JP2002049929A - Apparatus and method for generating image, game machine and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize a limited memory area for image display. SOLUTION: In this image generating device for displaying an image obtained by performing perspective projection transformation of a three-dimensional display object onto the projecting surface of a viewpoint coordinates system on a display 2, a VRAM 8 is shared by three buffers that are a frame buffer 81 for storing an image to be displayed on the display 2, a Z buffer 82 for storing the depth information of the three-dimensional display object and a texture buffer 83 for storing texture data used in texture mapping. Capacities allocated to the shared buffers 81, 82 and 83 are variable in accordance with, for instance, an image display area to the display 2, the number of simultaneously developed colors, and the depth decision accuracy between three-dimensional display objects.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image generating apparatus, a game apparatus, and an image generating method for displaying on a display an image obtained by performing perspective projection transformation of a three-dimensional display object onto a projection plane of a viewpoint coordinate system. In particular, the present invention relates to efficient allocation of a memory area shared by at least two of a frame buffer, a Z buffer, and a texture buffer.

[0002]

2. Description of the Related Art Hitherto, various types of image generating apparatuses have been known for use in, for example, a three-dimensional game or a simulator for controlling an airplane or various vehicles. In such an image generating apparatus, the three-dimensional object 300 shown in FIG.
Is stored in the apparatus in advance. This three-dimensional object 300 is a player (viewer) 302
Represents a display object such as a landscape that can be viewed through the screen 306. A perspective image (projected image) is obtained by performing perspective projection conversion of the image information of the three-dimensional object 300 as the display object on the screen 306. An image 308 is displayed on the screen 306.

In this apparatus, when the player 302 performs an operation such as rotation and translation using an operation panel 304, or is controlled by a program without operating the player 302, the player 302 or the player 302
The position and direction of the moving body on which the vehicle is mounted change, and a calculation process for determining how the image of the three-dimensional object 300 looks on the screen 306 in accordance with the change is performed. This calculation process is performed in real time following the operation of the player 302. As a result, the player 302 can see in real time a change in the scenery or the like accompanying a change in the position or direction of the player or the moving body on which the player is riding as a pseudo three-dimensional image, and simulates a virtual three-dimensional space. You will be able to experience it.

[0004]

An image generating apparatus of this type generally has a VRAM (Video Random Access Memory) for storing image information on the three-dimensional object 300. The VRAM has a memory area divided according to the type of information to be stored. For example, a frame buffer for storing an image to be displayed on a display,
A Z buffer for storing depth information of the three-dimensional object 300,
The memory area is divided into three, a texture buffer for storing texture data used for texture mapping.

[0005] In recent years, user demands for image quality have become severe, such as higher image quality and an increase in the number of simultaneous colors. However, in a program design stage, a VRAM having a limited storage capacity (for example, a 4M
B) by any distribution of frame buffer, Z buffer,
There was a gap between the image quality required by the user and the image quality that can be displayed within the usable capacity of each buffer designed by the designer because the assignment of each texture buffer was fixed. . Also, the usable capacity of each buffer is fixed at the program design stage and cannot be changed at the time of use. For example, when the buffer is used in a game device rich in scene change, a memory area in the VRAM is used. Was not always used efficiently.

For example, for a Z buffer for storing depth information (so-called Z value), 8 pixels,
Although an appropriate bit length can be selected from 16, 24, and 32 bits, the required capacity of the Z buffer increases as the accuracy of the depth information increases (the bit length increases). Therefore, if the required bit length per pixel for the depth information is fixed to 32 bits at the design stage, the usable capacity of the frame buffer and the texture buffer is reduced because the VRAM capacity has an upper limit. .

However, if the required bit length of the depth information is set short in the design stage, an error is likely to be included in the calculation result at the time of the depth determination, and the accuracy of the depth determination is reduced. For example, in the indoor stage, the required bit length per pixel for the depth information is 16 bits, but when the scene moves to the outdoor stage where a distant road or a distant building can be seen, the required bit length of the depth information is required. Is insufficient if it is not 24 or 32 bits.

However, in a scene such as a character selection screen where the drawing order of a three-dimensional object to be displayed on the display is predetermined or when only a two-dimensional object is displayed, the Z buffer may not be required. .
In such a case, if the capacity of the Z buffer can be reduced and the usable capacity of the texture buffer can be increased by that amount, a high-quality texture can be stored in the VRAM, and a high-quality image can be displayed. become.

Also, as in the case of expressing the world of gray scale, full color (for example, 25
In a scene not using (6 colors), the capacity of the frame buffer can be reduced, and the capacity of other buffers can be increased accordingly. The present invention has been made in view of such circumstances, and a purpose thereof is to effectively utilize a limited memory area for image display.

[0010]

To solve the above problems, the following means are employed. The invention according to claim 1 is an image generating apparatus for displaying an image obtained by performing perspective projection transformation of a three-dimensional display object on a projection plane of a viewpoint coordinate system on a display, wherein the image to be displayed on the display is provided. , A memory buffer shared by at least two of a frame buffer for storing depth data of the three-dimensional display object, and a texture buffer for storing texture data used for texture mapping. Is characterized in that the capacity allocated to the is variable.

According to a tenth aspect of the present invention, there is provided an image generating method for displaying, on a display, an image obtained by performing perspective projection conversion of a three-dimensional display object onto a projection plane of a viewpoint coordinate system. A memory area is shared by at least two of a frame buffer for storing an image to be displayed, a Z buffer for storing depth information of the three-dimensional display object, and a texture buffer for storing texture data used for texture mapping. It is characterized in that the capacity allocated to the buffer is variably controlled.

According to a nineteenth aspect of the present invention, there is provided a computer-readable recording medium storing a program for displaying on a display an image obtained by performing perspective projection transformation of a three-dimensional display object onto a projection plane of a viewpoint coordinate system. And
At least two of a frame buffer for storing an image to be displayed on the display, a Z buffer for storing depth information of the three-dimensional display object, and a texture buffer for storing texture data used for texture mapping.
And a step of variably controlling the capacity allocated to these shared buffers.

With the above configuration, the usable capacity allocated to at least two shared buffers among the frame buffer, the Z buffer, and the texture buffer is not fixed to the capacity at the time of design, and is displayed on the display. Since the available capacity allocated to each shared buffer can be increased or decreased according to the capacity required by each shared buffer for an image, the memory area for displaying images can be efficiently used.

According to a second aspect of the present invention, in the image generating apparatus according to the first aspect, the capacity allocated to each shared buffer can be changed according to the number of pixels required for display display. And

[0015] The invention described in claim 11 is the invention in claim 10.
In the image generation method described in (1), the capacity allocated to each shared buffer is variably controlled according to the required number of pixels for display display.

The invention described in claim 20 is the same as the claim 19.
Wherein the step of variably controlling the capacity allocated to each shared buffer in accordance with the number of pixels required for display display is provided.

With the above arrangement, when displaying an image on a display, for example, when displaying a horizontally long screen such as a cinema scope, the number of pixels required for display display is reduced. Thus, the required capacity of the frame buffer and the Z buffer is reduced, thereby increasing the usable capacity of the texture buffer.

According to a third aspect of the present invention, in the image generating apparatus according to the first aspect, the capacity allocated to each shared buffer can be changed according to a required bit length for one pixel of the display. It is characterized by.

The invention described in claim 12 is the invention in claim 10
In the image generation method described in (1), the capacity allocated to each shared buffer is variably controlled according to the required bit length for one pixel of the display.

The invention described in claim 21 is the same as the claim 19.
Wherein the step of variably controlling the capacity allocated to each shared buffer in accordance with the required bit length for one pixel of the display is provided.

With the above configuration, when displaying an image on the display, for example, it is possible to accurately determine the depth of a three-dimensional display object such as an attract screen before the game starts or a character selection screen after the game starts. If you do not need it, or if you do not want to generate full color simultaneously, such as when expressing the world of gray scale, by shortening the required bit length for one pixel of the display,
The required capacity of the frame buffer and the Z buffer is reduced, thereby increasing the usable capacity of the texture buffer.

According to a fourth aspect of the present invention, in the image generating apparatus according to the third aspect, the required bit length is a required value for the depth information.

[0023] The invention described in claim 13 is the twelfth invention.
In the image generation method described in (1), the required bit length is set to a required value for the depth information.

The invention described in claim 22 is the invention as claimed in claim 21.
The recording medium according to claim 1, further comprising a step of setting the required bit length to a required value for the depth information.

With the above configuration, when displaying an image on the display, for example, when a depth determination is not required, such as in an attract screen before the start of a game or a character selection screen after the start of a game, or when indoors, When high-precision depth determination is not required as in the case of an indoor display screen on a stage, the required bit length per pixel for the depth information is reduced, thereby reducing the required capacity of the Z buffer, thereby reducing the frame size. It becomes possible to increase the usable capacity of the buffer and the texture buffer.

According to a fifth aspect of the present invention, in the image generating apparatus of the third aspect, the required bit length is a required value for the number of simultaneous colors.

The invention described in claim 14 is the invention according to claim 12
Wherein the required bit length is set to a required value for the number of simultaneous colors.

According to the twenty-third aspect of the present invention,
The recording medium according to claim 1, further comprising a step of setting the required bit length to a required value for the number of simultaneous colors.

With the above configuration, when displaying images on a display, for example, when full-color is not simultaneously generated as in the case of displaying a gray scale world, the number of simultaneous colors per display pixel , The required capacity of the frame buffer is reduced, thereby increasing the usable capacity of the Z buffer and the texture buffer.

According to a sixth aspect of the present invention, there is provided a game apparatus comprising the image generating apparatus according to any one of the first to fifth aspects, wherein the three-dimensional display object is a character and an object appearing in a game. The capacity allocated to each shared buffer is variable according to the progress of the game.

According to a fifteenth aspect of the present invention, in the image generation method according to any one of the tenth to fourteenth aspects, the three-dimensional display object is a character and an object appearing in a game. The capacity is variably controlled according to the game progress.

According to a twenty-fourth aspect of the present invention, in the recording medium according to any one of the nineteenth to twenty-third aspects, the three-dimensional display object is a character and an object appearing in a game. Is variably controlled according to the progress of the game.

With the above-described configuration, even in a game device in which a scene changes according to the progress of a game, each shared buffer is used in accordance with the capacity required by each shared buffer for an image to be displayed on a display. Can be increased / decreased, so that the memory area for image display can be efficiently utilized.

According to a seventh aspect of the present invention, in the game apparatus according to the sixth aspect, the capacity allocated to the shared buffer includes an image display area on a display, the number of simultaneous colors, and a depth determination between three-dimensional display objects. It is characterized in that it can be changed when any of the accuracy changes.

The invention described in claim 16 is the same as the claim 15.
Wherein the capacity to be allocated to the shared buffer is variably controlled when any of the image display area on the display, the number of simultaneous colors, and the depth determination accuracy between three-dimensional display objects changes. And

The invention described in claim 25 is the invention according to claim 24.
And a step of variably controlling a capacity to be allocated to the shared buffer when any one of an image display area on a display, the number of simultaneous colors, and a depth determination accuracy between three-dimensional display objects changes. It is characterized by the following.

With the above configuration, when displaying a scene where the image display area on the display needs to be small, for example, when displaying a horizontally long screen whose top and bottom are narrow like a cinema scope, By reducing the number of pixels required for display display, the required capacity of the frame buffer and the Z buffer can be reduced, thereby increasing the usable capacity of the texture buffer.

In the case where the number of simultaneous colors is small, for example, when full-color is not simultaneously generated as in the case of expressing a gray scale world, or when the depth judgment is not required or the judgment accuracy is low, When displaying a good scene, for example, when displaying the attract screen before the start of the game or the character selection screen after the start of the game, by shortening the required bit length for one pixel of the display, the frame buffer or the The required capacity of the Z buffer can be reduced, thereby increasing the available capacity of the texture buffer.

According to an eighth aspect of the present invention, in the game apparatus according to the sixth aspect, the capacity allocated to the shared buffer can be changed at the time of stage switching or scene switching.

[0040] The invention described in claim 17 is based on claim 15.
In the image generation method described in the above, the capacity to be allocated to the shared buffer is variably controlled at the time of stage switching or scene switching.

The invention described in claim 26 is the invention described in claim 24.
Wherein the step of variably controlling the capacity allocated to the shared buffer at the time of stage switching or scene switching is provided.

With the above-described configuration, when the required capacity of each buffer can be changed at the time of stage switching or scene switching, the usage of each buffer is changed in accordance with the capacity required by each buffer at the stage or scene after switching. The available capacity can be efficiently distributed.

According to a ninth aspect of the present invention, in the game device according to the sixth aspect, the capacity allocated to the shared buffer is set when an attract screen is displayed before the game starts, when a character is selected after the game starts, and indoors. It is characterized in that it can be changed at the time of the scene transition from the indoor stage to the outdoor stage or vice versa, at the time of the scene transition from the indoor stage to the outdoor stage or vice versa.

[0044] The invention described in claim 18 is related to claim 15.
In the image generation method described in the above, the capacity allocated to the shared buffer is changed when an attract screen is displayed before a game is started, when a character is selected after a game is started, when a scene is shifted from an indoor stage to an outdoor stage indoors, or vice versa. It is characterized in that it is variably controlled at the time of a scene transition from an indoor stage to an outdoor stage or vice versa.

The invention described in claim 27 is based on claim 24.
In the recording medium described in the above, the capacity allocated to the shared buffer is determined when the attract screen is displayed before the game starts, when the character is selected after the game starts, when the scene is shifted from the indoor stage to the outdoor stage indoors, or vice versa. Variably controlling when the scene is shifted from the indoor stage to the outdoor stage or vice versa.

With the above arrangement, when a precise depth determination is not required, such as when an attract screen is displayed before the game starts or when a character is selected after the game starts, one pixel per display is used for the depth information. By shortening the required bit length per hit, the required capacity of the Z buffer can be reduced, thereby increasing the usable capacity of the frame buffer and the texture buffer.

In addition, when a scene transitions from an indoor stage to an outdoor stage indoors, or when a scene transitions from an indoor stage to an outdoor stage, a transition is made from a scene that does not require high-precision depth determination to a scene that does. In this case, by increasing the usable capacity of the Z-buffer, the bit length of the depth information is increased, thereby enabling highly accurate depth determination.

On the contrary, it is not necessary to start a scene that requires a high-precision depth judgment, such as when a scene changes from an outdoor stage to an indoor stage indoors or when a scene changes from an outdoor stage to an indoor stage. When moving to the scene, shorten the bit length of the depth information,
The usable capacity of the Z buffer can be reduced, thereby increasing the usable capacity of the frame buffer and the texture buffer.

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The image generation device according to the present embodiment is a device that displays a three-dimensional model on a display by expressing the three-dimensional model as a combination of polygons (for example, polygons such as triangles) that are unit figures and drawing the polygon. is there.

This image generating apparatus, as shown in FIG.
Control unit 1, display 2, ROM (Read-Only Memor
y) 3, RAM (Random Access Memory) 4, DMA (D
An irectMemory Access Channel) controller 5, a disk controller 6, a disk device 7, and a VRAM (memory area) 8 are main components. The control unit 1 further includes a coprocessor 111 and a geometry processor 1
And a drawing processor 12 to which the display 2 and the VRAM 8 are connected.
The control of the whole system such as the control of each element such as 4 is performed.

The main processor 11, for example, reads necessary graphic data from the RAM 4 in accordance with the progress of the game, performs processing such as coordinate conversion, clipping, and brightness calculation on the graphic data to create polygon data. I do. These operations are performed by the coprocessor 1
The polygon data generated at high speed by the 11 and the geometry processor 112 is output to the drawing processor 12 via the main bus 9.

The polygon data includes data (x, y, z, R, G, B, α) at each of the three vertices of the polygon. Here, the data (x, y, z) are the three-dimensional coordinates of each vertex, the data (R, G, B) are the red, green, and blue luminance values, and the data (α) is a mixture for specifying the transmittance. The coefficient is shown.

The VRAM 8 according to the present embodiment includes a frame buffer 81 for storing an image to be displayed on the display 2, depth information of a three-dimensional display object (so-called,
Z buffer) for storing texture data used for texture mapping, and a Z buffer 82 for storing texture data used for texture mapping. These three buffers 81, 82, 83 , That is, the usable capacity can be dynamically variably controlled based on a command from the main processor 11.

FIG. 2 is a flowchart showing a procedure for variably controlling the usable capacity of each of the buffers 81, 82, 83 in the VRAM 8. This flowchart is executed, for example, when a stage is switched or when a scene is changed. . In the present embodiment, “when the stage is switched” means, for example, when the image displayed on the display 2 shifts from the indoor stage to the outdoor stage, or vice versa, and even in the same indoor, the shift from the indoor stage to the outdoor stage occurs. The time when the scene is changed or vice versa, and the time when the scene is changed means the time when at least a part of the information stored in the frame buffer 81 changes.

When the stage is shifted to a new stage, first, in step S1, when displaying a plurality of polygons constituting a three-dimensional display object, what is the level of the depth determination accuracy required for erasing hidden surfaces and the like? To determine.
In the present embodiment, three levels of depth determination accuracy are prepared: high level, medium level, and low level.

The “high level” of the depth determination accuracy is defined as, for example, a three-dimensional model (FIG. 7) close to the viewpoint, such as an outdoor stage shown in FIG. 7 or an indoor outdoor stage shown in FIG.
In FIG. 8, a quay 501, a target 511 in FIG. 8) and a very distant three-dimensional model (a building 502 in FIG. 7, a window 512 in FIG. 8).
Are mixed, that is, when three-dimensional models having very distant Z values are mixed, or conversely, very close to the decimal point level in the depth direction (in the Z direction). In this case, the bit length of the Z buffer 82 is set to 32 bits.

On the other hand, the “low level” of the accuracy of the depth determination means that the three-dimensional model (the rocket launcher 52 in FIG. 9) is drawn in advance, as in the screen before the game shown in FIG.
1, rocket 522, and game title 523) are sorted, so that it is not necessary to hold depth information for each polygon, or a three-dimensional space, such as a character selection screen at the start of a game. Does not need to be drawn, and only the two-dimensional model needs to be drawn. In these cases, the bit length of the Z buffer 82 is 8
Set to bit.

The "medium level" has a determination accuracy intermediate between the "high level" and the "low level".
As in the indoor stage in the room shown in FIG. 10, there is a case where three-dimensional models (targets 531 and tables 532 in FIG. 10) having very distant or close Z values are not mixed. Has a required bit length of 16
Bit or 24 bits.

Here, the "middle level" is subdivided into "middle level 1" and "middle level 2", the required bit length of the Z buffer 82 at "middle level 1" is set to 16 bits, and
The required bit length of the Z buffer 82 at “middle level 2” may be set to 24 bits. Hereinafter, for convenience of explanation, a case will be described in which the required bit length of the Z buffer 82 at the “middle level” is set to 16 bits.

When the level of the depth determination accuracy is determined in step S1, it is determined in step S2 whether the depth determination accuracy belongs to "high level", "medium level", or "low level". If the determination result in step S2 is "high level", the process proceeds to step S3, and the bit length of the Z buffer 82 is set to 32 bits.

If the result of the determination in step S2 is "medium level", the flow advances to step S4 to set the bit length of the Z buffer 82 to 16 bits. Further, step S
If the determination result of step 2 is "low level", the process proceeds to step S5, and the bit length of the Z buffer 82 is set to 8 bits.

Next, in step S6, the necessary capacity of the Z buffer 82 according to the level of the depth determination accuracy is calculated. Specifically, the resolution is obtained by multiplying the resolution required for the new stage by the bit length of the Z buffer 82 set in any one of the processes in steps S3 to S5. For example, when a resolution of 640 × 512 pixels is required and the bit length of the Z buffer 82 is set to 8 bits, the required capacity of the Z buffer 82 =
640 × 512 × 8 = 320 KB.

Next, in step S7, the required capacity of the frame buffer 81 is calculated. Specifically, it is obtained by multiplying the required resolution for the new stage by the required bit length for the number of simultaneous colors. For example, 640x
If a resolution of 512 pixels is required and full color is required as the number of simultaneous colors, that is, if the required bit length for the number of simultaneous colors is 32 bits, the required capacity of the frame buffer 81 = 640 ×
256 × 32 × 2 = 1280 KB. Note that this calculation formula shows an example in the case of performing interlace display.

In step S8, the texture buffer 8
The usable capacity of No. 3 is calculated. Specifically, the required capacity is obtained by subtracting the required capacity of the Z buffer 82 calculated in step S6 and the required capacity of the frame buffer 81 calculated in step S7 from the VRAM capacity. For example, if the VRAM capacity is 4MB
, The available capacity of the texture buffer 83 = 4096− (320 + 1280) = 2496 KB.

As described above, according to the present embodiment, each of the shared buffers 81, 82,
The capacity allocated to the 83 is, for example, when displaying the attract screen (FIG. 9) before the start of the game, when shifting the scene from the indoor stage to the outdoor stage indoors (when shifting the scene from FIG. 10 to FIG. 8) or the like. The opposite time (from FIG. 8 to FIG.
0), at the time of the scene transition from the indoor stage to the outdoor stage (at the time of the scene transition from FIG. 8 or FIG. 10 to FIG. 9) or vice versa (the scene from FIG. 9 to FIG. 8 or FIG. 9). At the time of transition).

Therefore, when displaying the attract screen before the start of the game, it is not necessary to judge the depth. By setting the required bit length per pixel for the depth information to 8 bits, the required capacity of the Z buffer 82 is reduced. And the usable capacity of the frame buffer 81 and the texture buffer 83 can be increased.

In addition, when a scene transitions from an indoor stage to an outdoor stage indoors, or when a scene transitions from an indoor stage to an outdoor stage, a transition is made from a scene that does not require high-precision depth determination to a scene that requires it. In such a case, the usable capacity of the Z buffer 82 is increased, and the required bit length per pixel for the depth information is set to 32 bits.

On the contrary, it is not necessary to start a scene that requires a high-precision depth judgment, such as when a scene changes from an outdoor stage to an indoor stage indoors or when a scene changes from an outdoor stage to an indoor stage. When shifting to a scene, the usable capacity of the Z buffer 82 is reduced and the usable capacity of the frame buffer 81 and the texture buffer 83 is increased by reducing the bit length of the depth information from 32 bits to 16 bits. Becomes possible.

Hereinafter, how the capacities of the shared buffers 81, 82, and 83 change when the resolution, the number of simultaneous colors, the required bit length of the Z buffer 82, and the like are changed with reference to FIGS. This will be described with reference to four embodiments.

(Embodiment 1) The VRAM in this embodiment
Resolution, number of simultaneous colors, required bit length of Z buffer 82,
The settings of the frame buffer 81 are as follows. VRAM capacity: 4 MB (4096 KB) Resolution: 640 × 512 pixcel Simultaneous color generation number: 32 bit full color (Breakdown: R 8 bit, G 8 bit, B 8 bit, α 8 bit) Z buffer required bit length; 8 bit frame buffer; 0 lines for interlace display And two types based on one line each.

In this case, the required capacity of the Z buffer 82 is
Since this is a value obtained by multiplying the resolution by the required bit length of the Z buffer, 640 × 512 × 8 bits = 320 KB. On the other hand, the required capacity of the frame buffer 81 is a value obtained by multiplying the half of the resolution by the number of simultaneous colors and the number of lines, so that 640 × 256 × 32 bits × 2 = 1280 KB.

The usable capacity of the texture buffer 83 is a value obtained by subtracting the necessary capacity of the Z buffer 82 and the frame buffer 81 from the capacity of the VRAM, so that 4096 KB− (320 KB + 1280 KB) = 249.
6 KB. This state is conceptually illustrated in FIG. 3, where the Z buffer 82 is small, the frame buffer 81 is medium, and the texture buffer 83 is large.

(Embodiment 2) The VRAM in this embodiment,
Resolution, number of simultaneous colors, required bit length of Z buffer 82,
The settings of the frame buffer 81 are as follows. VRAM capacity: 4 MB (4096 KB) Resolution: 640 × 512 pixcel Simultaneous color generation number: 32 bit full color (Breakdown: R 8 bit, G 8 bit, B 8 bit, α 8 bit) Z buffer required bit length; 32 bit frame buffer; 0 lines for interlace display And two types based on one line each.

In this case, the required capacity of the Z buffer 82 is
Since it is a value obtained by multiplying the resolution by the required bit length of the Z buffer 82, 640 × 512 × 32 bits = 1280 KB. On the other hand, the required capacity of the frame buffer 81 is a value obtained by multiplying the half of the resolution by the number of simultaneous colors and the number of lines, so that 640 × 256 × 32 bits × 2 = 1280 KB.

The usable capacity of the texture buffer 83 is a value obtained by subtracting the required capacities of the Z buffer 82 and the frame buffer 81 from the VRAM capacity, so that 4096 KB− (1280 KB + 1280 KB) = 15
36 KB. This state is conceptually shown in FIG. 4, where the Z buffer 82 is medium, the frame buffer 81 is medium, and the texture buffer 83 is small.

(Embodiment 3) The VRAM in this embodiment,
Resolution, number of simultaneous colors, required bit length of Z buffer 82,
The settings of the frame buffer 81 are as follows. VRAM capacity: 4 MB (4096 KB) Resolution: 320 × 256 pixcel Simultaneous color development number: 32 bits full color (Breakdown: R 8 bits, G 8 bits, B 8 bits, α 8 bits) Z buffer required bit length; 32 bits Frame buffer; 0 lines for interlace display And two types based on one line each.

In this case, the required capacity of the Z buffer 82 is
Since the value is a value obtained by multiplying the resolution by the required bit length of the Z buffer 82, 320 × 256 × 32 bits = 320 KB. On the other hand, the required capacity of the frame buffer 81 is a value obtained by multiplying the half of the resolution by the number of simultaneous colors and the number of lines, so that 320 × 128 × 32 bits × 2 = 320 KB.

The usable capacity of the texture buffer 83 is a value obtained by subtracting the required capacity of the Z buffer 82 and the frame buffer 81 from the capacity of the VRAM, so that 4096 KB− (320 KB + 320 KB) = 3456.
KB. This state is conceptually illustrated in FIG. 5, where the Z buffer 82 is small, the frame buffer 81 is small, and the texture buffer 83 is large.

(Embodiment 4) The VRAM in this embodiment,
Resolution, number of simultaneous colors, required bit length of Z buffer 82,
The settings of the frame buffer 81 are as follows. VRAM capacity: 4 MB (4096 KB) Resolution: 320 x 256 pixcel Simultaneous color development number: 32 bit full color (Breakdown: R 8 bit, G 8 bit, B 8 bit, α 8 bit) Z buffer required bit length; 8 bit frame buffer; 0 lines for interlace display And two types based on one line each.

In this case, the required capacity of the Z buffer 82 is
Since the value is the value obtained by multiplying the resolution by the required bit length of the Z buffer 82, 320 × 256 × 8 bits = 80 KB. On the other hand, the required capacity of the frame buffer 81 is a value obtained by multiplying the half of the resolution by the number of simultaneous colors and the number of lines, so that 320 × 128 × 32 bits × 2 = 320 KB.

Since the usable capacity of the texture buffer 83 is a value obtained by subtracting the required capacity of the Z buffer 82 and the frame buffer 81 from the VRAM capacity, 4096 KB− (80 KB + 320 KB) = 3696 K
B. This state is conceptually illustrated in FIG. 6, where the Z buffer 82 is small, the frame buffer 81 is small, and the texture buffer 83 is large.

The first embodiment is an example of a case where the required bit length of the Z buffer 82 is 8 bits, that is, a case where a scene that does not require any depth judgment or a scene that does not require a strict depth judgment is displayed. . In this case, the Z buffer 8
2, the required capacity of the texture buffer 83 increases as much as the required capacity can be reduced. Therefore, the number of textures and the size of one texture that can be stored in the texture buffer 83 can be increased, and the display speed can be improved.

The second embodiment is an example where the required bit length of the Z buffer 82 is 32 bits, that is, a case where a scene requiring strict depth determination is displayed. In this case, the required capacity of the Z buffer 82 is increased as compared with the first embodiment.
3 usable capacity is reduced. Therefore, it is possible to strictly determine the depth in units of polygons, and it is possible to display a realistic image.

In the third embodiment, similarly to the second embodiment, when the required bit length of the Z buffer 82 is 32 bits,
In the case where strict depth determination is required,
Since the resolution is lower than that of the second embodiment, the required capacity of the Z buffer 82 and the frame buffer 81 is smaller than that of the second embodiment, and the usable capacity of the texture buffer 83 is further increased. Therefore, it is possible to achieve both high display speed and realistic image display.

The fourth embodiment is similar to the first embodiment when the required bit length of the Z buffer 82 is 8 bits, that is, when no depth determination is required or when strict depth determination is not required. However, since the resolution is lower than in the first embodiment, the required capacity of the frame buffer 81 is
And the usable capacity of the texture buffer 83 further increases. Therefore, the display speed can be further increased.

In these four embodiments, the resolution and the number of simultaneous colors are unchanged, that is, the required capacity of the frame buffer 81 is unchanged, and the usable capacity of the remaining Z buffer 82 and texture buffer 83 is increased or decreased. However, the present invention is not limited to such an example. The available capacity of the remaining Z buffer 82 and texture buffer 83 is increased or decreased while the resolution or the number of simultaneous colors is increased or decreased, that is, while the required capacity of the frame buffer 81 is increased or decreased. It does not matter.

[0087]

As is apparent from the above description, according to the present invention, the following effects can be obtained. (1) The available capacity allocated to each shared buffer can be increased or decreased according to the capacity required by each shared buffer for an image to be displayed on the display, so that the memory area for displaying images is efficiently utilized. be able to.

(2) By reducing the number of pixels required for display on the display in accordance with the required display area of the display, the required capacity of the frame buffer and the Z buffer can be reduced, thereby increasing the usable capacity of the texture buffer. This makes it possible to map high-quality textures to polygons.

(3) The required capacity of the frame buffer and the Z buffer is reduced by shortening the required bit length for one pixel of the display in accordance with the required simultaneous color development number of the display and the required depth determination accuracy. Since it is possible to increase the usable capacity of, high-quality textures can be mapped to polygons.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an image generation device according to the present invention.

FIG. 2 is a flowchart showing a control flow of buffer variable control performed on a VRAM from a control unit.

FIG. 3 is a diagram conceptually showing a buffer sharing ratio in a VRAM corresponding to the first embodiment.

FIG. 4 is a diagram conceptually showing a buffer sharing ratio in a VRAM corresponding to the second embodiment.

FIG. 5 is a diagram conceptually showing a sharing ratio of each buffer in a VRAM according to a third embodiment.

FIG. 6 is a diagram conceptually showing a sharing ratio of each buffer in a VRAM according to a fourth embodiment.

FIG. 7 is a diagram illustrating an example of an outdoor stage in which a required bit length of a Z buffer for one pixel of a display is set to 32 bits.

FIG. 8 is a diagram showing an example of an indoor outdoor stage in which a required bit length of a Z buffer for one pixel of a display is set to 32 bits.

FIG. 9 is a diagram illustrating an example of an attract screen before a game in which a required bit length of a Z buffer for one pixel of a display is set to 8 bits.

FIG. 10 is a diagram showing an example of an indoor stage in a room where a required bit length of a Z buffer for one pixel of a display is set to 16 bits.

FIG. 11 is a diagram illustrating a three-dimensional calculation process in the image generation device.

[Explanation of symbols]

 Reference Signs List 1 control unit 8 VRAM (memory area) 11 main processor 81 frame buffer 82 Z buffer 83 texture buffer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G06T 17/40 G06T 17/40 E

Claims (27)

[Claims] 1. An image generating apparatus for displaying on a display an image obtained by performing perspective projection conversion of a three-dimensional display object onto a projection plane in a viewpoint coordinate system, wherein the frame stores an image to be displayed on the display. At least two of a buffer, a Z buffer for storing depth information of the three-dimensional display object, and a texture buffer for storing texture data used for texture mapping.
An image generating apparatus comprising a shared memory area and a variable capacity assigned to these shared buffers. 2. The image generating apparatus according to claim 1, wherein a capacity allocated to each shared buffer can be changed according to a required number of pixels for display display. 3. The image generating apparatus according to claim 1, wherein a capacity allocated to each shared buffer can be changed according to a required bit length for one pixel of the display. 4. The image generation apparatus according to claim 3, wherein the required bit length is a required value for the depth information. 5. The image generation apparatus according to claim 3, wherein the required bit length is a required value for the number of simultaneous colors. 6. A game device provided with the image generation device according to claim 1, wherein the three-dimensional display object is a character and an object appearing in a game. A game device characterized in that the allocated capacity is variable according to the progress of the game. 7. The capacity allocated to the shared buffer can be changed when any of the image display area on the display, the number of simultaneous colors, and the accuracy of determining the depth between three-dimensional display objects changes. 7. The game device according to claim 6, wherein: 8. The game device according to claim 6, wherein the capacity allocated to the shared buffer can be changed at the time of stage switching or scene switching. 9. The capacity allocated to the shared buffer is determined when an attract screen is displayed before starting a game, when a character is selected after starting a game, when a scene is shifted from an indoor stage to an outdoor stage in an indoor room, or vice versa. 7. The game device according to claim 6, wherein the change can be made at the time of a scene transition from the stage to the outdoor stage or vice versa. 10. An image generation method for displaying on a display an image obtained by performing perspective projection transformation of a three-dimensional display object onto a projection plane in a viewpoint coordinate system, wherein the frame stores an image to be displayed on the display. At least two of a buffer, a Z buffer for storing depth information of the three-dimensional display object, and a texture buffer for storing texture data used for texture mapping.
An image generation method, wherein a memory area is shared and the capacity allocated to these shared buffers is variably controlled. 11. The image generation method according to claim 10, wherein a capacity allocated to each shared buffer is variably controlled according to a required number of pixels for display display. 12. The image generation method according to claim 10, wherein a capacity allocated to each shared buffer is variably controlled according to a required bit length for one pixel of the display. 13. The apparatus according to claim 1, wherein the required bit length is set to a required value for the depth information.
2. The image generation method according to 2. 14. The image generation method according to claim 12, wherein the required bit length is set to a required value for the number of simultaneous colors. 15. The image generation method according to claim 10, wherein the three-dimensional display object is a character and an object appearing in a game. An image generation method, wherein the image generation method is variably controlled in response to the request. 16. The apparatus according to claim 1, wherein a capacity to be allocated to the shared buffer is variably controlled when any one of an image display area on a display, the number of simultaneous colors, and a depth determination accuracy between three-dimensional objects changes. Item 16. The image generation method according to Item 15. 17. The image generation method according to claim 15, wherein the capacity allocated to the shared buffer is variably controlled at the time of stage switching or scene switching. 18. The capacity allocated to the shared buffer may be changed when an attract screen is displayed before a game is started, when a character is selected after a game is started, when a scene is shifted from an indoor stage to an outdoor stage indoors, or vice versa. 16. The image generating method according to claim 15, wherein the variable control is performed when a scene is shifted from a stage to an outdoor stage or vice versa. 19. A computer-readable recording medium which records a program for displaying an image obtained by performing perspective projection transformation of a three-dimensional display object on a projection plane of a viewpoint coordinate system on a display, wherein: At least two of a frame buffer for storing an image to be displayed, a Z buffer for storing depth information of the three-dimensional display object, and a texture buffer for storing texture data used for texture mapping.
A recording medium having a common memory area and variably controlling a capacity allocated to the shared buffer. 20. The method according to claim 19, further comprising the step of variably controlling a capacity allocated to each shared buffer in accordance with a required number of pixels for display display.
The recording medium according to the above. 21. The recording medium according to claim 19, further comprising a step of variably controlling a capacity allocated to each shared buffer according to a required bit length for one pixel of a display. 22. The recording medium according to claim 21, further comprising a step of setting the required bit length to a required value for the depth information. 23. The recording medium according to claim 21, further comprising a step of setting the required bit length to a required value for the number of simultaneous colors. 24. The recording medium according to claim 19, wherein the three-dimensional display object is a character and an object appearing in a game, wherein a capacity allocated to each shared buffer is determined according to a game progress situation. Characterized by comprising a step of variably controlling the recording medium. 25. A step of variably controlling a capacity to be allocated to the shared buffer when any one of an image display area on a display, the number of simultaneous colors, and a depth determination accuracy between three-dimensional display objects changes. 25. The recording medium according to claim 24, wherein: 26. The recording medium according to claim 24, further comprising a step of variably controlling a capacity allocated to said shared buffer at the time of stage switching or scene switching. 27. The capacity allocated to the shared buffer is determined when an attract screen is displayed before starting a game, when a character is selected after starting a game, when a scene is shifted from an indoor stage to an outdoor stage indoors, or vice versa. 25. The recording medium according to claim 24, further comprising a step of variably controlling when a scene is shifted from a stage to an outdoor stage or vice versa.