JP2001052198A - Device and method for generating image and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for generating image with which plotting processing of the next polygon can be immediately started when a polygon to be plotted does not include a non-plotting pixel and to provide a recording medium. SOLUTION: A non-plotting pixel-including flag is provided for showing whether the pixel of non-plotting is included or not for the unit of a polygon or the like and in the beginning of plotting processing, it is judged whether the non-plotting pixel-including flag is 'non-including' or not. When the non- plotting pixel-including flag is 'non-including', since it is not necessary to wait the judgement of whether a certain pixel is non-plotting or not, processing such as reference of a Z buffer and processing such as reference of a texture memory can be parallel executed and three-dimensional plotting processing can be executed at high speed.

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, method, and recording medium, and more particularly, to an image generating apparatus, method, and recording medium in a case where a polygon includes non-rendered pixels.

[0002]

2. Description of the Related Art For example, in a three-dimensional game device or the like that generates a three-dimensional image, various arithmetic processes such as a coordinate conversion process are performed in order to form a three-dimensional image that can be viewed from a predetermined viewpoint in a virtual three-dimensional space. I do. The object constituting the virtual three-dimensional space is represented by a plurality of polygons, and when there is an overlap between the plurality of polygons, a hidden surface portion in the back from the viewpoint is deleted, and a portion in the foreground is deleted. Is used in the drawing. Conventionally, a method using a Z buffer has been used for erasing the hidden surface portion.

As a method of using a conventional Z-buffer in a three-dimensional drawing process, there is a method of erasing a hidden surface using a Z-buffer. Here, the Z buffer is a storage device having a storage area corresponding to each pixel on the display screen, and each storage area stores depth information (Z value) indicating a distance from a viewpoint. Generally, the maximum value of the Z value is written in the Z buffer as an initial value, and the Z value corresponding to a pixel of a certain polygon is written in a storage area on the corresponding Z buffer. , The Z value corresponding to the pixel is set to be small. Conversely, a polygon closer to the viewpoint may be set to have a larger Z value corresponding to the pixel. When a certain pixel is updated, the Z value (old Z value) corresponding to this pixel is referred to, compared with the Z value (new Z value) to be newly drawn for this pixel, and viewed from the viewpoint. When the new Z value is before the old Z value, the priorities are correctly reflected in the drawing by updating the old Z value with the new Z value.

FIG. 3 shows a virtual three-dimensional space for explaining a case where a polygon to be drawn includes non-drawn pixels which are completely transparent. In FIG.
00 is a polygon A representing a part of a tree or the like in a virtual three-dimensional space, 303 is a completely transparent non-drawing part included in the polygon A300, and 305 is a polygon A30
307, a part of a leaf or the like which is not a non-drawing included in 0
Reference numerals 308 and 309 denote completely transparent non-drawing portions such as gaps between trees scattered in the non-drawing portion 305 of the polygon A300, and reference numeral 310 denotes a tree or the like behind the polygon A300 in the virtual three-dimensional space. Polygons B and 313 representing a part are completely transparent non-drawing parts included in the polygon B310, and 315 is a polygon B310
340 is a screen that displays a virtual three-dimensional space in two dimensions, 32
0 is the polygon A30 displayed on the screen 340
0 and 330 are polygons B displayed on the screen 340, XYZ coordinates are coordinates in a virtual three-dimensional space, ZA is a value on the Z axis indicating the depth of the polygon A300 from the screen 340, and ZB is a screen of the polygon B310. 34
This is a value on the Z axis indicating the depth from 0.

FIG. 4 shows a Z buffer 400 in a virtual three-dimensional space including the polygon A300 shown in FIG.
In FIG. 4, Z buffer 400 has a Z
A value, for example, a value on the Z axis is stored, and a maximum value M of the Z value is written as an initial value. The coordinates XY are shown in FIG.
Of the coordinates XYZ of the two-dimensional coordinates X of the screen 340
Corresponds to Y. In FIG. 4, reference numeral 410 denotes an area in which the Z value corresponding to the polygon A300 in FIG. 3 is stored and is surrounded by a dotted line, and reference numeral 420 denotes the Z value corresponding to the polygon B310 in FIG. The area is indicated by a dotted line. A ₁ , A _2, etc. are Z values indicating the depth of the polygon A 300, and B ₁ , B _2, etc. are Z values indicating the depth of the polygon B 310. The non-drawing portion 303 of the polygon A300 shown in FIG. 3 has the Z value set to M or B1 in FIG.
Viewed from the 40 side, polygon B overlapping background or back
It is shown that the drawing portion of 310 is visible. The Z value corresponding to the non-rendered portion 307, 308 or 309 such as the gap between the leaves of the tree of the polygon A300 shown in FIG.
In 407 (Z value B _9), 408 (Z value B ₁₀₎ or 409 (Z value B _{1 1)} are indicated by like, when viewed from the screen 340 side, the non-imaging portion such as a gap between the leaves 30
Polygon B310 behind 7, 308 or 309
It is shown that the drawing portion of can be seen.

FIG. 5 is a flowchart showing a process in the case where a polygon includes non-drawn pixels in the conventional image generation method. In FIG. 5, a polygon drawing start process is performed as an initial setting (step S100). Next, a Z buffer reference process surrounded by a dotted line is performed (step S160). That is, the XY coordinates on the screen 340 for the pixel to be drawn in the polygon are calculated (step S105), and the corresponding Z value (old Z value) on the Z buffer 400 is referred to using the calculated XY coordinates. (Step S110). The old Z value and the new Z value to be drawn (new Z value) are compared to determine which Z value is closer, for example, which Z value is smaller (step S115). If the new Z value is nearer, texture memory reference processing surrounded by a dotted line is performed (step S170). That is, texture coordinates corresponding to the pixel to be drawn are calculated (step S12).
0), and refer to the corresponding texture memory using the calculated texture coordinates (step S125). By referring to this texture memory, the opacity for each pixel is determined. Here, the opacity is a kind of parameter that takes a value from 0 to 1 indicating the opacity of the pixel. The opacity takes a value of 0 when the pixel is completely transparent and a value of 1 when the pixel is completely opaque. Take. The opacity for each pixel can be determined in consideration of other parameters, for example, the opacity in units of polygons and the opacity of the whole. If the pixel is ultimately completely transparent,
That is, if the opacity is 0, it is understood that the pixel is a non-drawing pixel. Then, it is determined whether or not the drawing is non-drawing (step S135). If the drawing is not non-drawing, drawing is performed on a frame buffer mainly storing color information other than the Z value (step S14).
0). In this case, for example, color calculation such as shading, translucent processing, and the like can be performed. The old Z value in the Z buffer is updated with the new Z value (step S145). It is determined whether all the polygons have been drawn (step S).
150), if not over yet, step S105
Return to and repeat. When the drawing is completed, it is determined whether or not to draw another polygon (step S155). When drawing is still to be performed, the process returns to step S100 and repeats. In step S115, if the part to be drawn is not the near side,
In other words, if it is hidden behind, there is no need to draw, and the process branches to step S150. If it is determined in step S135 that the pixel is not drawn, the flow branches to step S150 because drawing is not necessary. If there is no other polygon to be drawn, the process ends.

As described above, when the polygon to be drawn includes non-drawn pixels that are completely transparent, in order to correctly reflect the priority of drawing the pixel in front, the non-drawn pixel portion must be Corresponding Z
The buffer cannot be updated. On the other hand, if the polygon to be drawn does not include a completely transparent, non-drawn pixel, the corresponding Z buffer can be updated.
Therefore, in either case, it is necessary to determine whether or not the pixel to be rendered is non-rendered after the opacity is obtained by referring to the subsequent texture. An update had to be made.

[0008]

As described above, in the conventional three-dimensional drawing processing, it is determined whether or not a pixel to be drawn is non-drawn after the opacity is obtained by referring to the subsequent texture. Had to be done. Until this determination is made, it cannot be determined whether or not to update the Z buffer. Therefore, even if the polygon to be drawn does not include a non-drawing pixel, it is not possible to immediately proceed to the next polygon drawing processing. There was a problem. Accordingly, an object of the present invention is to solve the above-described problem, and it is desirable to set at least information indicating whether or not a non-drawing pixel is included in a size in a polygon unit so that drawing is performed. An object of the present invention is to provide an image generating apparatus, method and recording medium which can immediately proceed to the next polygon drawing process when the polygon does not include a non-drawn pixel.

[0009]

According to a first aspect of the present invention, there is provided an image generating apparatus for rendering a three-dimensional image, wherein the Z buffer stores information indicating the depth of the polygon to be rendered from the viewpoint. And flag means for indicating whether or not the polygon to be drawn includes a pixel which is not drawn; and when the flag means indicates that the polygon to be drawn does not include a pixel which is not drawn, the Z corresponding to the pixel of the polygon to be drawn. And a parallel processing means for concurrently executing reference to an area on the buffer and reference to a texture corresponding to a pixel of a polygon to be drawn.

According to a second aspect of the present invention, in the first aspect of the present invention, the flag means indicates whether or not a pixel which is not drawn in an object unit composed of a plurality of polygons is included. it can.

According to a third aspect of the present invention, there is provided an image generating method comprising:
An image generation method for drawing a two-dimensional image, comprising: a step of storing information indicating a depth of a polygon to be drawn from a viewpoint in a Z buffer; and a flag for setting a flag as to whether or not the polygon to be drawn includes a pixel which is not drawn. In the step, if the flag indicates that the polygon to be drawn does not include a pixel to be drawn in the flag step, the reference to the area on the Z buffer corresponding to the pixel of the polygon to be drawn and the pixel of the polygon to be drawn And a parallel processing step of executing the reference of the texture to be performed in parallel.

A recording medium according to a fourth aspect of the present invention is a computer-readable recording medium recording a program for executing the image generating method according to the third aspect.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 FIG. 1 is a block diagram schematically illustrating an image generating apparatus according to Embodiment 1 of the present invention.
In FIG. 1, reference numeral 110 denotes a CPU unit that outputs image data of a polygon object or the like and instructs image processing. For example, in the case of a game device or the like, the CPU unit controls the flow of the entire game and instructs image processing during game execution. CPU unit 120 performs C
An image operation unit 180 that performs an image operation based on the image data output from the PU unit 110 and an image processing instruction, 180
Is an image display unit such as a display for displaying an image under the control of the drawing control unit 140, and 100 is based on the image data output from the CPU unit 110 and an instruction for image processing.
This is a drawing processing unit that performs processes such as hidden surface processing and texture mapping. As shown in FIG. 1, the drawing processing unit 100 includes a drawing control unit 140 that controls the entire drawing process based on the image data output from the image calculation unit 120, and a Z buffer that stores a Z value indicating the depth for each pixel. 13
0, the frame buffer 15 mainly storing color information other than the Z value corresponding to each pixel on the image display unit 180
0, a texture memory 160 which stores a texture which is an original picture used for texture mapping for each pixel (texel).

FIG. 2 is a flowchart showing the processing of the image generation method of the present invention. An outline of the processing according to the first embodiment of the present invention will be described with reference to FIG.
A non-drawing pixel containing flag is set which indicates whether or not the drawing includes a pixel that is completely transparent.
A flag may be set to indicate whether or not a non-rendered portion is contained in an object unit composed of a plurality of polygons instead of a polygon unit. Set the non-drawing pixel containing flag to "contain" if non-drawing, that is, contain pixels that are completely transparent, in units such as polygons, otherwise set the non-drawing pixel containing flag to "non-contained". Set to. If the non-rendered pixel content flag is “contained”, the texture memory is referred to in the same manner as in the conventional rendering process, and then, as a result of a color operation or the like, it is determined whether or not the pixel is a non-rendered pixel. , Update the Z-buffer if it is not non-drawing.
Then, when the processing of one polygon is completed, the processing shifts to the processing of the next polygon. When the non-drawing pixel containing flag is “not including”, Z is immediately determined because Z does not become non-drawing.
Move to buffer update processing. Therefore, it is possible to immediately proceed to the processing of the next polygon.

Hereinafter, the flowchart shown in FIG. 2 will be described in detail. In FIG. 2, a first point different from the conventional processing is that, after the polygon drawing start processing (step S100), it is determined whether or not the above-described non-drawing pixel containing flag is “non-containing” (step S200). Is the point where If the non-drawing pixel inclusion flag is “contained”, the same processing as the conventional processing (from step S105 to step S105)
155). Step S100, Step S10
Steps S5 to S155 are the same as the conventional processing shown in the flowchart of FIG.

The second point different from the conventional processing is that when the non-rendered pixel containing flag is "not included", the Z buffer corresponding to step S160 when the containing flag is "contained" is referred to. Processing (Steps S205, S21)
0) and step S1 when the content flag is “content”
The processing (steps S220 and S225) such as reference to the texture memory corresponding to step S70 is performed in parallel (step S220).
203). Z corresponding to step S160
In processing such as buffer reference, pixel coordinates are calculated (step S205), and a Z buffer corresponding to the calculated pixel coordinates is referred to (step S210). On the other hand, in processing such as reference to the texture memory corresponding to step S170, texture coordinates are calculated (step S170).
220), refer to the texture memory corresponding to the calculated texture coordinates (step S225). After the parallel processing (the processing corresponding to step S160 and step S170) is completed, the new Z value is compared with the old Z value to determine whether or not the pixel to be drawn is on the near side (step S255). If so, the process branches to step S140, and if not, the process branches to step S150.

As described above, according to the first embodiment, a non-drawing pixel containing flag is provided to indicate whether or not a non-drawing pixel is contained in a unit such as a polygon, and the non-drawing pixel flag is provided at the beginning of the drawing process. It can be determined whether or not the pixel inclusion flag is “not included”. When the non-drawing pixel inclusion flag is “not including”, there is no need to wait for the determination of whether or not a certain pixel is non-drawing, so processing such as reference to the Z buffer and processing such as reference to the texture memory Can be executed in parallel, and the three-dimensional drawing processing can be executed at high speed.

Embodiment 2 A recording medium storing a computer program for realizing the functions of the first embodiment described above is supplied to the image generating apparatus of the present invention, and the computer (CPU unit 110 in FIG. 1) of the image generating apparatus is stored in the recording medium. Needless to say, the object of the present invention can be achieved by reading and executing the computer program. In this case, the recording medium is the CPU 110
Is input / output from a recording medium input / output unit (not shown) connected to the PC. In this way, the computer program itself read from the recording medium realizes the novel function of the image generating apparatus of the present invention, and the recording medium on which the computer program is recorded constitutes the present invention. Become. Examples of the recording medium on which the computer program is recorded include a CD-ROM, a floppy disk,
A hard disk, a ROM, a memory card, an optical disk, or the like can be used.

As described above, according to the second embodiment, a recording medium on which a computer program for realizing the functions of the first embodiment is recorded is supplied to the image generating apparatus of the present invention, and the computer (non- (Illustration) reads and executes a computer program stored in a recording medium, thereby achieving the object of the present invention.

[0021]

As described above, according to the image generating apparatus, method, and recording medium of the present invention, a non-drawing pixel containing flag indicating whether or not a non-drawing pixel is included in at least a polygon unit. By setting the above information, it is possible to provide an image generating apparatus, a method and a recording medium that can immediately proceed to the next polygon drawing process when the polygon to be drawn does not include a non-drawn pixel. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically illustrating an image generation device according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating a process of an image generation method according to the present invention.

FIG. 3 is a diagram illustrating a virtual three-dimensional space for explaining a case where a polygon to be drawn includes a completely transparent non-drawn pixel.

FIG. 4 is a diagram showing a virtual 3 including the polygon A300 in FIG.
FIG. 3 is a diagram illustrating a Z buffer 400 in a dimensional space.

FIG. 5 is a flowchart showing a process performed when a polygon includes non-drawn pixels in a conventional image generation method.

[Explanation of symbols]

100 drawing processing unit, 110 CPU unit, 120
Image operation unit, 130, 400 Z buffer, 140
Drawing control unit, 150 frame buffer, 160
Texture memory, 180 image display, 30
0 polygon A, 303, 307, 308, 309,
313 non-drawing part, 305, 315 drawing part,
310 polygon B, 320 polygon A on screen 340, 330 polygon B on screen 340, 340 screen, 407, 408, 409
410Z, where the polygon A is not drawn on the Z buffer
Polygon A area on buffer, 420 polygon B area on Z buffer.

Claims (4)

[Claims] 1. An image generating apparatus for rendering a three-dimensional image, comprising: a Z buffer storing information indicating a depth of a polygon to be rendered from a viewpoint; and indicating whether or not the polygon to be rendered includes pixels which are not rendered. Flag means; and if the flag means indicates that the polygon to be drawn does not include a pixel to be drawn, reference to an area on the Z buffer corresponding to the pixel of the polygon to be drawn and texture corresponding to the pixel of the polygon to be drawn. And a parallel processing means for executing the reference in parallel. 2. The image generating apparatus according to claim 1, wherein
An image generating apparatus according to claim 1, wherein said flag means indicates whether or not a pixel which is not drawn in an object unit composed of a plurality of polygons is included. 3. An image generation method for drawing a three-dimensional image, comprising: storing information indicating a depth of a polygon to be drawn from a viewpoint in a Z buffer; and determining whether the polygon to be drawn includes pixels not drawn. A flag step of setting a flag as a flag, and, in the flag step, when the flag indicates that the polygon to be drawn does not include a pixel that is not drawn, referencing and drawing an area on the Z buffer corresponding to the pixel of the polygon to be drawn A parallel processing step of concurrently executing a reference to a texture corresponding to a pixel of a polygon to be processed. 4. A computer-readable recording medium on which a program for executing the image generating method according to claim 3 is recorded.