JP2003281554A - Drawing device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a processing at high speed, when writing an image to a frame buffer by use of a mask memory, to reduce the power consumption. <P>SOLUTION: An image designated by a mask memory 21 is written in a frame buffer A, and reading of a frame buffer B is performed (a). The reading of the frame buffer A is then performed, and the writing in the frame buffer B is performed (b). When a clear area 24 is designated in the mask memory 21 in (c), an image having a corresponding clear area 31 is written in the frame buffer A, and the reading of the frame buffer B is performed. Thereafter, the writing and reading of the frame buffers A and B are performed (d) and (e). During this, the clear areas 31 are present in the written images and the displayed images, and two frame images have the same background. Accordingly, writing of an image to be updated can be performed only to the clear areas 24 and 31 of the mask memory 21 and the frame buffers. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing device and a drawing method for writing an image on a frame buffer.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram schematically showing a conventional drawing apparatus for writing an image on a frame buffer. Here, a case where a sprite is written as a drawing target image will be described. A sprite is a unit of a picture such as an animation in a computer game or the like, and a display portion and a background portion are usually drawn in a rectangle.

In FIG. 6, the sprite data is read from the sprite buffer A, enlarged, reduced, rotated, etc. are processed by the drawing engine 1 and then written into the frame buffer 3 via the mask arithmetic unit 2. During this time, the next sprite data is written to the sprite buffer B, and when the writing of the sprite buffer A to the frame buffer 3 is completed, the sprite buffer B is read and the sprite data is written to the drawing engine 1. The next sprite data is further written in the sprite buffer A.

In this way, the sprite buffer A,
Sprite data is written to and read from B alternately, and the read sprite data is written to the drawing engine 1
After being processed in (1), it is drawn by being written in the frame buffer 3 via the mask arithmetic unit 2. The frame buffer 3 has two frame buffers A and B (not shown) so that writing and reading are alternately performed, and the read sprite data is sent to a display device and displayed. .

The mask arithmetic unit 2 has a mask memory 21. In the mask memory 21, 1-bit data corresponding to each pixel (pixel) on the frame buffer 3 is written for a display pixel. This 1-bit data indicates with 1 or 0 whether or not the pixel contributes to the formation of an image to be written. Therefore, 1 or 0 data is written in the mask memory 21 by the total number of pixels. From the drawing engine 1, the address on the frame buffer of the sprite to be written and the pixel data at each address are calculated by the mask calculation device 2
Sent to.

The mask operation device 2 writes 1-bit data for each pixel in the mask memory 21 based on the address and the pixel data sent. Then, the mask arithmetic unit 2 controls writing of the pixel data into the frame buffer 3 based on the data in the mask memory 21. Writing is performed by a writing control device (not shown) in the mask operation device 2.

[0007]

In the above-mentioned conventional drawing apparatus, the mask memory 21 and the frame buffer 3 are used.
Is cleared and updated for each frame, but at this time, the data of the stationary portion such as the background is also rewritten. That is, since the same data is written twice in the still part of the image, high-speed processing is hindered and power consumption is wasted.

The present invention has been made to solve the above problems, and it is an object of the present invention to reduce the overhead of writing time of a mask memory and a frame buffer and power consumption so that efficient drawing can be performed. .

[0009]

In order to achieve the above object, a drawing apparatus according to the present invention is designed so that pixels of an image written in a frame buffer are designated by data written in a mask memory. In the image input means, an image input means for inputting an image to be written in the frame buffer, a setting means for setting a clear area in the mask memory, and a mask memory having a clear area set by the setting means are used. A writing control means is provided for writing the input image to the frame buffer and updating only the image of the portion corresponding to the clear area.

In the drawing method according to the present invention, the pixels of the image written in the frame buffer are designated by the data written in the mask memory, and a clear area is set in the mask memory and set. The input image is written in the frame buffer by using the mask memory having the clear area, and at that time, only the image of the portion corresponding to the clear area is updated.

[0011]

According to the present invention, therefore, the clear area is first set in the mask memory, and the input image is written in the frame buffer based on the mask memory having the clear area. By updating only the image of the portion corresponding to the area, it is not necessary to update the image of the stationary portion such as the background other than the clear area, and the drawing process can be speeded up.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a drawing device according to an embodiment of the present invention. In order to solve the above-described problem, the present embodiment does not clear the entire mask memory, but clears only a part of the image that needs to be updated, so that the cleared part is updated without updating the background or the like. It is intended to update only. Therefore, unnecessary writing can be omitted and the drawing process can be speeded up.

Clearing of the mask memory can be realized by mounting hardware having a drawing function dedicated to the mask memory, in which 1 bit always corresponds to 1 pixel. The mask memory stores "1" for pixels to be actually drawn and "0" for pixels not to be drawn. Therefore, it has a capacity of the same number of bits as the number of target pixels.

FIG. 1 is a block diagram showing a drawing apparatus having the above-mentioned function according to the present embodiment. In the present embodiment, as shown in the figure, a mask clear drawing device 4 is connected to the mask calculation device 2 and a mask clear control device 5 for controlling the mask clear drawing device 4 is provided.

FIG. 2 is a block diagram showing the configuration of the mask clear control device 5, which includes an interface 51 and a clear area table 52. The interface 51 is
Upon receiving a signal designating a clear area input from the outside, the clear area table 52 holds the address of the designated clear area.

FIG. 3 shows an example of designated clear areas 22 and 23 in the mask memory 21 in the mask arithmetic unit 2. (XLT1, YLT1) (XLT2, YLT2) indicates the coordinates of the upper left part of the rectangular area to be cleared in the clear area 22, and (XRB1, YRB1
1) (XRB2, YRB2) indicates the coordinates of the lower right part of the rectangular area to be cleared in the clear area 23. Therefore, by changing these coordinates, the shape, size, position, number, etc. of the clear area can be changed. When controlling the writing to the frame buffer 3, the portions other than these clear areas 22 and 23 of the mask memory 21 are not cleared.

The mask clear drawing device 4 has a function equivalent to that of a normal frame buffer drawing device.
Further, in the mask memory 21, one pixel always corresponds to one bit, and the function only for that purpose is sufficient.

Next, referring to FIG.
This will be described with reference to (a) to (e). First, as shown in (a), an image in which pixels are designated by the mask memory 21 is written in the frame buffer A in the frame buffer 3. Writing is performed via a writing control device (not shown) in the mask arithmetic unit 2. During this period, the frame buffer B is read and the image is displayed. When the reading is completed, the frame buffer A is read as shown in FIG.
The image designated by the mask memory 21 is written in.

Next, the mask clear control device 5 specifies the coordinates of the clear region to the mask clear drawing device 4, and based on this, the clear region 24 is set on the mask memory 21 as shown in (c), The clear area 24 is cleared and 1 or 0 designating a pixel of the sprite data is written. Then, in the frame buffer A, a clear area 31 corresponding to the clear area 24 is set, and an image is written only in this clear area 31. During this period, the frame buffer B is being read. After that, as shown in (d) and (e), the frame buffer A,
B writing and reading are alternately performed, and during this period, the clear area 31 is included in the written image and the displayed image.
Exists. The backgrounds of the two frame images are the same. Although the clear area 24 is supposed to be cleared, it may be overwritten.

Therefore, the clear area 2 of the mask memory 21
4 and the clear area 31 of the frame buffer 3 only needs to write the data of the image to be updated, and the process of writing the data of the still portion such as the background every time the frame changes can be omitted.

This embodiment is effective, for example, when writing the sprite 6 which exceeds the size of the clear area 24 in the mask memory 21, as shown in FIG. That is, the part of the sprite 6 beyond the clear area 24 is masked, so that part is not written,
The background is not damaged.

[0022]

As described above, according to the present invention, when controlling writing of an image into the frame buffer using the mask memory, a clear area is set in the mask memory and only the clear area is updated. By doing,
Since it is not necessary to update the still area such as the background other than the clear area, it is not necessary to update only the clear area in the frame buffer, and to write the rest area such as the background twice. Therefore, processing can be performed at high speed, and power consumption and the like can be reduced.

The clear area has its size, shape,
The position, the number, etc. can be variously changed. Also, when writing a sprite that exceeds the clear area,
Sprites can be drawn in a clear area of a predetermined size, and the background and the like can be prevented from being damaged.

[Brief description of drawings]

FIG. 1 is a block diagram showing a drawing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the mask clear controller of FIG.

3 is a configuration diagram showing the mask memory of FIG. 1. FIG.

FIG. 4 is a configuration diagram showing a write operation according to the embodiment of the present invention.

FIG. 5 is a configuration diagram illustrating how to write a sprite in a mask memory.

FIG. 6 is a block diagram showing a conventional drawing apparatus.

[Explanation of symbols]

1: Drawing engine, 2: Mask calculation device: 3: Frame buffer, 4: Mask clear drawing device, 5: Mask clear control device, 6: Sprite, 21: Mask memory, 2
2, 23, 24, 31: clear area, 51: interface, 52: clear area table

Claims (8)

[Claims] 1. A drawing apparatus in which pixels of an image written in a frame buffer are designated by data written in a mask memory, and image input means for inputting an image to be written in the frame buffer, and the mask memory An image input from the image input unit is written into the frame buffer by using a setting unit for setting a clear area and a mask memory having the clear area set by the setting unit. A drawing device provided with a write control means for updating only an image of a corresponding portion. 2. The size, shape, position of the clear area,
The drawing apparatus according to claim 1, further comprising a clear area changing unit that changes the number of the clear areas. 3. The drawing apparatus according to claim 1, wherein the image input unit inputs a sprite, and the writing control unit writes the sprite in the clear area. 4. The data written in the mask memory is one bit, wherein the data is one bit.
The described drawing device. 5. A drawing method in which pixels of an image written in a frame buffer are designated by data written in a mask memory, wherein a clear area is set in the mask memory, and a mask having the set clear area is set. A drawing method characterized in that an image inputted using a memory is written into a frame buffer, and at that time, only an image of a portion corresponding to the clear area is updated. 6. The clear area has a size, a shape,
6. The position and number can be changed.
The described drawing method. 7. The drawing apparatus according to claim 5, wherein the input image is a sprite, and the sprite is written in the clear area. 8. The data written in the mask memory is 1 bit, 5.
The described drawing device.