JPH09297860A - Three-dimensional image generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the three-dimensional image generating device which can know which body a polygon displayed at an arbitrary position on a screen to be belongs to. SOLUTION: This device is equipped with a processor 3 which reads three- dimensional body data consisting of several polygons out of a storage device and performs arithmetic processing for calculating a depth coordinate value Z and luminance I, a frame buffer 4 which stores luminance of each pixel, a Z-buffer memory 2 which stores the depth value Z of each pixel, an ID memory 1 which stores body ID data for discriminating the body, pixel by pixel, and a display device 5 such as a CRT which displays the contents stored in the frame buffer memory 4; when the processing of all bodies is completed, the body ID which is closest to an eyepoint is stored in the ID memory 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional image generating apparatus, and more particularly to a three-dimensional image generating apparatus that generates a three-dimensional image using three-dimensional graphic data and brightness representing brightness.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of a conventional three-dimensional image generating apparatus that realizes a three-dimensional image generating method. The conventional three-dimensional image generation apparatus includes a processor 3, a frame buffer memory 4, a Z buffer memory 2, and a CR, for example.
And a display device 5 made of T. The processor 3 reads out three-dimensional object data composed of several polygons from a storage device (not shown) and performs arithmetic processing such as calculation of the depth coordinate value Z and brightness I. The frame buffer memory 4 stores the brightness of the pixel, and the Z buffer memory 2 stores the depth value Z of the pixel. The display device 5 displays the contents stored in the frame buffer memory 4.

FIG. 6 is a flowchart showing a procedure of a method for generating a three-dimensional image by hidden surface removal called a Z-buffer algorithm, which is executed by the three-dimensional image generating apparatus shown in FIG.

First, the frame buffer memory 4 and the Z buffer memory 2 are initialized (step S101). That is, the maximum value of the depth coordinate value Z (the coordinate value of the position farthest from the viewpoint) is set in the Z buffer memory 2. Next, coordinate conversion is performed on the three-dimensional object data in the designated order (step S102). In this coordinate conversion, the vertex coordinates of a polygon (basic figure such as a triangle or a quadrangle) represented by the local coordinates of the object are scaled, rotated, translated, etc. by a method instructed by a storage device or the like and displayed. This conversion is necessary to correspond to the global coordinates that are the reference coordinate system of the image, and the object is placed at each position by this conversion.

Next, the polygons forming the object are sequentially scan-converted (step S103), and the depth coordinate value Z is calculated for each pixel in the scan-converted polygon (step S104). Next, the calculated depth coordinate value Z and the depth coordinate value ZB stored in the Z buffer memory 2 are compared (step S105) to calculate the calculated depth coordinate value Z.
Is closer to the viewpoint than ZB, the value in the Z buffer memory 2 is replaced with the calculated depth coordinate value Z (step S106), and shading calculation is performed (step S10).
The luminance of the pixel is obtained from 7) and stored in the frame buffer memory 4 (step S108). Step S10
In step 4, when the calculated depth coordinate value Z is in the back of the viewpoint from ZB, the processes of steps S106 to S108 are not performed.

Next, it is judged whether all the pixels inside the polygon have been processed (step S109), and if the processing has not been completed, the process returns to step S104. If the processing is completed in step S109, it is determined whether or not all the polygons forming the object have been processed (step 11).
0). If the processing is not completed, the process returns to step S103, and if it is completed, it is determined whether or not the processing for all objects is completed (step S111). If not completed, the process returns to step S102, and if completed, this routine is completed.

When the above processing is completed, only the brightness of the polygon closest to the viewpoint is stored in the frame buffer memory 4 for each pixel on the screen, and the desired three-dimensional image is generated. A three-dimensional image can be viewed by displaying the contents of this frame memory on a display device.

[0008]

As described above,
In the conventional three-dimensional generation device, only the brightness information is stored in the frame buffer memory 4 and only the depth information is stored in the Z buffer memory 2, and the polygon displayed at a certain position on the screen is the polygon of which object. I can't get information about what was there.

Therefore, in this conventional example, by calculating the coordinate value of the object in global coordinates, it is estimated what the polygon is displayed at a certain position on the screen. However, with this method, it is necessary to re-execute the hidden surface removal processing that has already been performed at the time of generating a three-dimensional image. In addition, the result remains at the level of knowing the approximate position of the object, so that the screen is accurately displayed. It is difficult to know what the polygon displayed at the position is.

Therefore, in the present invention, after the three-dimensional image is generated, an ID for accurately discriminating which object the displayed polygon at an arbitrary position on the screen belongs to becomes the source of the polygon. It proposes a method to know the object data.

A three-dimensional image generation method having means for adding an ID is disclosed in Japanese Patent Laid-Open No. 35883/1993. However, in the method disclosed in this publication, the means for adding the ID is used to reduce the calculation amount of the shading process, and the ID of the polygon is lost at the time of display. Since there is no means to connect the IDs of objects, IDs for object determination
Cannot be used as.

It is an object of the present invention to provide a three-dimensional image generation apparatus capable of accurately knowing which object a polygon displayed at an arbitrary position on a screen is after generating a three-dimensional image. To do.

[0013]

The above object is to provide three-dimensional graphic data defined by three-dimensional coordinates consisting of coordinates on a two-dimensional screen plane and z-coordinates representing the depth from the screen plane. A three-dimensional image generation apparatus for generating a three-dimensional image by using brightness representing brightness, wherein an object ID given to each figure data to identify the figure data including each pixel is stored for each pixel. Memory for storing the brightness of each pixel, a Z buffer memory for storing the z-coordinate value of each pixel, and a memory for storing graphic data corresponding to each object ID. A device and a Z-buffer algorithm for reading out graphic data stored in the storage device in a predetermined order, determining the front and back of the graphic using z coordinate values, and selecting graphic data closer to the viewpoint. The hidden surface erasing process based on the above is performed, the contents of the Z buffer memory and the ID memory are updated according to the selected graphic data, the brightness of each pixel is calculated from the updated contents of the Z buffer memory, and The present invention is achieved by the three-dimensional image generation device of the present invention, which comprises a processor for updating the contents of the frame buffer memory and a display device for displaying the contents of the frame buffer memory.

In the three-dimensional image generating apparatus of the present invention, the ID memory may be configured to store the object IDs of all the pixels on the screen plane.

In the three-dimensional image generation device of the present invention, the ID memory may be configured to store the object ID of a predetermined pixel on the screen plane.

In the three-dimensional image generating apparatus of the present invention,
When all the objects on the screen have been processed, the object ID closest to the viewpoint is stored in the ID memory.
After the three-dimensional image is generated, by referring to the object ID data in the ID memory at the arbitrary screen coordinates, it is possible to know from which object data the image displayed at the screen coordinates is generated.

Thus, in an interface using a three-dimensional image or a video game, it is possible to easily determine an object from the viewpoint position in the three-dimensional space represented by the three-dimensional image.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a three-dimensional image generating apparatus of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of a first embodiment of a three-dimensional image generation apparatus of the present invention. The three-dimensional image generation device includes a processor 3 and a frame buffer memory 4.
, A Z buffer memory 2, an ID memory 1 having the same coordinate space capacity as the frame buffer memory, and a display device 5 composed of, for example, a CRT.

The processor 3 reads three-dimensional object data composed of several polygons from a storage device (not shown) and performs arithmetic processing such as calculation of the depth coordinate value Z and the brightness I. The frame buffer memory 4 stores the brightness of the pixel, the Z buffer memory 2 stores the depth value Z of the pixel, and the ID memory 1 stores the object ID data. The display device 5 displays the contents stored in the frame buffer memory 4.

FIG. 4 is a flow chart for explaining the three-dimensional image generation method in this embodiment. This three-dimensional image generation method is executed by the three-dimensional image generation device shown in FIG.

A positive integer is given as an object ID to each object composed of several polygons. First,
Frame buffer memory 4, Z buffer memory 2 and ID
The memory 1 is initialized (S1). That is, the background brightness is stored in the frame buffer memory 4, the maximum value of the depth coordinate value Z (coordinate value at the position farthest from the viewpoint) is stored in the Z buffer memory 2, and the blank ID (no object is present) is stored in the ID memory 1. 0 is set as an ID which means that there is no.

Next, coordinate conversion is performed on the three-dimensional object data in the designated order (S2). In this coordinate transformation, the vertex coordinates of the polygon represented by the local coordinates of the object are scaled, rotated, translated, etc. by the method instructed by the storage device, etc., and are global coordinates that become the reference coordinate system of the displayed image. Is a transformation necessary to correspond to, and the transformation places the object at each position.

Next, the polygons forming the object are sequentially scan-converted (S3), and the depth coordinate value Z is calculated for each pixel in the scan-converted polygon (S4). Next, the calculated depth coordinate value Z is compared with the depth coordinate value ZB stored in the Z buffer memory 2 (S5), and when the calculated depth coordinate value Z is closer to the viewpoint than ZB,
The value of the Z buffer memory 2 is replaced with the calculated depth coordinate value Z (S6), and the brightness of the pixel is calculated by shading calculation (S7) and stored in the frame buffer memory 4 (S8). Next, the ID of the object currently being processed is set to I
Write to D memory (S9). In S4, when the calculated depth coordinate value Z is at the back of the viewpoint from ZB, S6 to S9.
Is not processed.

Next, it is judged whether or not all the pixels inside the polygon have been processed (S10), and if the processing has not been completed, the process returns to S4. If the processing is completed in S10, it is determined whether or not all the polygons forming the object have been processed (S11). If the processing is not completed, the process returns to S3,
If the processing has been completed, then it is determined whether processing of all objects has been completed (S12). If not finished, return to S2,
This routine ends.

Upon completion of the above processing, the ID memory 1 stores the object ID of the polygon closest to the viewpoint for each pixel on the screen. Further, the frame buffer memory 4 stores the brightness of the polygon closest to the viewpoint, and a desired three-dimensional image is generated. A three-dimensional image can be viewed by displaying the contents of this frame memory on a display device. Furthermore, I
By referring to the contents of the D memory 1, it is possible to know from which object the polygon at an arbitrary position of the displayed image is generated.

Of course, the object ID need not be limited to each object. It is also possible to assign a plurality of object IDs to one object in order to distinguish a part of the object. In this case, it may be considered that the object ID can be designated for each polygon. These are changes that originate from the data structure of the object represented by polygons and will not be discussed here in depth.

Next, the object discrimination processing from the viewpoint position in the three-dimensional image creating apparatus of this embodiment will be described.

For example, assume that an object ID = 2 is assigned to the switch and another object ID = 1 is assigned. When the object ID is acquired from the ID memory of screen coordinates (Xa, Ya) after the three-dimensional image is generated, it is determined whether or not the object ID is 2 is a switch. can do. By utilizing this, the process of discriminating the displayed object becomes much faster.

A specific specification method will be described with reference to FIGS. 7 and 8. Switch A indicated by 12a and 12b in the figure
The switch B and the desk 13 are arranged in the three-dimensional space as shown in FIG. It is assumed that the user moves the cursor polygon 11 in the three-dimensional space to move the cursor polygon 11 to the switch, and when the user clicks the interface, the process assigned to the switch is executed.

Here, the object ID of the switch A is ID =
1, the switch B has ID = 2, the desk has ID = 3, the other background has ID = 0, and the cursor polygon has ID = 0. Since the cursor polygon does not have a polygon at the center, the ID information of the center point is not lost.

First, a three-dimensional image is drawn by the above-mentioned apparatus of FIG. 1 (S201), whereby a three-dimensional image as shown in FIG. 7 is generated. Next, the cursor polygon 11
The position of is calculated (S202). The calculated position of the cursor polygon 11 is (Xc, Yc, Zc). X
c and Yc correspond to screen coordinates, and Zc corresponds to a depth value. Next, the collision of the cursor and the object is determined. This can be determined by the conditional expression of Zc−α0 ≦ Zbuf (Xc, Yc) ≦ Zc + α1. Here, α0 and α1 are margin values that determine how much margin should be provided between the switch surface and the cursor polygon to determine a collision. Zbuf (X
c, Yc) is the contents of the Z buffer memory 2 at the screen coordinates (Xc, Yc).

If this condition is not satisfied, the process proceeds to S209. If it is satisfied, it is determined whether or not the user clicked next (S204). S2 if not clicked
09 is transferred. If it is clicked, it is determined whether the switch A is clicked next (S20).
5). This determination is performed using the ID memory 1 of the present invention. The conditional expression is ID (Xc, Yx) = 1. Here, ID (Xc, Yc) is the contents of the ID memory 1 at the screen coordinates (Xc, Yc).

If this condition is satisfied, the process assigned to the switch A is performed (S208), and the process proceeds to S209. If not established, it is next determined whether or not it is the switch B (S206). The determination formula is ID (Xc, Yc) = 2. If this condition is satisfied, the process assigned to switch B is performed (S207), and the process proceeds to S209. If not established, the process moves to S209. S20
At 9, the viewpoint is moved and the cursor polygon is moved. Then, the process is returned to S201.

As described above, by using the ID memory, the interface program can be constructed very easily.

The second embodiment of the three-dimensional image generating apparatus of the present invention will be described below.
Embodiments will be described in detail with reference to the drawings.

FIG. 2 is a block diagram of a three-dimensional image generating apparatus according to the second embodiment of the present invention. The three-dimensional image generation device includes a processor 3 and a frame buffer memory 4.
And an ID having a capacity for the coordinate space smaller than the coordinate space of the Z buffer memory 2 and the frame buffer memory.
It is composed of a memory 1'and a display device 5 composed of, for example, a CRT.

The processor 3 reads out three-dimensional object data composed of some polygons from a storage device (not shown) and performs arithmetic processing such as calculation of the depth coordinate value Z and the brightness I. The frame buffer memory 4 stores the pixel brightness, the Z buffer memory 2 stores the pixel depth value Z, and the ID memory 1 ′.
Stores object ID data. The display device 5 displays the contents stored in the frame buffer memory 4.

FIG. 5 is a flow chart for explaining the three-dimensional image generation method in this embodiment. In the figure, FIG.
The same processes as those in the flowchart in FIG. This three-dimensional image generation method is executed by the three-dimensional image generation device shown in FIG.

As in the first embodiment, a positive integer is given as an object ID to each object composed of several polygons.

First, the frame buffer memory 4, the Z buffer memory 2, and the ID memory 1 are initialized (S1). That is, the background brightness is stored in the frame buffer memory 4 as Z
The maximum value of the depth coordinate value Z (the coordinate value at the position farthest from the viewpoint) is set in the buffer memory 2, and 0 is set as the blank ID (ID meaning that there is no object) in the ID memory 1.

Next, coordinate conversion is performed on the three-dimensional object data in the designated order (S2). In this coordinate transformation, the vertex coordinates of the polygon represented by the local coordinates of the object are scaled, rotated, translated, etc. by the method instructed by the storage device, etc., and are global coordinates that become the reference coordinate system of the displayed image. Is a transformation necessary to correspond to, and the transformation places the object at each position. Next, the polygons forming the object are sequentially scan-converted (S3), and the depth coordinate value Z is calculated for each pixel in the scan-converted polygon (S4).

Next, the calculated depth coordinate value Z is compared with the depth coordinate value ZB stored in the Z buffer memory 2 (S5). If the calculated depth coordinate value Z is closer to the viewpoint than ZB, The value of the Z buffer memory 2 is replaced with the calculated depth coordinate value Z (S6), and the brightness of the pixel is calculated by shading calculation (S7) and stored in the frame buffer memory 4 (S8). Next, it is judged whether or not the coordinates currently handled are the coordinates in the ID memory (S9
A) If it is within the coordinates, write the ID of the object currently being processed in the ID memory (S9). In S4, when the calculated depth coordinate value Z is at the back of the viewpoint from ZB, S6 to S
The process of 9 is not performed.

Next, it is judged whether all the pixels inside the polygon have been processed (S10), and if the processing has not been completed, S
Return to 4. If the processing is completed in S10, it is determined whether or not all the polygons forming the object have been processed (S11). If the processing has not been completed, the process returns to S3, and if it has been completed, then it is determined whether or not the processing of all objects has been completed (S12). If not finished, return to S2,
If finished, this routine is finished.

When the above processing is completed, the ID memory 1 stores the object ID of the polygon closest to the viewpoint for some of the pixels on the screen. In addition, the frame buffer memory 4 stores the brightness of the polygon closest to the viewpoint for each pixel on the screen, and a desired three-dimensional image is generated. A three-dimensional image can be viewed by displaying the contents of this frame memory on a display device. Further, by referring to the contents of the ID memory 1, it is possible to know from which object the polygon in the position of a partial range of the displayed image is generated.

Here, the partial range may be a single point. In the use example as shown in FIG. 7 described above, the coordinates (Xc, Yc) can be calculated in advance, so it is possible to determine from which object the polygon is generated by only having the ID memory for this coordinate. I can know. Of course, the range of the ID memory may be assigned to arbitrary coordinates instead of fixed coordinates.

Regarding the object discrimination processing from the viewpoint position in the three-dimensional image creating apparatus of the present embodiment, the above-mentioned first
The description is omitted because it is the same as that described in the above embodiment.

[0048]

According to the three-dimensional image generating apparatus of the first aspect, it is possible to accurately and easily refer to which object the polygon displayed on the screen is after generating the three-dimensional image. . As a result, it becomes possible to easily determine the object from the viewpoint position in the three-dimensional space represented by the three-dimensional image.

According to the three-dimensional image generation apparatus of the second aspect, since the object IDs corresponding to all the pixels on the screen are stored in the ID memory, the polygon at an arbitrary position on the screen is an object. You can accurately and easily refer to the one.

According to the three-dimensional image generating apparatus of the third aspect, only the object IDs of the pixels in the necessary area on the screen are stored in the ID memory, so that the memory resources can be effectively used. It will be possible.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of a three-dimensional image generation apparatus of the present invention.

FIG. 2 is a block diagram of a second embodiment of a three-dimensional image generation apparatus of the present invention.

FIG. 3 is a block diagram of a conventional three-dimensional image generation device.

4 is a flowchart of a three-dimensional image generation method by the device of FIG.

5 is a flowchart of a three-dimensional image generation method by the apparatus of FIG.

FIG. 6 is a flowchart of a conventional three-dimensional image generation method.

FIG. 7 is an explanatory diagram of how to use an object ID.

FIG. 8 is a flowchart of an object determination method based on an object ID.

[Explanation of symbols]

 1, 1'ID memory 2 Z buffer frame memory 3 processor 4 frame buffer memory 5 display device 11 cursor polygons 12a, 12b switch 13 desk 14 background

Claims (3)

[Claims] 1. Using three-dimensional graphic data defined by three-dimensional coordinates consisting of coordinates on a two-dimensional screen plane and z-coordinates representing the depth from the screen plane, and brightness representing brightness. A three-dimensional image generation device for generating a three-dimensional image, which is an ID for storing, for each pixel, an object ID assigned to each figure data to identify the figure data including each pixel.
A memory, a frame buffer memory for storing the brightness of each pixel, a Z buffer memory for storing the z coordinate value of each pixel, and a storage device for storing graphic data corresponding to each object ID, The graphic data stored in the storage device is read out in a predetermined order, the front and back of the graphic are judged using the z coordinate value, and graphic data closer to the viewpoint is selected.
Perform hidden surface removal processing based on the buffer algorithm,
A processor that updates the contents of the Z buffer memory and the ID memory according to the selected graphic data, calculates the brightness of each pixel from the updated contents of the Z buffer memory, and updates the contents of the frame buffer memory. And a display device that displays the contents of the frame buffer memory. 2. The three-dimensional image generation apparatus according to claim 1, wherein the ID memory stores object IDs of all pixels on the screen plane. 3. The three-dimensional image generation device according to claim 1, wherein the ID memory stores an object ID of a predetermined pixel on the screen plane.