JPH07182534A - Three-dimensional computer graphics system - Google Patents

Abstract

PURPOSE:To provide the three-dimensional computer graphics system which enables plotting by preparing the capacity of a VRAM just for pictures. CONSTITUTION:Three-dimensional model data are called from a recorder 1 and written in a memory 2. The coordinate is transformed at a coordinate transforming part 3 by applying affine transformation and perspective transformation to a display coordinate system, and those data are written in the memory 2 again. The Y direction of the display coordinate system (the longitudinal direction of a picture) is sorted by a sorting part 4 and recorded in a memory 5. At a picture managing part 6, the address information of a VRAM 7 is provided from a display control part 8 just calling the VRAM 7 for present indication. A division inspecting part 9 investigates whether it is necessary to perform polygon division concerning the upper data of the sorted data, plotting processing is performed by a plotting processing part 10 and texture mapping is performed by calling texture data from a texture data memory 13 by a texture processing part 12 as needed. When it is not necessary to perform the division, the data are stored in the VRAM 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional computer graphics system capable of interactive processing.

[0002]

2. Description of the Related Art Conventionally, in a three-dimensional computer graphic system capable of interactive processing, there is a problem of processing speed, and the appearance order of polygon data forming a three-dimensional model is not constant due to the conditions at the time of drawing. Therefore, the VRAM for image display has a double buffer structure.

In a normal TV or the like, image data is always transferred sequentially, and there is no problem in display when accessing the VRAM unless the write address exceeds the read address, and the capacity of the VRAM is the same as the screen display. If there was no problem.

However, the above-described three-dimensional computer graphics system capable of interactive processing requires complicated and slow calculation such as coordinate conversion processing from the coordinates of the three-dimensional model to the display coordinate system and light source calculation. However, the drawing is not always completed within the display time of the standard frame.

Even if there are many three-dimensional models to be displayed and the appearance order is sorted from the upper left to the lower left of the screen first, the order may change due to the movement of the viewpoint. Here, when the capacity of the VRAM is only for the screen, there is a problem that the area to be written for drawing cannot be written because the call from the VRAM for display has not been completed. This was not a problem that could be solved even if the system processing became faster.

[0006]

As described above, according to the conventional three-dimensional computer graphics system,
VR due to processing speed and model drawing order
There is a drawback that the AM has twice the screen capacity and it is necessary to draw while switching by the double buffer method. Further, even if the processing speed of the CPU becomes high, there is a problem that the drawing order becomes a problem, and the capacity of the VRAM requires two screens.

Therefore, the present invention eliminates the above-mentioned drawbacks, and
An object of the present invention is to provide a three-dimensional computer graphics system capable of drawing by preparing a RAM capacity for the screen.

[0008]

In order to achieve the above object, according to the present invention, means for storing model information composed of polygons, and coordinates for converting to a display coordinate system based on the model information. Conversion calculation means, brightness calculation means for calculating the brightness of each vertex of the polygon, geometry calculation means having the brightness calculation means, and rendering means for rendering the polygon according to the calculation result of the geometry calculation means. , A sorting means for sorting the model information in the display coordinate system, a screen dividing means for dividing the display screen into a plurality of parts, and a VRAM corresponding to the display screen divided by the dividing means for displaying the screen already. Determine whether it is possible to write pixel data obtained from the new polygon after reading is completed Determining means, if the result of the determining means is possible, means for writing in the VRAM the pixel data that can be drawn from the result of the sorting means, and the polygon forming the model is divided by the screen dividing means. When the display screen is displayed, the polygon is divided inside the computer to newly generate the polygon, and when texture is mapped to the polygon, the polygon is newly added to the vertex of the polygon. Second generation means for generating the corresponding texture coordinates inside the computer.

[0009]

With this structure, the display screen is divided into a plurality of parts to form a virtual double buffer structure, and the coordinate values of the polygon to be drawn are sorted in advance before being displayed. The display order can be arranged, and even if the capacity of the VRAM is made equal to the double-sided size, sequential drawing can be performed as in the conventional TV. This can reduce the cost of the entire system.

[0010]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a three-dimensional computer graphics system according to an embodiment of the present invention. In FIG. 1, 1 is a recording device for recording three-dimensional model data and the like, 2 is a memory for reading the model data read from the recording device 1, and 3 is the coordinates of the model data using affine transformation and perspective transformation. The coordinate conversion units 3 and 4 for conversion perform sorting in the Y direction, which is the vertical direction of the screen of the display coordinate system, 5 denotes a memory for recording the data sorted by the sorting unit 4, and 6 denotes the address information of the VRAM 7. A screen management unit that manages the display of the screen, and 7 is a VR that records the image to be displayed
AM, 8 is a display control unit that calls the VRAM 7 and controls the display, 9 is a division inspection unit that checks whether or not it is necessary to perform polygon division on the sorted data, 10
Is a drawing processing unit that performs drawing processing such as gentle surface processing and sewing, 11 is a polygon dividing unit that divides polygons,
12 is a texture processing unit for performing texture processing, 13 is a texture data memory for recording texture data,
A CRT 14 displays an image.

Preliminarily recorded three-dimensional model data is called from the recording device 1 and written in the memory 2. Based on this model data, the coordinate transformation unit 3 transforms the display coordinate system using affine transformation and perspective transformation, and rewrites it in the memory 2. Based on this result, the sorting unit 4
At, the sorting is performed in the Y direction (vertical direction of the screen) of the display coordinate system, and the result is recorded in the memory 5.

In the screen management section 6, the VR is displayed for the current display.
The address information of the VRAM 7 is obtained from the display control unit 8 calling the AM 7. For example, when the screen is divided into two, it is determined whether the upper part of the screen is called or the lower part. If the lower part of the screen is called, the division inspection unit 9 checks whether or not the upper data needs to be polygon-divided in the sorted data, and the drawing processing unit 10 determines whether hidden surface processing or shading is performed. Drawing processing is performed, and if texture mapping is necessary, the texture processing unit 12 calls texture data from the texture data memory 13 and performs mapping. If there is no need for division, it is stored in the VRAM 7.

When the polygon data spans the scan lines for screen division, the division inspection unit 9 sends a polygon division instruction to the polygon division unit 11. As shown in FIG. 2, the polygon division unit 11 utilizes yt and the brightness value it of the new division point t from the drawing processing unit 10 by utilizing that one side of the polygon A is parallel to the scan line. , X coordinate value zt is obtained, the vertex t of a new polygon is set, and stored in the memory 5. Here, the divided scan line coordinate value is t-1.

Further, when the texture is attached to the polygon A from the divided coordinate values, the coordinate point d (u, v) corresponding to the coordinate t of the divided point in the texture coordinates of FIG. 3 is obtained. Of the polygons B and C divided from the polygon A, the polygon B has already been drawn. Therefore, when performing texture mapping, the texture processing unit 12 stores the texture data corresponding to the polygon B in the texture data memory. Called from 13, drawing processing unit 1
The drawing processing is performed at 0, and then the texture processing unit 12 performs mapping on the polygon C in the same manner as the polygon B, and stores it in the VRAM 7.

In this embodiment, the screen management unit 6 manages the division of the screen to form a virtual double buffer structure, and further, the coordinate values of polygons to be drawn are sorted in advance before being displayed. Due to
The display order of the images is made uniform, which makes it possible to draw the polygon graphics with only the VRAM for the screen.

FIG. 4 is a block diagram showing the configuration of a three-dimensional computer graphics system according to another embodiment of the present invention. The model data is called from the recording device 20 and written in the memory 21. Based on this data, the coordinate conversion unit 22 performs coordinate conversion using the affine transformation and perspective transformation in the display coordinate system, and writes it in the memory 23. Based on this result, the sorting unit 24 sorts in the Y direction, which is the vertical direction of the screen of the display coordinate system, and stores the result in the memory 25.

In the screen management unit 26, it is checked whether the ideographic control unit 29 calling the VRAM 27 needs to perform polygon division on the upper data for the current display, and the drawing processing unit 30 performs gentle surface processing and shading. Drawing process. If texture mapping is required, the texture processing unit 31 calls texture data from the texture data memory 32 and performs mapping.

If there is no need for division, it is stored in the VRAM 27. As shown in FIG. 5A, polygons A and B
, If they extend over the scan line MN for image division, the division processing unit 29 determines that the adjacent polygons A and B are adjacent to each other.
Look up information in. In addition, adjacent polygons A and B
When the edges are in contact with each other on the side f-h, the polygon is divided as shown in FIG.

Here, as shown in FIG. 2, utilizing the fact that one side of the polygon dividing unit 33 and the polygon A to be divided is parallel to the scan line, yt and a new dividing point t from the drawing processing unit 30 are used. The brightness value It, the X coordinate value Xt, and the Z coordinate value zt are obtained, and the vertex t of the new polygon is set and stored in the memory 25.

Further, from this divided coordinate value, the polygon A
When a texture is pasted on, the coordinate point d (u, v) corresponding to the coordinate t of the division point is obtained in texture coordinates.
Of the polygons B and C divided from the polygon A, the polygon B has already been drawn,
The texture data is called from the texture data memory 32 and the mapping process is performed. After that, the pixel data is stored in the VRAM 27.

In this embodiment, when a texture is attached to a polygon, a coordinate point d is obtained for the coordinate t of the division point and the divided polygons are separately mapped, so that only a VRAM for the screen is prepared. Thus, it is possible to provide a three-dimensional computer graphics system.

[0022]

As described above, according to the present invention, it is possible to provide a three-dimensional computer graphics system capable of drawing polygon graphics only by preparing the capacity of the VRAM for the screen.

[Brief description of drawings]

FIG. 1 is a block diagram showing a three-dimensional computer graphics system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of polygon division in the embodiment shown in FIG.

FIG. 3 is an explanatory diagram of texture coordinate division in the embodiment shown in FIG.

FIG. 4 is a block diagram showing a three-dimensional computer graphics system according to another embodiment of the present invention.

FIG. 5 is an explanatory diagram of optimal division in the embodiment shown in FIG.

[Explanation of symbols]

1 ... Recording device, 2 ... Memory, 3 ... Coordinate conversion unit, 4 ... Sorting unit, 5 ... Memory, 6 ... Screen management unit, 7 ... VRA
M, 8 ... Display control unit, 9 ... Division inspection unit, 10 ... Drawing process, 11 ... Polygon division unit, 12 ... Texture processing unit,
13 ... Texture data memory, 14 ... CRT.

Claims (4)

[Claims] 1. A means for storing model information composed of polygons, a coordinate transformation calculation means for transforming into a display coordinate system based on the model information, and a luminance for performing luminance calculation of each vertex of the polygon. Calculation means, geometry calculation means having the brightness calculation means, rendering means for rendering the polygons according to the calculation result of the geometry calculation means, sorting means for sorting the model information in the display coordinate system, Screen division means for dividing the display screen into a plurality of pieces, and pixel data obtained from the new polygon after the corresponding VRAM for the display screen divided by the division means has already been read for screen display. And a judgment means for judging whether it is possible to write, and the result of the judgment means is possible. When the pixel data that can be drawn from the result of the sorting means is written in the VRAM, and when the polygons forming the model straddle the display screen divided by the screen dividing means, the polygons are stored inside the computer. First generating means for dividing and newly generating the polygon; and second mapping means for newly generating texture coordinates corresponding to the vertices of the polygon inside the computer when a texture is mapped to the polygon. A three-dimensional computer graphics system comprising: 2. The three-dimensional computer graphics system according to claim 1, wherein the sorting means sorts in the vertical direction of the display screen, which is the Y direction of the vertices of the polygon. 3. The three-dimensional computer graphics system according to claim 1, wherein the display screen is divided in the scan line direction of the display screen. 4. When dividing the polygon, a scan line that divides the display screen is defined as one side of the polygon, and the brightness and coordinate information of the vertices of the divided polygon are calculated before the division and drawing is possible. 2. The three-dimensional computer graphics system according to claim 1, wherein after the drawing operation is performed on the polygons that are divided at times, the polygons are written in the frame buffer.