layer, one of the two storage areas is assigned to the display buffer, the other is assigned to the write buffer,
Layers other than the double buffer configuration layer are single buffer configuration layers to which a single storage area is allocated, and in the single buffer configuration layer, a single storage area is allocated to the display and write combined buffer,
For each layer of at least one double buffer configuration, the drawing processing unit performs drawing in the writing buffer of the layer based on the image information of the layer supplied from the outside,
For each layer of at least one single buffer configuration, the rendering processing unit performs rendering in the display and writing combined buffer of the layer based on image information of the layer supplied from the outside,
The reading unit reads an image from the single buffer configuration layer display buffer and the double buffer configuration layer display and writing combined buffer,
The image composition unit composes the read image,
When the image information is updated for a number of layers larger than S among the first to Nth layers,
The drawing management unit designates the highest layer among the layers whose image information has been updated as a cover layer,
The memory control unit allocates one of the storage areas previously used as the reserve buffer to the writing buffer for the cover layer, and has been used as a display and writing combined buffer until then for the cover layer. Allocate storage area to display buffer,
The drawing processing unit draws and draws the image to be displayed next to the cover layer and the layer lower than the cover layer in order from the lowest layer in the writing buffer of the cover layer. Make the area opaque,
When the drawing and the opacity setting are completed, the memory control unit allocates a storage area that has been used as a writing buffer in the cover layer to a new display buffer and is used as a display buffer until then. The storage area is assigned to a new writing buffer, so that the image stored in the storage area where the opaque setting has been made shifts to the opaque composition state used for image composition,
In the opaque composition state, the drawing processing unit is
Drawing each image of the layer whose image information is updated lower than the cover layer in the display and writing combined buffer of the layer,
Draw the image to be displayed next to the cover layer in the writing buffer of the cover layer,
When the drawing in the opaque composite state is completed, the memory control unit allocates a storage area that has been used as a writing buffer in the cover layer to a new display / writing buffer of the cover layer, and the cover layer In this case, the storage area previously used as the display buffer is assigned to a new spare buffer so that the image stored in the new display / writing buffer of the cover layer is used for image composition. It is characterized by shifting to.

  According to the present invention, it is possible to suppress flickering of a screen when rewriting an image with a smaller memory capacity. In addition, even when image information is updated in a plurality of layers, it is possible to quickly rewrite images in a plurality of layers. Furthermore, it is possible to cope with a case where a semi-transparent object exists in the image.

It is a block diagram which shows an example of the hardware constitutions of the image composition display apparatus which concerns on Embodiment 1 of this invention. 2 is a functional block diagram of the image composition display device in Embodiment 1. FIG. 4 is a flowchart illustrating an example of the operation of the image composition display device in the first embodiment. It is a flowchart which shows an example of a process of step S103 of FIG. (A)-(d) is a figure which shows the example of operation | movement of drawing and image composition when the image information of a lower layer is updated among the processes of FIG. (A)-(c) is a figure which shows the example of operation | movement of drawing and image composition when the image information of a lower layer is updated among the processes of FIG. (A)-(f) is a figure which shows an example of the image drawn at each step of the process shown by Fig.5 (a)-FIG.6 (c), and a synthesized image. (A)-(h) is a figure which shows an example of the image drawn at each step of the process shown by Fig.5 (a)-FIG.6 (c), and a synthesized image. (A)-(h) is a figure which shows an example of the image drawn at each step of the process shown by Fig.5 (a)-FIG.6 (c), and a synthesized image. (A)-(h) is a figure which shows an example of the image and synthetic | combination image drawn when image information is further updated after the state of FIG.9 (e)-(h). It is a flowchart which shows an example of the process of step S104 of FIG. It is a functional block diagram of the image composition display device concerning Embodiment 2 of the present invention. 10 is a flowchart illustrating an example of an operation of the image composition display device according to the second embodiment. It is a flowchart which shows an example of the process of step S203 of FIG. It is a functional block diagram of the image composition display device concerning Embodiment 3 of the present invention. 14 is a flowchart illustrating an example of an operation of the image composition display device according to the third embodiment. It is a flowchart which shows an example of a process of step S303 of FIG. (A) And (b) is a figure which shows the example of the change of the role of a storage area, and the operation | movement of drawing to a storage area in an example of step S303. (A) And (b) is a figure which shows the example of the change of the role of a storage area, and the operation | movement of drawing to a storage area in an example of step S303. It is a flowchart which shows the process which can be performed instead of the process of step S312 of FIG. (A) is a figure which shows the example of the change of the role of a storage area at the time of performing the process of FIG. 20, and the operation | movement of drawing to a storage area, (b) can be performed following the process of FIG. It is a figure which shows the example of the operation | movement of a change of the role of a storage area, and the drawing to a storage area at the time of processing. It is a functional block diagram of the image composition display device concerning Embodiment 4 of the present invention. 15 is a flowchart illustrating an example of the operation of the image composition display device 1d according to the fourth embodiment. It is a flowchart which shows an example of a process of step S403 of FIG. It is a flowchart which shows an example of a process of step S403 of FIG. (A) And (b) is a figure which shows the example of the operation | movement of the change of the role of a storage area, and the drawing operation | movement to a storage area in an example of the process of FIG.24 and FIG.25. (A) And (b) is a figure which shows the example of the operation | movement of the change of the role of a storage area, and the drawing operation | movement to a storage area in an example of the process of FIG.24 and FIG.25. (A) And (b) is a figure which shows the example of the operation | movement of the change of the role of a storage area, and the drawing operation | movement to a storage area in an example of the process of FIG.24 and FIG.25. FIG. 26 is a diagram illustrating an example of a change in the role of a storage area and a drawing operation in the storage area in the example of the processing of FIGS. 24 and 25. (A) And (b) is a figure which shows the example of the operation | movement of the change of the role of a storage area, and the drawing operation | movement to a storage area in an example of the process of FIG.24 and FIG.25. (A) And (b) is a figure which shows the example of the operation | movement of the change of the role of a storage area, and the drawing operation | movement to a storage area in an example of the process of FIG.24 and FIG.25. (A) And (b) is a figure which shows the example of the operation | movement of the change of the role of a storage area, and the drawing operation | movement to a storage area in an example of the process of FIG.24 and FIG.25. (A) And (b) is a figure which shows the example of the operation | movement of the change of the role of a storage area, and the drawing operation | movement to a storage area in an example of the process of FIG.24 and FIG.25. It is a flowchart which shows an example of a process of step S404 of FIG. (A) And (b) is a figure which shows the example of the operation | movement of the change of the role of a storage area, and the drawing operation | movement to a storage area in an example of the process of FIG. (A) And (b) is a figure which shows the example of the operation | movement of the change of the role of a storage area, and the drawing operation | movement to a storage area in an example of the process of FIG.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing an example of a hardware configuration of an image composition display device according to Embodiment 1 of the present invention.
The illustrated image composition display device 1 includes a CPU 11, a GPU 12, a nonvolatile memory 13, a RAM 14, an input device 15, and an output device 16, which are connected to each other via a system bus 17.

The image composition display device 1 draws the image G1 of the upper layer L1 and the image G2 of the lower layer L2 based on the information supplied from the input device 15, and synthesizes them by superimposing the drawn images. Is displayed on the output device 16.
The information supplied from the input device 15 includes image information representing an image to be drawn next for each layer and information indicating whether the image information has been updated.

The upper layer image is an image arranged on the front side in the superposition for synthesis, and the lower layer image is an image arranged on the back side in the superposition for synthesis.
For example, a layer having a higher frequency of image information update is assigned to a higher layer.

The input device 15 includes, for example, a keyboard, a mouse, a touch panel, and a communication module (such as a communication circuit).
The output device 16 is a display device configured by, for example, an LCD (Liquid Crystal Display).
The nonvolatile memory 13 stores a program. The CPU 11 and the GPU 12 operate according to a program stored in the nonvolatile memory 13.
The RAM 14 stores information input by the input device 15 and data generated in the course of processing by the CPU 11 and the GPU 12.

FIG. 2 is a functional block diagram of the image composition display device 1. As illustrated in FIG. 2, the image composition display apparatus includes an image generation unit 210, storage areas Ma, Mb, Mc, a memory control unit 222, a reading unit 224, and an image composition unit 230. The image generation unit 210 includes a drawing management unit 212 and a drawing processing unit 214.
The functions of the drawing management unit 212, the memory control unit 222, and the reading unit 224 are realized by the CPU 11 executing a program stored in the nonvolatile memory 13.
The function of the drawing processing unit 214 and the function of the image composition unit 230 are realized by the GPU 12 executing a program stored in the nonvolatile memory 13.

The storage areas Ma, Mb, Mc are formed in the RAM 14 of FIG. Each of the storage areas Ma, Mb, and Mc stores image data for one screen and is also called a plane memory.
The storage areas Ma and Mb constitute a double buffer storage unit for the image G1 of the upper layer L1. The storage unit of the double buffer configuration has two storage areas (for example, Ma and Mb), and one of the two storage areas (for example, Ma) is allocated to the display frame buffer B1r and used as the display frame buffer B1r. The other (Mb) is assigned to the write frame buffer B1w and used as the write frame buffer B1w. The role of the storage area can be changed. When writing to the storage area used as the writing frame buffer B1w is completed, the storage area is allocated for display thereafter and used as the display frame buffer B1r until then. The allocated storage area is thereafter allocated for writing.

  The storage area Mc constitutes a single buffer configuration storage unit of the lower layer L2, and is used as the frame buffer B2 of the lower layer L2. In the single buffer configuration, the same storage area is used as a display frame buffer and also as a write frame buffer. That is, the same storage area is used as a frame buffer for both display and writing.

Hereinafter, in order to shorten the notation, the display frame buffer may be referred to as “R buffer”, the write buffer may be referred to as “W buffer”, and the display / write frame buffer may be simply referred to as “shared buffer”. Furthermore, these are sometimes simply referred to as “buffers”.
Also, the double buffer configuration is referred to as “DB configuration”, the double buffer configuration layer is referred to as “DB layer”, the single buffer configuration is referred to as “SB configuration”, and the single buffer configuration layer is referred to as “SB layer”. There is.

  Control for determining the roles of the storage areas Ma, Mb, and Mc and changing the roles is performed by the memory control unit 222.

The images stored in the buffers B1r and B2 are read and used for image composition in the image composition unit 230.
The image composition is performed by, for example, transmission composition using an alpha value (opacity) stored together with image data in one or both of the buffers B1r and B2.

The drawing processing unit 214 draws an image in the buffers B1w and B2 (storage areas used as the buffers).
The drawing processing unit 214 performs drawing based on the image information of each layer supplied from the input device 15. Image drawing is performed for each object.
The drawing management unit 212 determines whether or not the image needs to be rewritten based on the information supplied from the input device 15 and indicating whether or not the image information has been updated. It is determined whether it is necessary, and the drawing processing unit 214 and the memory control unit 222 are controlled based on the determination result.

FIG. 3 is a flowchart illustrating an example of the operation of the image composition display device 1 according to the first embodiment.
The process of FIG. 3 is started when the operation of the image composition display device 1 starts, for example.

  In the following, it is assumed that the storage area Ma is used as the R buffer B1r and the storage area Mb is used as the W buffer B1w at the start of the processing of FIG.

  The drawing management unit 212 determines the next image to be displayed on the output device 16 based on the information supplied from the input device 15, and plays the role of the storage areas Ma to Mc in the memory control unit 222 to generate the image. Control is performed and the drawing processing unit 214 performs drawing.

  In determining the image to be displayed on the output device 16, the drawing management unit 212 has updated the image information on at least one of the plurality of layers L 1 and L 2 based on the information supplied from the input device 15 (rewriting is performed). It is determined whether or not it is necessary (S101). If the image information has not been updated (NO in S101), the same determination is repeated to wait for the update of the image information.

If the image information has been updated (YES in S101), it is next determined whether or not the image information has been updated for the upper layer L1 (S102).
If the image information has been updated for the upper layer L1 (YES in S102), the rewrite step S103 is performed. If the image information has not been updated for the upper layer L1 (NO in S102), the rewrite step S104 is performed.

When the process of step S103 or S104 ends, the determination of step S105 is performed.
In step S105, the drawing management unit 212 determines whether or not the system termination condition is satisfied. If not, the process returns to step S101 and repeats the operation.
For example, if the power of the image composition display device is off, “it is determined that the system termination condition is satisfied.

Hereinafter, the process in step S103 will be described with reference to FIG.
FIG. 4 is a flowchart showing an example of the process of step S103 of FIG.

In step S103, the drawing management unit 212 first determines whether the image information has been updated for the lower layer L2 (S111).
If the image information is also updated for the lower layer L2 (YES in S111), the process proceeds to step S112. If the image information is not updated for the lower layer L2, the process proceeds to step S117.

First, the case where the process proceeds from step S111 to step S112 will be described.
FIG. 5A to FIG. 6C are diagrams illustrating examples of drawing and image composition operations when the process proceeds from step S111 to step S112 in FIG. In FIG. 5A, Δ indicates that the image information has been updated. Fig.7 (a)-FIG.9 (h) show an example of the image drawn at each step of the process shown by Fig.5 (a)-FIG.6 (c), and a synthesized image.
In FIGS. 5A to 6C, an image of the layer Li (i is 1 or 2) is denoted by Gi. Also, in FIGS. 5A to 6C and FIGS. 7A to 9H, the change in the image content due to the update of the image information is different from the character j as (j) following Gi. (P, q, r, s, etc.) are assigned.
The same applies to other similar figures appearing below.

For example, before the process of step S112 is started, the image G1 (p) is stored in the buffer B1r of the layer L1 and the image G2 (p) is stored in the buffer B2 of the layer L2 as shown in FIG. ) Is stored.
In this case, an image (G2 (p) + G1 (p)) obtained by combining the image G1 (p) and the image G2 (p) is output as the combined image Gc.

  An example of the image G1 (p) stored in the buffer B1r is shown in FIG. 7D, and an example of the image G2 (p) stored in the buffer B2 is shown in FIG. The composite image Gc is shown in FIG.

In step S112, the drawing processing unit 214 draws the image G2 (q) to be displayed next to the lower layer L2 in the buffer B1w of the upper layer L1 (FIG. 5B).
As the “next image to be displayed”, an image represented by the updated image information is drawn. The process proceeds from step S111 to step S112 because the image information is updated for the lower layer L2. An example of the drawn image G2 (q) is shown in FIG.

  Next, in step S113, the drawing processing unit 214 draws the image G1 (q) to be displayed next to the upper layer L1 on the buffer B1w written in step S112 (FIG. 5C). . As the “next image to be displayed”, an image represented by the updated image information is drawn. The process in FIG. 4 is performed because it is determined in step S102 that the image information has been updated for the upper layer L1. An example of the drawn image G1 (q) is shown in FIG.

As a result of drawing in steps S112 and S113, the image shown in FIG. 7E is stored in the buffer B1w. This image is obtained as a result of overwriting the images G2 (q) and G1 (1). In FIGS. 5C and 7E, “G2 (q) + G1 (q)” is obtained. It is shown. Further, FIG. 5C shows a process for generating an image G2 (q) + G1 (q) by overwriting the image G1 (q) on the image G2 (q).
“G2 (q) => G2 (q) + G1 (q)”
It is represented by

In the drawing in steps S112 and S113, in the region where the images overlap each other, the drawing processing unit 214 overwrites the previous image with an image drawn later, as in the example shown in FIG. That is, only the image drawn later remains, and the image drawn before that is deleted. However, in an area where an alpha value is set, an image having a calculated pixel value is drawn by multiplying the pixel value of each image by a coefficient corresponding to the alpha value.
For example, if the alpha value of the image G1 of the layer L1 and alpha _1, during the processing of the step S112, and draws an image obtained by multiplying the coefficient _(1-α 1) in the image G2 of the layer L2, the step S113 during processing, it draws an image obtained by multiplying the alpha ₁ alpha value (factor equal to) the image G1 of the layer L1. At that time, the already written image (G2 × (1-α ₁ )) is read, and the image obtained by adding the layer L1 image (G1 × α ₁ ) is written.

Instead, the image G2 of the layer L2 is drawn as it is in step S112, and the image G2 is read from the buffer B1w and multiplied by the coefficient (1-α ₁ ) in the process of step S113, and this is multiplied by the image G1 of the layer L1. by adding the image obtained by multiplying the alpha value alpha ₁ in the synthesized image obtained by the addition, it is also possible to write to the buffer B1w.

By performing such processing, an image in which the image G1 of the layer L1 and the image G2 of the layer L2 are blended at a ratio of α ₁ : (1-α ₁ ) is written in the buffer B1w.

  After the drawing in step S113, the image in the buffer B1w is set to be opaque (S114). This is to completely hide the image in the buffer B2 in the lower layer L2 when combining with the image stored in the buffer B2 in the lower layer L2 described later.

  Next, in step S115, the memory control unit 222 swaps the R buffer B1r and the W buffer B1w of the upper layer (FIG. 5D). That is, the roles of the storage areas Ma and Mb used as the R buffer B1r and the W buffer B1w are changed. Specifically, the storage area Ma previously used as the R buffer B1r (assigned to the R buffer B1r) is assigned to the new W buffer B1w and used as the W buffer B1w until then (the W buffer The storage area Mb (allocated to B1w) is allocated to a new R buffer B1r.

  As a result of the replacement (change of the role of the storage area), the image stored in the storage area Mb used as the new R buffer B1r (FIG. 8C) and the image stored in the buffer B2 (FIG. Based on a)), a composite image (FIG. 8D) is formed.

Since the image stored in the buffer B1r is set to be opaque, the image stored in the buffer B2 (G2 (p) in FIG. 8A) is completely hidden, and the composite image (FIG. 8). (D)) is apparently the same as the image in the buffer B1r (G2 (q) + G1 (q) in FIG. 8C).
The fact that the image G2 (p) stored in the buffer B2 is completely hidden is represented by [G2 (p) +] using parentheses [] in FIG. 5D, FIG. 8D, and the like. .
A state in which an image stored in a buffer set to be opaque in this manner is used for composition, and an image stored in a buffer in a layer lower than the buffer is hidden is referred to as an “opaque composition state”.

In step S116, the drawing processing unit 214 draws the image G2 (q) to be displayed next to the lower layer L2 in the buffer B2 of the lower layer L2 (FIG. 6A). An example of the rendered image G2 (q) is shown in FIG.
This “image to be displayed next” is the same image as the image (image represented by the updated image information) G2 (q) drawn in the buffer B1w of the upper layer L1 in the previous step S112, or the lower layer When the image information of L2 is further updated, an image represented by the further updated image information is drawn. FIG. 8E shows a case where the same image as the image G2 (q) drawn in the buffer B1w in step S112 is drawn in the buffer B2.

While the image is rewritten by drawing in the buffer B2 in step S116, the image read from the buffer B2 is hidden (made opaque) by the image read from the buffer B1r of the upper layer L1. Therefore, in the composite image, the image being rewritten does not appear in the table. In FIG. 6 (a), G2 (p) => G2 (q)
In the composite image Gc, the image being rewritten does not appear in the table.
[G2 (p) => G2 (q) +]
It shows with.
Since the image being rewritten does not appear in the table, flickering in the composite image can be prevented.

Following step S116, the process of step S117 is performed.
In step S117, the drawing processing unit 214 draws an image to be displayed next to the upper layer L1 in the buffer B1w (storage area Ma) of the upper layer L1 (FIG. 6B).
This “image to be displayed next” is the same image as the image (image represented by the updated image information) G1 (q) drawn in the buffer B1w in the previous step S113, or the image information of the upper layer L1. When is further updated, the image G1 (r) represented by the further updated image information is drawn.
FIG. 6B and FIG. 9B show a case where “an image represented by further updated image information” G1 (r) is drawn. In FIG. 6B, the fact that there has been a further update is indicated by ▲.

  Next, in step S118, the memory control unit 222 replaces the R buffer B1r and the W buffer B1w of the upper layer L1 (FIG. 6C). That is, the storage area Mb used as the R buffer B1r is assigned to the new W buffer B1w, and the storage area Ma used as the W buffer B1w is assigned to the new R buffer B1r (FIG. 9E).

As a result of the replacement, the image (G1 (r) in FIG. 9 (f)) stored in the new R buffer B1r (storage area Ma) and the image stored in the buffer B2 of the lower layer L2 (FIG. 9 ( Based on G2 (q)) of e), a composite image (FIG. 9 (h)) is formed. This state is referred to as a “transparent composite state” in contrast to the “opaque composite state” described above. This is because the image stored in the new buffer B1r (storage area Ma) is not set to be opaque.
In step S118, the process of step S103 ends, and then the process proceeds to step S105.

As described above, in step S111, when the image information is not updated for the lower layer L2 (thus, when the image information is updated only for the upper layer L1), the step after step S111 is step S117.
In step S117, the rendering processing unit 214 writes to the W buffer B1w of the upper layer L1, and in step S118, the memory control unit 222 replaces the buffer of the upper layer L1.
These processes can be performed in the same manner as described with reference to FIGS. 6B, 6C, 9B, 9F, and 9G.

Thereafter, as long as the state in which the image information is updated only for the upper layer L1 continues, the determination result of step S111 is NO, and the processes of steps S117 and S118 are repeated.
In FIGS. 10A to 10H, after the states shown in FIGS. 9E to 9H, the image information of the lower layer L1 is not updated and the image information of the upper layer L1 is updated. Examples of an image to be drawn and a composite image are shown.

As described above, if NO in step S102, that is, if the image information is updated only for the lower layer L2, the process of step S104 is performed. Step S104 is performed by one of the following two methods.
In the first method (S104a), the same procedure as in step S103 is performed.
In the second method (S104b), the W buffer B1w of the upper layer L1 is temporarily used as the W buffer B2w of the lower layer L2, the lower layer L2 has a DB configuration, and the image information is updated only for the upper layer L1. Then, the image of the lower layer L2 is rewritten by the same method as in the case where the process proceeds (from S111 to S117).

  The process of step S104 in the case of the first method (S104a) is the same as that described with reference to FIG. However, in step S113, the same image that has been stored in the R buffer B1r until then is displayed as “next image to be displayed”. In step S117, “next image to be displayed” The same image as that stored in the R buffer B1r, or when the image information of the upper layer L1 is updated during the processing of steps S101 to S116, the image G1 represented by the updated image information is drawn. To do.

FIG. 11 shows a procedure for performing the process of the second method (S104b).
First, in step S121, the role of the storage area (for example, Mb) used as the W buffer B1w of the upper layer L1 is changed and assigned to the W buffer B2w of the lower layer L2. At the same time, the role of the storage area Mc used as the shared buffer B2 of the lower layer L2 is changed to the R buffer of the lower layer L2. Thereby, the lower layer L2 becomes a DB layer, and the upper layer L1 becomes an SB layer.

  In step S122, an image to be displayed next to the lower layer L2 is drawn in the W buffer B2w (storage area Mb) of the lower layer L2.

  In step S123, the memory control unit 222 allocates the storage area Mb used as the W buffer B2w of the lower layer L2 to the shared buffer B2 of the lower layer L2, and the storage area Mc that has been used as the R buffer B2r until then. Are assigned to a new W buffer B1w of the upper layer L1.

  In step S122, while the image to be displayed next to the lower layer L2 is written in the W buffer B2w of the lower layer L2, the composition is performed on the image stored in the R buffer B2r of the lower layer L2 and the upper layer L1. Since it is performed using the image stored in the shared buffer B1, it is possible to prevent the composite image from flickering by rewriting the W buffer B2w.

[Modification 1-1]
In the example described with reference to FIG. 4, after the image of the lower layer L2 is drawn in step S112, the image of the upper layer L1 is drawn in step S113. However, if the object included in the lower layer L2 image to be rendered in step S112 is hidden by the object included in the upper layer L1 image rendered in the next step S113, and is hidden. May skip the drawing of the object in step S112. By doing so, processing can be made faster.

[Modification 1-2a]
In the example described with reference to FIG. 4, it is assumed that the entire lower layer L2 image is rewritten in step S112.
When only a partial area of the image is required to be changed according to the image information of the lower layer L2, only the changed area is drawn in the buffer B1w of the upper layer L1 in step S112, and only the changed area is displayed in step S116. May be drawn in the buffer of the lower layer L2.
By doing so, it is possible to reduce the amount of drawing and speed up the processing.
Drawing only the change area can be performed by using a function such as a mask or a scissor.

[Modification 1-2b]
Further, in the process of step S112 in FIG. 4, it is determined for each drawing object whether or not the object exists in the change area, and if it does not exist, the drawing may be skipped. By doing so, it is possible to further speed up the processing.

[Modification 1-2c]
Further, in the case where only the changed area is drawn in steps S112 and S116, the image information of the lower layer L2 is further updated between step S112 and step S116, and the change required by the further updated image information. If the area does not fit within the change area drawn in step S112, the same image as that drawn in step S112 is drawn in step S116. In this case, an image represented by the further updated image information is drawn in the processing of steps S112 to S118 performed based on the determination results in steps S101, S102, and S111.

[Effects of Embodiment 1]
According to the present embodiment configured as described above, the following effects can be obtained.
(A) Compared with the case where the storage units of all layers have a double buffer configuration, the required memory capacity can be reduced, and the flickering of the screen can be suppressed.
(B) When the image information is updated for both the upper layer and the lower layer, the images of both layers can be rewritten quickly.
(C) It is possible to cope with a case where a semi-transparent object exists in the upper layer image. This is because the image blended at the ratio α ₁ : (1−α ₁ ) corresponding to the alpha value (α ₁ ) of the image of the layer L1 is written in the W buffer of the upper layer in steps S112 and S113.

Embodiment 2. FIG.
In the first embodiment, the number of layers is two. Next, an example of a configuration in which the number of layers is three or more will be described as a second embodiment. Hereinafter, a case where the number of layers is four will be described.
The hardware configuration is the same as that described with reference to FIG.

  FIG. 12 is a functional block diagram of the image composition display device 1b according to the second embodiment. The image composition display device 1b in FIG. 12 is generally the same as the image composition display device 1 in FIG. However, five storage areas Ma to Me in the RAM 14 are used. Each of the storage areas Ma to Me stores data for one screen.

Layers L1, L2, L3, and L4 are higher in the order described. That is, the layer L1 is the highest layer, the layer L2 is the next layer, the layer L3 is the next layer, and the layer L4 is the lowest layer. In other words, the layer Li (i is 1, 2, 3, or 4) has a higher rank as i is smaller. In superposition for composition by superposition, the higher the order of layers, the more images are arranged on the front side. In general, a layer having a higher frequency of image information update is assigned a higher rank.
In the following description, “layers other than the highest layer” may be collectively referred to as “lower layers”.

  The storage areas Ma and Mb constitute a DB storage unit for the image G1 of the layer L1. That is, one of the storage areas Ma and Mb (for example, Ma) is used as the R buffer B1r, and the other (Mb) is used as the W buffer B1w. The role of the storage area can be changed.

  The storage areas Mc to Me constitute an SB configuration storage unit for the images G2, G3, and G4 of the layers L2, L3, and L4, respectively, and the dual-purpose buffers B2, B3, and B4 of the layers L2, L3, and L4, respectively. Used.

Control for determining the roles of the storage areas Ma to Me and changing the roles is performed by the memory control unit 222.
The images stored in the buffers B1r, B2, B3, and B4 are read and used for image composition in the image composition unit 230.
The image composition is performed by, for example, transmission composition using an alpha value or the like stored together with image data in the buffers B1r, B2, B3, and B4.

  FIG. 13 is a flowchart illustrating an example of the operation of the image composition display device 1b according to the second embodiment. The processing in FIG. 13 is started together with the operation of the image composition display device 1b, for example.

  In the following, it is assumed that the storage area Ma is used as the R buffer B1r and the storage area Mb is used as the W buffer B1w at the start of the processing of FIG.

  The drawing management unit 212 determines the next image to be displayed on the output device 16 based on the information supplied from the input device 15, and plays the role of the storage areas Ma to Me in the memory control unit 222 to generate the image. Control is performed and the drawing processing unit 214 performs drawing.

  In determining the image to be displayed on the output device 16, the drawing management unit 212 determines whether the image information has been updated for at least one of the plurality of layers L <b> 1 to L <b> 4 based on the information supplied from the input device 15. Determine (S201). If the image information has not been updated (NO in S201), the same determination is repeated to wait for the update of the image information.

If the image information has been updated (YES in S201), it is determined whether the image information has been updated for the highest layer L1 (S202).
If the image information has been updated for the uppermost layer L1 (YES in S202), the rewrite step S203 is performed. If the image information has not been updated for the highest layer L1 (NO in S202), the rewrite step S204 is performed.

When the process of step S203 or S204 ends, the process of step S205 is performed. The process in step S205 is the same as step S105 in the first embodiment.
If it is determined in step S205 that the system termination condition is satisfied, the operation is terminated. If the system termination condition is not satisfied, the process returns to step S201 to repeat the operation.

Hereinafter, the process in step S203 will be described with reference to FIG.
FIG. 14 is a flowchart illustrating an example of the process of step S203.

In step S203, the drawing management unit 212 determines whether image information has been updated for at least one of the lower layers L2 to L4 (S211).
If the image information has been updated for at least one of the layers L2 to L4, the process proceeds to step S212. If the image information has not been updated for any of the layers L2 to L4, the process proceeds to step S217.

In step S212, the drawing processing unit 214 stores the images G2, G3, and G4 to be displayed next to the layers L2 to L4 in the W buffer B1w of the uppermost layer L1 in order from the lowermost layer L4 (G4, G3, and G2). (In order).
As the “image to be displayed next”, an image represented by the updated image information is drawn in the layer in which the image information is updated, and has been used for image synthesis in the layer in which the image information is not updated. The same image as the image (that is, the image stored in the buffer (B2, B3, B4) of the layer) is drawn.

  The subsequent steps S213, S214 and S215 are the same as steps S113, S114 and S115 described in the first embodiment with reference to FIG. However, it is necessary to replace “upper” with “top” and replace layer L2 with layers L2 to L4.

That is, in step S213, the drawing processing unit 214 draws the image G1 to be displayed next to the uppermost layer L1 on the buffer B1w written in step S212.
In step S213, an image represented by the updated image information is drawn as “the image to be displayed next”. The process in FIG. 14 is performed because it is determined in step S202 that the image information has been updated for the uppermost layer L1.

In the drawing in steps S212 and S213, in the area where the images overlap each other, the previous image is overwritten with the image drawn later. That is, only the image drawn later remains, and the image drawn before that is deleted. However, in the region where the alpha value is set, the pixel value of each image is multiplied by a coefficient corresponding to the alpha value and combined to draw an image having the calculated pixel value.
For example, if the alpha values of the images G1, G2, and G3 of the layers L1, L2, and L3 are α ₁ , α ₂ , and α ₃ , respectively,
Gc
= [{G4 × (1-α ₃ ) + G3 × α ₃ } × (1-α ₂ ) + G2 × α ₂ ] × (1-α ₁ ) + G1 × α ₁
The image calculated in is written in the buffer B1w.
For that purpose, for example, regarding the first embodiment, the same processing as that described with respect to steps S112 and S113 may be repeated.

  After the drawing in step S213, the drawing processing unit 214 sets the image in the buffer B1w to be opaque (S214). This is because the images of the buffers B2, B3, and B4 of the lower layers L2, L3, and L4 are completely combined with the images stored in the buffers B2, B3, and B4 of the lower layers L2, L3, and L4, which will be described later. This is to hide it.

  Next, in step S215, the memory control unit 222 switches the R buffer B1r and the W buffer B1w of the highest layer L1. That is, the storage area Ma used as the R buffer B1r is assigned to the new W buffer B1w, and the storage area Mb used as the W buffer B1w is assigned to the new R buffer B1r.

  By the replacement, an opaque setting is made, and a composite image is formed based on the image stored in the storage area Mb newly assigned to the R buffer B1r and the image stored in the buffers B2, B3, and B4. Shift to a state (opaque composite state).

  In this opaque composition state, since the image stored in the R buffer B1r is set to be opaque, the images stored in the buffers B2, B3, and B4 are completely hidden, and the composite image is stored in the buffer. It looks the same as the B1r image.

In step S216, the drawing processing unit 214 then displays an image to be displayed next (represented by the updated image information) in each of at least one lower layer (a layer other than the highest layer) whose image information has been updated. Image) is drawn in the buffer of the layer.
As the “image to be displayed next”, the same image as the image drawn in the W buffer B1w of the uppermost layer L1 in the previous step S212 (the image represented by the updated image information), or the lower layer When the image information is further updated, an image represented by the further updated image information is drawn.

  Note that when drawing images of a plurality of layers in step S216, the drawing order for the plurality of layers is not limited, and the drawing for the plurality of layers may be performed simultaneously (in parallel).

  While the image is rewritten by drawing in the buffer (one or more of B2, B3, and B4) in step S216, the image read from these buffers does not appear in the composite image. This is because the image read from the buffer B1r is set to be opaque. Since the image being rewritten does not appear in the table, flickering in the composite image can be prevented.

Following step S216, the processes of steps S217 to S218 are performed. These processes are the same as steps S117 to S118 in the first embodiment.
However, “upper” in the first embodiment needs to be read as “top”, and “layer L2” needs to be read as “layers L2, L3, L4”.

That is, in step S217, the drawing processing unit 214 draws the image G1 to be displayed next to the uppermost layer L1 in the W buffer B1w (storage area Ma) of the uppermost layer L1.
As this “image to be displayed next”, the same image as the image (image represented by the updated image information) G1 drawn in the buffer B1w in the previous step S213, or the image information of the highest layer L1 is further included. If updated, the image G1 represented by the further updated image information is drawn.

Next, in step S218, the memory control unit 222 swaps the R buffer B1r and the W buffer B1w of the highest layer L1.
A composite image based on the image stored in the new R buffer B1r (storage area Ma) and the images stored in the lower layer buffers B2, B3, and B4, which are not set to be opaque due to the replacement. The state shifts to a state (transparent synthetic state).
In step S218, the process of step S203 ends.

The process of step S204 can be performed similarly to the process of step S203.
However, in step S213, the same image as that stored in the R buffer B1r until then is displayed as “the image to be displayed next”. In step S217, as the “image to be displayed next”, the same image as that stored in the R buffer B1r until now, or the image information of the uppermost layer L1 is displayed during the processing in steps S201 to S216. If further updated, the image G1 represented by the updated image information is drawn.

[Modification 2-1]
In the second embodiment, similarly to the first embodiment, in the example described with reference to FIG. 14, the lower layer image is drawn in step S212, and then the uppermost layer image is drawn in step S213. However, it is determined whether or not the object included in each image of the lower layer to be rendered in step S212 is hidden by the object included in any of the images of the higher layer that is subsequently rendered. When the object is hidden, the object drawing (drawing in S212) of the layer (the layer hidden by any of the higher layers drawn later) may be skipped. By doing so, processing can be made faster.
In this case, “any image of a higher layer rendered after that” is rendered later in the same step S212 in addition to the image of the uppermost layer rendered in step S213. Images of higher layers (higher layers of lower layers) are included.

[Modification 2-2a]
In the example described with reference to FIG. 14, it is assumed that the entire image of each lower layer is rewritten in step S212.
If it is necessary to change only a partial area of the image of the layer according to the image information of any of the lower layers, only the changed area is drawn in the buffer B1w of the highest layer in step S212, In S216, only the change area may be drawn in the corresponding lower layer buffer.
By doing so, it is possible to reduce the amount of drawing and further speed up the processing.

[Modification 2-2b]
Further, in the process of step S212 in FIG. 14, it is determined for each drawing object whether or not the object exists in the change area, and if it does not exist, the drawing may be skipped. By doing so, it is possible to further speed up the processing.

[Modification 2-2c]
Further, in the case where only the change area of the image of the layer whose image information is updated in steps S212 and S216, the image information of the layer is further updated between step S212 and step S216, and after the further update If the change area required by the image information does not fit within the change area drawn in step S212, the same image as that drawn in step S212 is drawn in step S216. In this case, next, the image represented by the further updated image information is drawn in the processing of steps S212 to S218 performed based on the determination results in steps S201, S202, and S211.

[Modification 2-3]
Further, in step S212, for each of the lower layers for which the image information has not been updated (layers other than the highest layer), the same image as that stored in the buffer of that layer is rendered in the W buffer B1w. Become. Therefore, instead of performing such drawing in the W buffer B1w, the image stored in the buffer of the lower layer is transferred to the W buffer B1w of the uppermost layer, so that the image is transferred to the W buffer B1w of the uppermost layer L1. Writing may be performed. The above transfer can be performed by, for example, bit block transfer (Bitblt).

  Although the case where the number of layers is 2 in the first embodiment has been described and the case where the number of layers is 4 in the second embodiment, the present invention is applicable even when the number of layers is other than 2, 4. Can be applied.

  Generally speaking, when the number of layers is N (N is an integer equal to or greater than 2), that is, the image composition display device (1, 1b) superimposes the images of the first to Nth layers. The features of the configuration in the case of combining and displaying a combined image are summarized as follows. In the following description, reference numerals in parentheses indicate corresponding components or processing steps in the configuration described with reference to the above drawings.

(2a) The image of the nth layer (where n is any one of 1 to (N-1)) is an upper layer than the image of the (n + 1) th layer, and the image of the higher layer is In the superposition for the synthesis, they are arranged on the front side.
(2b) The first to (N + 1) th storage areas in the RAM 14 are used.

(2c1) The first and (N + 1) th storage areas are assigned to the first layer, and the first layer is a DB layer to which two storage areas are assigned.
(2c2) The second to Nth storage areas are assigned to the second to Nth layers, respectively, and the second to Nth layers are SB layers to which a single storage area is assigned.

(2d1) The drawing processing unit (214) performs drawing in the W buffer of the first layer and the shared buffers of the second to Nth layers based on the image information of each layer supplied from the outside.
(2d2) The reading unit (220) reads an image from the R buffer of the first layer and the shared buffers of the second to Nth layers,
(2d3) The image composition unit (230) composes the read image.

(2e) When the image information is updated for at least one of the second to Nth layers (S201), the rendering processing unit (214) stores the first to the first buffer in the W buffer (B1w) of the first layer. The next image to be displayed of the N layer is drawn by overlapping in order from the lowest layer (S212, S213), and the drawn region is set to be opaque (S214).

(2f) When the above-described drawing and opacity settings are completed, the memory control unit (222) has been used as the W buffer (B1w) in the first layer until now (assigned to the W buffer). An area is allocated to a new R buffer (B1r), and a storage area previously used as an R buffer (B1r) (allocated to the R buffer) is allocated to a new W buffer. The image stored in the storage area that has been performed shifts to the opaque composition state used for image composition (S215).

(2g) Then, in the above-described opaque composition state, the drawing processing unit (214) converts each image of at least one of the second to Nth layers in which the image information is updated, Drawing is performed in the shared buffer (S216), and the image to be displayed next to the first layer is drawn in the W buffer of the first layer (S217).
(2h) Then, when the drawing in the opaque composition state is completed, the memory control unit (222) allocates the storage area that has been used as the W buffer so far to the new R buffer in the first layer, and The storage area that has been used as the R buffer until this time is allocated to the new W buffer, whereby the image stored in the new R buffer of the first layer shifts to the transparent composition state used for image composition (S218). ).

  In the processing (S212, S213) in which the images to be displayed next of the first to Nth layers are drawn in order from the lowest layer (S212, S213), the drawing processing unit (214) When the information is updated, the image represented by the updated image information is rendered as an image to be displayed next. When the image information of the first layer is not updated, the first The same image as the image stored in the R buffer of one layer is rendered as an image to be displayed next, and for each of the layers in which the image information of the second to Nth layers is updated, The image represented by the updated image information is rendered as the next image to be displayed, and for each of the second to Nth layers for which the image information has not been updated, Store in dual-purpose buffer The same image that has been, then it is also possible to draw an image to be displayed.

  In the process (2f2) of drawing the images to be displayed next on the first to Nth layers in order from the lowest layer, the drawing processing unit (214) includes the second to Nth layers. Of each image to be displayed next, drawing may be omitted for an image portion that will be hidden by a higher-order image drawn after that.

  In the above configuration, if N is 2, it corresponds to the configuration of FIG. 2, and if N is 4, it corresponds to the configuration of FIG.

  The uppermost layer is used for overwriting the image of the layer and the lower layer, so that the uppermost layer is referred to as “overwrite layer” or “cover layer” for convenience. Sometimes called. The same applies to the upper layers of the first embodiment.

[Effects of Embodiment 2]
According to the present embodiment, the same effect as in the first embodiment can be obtained even if the number of layers is three or more.

Embodiment 3 FIG.
In the second embodiment, there is only one DB layer. Next, a configuration having a plurality of DB layers will be described as a third embodiment.
In the following, the number of layers is 8, and among the eight layers L1 to L8, the storage units of the layers L1, L3, L5, and L8 are of the DB configuration, and the other layers L2, L4, L6, and L7 A case where the storage unit has an SB configuration will be described.
The hardware configuration is the same as that described with reference to FIG.

  FIG. 15 is a functional block diagram of the image composition display device 1c according to the third embodiment. The image composition display device 1c in FIG. 15 is generally the same as the image composition display device 1b in FIG. However, twelve storage areas Ma to Ml are used instead of the five storage areas Ma to Me of FIG. Each of the storage areas Ma to Ml stores data for one screen.

  The layer Li (i is any one of 1 to 8) has a higher rank as i is smaller. That is, the layer L1 is the highest layer and the layer L8 is the lowest layer. At the time of composition by superposition, the higher the order of layers, the more images are arranged on the front side.

For example, the storage areas Ma and Mb constitute a DB storage unit for the image G1 of the layer L1.
The storage areas Md and Me constitute a storage unit having a DB configuration for the image G3 of the layer L3.
The storage areas Mg and Mh constitute a DB configuration storage unit for the image G5 of the layer L5.
The storage areas Mk and Ml constitute a DB configuration storage unit for the image G8 of the layer L8.
The storage areas Mc, Mf, Mi, and Mj constitute SB configuration storage units for the images G2, G4, G6, and G7 of the layers L2, L4, L6, and L7, respectively, and the layers L2, L4, L6, Used as dual-purpose buffers B2, B4, B6, B7 for L7 images G2, G4, G6, G7.
It is desirable that a layer in which image information is updated more frequently among the layers is a DB layer.

Control for determining roles and changing roles of the storage areas Ma to Ml is performed by the memory control unit 222.
The images stored in the buffers B1r, B2, B3r, B4, B5r, B6, B7, and B8r are read out and used for image composition in the image composition unit 230.
The image composition is performed by, for example, transmission composition using an alpha value or the like stored together with image data in the buffers B1r, B2, B3r, B4, B5r, B6, B7, and B8r.

  FIG. 16 is a flowchart illustrating an example of the operation of the image composition display device 1c according to the third embodiment. The process of FIG. 16 is started together with the start of the operation of the image composition display device 1c, for example.

  The drawing management unit 212 determines the next image to be displayed on the output device 16 based on the information supplied from the input device 15, and the memory control unit 222 plays the roles of the storage areas Ma to Ml to generate the image. Control is performed and the drawing processing unit 214 performs drawing.

  In determining the image to be displayed on the output device 16, the drawing management unit 212 determines whether the image information has been updated for at least one of the plurality of layers L <b> 1 to L <b> 8 based on the information supplied from the input device 15. Determine (S301). If the image information has not been updated (NO in S301), the same determination is repeated to wait for the update of the image information.

If the image information has been updated (YES in S301), it is determined whether the image information has been updated for at least one SB layer (S302).
If the image information has been updated for at least one SB layer (YES in S302), the rewrite step S303 is performed. If not (that is, if the image information is updated only for the DB layer), the rewriting step S304 is performed.

When the process of step S303 or S304 ends, the process of step S305 is performed. The process of step S305 is the same as the process of step S105 in the first embodiment.
If it is determined in step S305 that the system termination condition is satisfied, the operation is terminated. If the system termination condition is not satisfied, the process returns to step S301 to repeat the operation.

  FIG. 17 is a flowchart illustrating an example of the process in step S303. FIG. 18A to FIG. 19B show examples of changes in the role of the storage area and drawing operations in the storage area in an example of step S303. In Fig.18 (a)-FIG.19 (b), the image of layers L1-L8 is each shown by G1-G8, and the code | symbol which shows a layer is abbreviate | omitted. The same applies to other similar figures below.

  In the following, at the start of the process of FIG. 16, as shown in FIG. 18A, the storage area Ma is used as the buffer B1r, the storage area Mb is used as the buffer B1w, and the storage area Md is used as the buffer. Used as B3r, storage area Me used as buffer B3w, storage area Mg used as buffer B5r, storage area Mh used as buffer B5w, storage area Mk used as buffer B8r, storage Assume that the area Ml is used as the buffer B8w, and the storage areas Mc, Mf, Mi, and Mj are used as the buffers B2, B4, B6, and B8, respectively.

  In step S303, first, in step S311, the drawing management unit 212 determines that the lowest DB layer of one or more higher DB layers than any one of at least one SB layer whose image information has been updated. Is designated as the cover layer. As described later, the cover layer is a layer in which images of the layer and lower layers are overwritten in the buffer of the layer, and is also referred to as an “overwrite layer”.

  For example, it is assumed that the image information is updated for the layers L1, L6, and L7 as indicated by Δ in FIG. Of the layers whose image information has been updated, layers L6 and L7 are SB layers, and layer L1 is a DB layer. Further, the DB layers higher than the layers L6 and L7 are the layers L1, L3, and L5, and the lowest layer among them is the layer L5. In this case, the layer L5 is designated as the cover layer.

In step S312, the drawing processing unit 214 displays the image G6 to be displayed next to the lower layers L6 to L8 in the W buffer B5w (storage area Mh) of the cover layer L5 specified in step S311. G8 is drawn in order from the lowest layer (in the order of G8, G7, and G6) (FIG. 18A).
As the “image to be displayed next”, an image represented by the updated image information is drawn in the layer in which the image information is updated, and has been used for image synthesis in the layer in which the image information is not updated. The same image as that (the image stored in the buffer of each layer) is drawn.

In step S313, the drawing processing unit 214 draws the image G5 to be displayed next to the layer L5 on the W buffer B5w (storage area Mh) of the cover layer L5 specified in step S311.
In step S313, when the image information is updated for the cover layer L5 as the “image to be displayed next”, the image represented by the updated image information is drawn, and the image information for the cover layer L5 is displayed. If it has not been updated, the same image that has been used for image synthesis until then is drawn. In the example of FIG. 18A, since the image information is not updated for the cover layer, the same image that has been used for image synthesis until then is drawn.

  In the drawing in steps S312 and S313, in the area where the images overlap each other, the previous image is overwritten with the image drawn later. That is, only the image drawn later remains, and the image drawn before that is deleted. However, in the region where the alpha value is set, the pixel value of each image is multiplied by a coefficient corresponding to the alpha value and combined to draw an image having the calculated pixel value. This process can be performed in the same manner as described in the second embodiment.

  After the drawing in step S313, the drawing processing unit 214 sets the image of the W buffer B5w of the cover layer L5 to be opaque (S314). This is because the images of the buffers B6 to B8 of the lower layers L6 to L8 are completely hidden when they are combined with the images stored in the buffers B6 to B8 of the lower layers L6 to L8, which will be described later. It is to make it.

Next, in step S315, the drawing management unit 212 determines whether or not there is a DB layer whose image information is updated above the cover layer (for example, L5) specified in step S311.
If “exists” (YES in S315), the process of step S316 is performed. If not (NO in S315), the process proceeds to step S318.
In the example of FIG. 18A, since the image information is updated for the DB layer L1 higher than the cover layer L5, the process proceeds to step S316.

  In step S316, the drawing processing unit 214 displays the layer L1 next to the layer L1 in the W buffer B1w (storage area Mb) of the DB layer L1 higher than the cover layer L5 specified in step S311 and whose image information has been updated. An image G1 to be drawn is drawn.

  In FIG. 18A, the number of DB layers whose image information has been updated, which is higher than the cover layer L5, is 1, but when there are a plurality of such DB layers, such a plurality of DB layers In the W buffer, an image to be displayed next to the same layer is drawn.

  In step S317, the memory control unit 222 replaces the R buffer B5r, B1r and the W buffer B5w, B1w with the cover layer L5 specified in step S311 and the layer L1 drawn in step S316. That is, the storage areas Ma and Mg used as the R buffers B1r and B5r are allocated to the new W buffers B1w and B5w, and the storage areas Mb and Mh used as the W buffers B1w and B5w are assigned to the new R buffers B1r, Assigned to B5r (FIG. 18B).

  In step S318, the memory control unit 222 replaces the R buffer and the W buffer of the cover layer (for example, L5) designated in step S311. That is, the storage area Mg used as the R buffer B5r is allocated to the new W buffer B5w, and the storage area Mh used as the W buffer B5w is allocated to the new R buffer B5r.

  By replacing step S317 or S318, a composite image is formed based on the images stored in the buffers B1r, B2, B3r, B4, B5r, B6, B7, and B8r, including the buffer B5r set to be opaque. Shift to a state (opaque composite state).

In this opaque composition state, since the image stored in the R buffer B5r is set to be opaque, the images stored in the buffers B6, B7, and B8r of the lower layers L6 to L8 are complete. The composite image is apparently the same as the composite of the images stored in the buffers B1r, B2, B3r, B4, and B5r.
Following step S317 or S318, the process of step S319 is performed.

In step S319, as shown in FIG. 19A, the drawing processing unit 214 displays the next image to be displayed in at least one SB layer L6, L7 whose image information has been updated, in the same layer L6, L7. Draw in the shared buffers B6 and B7.
This “image to be displayed next” is the same image as the image (the image represented by the updated image information of the layers L6 and L7) drawn in the buffer B5w of the cover layer in the process of immediately preceding step S312. Alternatively, when the image information of these layers L6 and L7 is further updated, an image represented by the further updated image information is drawn.

  In step S319, while image rewriting is performed by drawing on the buffers B6 and B7, images read from these buffers do not appear in the composite image. This is because the image read from the cover layer buffer B5r (storage area Mh) is set to be opaque. Since the image being rewritten does not appear in the table, flickering in the composite image can be prevented.

  Next, in step S320, as shown in FIG. 19A, the drawing processing unit 214 draws the image G5 to be displayed next to the same layer L5 in the W buffer B5w (storage area Mg) of the cover layer L5. The image G1 to be displayed next to the same layer L1 is drawn in the W buffer B1w (storage area Ma) of the DB layer L1 in which the image information higher than the cover layer is updated.

  Note that the order of steps S319 and S320 may be changed, and these processes may be performed simultaneously (in parallel). In step S319, as in the example of FIG. 19A, when images of a plurality of layers are drawn, there is no restriction on the drawing order of the layers, and drawing of the layers is performed simultaneously (parallel). And you can go there.

Next, in step S321, the memory control unit 222 replaces the R buffer and the W buffer of the DB layer on which the drawing is performed in step S320 (FIG. 19B). In other words, the storage areas Mb and Mh that have been used as the R buffers B1r and B5r are assigned to the new W buffers B1w and B5w, and the storage areas Ma and Mg that have been used as the W buffers B1w and B5w are replaced with the new storage areas Ma and Mg. Are allocated to the R buffers B1r and B5r (FIG. 19B).
By replacement, new R buffers B1r, B5r (storage areas Ma, Mg), R buffers B3r, B8r (storage areas Md, Mk), and shared buffers B2, B4, B6, B7 (storage areas Mc, Mf, Mi, A state in which a composite image is formed on the basis of the image stored in Mj), that is, an image stored in the storage area Mg newly allocated to the R buffer B5r that is not set to be opaque is used for composition. Transition to the transparent composite state used.
In step S321, the process of step S303 ends.

The processing in step S304 is rewriting in the DB layer and can be performed by a conventionally known method. For example, the drawing processing unit 214 draws an image to be displayed next to the same layer in the W buffer Biw (i is 1, 3, 5, or 8) of the DB layer in which the image information is updated, and the memory control unit 222 replaces the R buffer and the W buffer of the DB layer on which the drawing has been performed. In other words, the storage area that has been used as the R buffer is assigned to a new W buffer, and the storage area that has been used as the W buffer is assigned to a new R buffer.
These processes are the same as steps S320 and S321. However, in steps S320 and S321, drawing and replacement are performed even in the cover layer, but in step S304, there is no cover layer and drawing and replacement in the cover layer are not performed.

[Modification 3-1]
In the example described with reference to FIG. 17, an image of a layer lower than the cover layer is drawn in step S312, and then an image of the cover layer is drawn in step S313. However, as described in the second embodiment, the object included in each image of the layer to be rendered in step S312 is included in any image of the higher layer that is subsequently rendered. It is possible to determine whether or not the object is hidden, and in the case of being hidden, the drawing of the object (drawing in S312) may be skipped. By doing so, processing can be made faster.
In this case, “an image of a higher layer drawn after that” is drawn later in the same step S312 in addition to the image of the cover layer drawn in step S313. An image of a layer (a higher layer among lower layers than the cover layer) is included.

[Modification 3-2a]
In the example described with reference to FIG. 17, it is assumed that the image of the layer lower than the cover layer is completely rewritten in step S312.
If the image information for any of the layers below the cover layer requires that only a partial area of the image of the layer be changed, in step S312, only the changed area is stored in the cover layer buffer (for example, B5w), and only the changed area may be drawn in the buffer (B6, B7) of each layer (L6, L7) in step S319. By doing so, it is possible to reduce the amount of drawing and speed up the processing.

[Modification 3-2b]
Further, in the processing of step S312 in FIG. 17, it is determined for each drawing object whether or not the object exists in the change area, and if it does not exist, the drawing may be skipped. By doing so, it is possible to further speed up the processing.

[Modification 3-2c]
Furthermore, in steps S312 and S319, only the change area of the image of the layer whose image information has been updated that is lower than the cover layer is drawn, and the image information of the layer is further updated between step S312 and step S319. If the change area required by the further updated image information does not fit within the change area drawn in step S312, the same image as that drawn in step S312 is drawn in step S319. In this case, the image represented by the further updated image information is drawn in the processing of steps S312 to S321 performed based on the determination results in steps S301 and S302.

[Modification 3-3]
In step S312, for each layer lower than the cover layer (for example, L8) for which image information has not been updated, the same image as the image stored in the buffer (B8r) of the layer is displayed as the cover layer L5. Is drawn in the buffer B5w. Therefore, instead of performing drawing in the W buffer B5w of the cover layer, the image stored in the buffer (B8r) of the layer (L8) where the image information is not updated is used as the W buffer B5w of the cover layer L5. And may be written to the W buffer B5w of the cover layer L5. The above transfer can be performed by, for example, bit block transfer (Bitblt).
When images of a plurality of layers are written in the buffer B5w of the cover layer L5, the writing is performed so that the images of the plurality of layers are sequentially performed from the lower side and overlap each other. By sequentially writing in this way, images of a plurality of layers are synthesized.

[Modification 3-4]
If one or more DB layers exist below the cover layer (L5) specified in step S311, the processing in steps S312a to S312c shown in FIG. 20 is performed instead of the processing in step S312 in FIG. It is good to do.
FIG. 21A shows the change in the role of the buffer and the operation on the buffer in this case.

First, in step S312a, each of the one or more DB layer W buffers lower than the cover layer is assigned to the SB layer in which the image information is updated, and next to the SB layer in which the image information is updated. The image to be displayed is drawn in the W buffer of the assigned DB layer.
For example, when the number of DB layers lower than the cover layer (for example, L5) is one (only the layer L8) as in the examples of FIGS. 18 (a) to 19 (b), the layer L8 is represented as image information. Is assigned to one of the updated SB layers L6 and L7, and an image to be displayed next to the assigned layer is drawn in the W buffer of the DB layer. For example, when the layer L7 is assigned, the image G7 of the layer L7 is drawn in the W buffer B8w (FIG. 21A).

  Next, in step S312b, the image written in the buffer B8w drawn in step S312a is transferred and written to the W buffer B5w of the cover layer L5 by bit block transfer (Bitblt) or the like (FIG. 21A). .

  Next, in step S312c, among the SB layers (L6, L7) whose image information has been updated, the image of the layer (L6) that has not been assigned to any of the DB layers lower than the cover layer in step S312a, Drawing is performed on the W buffer (B5w) of the cover layer (FIG. 21A). This drawing is performed so as to overlap the image written in step S312b.

  As described above, the number of DB layers (L8) lower than the cover layer (L5) designated in step S311 is 1 in the SB layers (L6, L7) in which the image information is updated. When the number is smaller than the number (2 in the above example), the SB layer (for example, L6) to which the DB layer (L8) lower than the cover layer is not assigned is the same as the process of step S312 of FIG. Drawing directly on the W buffer (B5w) of the designated cover layer (L5). In this case, the lower layer image (image written by transfer from the W buffer (B8w) of another DB layer) or the lower layer image drawn earlier is written so as to overlap.

In this case, instead of “drawing” in the subsequent step S319, as shown in FIG. 21B, the combined buffer B7 of the layer (L7) drawn in the W buffer (B8w) of the DB layer (L8). The W buffer (B8w) on which the image of the layer (L7) is drawn may be replaced. That is, in step S319, the storage area Ml that has been used as the W buffer B8w of the layer L8 so far is allocated to the new shared buffer B7 of the layer L7, and the storage area Mj that has been used as the shared buffer B7 until then is assigned to the layer L7. It may be assigned to a new W buffer B8w.
In this way, the image information update result can be reflected in the composite image without performing the second drawing (step S319 in FIG. 17) for the image of the layer L7.

[Modification 3-5a]
Unlike the above example, when the number of DB layers lower than the cover layer (L5) specified in step S311 is equal to or greater than the number of SB layers whose image information has been updated, the image information is updated. All the SB layers can be assigned to the DB layer lower than the cover layer. In this case, one or more SB layer images with updated image information are drawn in the assigned DB layer W buffer, and then the image drawn in the DB layer W buffer is changed to the cover layer. Can be transferred to the W buffer by bit block transfer or the like. Also in this case, the images are transferred sequentially from the lowest layer (lower layer images first) and sequentially overwritten.

[Modification 3-5b]
In the case of using the method of the above modified example 3-5b and further performing the processing of steps S312a to S312c instead of step S312, in step S312a, the W buffer of the DB layer lower than the cover layer is used. The shared buffer (B7) of the layer (L7) to which (for example, B8w (Ml)) is assigned may be interchanged with the W buffer (B8) assigned to the layer. By doing so, the drawing of step S319 in FIG. 17 can be omitted.

[Modification 3-6]
Also, in steps S316 and S317 of FIG. 16, only the layer whose image information has been updated among the upper DB layers (L1 and L3) than the cover layer (L5) specified in step S311 is the image of that layer. Are drawn in the buffer (S316) and the buffer is replaced (S317). However, for the DB layer higher than the cover layer in which the image information has not been updated, the image of the layer in the buffer (S316) and the buffer replacement (S317) may be performed.
Similarly, in steps S320 and S321, only the layer in which the image information of the DB layers (L1, L3, L5, and L8) is updated is drawn in the buffer (S320) and the buffer is replaced (S321). However, for a DB layer whose image information has not been updated, drawing of the image of the layer in the buffer (S320) and replacement of the buffer (S321) may be performed.

  In the third embodiment, the number of layers is 8 and the number of DB configuration layers is 4. However, even if the number of layers is other than 8, the number of DB configuration layers is also different. Even if it is other than 4, the present invention can be applied.

  Generally speaking, when the number of layers is N (N is an integer greater than or equal to 2) and the number of layers in the DB configuration is M, that is, the image composition display device (1c) has the first to Nth. The features of the configuration in the case where the images of the layers (N is an integer of 3 or more) are combined to display the combined image are summarized as follows. In the following description, reference numerals in parentheses indicate corresponding components or processing steps in the configuration described with reference to the above drawings.

(3a) The image of the nth layer (where n is any one of 1 to (N-1)) is a higher layer than the image of the (n + 1) th layer, and the image of the higher layer is In the superposition for the synthesis, they are arranged on the front side.
(3b) First to (N + M) storage areas (M is an integer larger than 1 and smaller than N) in the RAM 14 are used.

(3c1) The first to Nth storage areas are allocated to the first to Nth layers, respectively.
(3c2) The (N + 1) to (N + M) recording areas are allocated to M layers of the first to Nth layers, and the M layers are allocated with two storage areas. A layer.
(3c3) Of the first to Nth layers, (N−M) layers other than M layers are SB layers to which a single storage area is allocated.
(3c4) The M layers include the first layer.

(3d1) For each of the M DB layers, the rendering processing unit (214) performs rendering in the W buffer of the layer based on the image information of the layer supplied from the outside, and (N−M For each of the SB layers, the drawing processing unit (214) performs drawing in the shared buffer of the layer based on the image information of the layer supplied from the outside.
(3d2) The reading unit (224) reads an image from the R buffer of M layers and the shared buffer of (N−M) layers,
(3d3) The image composition unit (230) synthesizes the read images.

(3e) When the image information is updated for at least one of the first to Nth layers (S301, S302),
(3e1) The drawing management unit (212) designates a DDB layer higher than any of the above-described at least one SB layer whose image information has been updated as a cover layer (S311),
(3e2) The drawing processing unit (214) draws the cover layer and the image to be displayed next to the lower layer of the cover layer in the W buffer of the cover layer in order from the lowest layer. (S312 and S313), the rendered area is set to be opaque (S314).

(3f) When the above-described drawing and opacity settings are completed, the memory control unit (222) uses the storage area previously used as the W buffer (assigned to the W buffer) in the cover layer as a new R An image stored in the storage area in which the opaque area is set by allocating the storage area that has been assigned to the buffer and used as the R buffer until then (assigned to the R buffer) to the new W buffer. Shift to an opaque composition state used for image composition (S317, S318).

(3g) Then, in the above-described opaque composition state, the drawing processing unit (214) draws each image of at least one SB layer in which the image information is updated in the shared buffer of the layer (S319), The image to be displayed next to the cover layer is drawn in the W buffer of the cover layer (S320).
(3h) When the drawing in the above-described opaque composition state is completed, the memory control unit (222) allocates the storage area that has been used as the W buffer so far to the new R buffer in the cover layer, and until then R The storage area used as a buffer is allocated to a new W buffer, and the image stored in the new R buffer of the cover layer is shifted to a transparent composition state used for image composition (S321).

  In the processing (S312 and S313) for rendering the image to be displayed next to the cover layer and the layer lower than the cover layer in order from the lowest layer (S312 and S313), the rendering processing unit (214) If the image information has been updated, the image represented by the updated image information of the cover layer is rendered as the image to be displayed next. If the image information of the cover layer has not been updated, The same image as the image stored in the R buffer of the cover layer is rendered as an image to be displayed next. For each of the layers in which the image information of the layers below the cover layer is updated, the update is performed. The image represented by the later image information is rendered as an image to be displayed next, and the image information in the layer lower than the cover layer is not updated. For each of the above, the same image as the image stored in the R buffer (B8r in FIG. 18) or the shared buffer (B6, B7 in FIG. 18) of the layer may be drawn as the next image to be displayed. good.

In the process (3f2) of drawing the image to be displayed next to the cover layer and the layer lower than the cover layer in order from the lowest layer, the drawing processing unit (214)
Of the images to be displayed next in each of the layers below the cover layer, drawing may be omitted for an image portion that is drawn after that and is hidden by a higher image.

[Effects of Embodiment 3]
According to the present embodiment, the same effect as described in the first embodiment can be obtained even in a configuration in which a plurality of DB layers exist.

Embodiment 4 FIG.
In the second embodiment and the third embodiment, the DB layer is fixed. Next, a configuration in which the DB layer is dynamically changed will be described as a fourth embodiment.

  In order to enable dynamic change of the DB layer, a storage area larger than the number (N) of layers is used. For example, a storage area having S (S <N) more than the number of layers is used, and the S storage areas are used as spare buffers. The remaining storage area is used as a shared buffer for each layer. Then, in the layer in which the image information is updated, the spare buffer is assigned to the W buffer to temporarily make the DB configuration. When drawing to the W buffer is finished, the buffer is replaced, and the DB configuration is returned to the SB configuration, and the remainder is left. Return the buffer to the spare buffer.

Hereinafter, a configuration in which the number N of layers is 8, S is 2, and 10 (= N + S) storage areas in which image data for one screen can be stored is prepared.
The hardware configuration is the same as that described with reference to FIG.

  FIG. 22 is a functional block diagram of the image composition display device 1d according to the fourth embodiment. The image composition display device 1d in FIG. 22 is generally the same as the image composition display device 1c in FIG. However, 10 storage areas Ma to Mj are provided instead of the 12 storage areas Ma to Ml in FIG.

  Of the 10 storage areas Ma to Mj in the RAM 14, 8 storage areas are used as shared buffers for the layers L1 to L8, respectively, and the remaining 2 storage areas are used as spare buffers. The shared buffer constitutes an SB configuration storage unit.

  Similar to the third embodiment, the layer Li (i is any one of 1 to 8) has a higher rank as i is smaller. That is, the layer L1 is the highest layer and the layer L8 is the lowest layer. At the time of composition by superposition, the higher the order of layers, the more images are arranged on the front side.

Control for determining roles and changing roles of the storage areas Ma to Mj is performed by the memory control unit 222.
The images stored in the eight-layer shared buffer (or R buffer) are read out and used for image composition in the image composition unit 230.
The image composition is performed by, for example, transmission composition using an alpha value or the like stored together with image data in a shared buffer (or R buffer) of eight layers.

  FIG. 23 is a flowchart illustrating an example of the operation of the image composition display device 1d according to the fourth embodiment. The process of FIG. 23 is started together with the start of the operation of the image composition display device 1d, for example.

24 and 25 are flowcharts showing an example of the process in step S403 of FIG. FIGS. 26A to 29 and FIGS. 30A to 33B are examples of changes in the role of the storage area and drawing operations in the storage area in the example of the processing of FIGS. 24 and 25. Indicates.
FIG. 34 is a flowchart illustrating an example of the process of step S404 of FIG. FIG. 35A to FIG. 36B show an example of a change in the role of the storage area and an operation of drawing in the storage area in the example of the process of FIG.

  Hereinafter, at the start of the processing of FIG. 22, for example, as shown in FIGS. 26 (a) and 35 (a), the storage areas Ma to Mh are used as the shared buffers B1 to B8 of the layers L1 to L8. Assume that Mi and Mj are used as spare buffers Ra and Rb.

  The drawing management unit 212 determines the next image to be displayed on the output device 16 based on the information supplied from the input device 15 and generates the image, so that the memory control unit 222 has the roles of the storage areas Ma to Ml. The control is performed, and the drawing processing unit 214 controls the drawing.

  In determining the image to be displayed on the output device 16, the drawing management unit 212 determines whether the image information has been updated for at least one of the plurality of layers L <b> 1 to L <b> 8 based on the information supplied from the input device 15. Determination is made (S401). If the image information has not been updated (NO in S401), the same determination is repeated to wait for the update of the image information.

If the image information has been updated (YES in S401), it is determined whether or not the image information has been updated for a number of layers exceeding the number S (= 2) of the spare buffers Ra and Rb (S402).
When the image information has been updated for the number of layers exceeding the number S (= 2) of the spare buffers Ra and Rb (YES in S402), the rewrite step S403 is performed. Otherwise, the rewrite step S404 is performed.

For example, as indicated by ◇ in FIG. 26A, when the image information is updated for L5, L6, and L7, the process of step S403 is performed as a result of the determination of step S402.
On the other hand, as indicated by Δ in FIG. 35A, when the image information is updated only for L6 and L7, the process of step S404 is performed as a result of the determination of step S402 of FIG.

When the process of step S403 or S404 ends, the determination of step S405 is performed. The process in step S405 is the same as step S105 in the first embodiment.
If it is determined in step S405 that the system termination condition is satisfied, the operation is terminated. If the system termination condition is not satisfied, the process returns to step S401 to repeat the operation.

Hereinafter, the process in step S403 will be described with reference to FIGS. 24 to 25 and FIGS. 26 (a) to 29 and FIGS. 30 (a) to 33 (b).
In step S411 in FIG. 24, the drawing management unit 212 designates the uppermost layer L5 of the layers L5, L6, and L7 whose image information has been updated as the cover layer, and the memory control unit 222 configures the cover layer as a DB configuration. (FIG. 26B). For the DB configuration, for example, the storage area Mi that was the spare buffer Ra is used. That is, the storage area Mi that was the spare buffer Ra is allocated to the W buffer B5w of the cover layer L5, and the role of the storage area Me that has been used as the shared buffer B5 is changed to the R buffer B5r.

In step S412, the drawing processing unit 214 displays the images G6 to G8 to be displayed next to the lower layers L6 to L8 lower than the cover layer in the W buffer B5w (storage area Mi) of the cover layer L5. Drawing is performed in order from the layer (in the order of G8, G7, and G6) (FIG. 26B).
As the “image to be displayed next”, an image represented by the updated image information is drawn in the layer in which the image information is updated, and has been used for image synthesis in the layer in which the image information is not updated. The same image as that (that is, the image stored in the buffer of the same layer) is drawn.

In step S413, the drawing processing unit 214 draws the image to be displayed next to the layer L5 on the W buffer B5w (storage area Mi) of the cover layer L5 (FIG. 26B).
As the “image to be displayed next”, an image represented by the updated image information is drawn.

  In the drawing in steps S412 and S413, in the area where the images overlap each other, the previous image is overwritten with the image drawn later. That is, only the image drawn later remains, and the image drawn before that is deleted. However, in the region where the alpha value is set, the pixel value of each image is multiplied by a coefficient corresponding to the alpha value and combined to draw an image having the calculated pixel value. This process can be performed in the same manner as described in the second embodiment.

  After drawing in step S413, the drawing processing unit 214 sets the image of the W buffer B5w (storage area Mi) of the cover layer L5 to be opaque (S414). This is because the images of the buffers B6 to B8 of the lower layers L6 to L8 are completely hidden when they are combined with the images stored in the buffers B6 to B8 of the lower layers L6 to L8, which will be described later. It is to make it.

Next, in step S415, the memory control unit 222 switches the R buffer B5r and the W buffer B5w of the cover layer L5. That is, the storage area Mi that has been used as the W buffer B5w is assigned to the new R buffer B5r, and the storage area Me that has been used as the R buffer B5r is assigned to the new W buffer B5w (FIG. 27A )).
By the replacement, the opaque setting is made, and the state shifts to the opaque combining state in which the image stored in the storage area Mi allocated to the new R buffer B5r is used for combining.

Next, in step S416, whether or not the image information is further updated while the drawing management unit 212 is performing at least one of the layers higher than the cover layer L5 and performing the processes of the previous steps S411 to S415. Determine.
If the image information is further updated (YES in S416), the process proceeds to step S417. Otherwise (NO in S416), the process proceeds to step S423 (FIG. 25).

In step S417, the drawing management unit 212 determines that the number of layers that are higher than the cover layer (L5) and whose image information has been updated during the processing of the immediately preceding steps S411 to S415 is determined at that time. It is determined whether or not the number is larger than the number of remaining spare buffers (the number of original spare buffers minus 1, that is, (2-1 = 1) in the above example).
If so (YES in S417), the process proceeds to step S418. If not (NO in S417), the process proceeds to step S421 (FIG. 25).

For example, as shown by ♦ in FIG. 27 (b), when the image information is updated for the layers L2, L6, and L8 during the processing of the previous steps S411 to S415, it is higher than the cover layer L5. Since the layer in which the image information of the layer is updated is only the layer L2 (one), NO is determined in step S417, and the process proceeds to step S421.
On the other hand, for example, as indicated by ♦ in FIG. 30A, when the image information is updated for the layers L2, L4, L6, and L8 during the processing of the immediately preceding steps S411 to S415, the cover layer L5 Since the layers in which the image information of the upper layer is updated are the layers L2 and L4 (two), YES is determined in the step S417, and the process proceeds to the step S418.

  In step S421, the memory control unit 222 uses a spare buffer Rb () that is a layer higher than the cover layer L5 and in which the image information is updated during the processing of the immediately preceding steps S411 to S415. The storage area Mj) is used to create a DB configuration. That is, the spare buffer Rb (storage area Mj) is set as the W buffer B2w of the layer, and the shared buffer B2 (storage area Mb) is set as the R buffer B2r (FIG. 28A).

  Next, in step S422, the drawing processing unit 214 draws an image to be displayed next to the layer in the W buffer B2w of the layer having the DB configuration in step S421 (FIG. 28A).

  Next, in step S423, the drawing processing unit 214 displays the images G6, G7, and G8 to be displayed next to the layers L6, L7, and L8 that are lower than the cover layer L5 and whose image information has been updated. Are drawn in the shared buffers B6, B7 and B8 (FIG. 28A).

  Next, in step S424, the drawing processing unit 214 draws the image G5 to be displayed next of the cover layer L5 in the W buffer B5w of the layer (FIG. 28A).

Note that the order of steps S422, S423, and S424 may be changed, and these processes may be performed simultaneously (in parallel).
In step S423, as in the example of FIG. 28A, when images of a plurality of layers are drawn, there is no restriction on the drawing order for the plurality of layers, and drawing for a plurality of layers is performed simultaneously (parallel). And you can go there. When there are a plurality of layers having the DB configuration in step S421, the same applies to the drawing order in step S422.

Next, in step S425, the memory control unit 222 replaces the R buffer B5r and the W buffer B5w of the cover layer L5. That is, the storage area Me previously used as the W buffer B5w is allocated to the new R buffer B5r, and the storage area Mi previously used as the R buffer B5r is allocated to the new W buffer B5w (FIG. 28B). )).
By the replacement, an image stored in the storage area Me newly assigned to the R buffer B5r, which is not set to be opaque, shifts to a transparent composition state used for composition.

Further, if there are layers having the DB configuration in step S421, the R buffer and W buffer of those layers are also switched.
In the example assumed in FIG. 28A, the layer L2 has a DB configuration in step S421. Therefore, in step S425, the storage area Mj that has been used as the W buffer B2w is changed to the new R buffer B2r, and the storage area Mb that has been used as the R buffer B2r is changed to the new W buffer B2w. (FIG. 28B).

  Next, in step S426, the layer whose buffer has been replaced in step S425 is returned from the DB configuration to the SB configuration (FIG. 29). That is, the W buffers B2w (Mb) and B5w (Mi) are changed to spare buffers Ra and Rb, and the R buffers B2r (Mj) and B5r (Me) are changed to shared buffers B2 and B5.

In the above example, the role of the buffer is changed in two steps in steps S425 and S426, but may be performed in one step. That is, the storage area Me used as the W buffer B5w of the cover layer L5 is allocated to the new dual-purpose buffer B5, and the storage area Mi used as the R buffer B5r of the cover layer L5 is used as the new spare buffer Rb. It is also good. Similarly, in step S421, the storage area Mj used as the W buffer B2w of the layer L2 in which the layer L2 has the DB configuration is allocated to the new dual-purpose buffer B2, and the storage area Mb used as the R buffer B2r of the layer L2 May be used as a new spare buffer Ra.
Such a role change in one stage is equivalent to a role change in two stages of steps S425 and S426.

  As described above, when the result of the determination in step S417 is “YES”, the process proceeds to step S418. In the following, as an example, as indicated by ♦ in FIG. 30A, the image information is updated for the layers L2, L4, L6, and L8, and the image information of the layers higher than the cover layer L5 is updated. Is assumed to be in layers L2 and L4 (two).

  In step S418, the cover layer is returned to the SB configuration (FIG. 30B). That is, the storage area Me that has been used as the W buffer B5w is allocated to the new dual-purpose buffer B5, and the storage area Mi that has been used as the R buffer B5r is used as the new spare buffer Ra.

After step S418, the process returns to step S411.
In step S411, the drawing management unit 212 sets the highest layer L2 among the layers L2, L4, L6, and L7 whose image information has been updated as a new cover layer, and the memory control unit 222 sets the cover layer as, for example, Then, the DB configuration is made by using the storage area Mi that was the spare buffer Ra (FIG. 31A).
That is, the storage area Mb that has been used as the shared buffer B2 is assigned to the new R buffer B2r, and the storage area Mi that has been the spare buffer Ra is assigned to the new W buffer B2w.

  In step S412, the drawing processing unit 214 displays the images G3 to G8 to be displayed next to the lower layers L3 to L8 lower than the cover layer in the W buffer B2w (storage area Mi) of the cover layer L2. Drawing is performed in order from the layer (in the order of G8, G7, G6, G5, G4, and G3) (FIG. 31A).

  Next, in step S413, the drawing processing unit 214 draws an image to be displayed next to the layer L2 on the W buffer B2w (storage area Mi) of the cover layer L2 (FIG. 31A).

  After the drawing in step S413, the drawing processing unit 214 sets the image of the W buffer B2w (storage area Mi) of the new cover layer L2 to be opaque (S414).

  In step S415, the memory control unit 222 replaces the R buffer B2r and the W buffer B2w of the cover layer L2. That is, the storage area Mi that has been used as the W buffer B2w is allocated to the new R buffer B2r, and the storage area Mb that has been used as the R buffer B2r is allocated to the new W buffer B2w (FIG. 31B). )).

Next, in step S416, the drawing management unit 212 determines whether or not the image information is further updated during the processes of the immediately preceding steps S411 to S415 in at least one of the layers higher than the cover layer L2. .
If the image information is further updated (YES in S416), the process proceeds to step S417. If not (NO in S416), the process proceeds to step S423 (FIG. 25).

In the following, it is assumed that after the second processing of Steps S411 to S415 as shown in FIGS. 31A and 31B, YES in Step S416 and NO in Step S417.
For example, as shown by ☆ in FIG. 32A, it is assumed that the image information is updated for the layers L1, L4, L5, and L6 during the processing of the previous steps S411 to S415. In this case, since only the layer L1 is updated in the image information among the layers higher than the cover layer L2 (the number of higher layers in which the image information is updated = 1)
≦ (Number of remaining spare buffers = 1)
Thus, YES is determined in the step S416, NO is determined in the step S417, and as a result, the process proceeds to the step S421.

  In step S421, the memory control unit 222 determines that the layer L1 that is an upper layer than the cover layer L2 and in which the image information has been updated during the processing of the immediately preceding steps S411 to S415 is used as a spare buffer Rb ( The storage area Mj) is used to create a DB configuration. That is, the spare buffer Rb (storage area Mj) is set as the W buffer B1w of the layer L1, and the shared buffer B1 (storage area Ma) is set as the R buffer B1r (FIG. 32 (b)).

  Next, in step S422, the drawing processing unit 214 draws an image to be displayed next to the layer in the W buffer B1w of the layer L1 having the DB configuration in step S421 (FIG. 32B).

  In step S423, the drawing processing unit 214 then displays the images G4, G5, and G6 to be displayed next to the layers L4, L5, L6, L7, and L8 that have lower image information than the cover layer L2. , G7, G8 are drawn in the shared buffers B4, B5, B6, B7, B8 of the layer (FIG. 32B).

  Next, in step S424, the drawing processing unit 214 draws the image G2 to be displayed next of the cover layer L2 in the W buffer B2w of the layer (FIG. 32B).

  Next, in step S425, the memory control unit 222 switches the R buffer B2r and the W buffer B2w of the cover layer L2. That is, the storage area Mb previously used as the W buffer B2w is allocated to the new R buffer B2r, and the storage area Mi previously used as the R buffer B2r is allocated to the new W buffer B2w (FIG. 33 (a )). By the replacement, an image stored in the storage area Mb newly assigned to the R buffer B2r, which is not set to be opaque, shifts to a transparent composition state used for composition.

Further, if there are layers having the DB configuration in step S421, the R buffer and W buffer of those layers are also switched.
In the example assumed in FIG. 32B, the layer L1 has a DB configuration in step S421. Therefore, in step S425, the storage area Mj that has been used as the W buffer B1w is allocated to the new R buffer B1r, and the storage area Ma that has been used as the R buffer B1r is allocated to the new W buffer B1w. (FIG. 33A).

Next, in step S426, the layer whose buffer has been replaced in step S425 is returned from the DB configuration to the SB configuration (FIG. 33B). That is, the W buffers B1w (Ma) and B2w (Mi) are changed to spare buffers Ra and Rb, and the R buffers B1r (Mj) and B2r (Mb) are changed to shared buffers B1 and B2.
The process of step S403 ends at step S426.

As described above, if the number of layers whose image information has been updated is equal to or less than the number of spare buffers (NO in S402), the process of step S404 is performed.
For example, as indicated by Δ in FIG. 35A, when the image information is updated only for the layers L6 and L7, NO is obtained in step S402.

Hereinafter, the process in step S404 will be described with reference to FIGS. 34 and 35 (a) to 36 (b).
In step S431, the memory control unit 222 sets all the layers L6 and L7 whose image information has been updated to the DB configuration (FIG. 35B). For example, the spare buffers Ra and Rb (storage areas Mi and Mj) are allocated to the W buffers B6w and B7w thereafter, and the shared buffers B6 and B7 are allocated to the R buffers B6r and B7r thereafter.

  In step S432, the drawing processing unit 214 draws the images G6 and G7 to be displayed next to the layers L6 and L7 in the W buffers B6w and B7w of the layer (FIG. 35B).

Next, in step S433, the memory control unit 222 replaces the R buffers B6r and B7r and the W buffers B6w and B7w of the layers L6 and L7 on which the drawing has been performed in step S432 (FIG. 36A).
That is, the previous R buffers B6r (Mf) and B7r (Mg) are assigned to the W buffers B6w and B7w thereafter, and the previous W buffers B6w (Mi) and B7w (Mj) are assigned to the R buffers B6r and B7r thereafter. Assign to.

  Next, in step S434, the memory control unit 222 returns the layer in which the buffer is replaced in step S433 to the SB configuration (FIG. 36B). That is, the previous R buffers B6r (Mi) and B7r (Mj) are allocated to the subsequent buffers B6 and B7, and the previous W buffers B6w (Mf) and B7w (Mg) are subsequently allocated to the spare buffers Ra and Rb. assign.

In the above example, the role of the buffer is changed in two steps in steps S433 and S434, but may be performed in one step. This is the same as described for steps S425 and S426 in FIG.
The process of step S404 ends with the process of step S434.

[Modification 4-1]
In the example described with reference to FIG. 24, after drawing an image of a layer lower than the cover layer in step S412, the image of the cover layer is drawn in step S413. However, as described in the second and third embodiments, an object included in each image of the layer to be rendered in step S412 is an image of any higher layer that is subsequently rendered. It is possible to determine whether or not the object is hidden by the object included in the object, and in the case of being hidden, the drawing of the object (drawing in S412) may be skipped. By doing so, processing can be made faster.
In this case, “any image of a higher layer drawn after that” includes an image of a cover layer drawn in step S413 and a layer drawn later in the same step S412. An image of (a higher layer of lower layers than the cover layer) is included.

[Modification 4-2a]
In the example described with reference to FIG. 24, it is assumed that the image of the layer lower than the cover layer is completely rewritten in step S412.
If only a partial area of the image of the layer is required to be changed for any one of the layers below the cover layer according to the image information, only the changed area is stored in the cover layer buffer (for example, in step S412). B5w) and only the changed area may be drawn in the buffer (B6, B7) of the layer (L6, L7) in step S423. By doing so, it is possible to reduce the amount of drawing and speed up the processing.

[Modification 4-2b]
Further, in the process of step S412 in FIG. 24, it is determined for each drawing object whether or not the object exists in the change area, and if it does not exist, the drawing may be skipped. By doing so, it is possible to further speed up the processing.

[Modification 4-2c]
Furthermore, in steps S412, S423, when only the image change area of the layer updated with the image information lower than the cover layer is drawn, the image information of the layer is further updated between step S412 and step S423. If the change area required by the further updated image information does not fit within the change area drawn in step S412, the same image drawn in step S412 is drawn in step S423. In this case, next, the image represented by the further updated image information is drawn in the processes of steps S412 to S426 performed based on the determination results in steps S401 and S402.

[Modification 4-3]
In step S412, for the layer lower than the cover layer (for example, L8) for which the image information has not been updated, the same image as the image stored in the buffer (B8) of the layer is used as the W of the cover layer L5. Drawing is performed in the buffer B5w. Therefore, instead of drawing the cover layer in the W buffer B5w, the image stored in the buffer (B8) of the layer (L8) whose image information is not updated is transferred to the buffer B5w of the cover layer L5. And it is good also as writing in W buffer B5w of cover layer L5. The above transfer can be performed by, for example, bit block transfer (Bitblt).
When images of a plurality of layers are written in the buffer B5w of the cover layer L5, the writing is performed so that the images of the plurality of layers are sequentially performed from the lower side and overlap each other. By sequentially writing in this way, images of a plurality of layers are synthesized.

[Modification 4-4]
In addition, when there are a plurality of spare buffers, the processing can be further speeded up by performing the following processing instead of the processing in steps S412 and S418.
First, instead of the processing in step S412, the remaining spare buffer (the spare buffer remaining after allocation of the cover layer to the W buffer in step S411) is updated with the image information below the cover layer. Are assigned to the W buffers of the other layers, and at the same time, the shared buffers of those layers are changed to R buffers.
Then, each image represented by the updated image information of the layer to which the W buffer is assigned is rendered in the W buffer of the layer.
The rendered image is transferred to the W buffer of the cover layer by bit block transfer or the like.
If there is a lower layer than the cover layer to which no spare buffer has been assigned (YES in S412d), the image to be displayed next to those layers is directly drawn in the W buffer of the cover layer.
Images of a plurality of layers written by the above transfer or direct drawing are sequentially written from the lower side and are combined so as to overlap each other. In this case, the lower layer image is written earlier.

Thereafter, the following process is performed instead of the process of step S423. That is, the R buffer and the W buffer are switched for the layer in which the spare buffer is allocated to the W buffer in step S412.
Further, after replacement, the SB configuration is restored. That is, the replaced R buffer is changed to a shared buffer, and the replaced W buffer is set as a spare buffer.
By doing so, for the layer in which the spare buffer is assigned to the W buffer in step S412, the number of times of drawing the image represented by the updated image information can be reduced to one.
In addition, when there is a layer whose image information has been updated, which is lower than the cover layer, to which no spare buffer has been allocated, an image to be displayed next to those layers (an image represented by the updated image information ) Is drawn in the shared buffer of the layer.

  In the fourth embodiment, the case where the number of layers is 8 and the number of spare buffers is 2 has been described. However, even if the number of layers is other than 8, the number of spare buffers is other than 2. However, the present invention can be applied.

  Generally speaking, when the number of layers is N (N is an integer equal to or larger than 2) and the number of spare buffers is S, that is, the image composition display device (1d) has the first to Nth layers. The following summarizes the characteristics of the configuration in which images are synthesized by superimposing (N is an integer of 3 or more) and a synthesized image is displayed. In the following description, reference numerals in parentheses indicate corresponding components or processing steps in the configuration described with reference to the above drawings.

(4a) The image of the n-th layer (n is any one of 1 to (N-1)) is a higher layer than the image of the (n + 1) layer, and the image of the higher layer is In the superposition for the synthesis, they are arranged on the front side.
(4b) The first to (N + S) storage areas in the RAM 14 (S is an integer greater than or equal to 1 and smaller than N) are used.

(4c1) Of the first to (N + S) storage areas, N storage areas are normally allocated to the shared buffers for the first to Nth layers, respectively.
(4c2) Each of the S storage areas among the first to (N + S) storage areas is normally a spare buffer, and is allocated to a W buffer of any layer as necessary. By allocating the storage area of the layer that has been used as a shared buffer so far (allocated to the shared buffer) to the R buffer, the layer is switched to the DB layer to which the two storage areas are allocated.
(4c3) The layers other than the DB layer are SB layers to which a single storage area is allocated.

(4d1) For each of at least one DB layer, the rendering processing unit (214) performs rendering in the W buffer of the layer based on the image information of the layer supplied from the outside, and at least one SB For each of the layers, the drawing processing unit (214) performs drawing in the shared buffer of the layer based on the image information of the layer supplied from the outside.
(4d2) The reading unit (224) reads an image from the R buffer of the SB layer and the shared buffer of the DB layer,
(4d3) The image composition unit (230) synthesizes the read images.

(4e) When the image information is updated for a larger number of layers than S among the first to Nth layers (S402),
(4e1) The drawing management unit (212) designates the highest layer among the layers whose image information has been updated as a cover layer (S411),
(4e2) The memory control unit (222) allocates one of the storage areas (Ma) used as a spare buffer (assigned to the spare buffer) to the W buffer of the cover layer, The storage area previously used as a shared buffer is allocated to the R buffer (S411),
(4e3) The drawing processing unit (214) draws the image to be displayed next to the cover layer and the layer lower than the cover layer in the W buffer of the cover layer in order from the lowest layer. Then (S412 and S413), the rendered area is set to be opaque (S414).

(4f) When the above drawing and opacity settings are completed, the memory control unit (222) uses the storage area previously used as the W buffer in the cover layer (assigned to the W buffer) as a new R buffer. The storage area that was previously used as the R buffer (assigned to the R buffer) is assigned to a new W buffer, so that the image stored in the storage area where the opaque setting has been made The process proceeds to the opaque composition state used for image composition (S415).

(4g) Then, in the above-described opaque composition state, the drawing processing unit (214) draws each image of the layer whose image information is updated, which is lower than the cover layer, in the shared buffer of the layer (S423). ) The image to be displayed next to the cover layer is drawn in the W buffer of the cover layer (S424).
(4h) When the drawing in the opaque composite state is completed, the memory control unit (222) allocates the storage area that has been used as a W buffer in the cover layer to the new combined buffer of the cover layer, The storage area previously used as the R buffer in the cover layer is allocated to a new spare buffer (Ra), whereby the image stored in the new shared buffer of the cover layer is used for image composition. The state is shifted to (S425).

  In the process (S412) of drawing the image to be displayed next to the cover layer and the layer lower than the cover layer in order from the lowest layer (S412), the drawing processing unit (214) The image represented by the updated image information is rendered as an image to be displayed next, and for each of the layers in which the image information of the layers lower than the cover layer is updated, the updated image information Is drawn as an image to be displayed next, and each of the layers whose image information is not updated among layers below the cover layer is stored in the shared buffer of the layer. The same image as the image may be drawn as an image to be displayed next.

  In the process (S412) of drawing the image to be displayed next to the cover layer and the layer lower than the cover layer in order from the lowest layer (S412), the drawing processing unit (214) is lower than the cover layer. Of the images to be displayed next in each of the layers, drawing may be omitted for an image portion that will be hidden by a higher-order image drawn later.

  When the number of layers for which image information has been updated is S or less, by assigning spare buffers to all the layers for which image information has been updated, all the layers are configured as a double buffer so that the image can be rewritten. It is good to do.

[Effects of Embodiment 4]
According to the present embodiment, the same effect as described in the first embodiment can be obtained even in a configuration in which the DB layer is dynamically changed.

  In each of the above embodiments, the drawing management unit 212, the memory control unit 222, and the reading unit 224 are realized by the CPU 11 executing a program, and the drawing processing unit 214 and the image composition unit 230 are programmed by the GPU 12. In other words, it has been described that the rendering management unit 212, the rendering processing unit 214, the memory control unit 222, the reading unit 224, and the image composition unit 230 are configured by software. However, these may be configured by hardware or may be configured by a combination of hardware and software.

  Although the present invention has been described above as an image composition display device, the image composition display method implemented by the image composition display device also forms part of the present invention. The image composition display method of the present invention can also be realized by software, that is, by a programmed computer. Therefore, a program for causing a computer to execute each process of the image composition display apparatus or image composition display method of the present invention, and a computer-readable recording medium on which such a program is recorded also form a part of the present invention.

  11 CPU 11, 12 GPU, 13 Non-volatile memory, 14 RAM, 15 Input device, 16 Output device, 17 System bus, 210 Image generation unit, 212 Drawing management unit, 214 Drawing processing unit, 222 Memory control unit, 224 Reading unit, 230 Image composition unit, Ma to Ml storage area.

When the process of step S103 or S104 ends, the determination of step S105 is performed.
In step S105, the drawing management unit 212 determines whether or not the system termination condition is satisfied. If not, the process returns to step S101 and repeats the operation.
For example, if the power of the image composition display device is off, it is determined that “the system termination condition is satisfied ” .

[Modification 3-6]
Also, in steps S316 and S317 of FIG. 16, only the layer whose image information has been updated among the upper DB layers (L1 and L3) than the cover layer (L5) specified in step S311 is the image of that layer. Are drawn in the buffer (S316) and the buffer is replaced (S317). However, for the DB layer higher than the cover layer in which the image information has not been updated, the image of the layer in the buffer (S316) and the buffer replacement (S317) may be performed.
Similarly, in steps S320 and S321, drawing (S320) in the buffer and buffer replacement (S321) are performed only for the layer in which the image information of the DB layers (L1, L3, L5, and L8 ) is updated. However, even for a DB layer whose image information has not been updated, drawing of the image of the layer in the buffer (S320) and replacement of the buffer (S321) may be performed.

Hereinafter, the process in step S404 will be described with reference to FIGS. 34 and 35A to 36B.
In step S431, the memory control unit 222 sets all the layers L6 and L7 whose image information has been updated to the DB configuration (FIG. 35B). For example, the spare buffers Ra and Rb (storage areas Mi and Mj) are allocated to the W buffers B6w and B7w thereafter, and the shared buffers B6 and B7 are allocated to the R buffers B6r and B7r thereafter.

Claims (16)

In an image composition display device for compositing by superimposing images of first to Nth layers (N is an integer of 2 or more) and displaying a composite image,
The image of the nth layer (n is any one from 1 to (N-1)) is a higher layer than the image of the (n + 1) th layer, and the higher layer image is Placed on the front side in the overlay for
A first to (N + 1) th storage area, a drawing processing unit, a memory control unit, a reading unit, and an image composition unit;
The first and (N + 1) storage areas are allocated to the first layer, the first layer is a double buffer configuration layer to which two storage areas are allocated, and the double buffer configuration layer , One of the two storage areas is assigned to the display buffer, the other is assigned to the write buffer,
The second to Nth storage areas are assigned to second to Nth layers, respectively, and the second to Nth layers are single buffer configuration layers to which a single storage area is assigned, and In each of the layers of the single buffer configuration, the allocated single storage area is allocated to the display and writing combined buffer,
The drawing processing unit performs drawing on the first layer writing buffer and the second to Nth layer display and writing combined buffers based on image information of each layer supplied from the outside. ,
The reading unit reads an image from the display buffer for the first layer and the display and write buffer for the second to Nth layers;
The image composition unit composes the read image,
When the image information of at least one of the second to Nth layers is updated, the drawing processing unit stores the first to Nth layers in the writing buffer of the first layer. , Draw the next image to be displayed in order from the lowest layer, set the rendered area to opaque,
When the drawing and the opacity setting are completed, the memory control unit allocates a storage area that has been used as a writing buffer in the first layer to a new display buffer and uses the storage area as a display buffer until then. Allocate the storage area that was used to a new writing buffer, so that the image stored in the storage area where the opaque setting has been made transitions to the opaque composition state used for image composition,
In the opaque composition state, the drawing processing unit is
Drawing each image of at least one layer of the second to Nth layers, in which image information is updated, in a display / write buffer for the layer;
Drawing an image to be displayed next to the first layer in the writing buffer of the first layer;
When the drawing in the opaque composition state is completed, the memory control unit allocates a storage area that has been used as a writing buffer in the first layer to a new display buffer, and uses it as a display buffer until then. The storage area used is allocated to a new writing buffer, whereby the image stored in the new display buffer of the first layer is shifted to a transparent composition state used for image composition. An image composition display device. In the process of drawing the first to Nth layers by overlapping the images to be displayed next in order from the lowest layer, the drawing processing unit includes:
When the image information of the first layer is updated, the image represented by the updated image information is drawn as the image to be displayed next,
When the image information of the first layer is not updated, the same image as the image stored in the display buffer of the first layer is drawn as the image to be displayed next,
For each of the layers in which the image information of the second to Nth layers is updated, the image represented by the updated image information is drawn as the image to be displayed next,
For each of the layers of the second to Nth layers in which the image information is not updated, the same image as the image stored in the display / write buffer of the layer is to be displayed next. The image composition display device according to claim 1, wherein: In the process of drawing the first to Nth layers by overlapping the images to be displayed next in order from the lowest layer, the drawing processing unit includes:
Of the images to be displayed next in each of the second to Nth layers, drawing is omitted for an image portion that will be hidden by a higher-order image drawn after that. The image composition display device according to claim 1.   4. The image composition display device according to claim 1, wherein N is 2. 5. In an image composition display device that combines images by superimposing images of first to Nth layers (N is an integer of 3 or more) and displays a composite image.
The image of the nth layer (n is any one from 1 to (N-1)) is a higher layer than the image of the (n + 1) th layer, and the higher layer image is Placed on the front side in the overlay for
First to (N + M) storage areas (M is an integer greater than 1 and less than N), a drawing management unit, a drawing processing unit, a memory control unit, a reading unit, and an image composition unit;
The first to Nth storage areas are allocated to the first to Nth layers, respectively.
The (N + 1) th to (N + M) recording areas are assigned to M layers of the first to Nth layers, and the M layers are assigned with two storage areas. As a buffer configuration layer, in the double buffer configuration layer, one of the two storage areas is allocated to the display buffer, the other is allocated to the write buffer,
Of the first to Nth layers, (N−M) layers other than the M layers are layers of a single buffer configuration to which a single storage area is allocated, and the single buffer configuration In this layer, a single storage area is allocated to the display / write buffer,
The M layers include the first layer,
For each of the M double buffer layers, the drawing processing unit performs drawing in the writing buffer of the layer based on image information of the layer supplied from the outside,
For each of the (N−M) single buffer configuration layers, the rendering processing unit performs rendering in the display / write buffer for the layer based on image information of the layer supplied from the outside. Done
The reading unit reads an image from the M layer display buffer and the (NM) layer display and write buffer,
The image composition unit composes the read image,
When the image information is updated for at least one single buffer configuration layer among the first to Nth layers,
The drawing management unit designates, as a cover layer, a layer of a double buffer configuration that is higher than any of the at least one single buffer configuration layer in which the image information is updated,
The drawing processing unit draws and draws the image to be displayed next to the cover layer and the layer lower than the cover layer on the writing buffer of the cover layer in order from the lowest layer. Make the area opaque,
When the drawing and the opacity setting are completed, the memory control unit allocates a storage area that has been used as a writing buffer in the cover layer to a new display buffer and is used as a display buffer until then. The storage area that has been allocated is assigned to a new writing buffer, whereby the image stored in the storage area in which the opaque setting has been made shifts to an opaque composition state used for image composition,
In the opaque composition state, the drawing processing unit is
Drawing each image of the layer of the at least one single buffer configuration in which the image information has been updated, in the display and writing combined buffer of the layer;
Draw an image to be displayed next to the cover layer in the writing buffer of the cover layer,
When the drawing in the opaque composite state is completed, the memory control unit allocates a storage area that has been used as a writing buffer in the cover layer to a new display buffer, and is allocated to the display buffer until then. The image storage method is characterized in that the storage area that has been allocated is assigned to a new writing buffer, whereby the image stored in the new display buffer of the cover layer is shifted to a transparent composition state used for image composition. Display device. In the process of drawing the image to be displayed next to the cover layer and the layer lower than the cover layer in order from the lowest layer, the drawing processing unit includes:
When the image information of the cover layer is updated, the image represented by the image information after the update of the cover layer is drawn as the image to be displayed next,
When the image information of the cover layer has not been updated, the same image as the image stored in the display buffer of the cover layer is drawn as the image to be displayed next,
For each of the layers in which the image information of the layers below the cover layer is updated, the image represented by the updated image information is drawn as the image to be displayed next,
For each of the layers whose image information is not updated among layers below the cover layer, the same image as the image stored in the display buffer of the layer or the display / write buffer is used next. The image composition display device according to claim 5, wherein the image is displayed as an image to be displayed. In the process of drawing the image to be displayed next to the cover layer and the layer lower than the cover layer in order from the lowest layer, the drawing processing unit includes:
Of the images to be displayed next in each of the layers below the cover layer, drawing is omitted for an image portion that will be hidden by a higher image drawn after that. The image composition display device according to claim 5 or 6. In an image composition display device that combines images by superimposing images of first to Nth layers (N is an integer of 3 or more) and displays a composite image.
The image of the nth layer (n is any one from 1 to (N-1)) is a higher layer than the image of the (n + 1) th layer, and the higher layer image is Placed on the front side in the overlay for
First to (N + S) storage areas (S is an integer greater than or equal to 1 and smaller than N), a drawing management unit, a drawing processing unit, a memory control unit, a reading unit, and an image composition unit ,
Of the first to (N + S) storage areas, N storage areas are normally allocated to the display and write combined buffers for the first to Nth layers, respectively.
Each of the S storage areas of the first to (N + S) storage areas is normally a spare buffer, and is allocated to a write buffer in any layer as necessary. By allocating a storage area of a layer that has been used as a display / write buffer to the display buffer, the layer is switched to a double buffer configuration layer to which two storage areas are allocated. In the layer, one of the two storage areas is assigned to the display buffer, the other is assigned to the write buffer,
Layers other than the double buffer configuration layer are single buffer configuration layers to which a single storage area is allocated, and in the single buffer configuration layer, a single storage area is allocated to the display and write combined buffer,
For each layer of at least one double buffer configuration, the drawing processing unit performs drawing in the writing buffer of the layer based on the image information of the layer supplied from the outside,
For each layer of at least one single buffer configuration, the rendering processing unit performs rendering in the display and writing combined buffer of the layer based on image information of the layer supplied from the outside,
The reading unit reads an image from the single buffer configuration layer display buffer and the double buffer configuration layer display and writing combined buffer,
The image composition unit composes the read image,
When the image information is updated for a number of layers larger than S among the first to Nth layers,
The drawing management unit designates the highest layer among the layers whose image information has been updated as a cover layer,
The memory control unit allocates one of the storage areas previously used as the reserve buffer to the writing buffer for the cover layer, and has been used as a display and writing combined buffer until then for the cover layer. Allocate storage area to display buffer,
The drawing processing unit draws and draws the image to be displayed next to the cover layer and the layer lower than the cover layer in order from the lowest layer in the writing buffer of the cover layer. Make the area opaque,
When the drawing and the opacity setting are completed, the memory control unit allocates a storage area that has been used as a writing buffer in the cover layer to a new display buffer and is used as a display buffer until then. The storage area is assigned to a new writing buffer, so that the image stored in the storage area where the opaque setting has been made shifts to the opaque composition state used for image composition,
In the opaque composition state, the drawing processing unit is
Drawing each image of the layer whose image information is updated lower than the cover layer in the display and writing combined buffer of the layer,
Draw the image to be displayed next to the cover layer in the writing buffer of the cover layer,
When the drawing in the opaque composite state is completed, the memory control unit allocates a storage area that has been used as a writing buffer in the cover layer to a new display / writing buffer of the cover layer, and the cover layer In this case, the storage area previously used as the display buffer is assigned to a new spare buffer so that the image stored in the new display / writing buffer of the cover layer is used for image composition. An image composition display device characterized by being transferred to. In the process of drawing the image to be displayed next to the cover layer and the layer lower than the cover layer in order from the lowest layer, the drawing processing unit includes:
For the cover layer, draw the image represented by the updated image information as the image to be displayed next,
For each of the layers in which the image information of the layers below the cover layer is updated, the image represented by the updated image information is drawn as the image to be displayed next,
For each layer whose image information is not updated among layers below the cover layer, the same image as the image stored in the display / write buffer of the layer is to be displayed next. The image composition display device according to claim 8, wherein the image composition display device is drawn as In the process of drawing the image to be displayed next to the cover layer and the layer lower than the cover layer in order from the lowest layer, the drawing processing unit includes:
Of the images to be displayed next in each of the layers below the cover layer, drawing is omitted for an image portion that will be hidden by a higher image drawn after that. The image composition display device according to claim 8 or 9. When the number of layers in which the image information is updated is S or less,
The rewriting of an image is performed by allocating the spare buffer to all the layers in which the image information has been updated, thereby switching all the layers to a double buffer configuration. The image composition display device according to claim 1. In an image composition display method of combining images by superimposing images of first to Nth layers (N is an integer of 2 or more) and displaying a composite image,
The image of the nth layer (n is any one from 1 to (N-1)) is a higher layer than the image of the (n + 1) th layer, and the higher layer image is Placed on the front side in the overlay for
Using the first to (N + 1) th storage areas,
The first and (N + 1) storage areas are allocated to the first layer, the first layer is a double buffer configuration layer to which two storage areas are allocated, and the double buffer configuration layer , One of the two storage areas is assigned to the display buffer, the other is assigned to the write buffer,
The second to Nth storage areas are assigned to second to Nth layers, respectively, and the second to Nth layers are single buffer configuration layers to which a single storage area is assigned, and In each of the layers of the single buffer configuration, the allocated single storage area is allocated to the display and writing combined buffer,
Based on the image information of each layer, drawing is performed in the writing buffer of the first layer and the display and writing combined buffer of the second to Nth layers,
Read images from the first layer display buffer and the second through Nth layer display and write buffers,
Synthesize the read image,
When the image information of at least one of the second to Nth layers is updated, it should be displayed next to the first to Nth layers in the writing buffer of the first layer. Draw images in order from the lowest layer, set the rendered area to be opaque,
When the drawing and the opacity setting are completed, in the first layer, a storage area that has been used as a writing buffer until then is allocated to a new display buffer, and a storage area that has been used as a display buffer until then. Is assigned to a new writing buffer, whereby the image stored in the storage area where the opaque setting has been made shifts to the opaque composition state used for image composition,
In the opaque composite state,
Drawing each image of at least one layer of the second to Nth layers, in which image information is updated, in a display / write buffer for the layer;
Drawing an image to be displayed next to the first layer in the writing buffer of the first layer;
When the drawing in the opaque composition state is completed, the storage area that has been used as a writing buffer in the first layer is allocated to a new display buffer, and the storage area that has been used as a display buffer until then. Is transferred to a new writing buffer, whereby the image stored in the new display buffer of the first layer is shifted to a transparent composition state used for image composition. . In an image composition display method for combining images by superimposing images of first to Nth layers (N is an integer of 3 or more) and displaying a composite image,
The image of the nth layer (n is any one from 1 to (N-1)) is a higher layer than the image of the (n + 1) th layer, and the higher layer image is Placed on the front side in the overlay for
First to (N + M) storage areas (M is an integer greater than 1 and less than N) are used.
The first to Nth storage areas are allocated to the first to Nth layers, respectively.
The (N + 1) th to (N + M) recording areas are assigned to M layers of the first to Nth layers, and the M layers are assigned with two storage areas. As a buffer configuration layer, in the double buffer configuration layer, one of the two storage areas is allocated to the display buffer, the other is allocated to the write buffer,
Of the first to Nth layers, (N−M) layers other than the M layers are layers of a single buffer configuration to which a single storage area is allocated, and the single buffer configuration In this layer, a single storage area is allocated to the display / write buffer,
The M layers include the first layer,
For each layer of the M double buffer configuration, drawing is performed in the writing buffer of the layer based on the image information of the layer,
For each of the (N−M) single buffer configuration layers, drawing is performed in the display / write buffer of the layer based on the image information of the layer,
Read an image from the M layer display buffer and the (NM) layer display and write buffer,
Synthesize the read image,
When the image information is updated for at least one single buffer configuration layer among the first to Nth layers,
A layer having a double buffer configuration, higher than any of the at least one single buffer configuration layer in which the image information has been updated, is designated as a cover layer,
An image to be displayed next to the cover layer and a layer lower than the cover layer is drawn in order from the lowest layer in the writing buffer of the cover layer, and an opaque setting is set in the drawn area. Done
When the drawing and opacity settings are completed, the storage area previously used as the writing buffer is allocated to the new display buffer in the cover layer, and the storage area previously used as the display buffer is newly assigned. The image stored in the storage area where the opaque setting is made is shifted to an opaque composition state used for image composition.
In the opaque composite state,
Drawing each image of the layer of the at least one single buffer configuration in which the image information has been updated, in the display and writing combined buffer of the layer;
Draw an image to be displayed next to the cover layer in the writing buffer of the cover layer,
When the drawing in the opaque composite state is completed, the storage area previously used as the writing buffer is allocated to the new display buffer in the cover layer, and the storage area previously allocated to the display buffer is newly assigned. An image composition display method characterized in that an image stored in a new display buffer of the cover layer is shifted to a transparent composition state used for image composition. In an image composition display method for combining images by superimposing images of first to Nth layers (N is an integer of 3 or more) and displaying a composite image,
The image of the nth layer (n is any one from 1 to (N-1)) is a higher layer than the image of the (n + 1) th layer, and the higher layer image is Placed on the front side in the overlay for
Using the first to (N + S) storage areas (S is an integer greater than or equal to 1 and less than N),
Of the first to (N + S) storage areas, N storage areas are normally allocated to the display and write combined buffers for the first to Nth layers, respectively.
Each of the S storage areas of the first to (N + S) storage areas is normally a spare buffer, and is allocated to a write buffer in any layer as necessary. By allocating a storage area of a layer that has been used as a display / write buffer to the display buffer, the layer is switched to a double buffer configuration layer to which two storage areas are allocated. In the layer, one of the two storage areas is assigned to the display buffer, the other is assigned to the write buffer,
Layers other than the double buffer configuration layer are single buffer configuration layers to which a single storage area is allocated, and in the single buffer configuration layer, a single storage area is allocated to the display and write combined buffer,
For each of the layers having at least one double buffer configuration, drawing is performed in the writing buffer of the layer based on the image information of the layer,
For each layer of at least one single buffer configuration, drawing is performed in the display and writing combined buffer of the layer based on the image information of the layer,
Read an image from the display buffer of the single buffer configuration layer, and the display and write buffer of the double buffer configuration layer,
Synthesize the read image,
When the image information is updated for a number of layers larger than S among the first to Nth layers,
Specify the highest layer among the layers with updated image information as the cover layer,
Any one of the storage areas that have been used as the spare buffer until then is assigned to the cover layer writing buffer, and the storage area of the cover layer that has been used as a display and writing buffer is used for display. Assigned to the buffer,
In the cover layer's writing buffer, draw the image to be displayed next to the cover layer and the layer lower than the cover layer in order, starting from the lowest layer, and set the rendered area to opaque. Done
When the drawing and the opacity setting are completed, the storage area previously used as the writing buffer in the cover layer is allocated to the new display buffer, and the storage area previously used as the display buffer is newly assigned. Allocating to the writing buffer, the image stored in the storage area where the opaque setting has been made shifts to the opaque composition state used for image composition,
In the opaque composite state,
Drawing each image of the layer whose image information is updated lower than the cover layer in the display and writing combined buffer of the layer,
Draw the image to be displayed next to the cover layer in the writing buffer of the cover layer,
When the drawing in the opaque composite state is completed, the storage area that has been used as a writing buffer in the cover layer is allocated to a new display / writing buffer in the cover layer, and the display buffer is used in the cover layer until then. The storage area used as a storage buffer is allocated to a new spare buffer, whereby the image stored in the new display / writing buffer of the cover layer is shifted to a transparent composition state used for image composition. An image composition display method.   The program which makes a computer perform the process in the image composition display method of any one of Claim 12 to 14.   A computer-readable recording medium on which the program according to claim 15 is recorded.

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