JP4313892B2 - Drawing apparatus, drawing method, and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drawing apparatus and a drawing capable of displaying an object having a fixed shape with a small number of polygons regardless of the viewing direction, such as an effect or a pillar, which is stereoscopic, such as explosion or smoke The present invention relates to a method and a recording medium.
[0002]
[Prior art]
FIG. 5 shows a conventional display example for displaying a polygon or sprite with a texture pasted in a 3D space. In such a display example, there is a technical problem that a stereoscopic effect cannot be expressed when intersecting with a 3D object.
[0003]
As a drawing apparatus of a conventional scanning display device that solves this technical problem, for example, there is one disclosed in JP-A-8-315178.
[0004]
This drawing apparatus realistically shows the state of intersection between a sprite and a CG pattern including background data, or the intersection between a sprite and a sprite that is generated based on three-dimensional information between the sprite and another sprite. Display is considered.
[0005]
This drawing apparatus includes a Z buffer for storing Z values of pixel coordinates of sprites and other image patterns, a frame buffer for storing pixel data of sprites and other image patterns, Z values of sprites and other images. Compared with the Z value of the pattern for each pixel, the Z value in the foreground is stored in the Z buffer, and the pixel data corresponding to the Z value is stored in the frame buffer. is there.
[0006]
By providing the above configuration, when a predetermined Z value is given to the sprite image for each pixel or for each pixel, while the Z value corresponding to the address of each pixel constituting the other image pattern is closer to the front Pixel data corresponding to the Z value is stored in the frame buffer, and if the Z value is in front, the pixel data corresponding to the Z value is stored in the frame buffer, and these frame buffer and Z buffer By displaying sprites or other image patterns for each pixel based on the data, the previous pattern is displayed in two or more patterns intersecting each other. On the other hand, the pattern on the back side is hidden behind the previous pattern so as not to be displayed.
[0007]
[Problems to be solved by the invention]
However, the conventional drawing apparatus synthesizes sprites having depth information into a three-dimensional space made of polygons by providing sprite controllers individually. Therefore. The conventional drawing apparatus has a technical problem that the coordinate calculation is complicated because the sprite, the other three-dimensional object, and the geometric operation unit are not shared.
[0008]
The present invention has been made based on such a background, and an object of the present invention is to provide a drawing apparatus, a drawing method, and a recording medium capable of expressing a stereoscopic effect by simplifying geometric calculation processing.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a rendering process including a rendering process including a hidden surface process based on a size comparison between a Z value of pixel data generated by polygon calculation from polygon data and a Z value read from a Z buffer. In the apparatus, offset Z value corresponding to the Z value of the pixel data is read out from the depth information memory, and the offset Z value is added to the Z value of the pixel data, according to the comparison result of the comparison unit. And a means for writing the Z value of the pixel into a Z buffer, and reading out the pixel data from a texture memory and writing it into a frame buffer.
[0010]
In order to achieve the above object, the present invention is characterized by comprising offset determining means for determining whether or not to add an offset Z value according to a flag value attached to the polygon data, in addition to the above-described configuration. To do.
[0011]
In order to achieve the above object, the present invention is characterized in that depth data corresponding to each pixel constituting original picture data stored in the texture memory is used as an offset Z value.
[0012]
In order to achieve the above object, the present invention is characterized in that the original picture data includes original picture data having no directivity.
[0013]
In order to achieve the above object, the present invention provides a reading step of reading a Z value from a Z buffer based on X and Y coordinate data of pixels constituting polygon data, and the Z value read from the Z buffer and the pixel In a drawing method comprising a comparison step for comparing the size with a Z value and a step of writing the Z value in the Z buffer according to the result of the comparison step, an offset Z value corresponding to the Z value of the pixel is stored in a depth information memory. The offset addition step of adding the offset Z value to the Z value of the pixel, writing the Z value of the pixel into the Z buffer, and writing the pixel data constituting the original picture data corresponding to the pixel into the texture memory Reading from and writing to a frame buffer.
[0014]
In order to achieve the above object, the present invention has an offset determination step for determining whether or not to add an offset Z value according to a flag value attached to the polygon, in addition to the above-described configuration. To do.
[0015]
The present invention also includes a recording medium storing a method performed by the apparatus of the present invention and a program capable of constructing the apparatus of the present invention.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a drawing apparatus and a drawing method of the present invention will be described in detail with reference to the drawings.
[0017]
FIG. 1 is a block diagram showing an embodiment of a drawing apparatus according to the present invention, FIG. 3A is a schematic diagram showing an original picture showing an explosion pattern, and FIG. 3B is a diagram showing FIG. It is a schematic diagram which shows the depth data corresponding to the pixel which comprises the original picture shown in FIG.
[0018]
The rendering apparatus according to the present embodiment performs rendering processing including hidden surface processing by comparing the Z value of pixel data generated by polygon calculation from polygon data with the Z value read from the Z buffer.
[0019]
As shown in FIG. 1, the drawing apparatus according to the present embodiment includes a geometric operation unit 1, a texture memory 2, a depth information memory 3, a drawing processing unit 4, a Z buffer 5, a frame buffer 6, and a display unit. 7 Each member will be described below.
[0020]
The geometric processing unit 1 corresponds to a geometry calculation unit and sends polygon data including polygon vertex coordinate data to the drawing processing circuit 4. In the present embodiment, the polygon data output from the geometric calculation unit 1 has a flag value set for each polygon. Such a flag value indicates whether or not to use the data in the depth information memory 3.
[0021]
Here, the reason why the flag value is set in units of polygons is that a polygon on which original picture data having no directivity is pasted is determined in advance at the stage of creating a program. Therefore, by setting a flag value in units of polygons, rendering processing is unified by distinguishing normal original picture data for expressing the texture of an object and the like from original picture data having no directivity.
[0022]
The texture memory 2 stores original picture data when a pattern is pasted on an object surface and texture mapping is performed to express, for example, a texture or a pattern. The original picture data stored in the texture memory 2 includes brightness, hue, and the like.
[0023]
The texture memory 2 in the present embodiment stores original picture data having no directivity in addition to the original picture data for expressing the texture and pattern of the object.
[0024]
Here, the original picture data having no directivity means three-dimensional original picture data such as effects and pillars whose viewing direction is determined and explosion patterns and smoke having a fixed shape regardless of the viewing direction.
[0025]
The original picture data shown in FIG. 3 shows an explosion pattern as a representative example of the original picture having no directivity.
[0026]
FIG. 3A schematically shows pixel data stored in the texture memory 2. Since such pixel data includes data relating to brightness and hue for mapping to polygons, it is possible to express colors for making the explosion pattern look realistic.
[0027]
Depth data corresponding to the pixels constituting the explosion pattern is stored in the depth data memory 3 as shown in FIG. In FIG. 3B, the squares delimited by dotted lines conceptually indicate pixels. The Z value corresponding to such a pixel is set to an individual value so as to realistically represent the explosion pattern.
[0028]
The explosion pattern includes data for displaying as completely transparent as shown in FIG. In this embodiment, in order to show complete transparency, a Z value indicating that the screen is at infinity is set. A complicated original picture can be expressed by a single piece by such complete transparency processing. Also, the four vertex coordinate data of the explosion pattern shown in FIG. 3B correspond to the four vertex coordinate data of the polygon.
[0029]
The depth information memory 3 is a memory that stores depth data corresponding to each pixel constituting original picture data having no directivity stored in the texture memory 2. The depth data describes the screen as 0, the back side of the screen as a positive value, and the front side of the screen as a negative value.
[0030]
For example, among the pixels constituting the explosion pattern shown in FIG. 3, the pixel in front of the screen has a small positive value, and among the pixels constituting the explosion pattern shown in FIG. 3, the pixel on the far side of the screen has a large positive value. .
[0031]
Such depth data is used as an offset Z value when removing hidden surfaces in rendering processing. Since the hidden surface processing is performed using the depth data corresponding to each pixel constituting the original picture data having no directivity as described above, the original picture having no directivity and the non-directional original picture are described as described with reference to FIGS. The boundary surface with the polygon is expressed realistically.
[0032]
On the other hand, the pixels constituting the texture in front of the screen from the depth data are not displayed on the display unit 7 by the clipping process.
[0033]
The drawing processing unit 4 is a circuit that outputs image data that has been subjected to rendering processing using polygon geometric shape data that has undergone coordinate conversion by the geometric operation unit 1 as an input.
[0034]
The drawing processing unit 4 generates pixel data constituting the outline of the polygon and pixel data constituting the inside of the polygon from the vertex coordinate data of the polygon data input from the geometric operation unit 1, and performs texture mapping and color calculation. The pixel data subjected to the translucent process and the hidden surface process by the Z buffer method is output to the frame buffer 6.
[0035]
Although not clearly illustrated, the drawing processing unit 4 includes a texture memory 2, a depth information memory 3, a Z buffer 5, and a frame buffer 6 and a memory control function for performing data writing and reading processing. More specifically, a control unit for the Z buffer 5 is provided which reads a Z value from the Z buffer 5 based on X and Y coordinate data of pixel data constituting the polygon data. A writing control means for the frame buffer 6 for controlling writing in the frame buffer 6 is provided.
[0036]
The Z buffer 5 is a memory for holding a Z coordinate for each pixel in order to perform hidden surface processing by the Z buffer method.
[0037]
The frame buffer 6 stores pixel data to be displayed on the display unit 7.
[0038]
The display unit 7 is, for example, a CRT device that receives a video signal from the frame buffer 6 and displays a predetermined image.
[0039]
Next, rendering processing in the present embodiment will be described with reference to FIG.
FIG. 2 is a flowchart showing a rendering process in software in the drawing apparatus according to the present embodiment.
[0040]
This rendering processing routine is started by a main routine (not shown), and is executed in units of polygons input from the geometric operation unit 1. Therefore, if there are polygons to be processed next, start again. Will do.
[0041]
First, a rendering process that includes a synthesis process of polygon data input from the geometric operation unit 1 and original picture data (including original picture data having no directivity) input from the texture memory 2 will be described.
[0042]
When the rendering processing routine shown in FIG. 2 is started, the drawing processing unit 4 reads vertex coordinate data corresponding to one piece of polygon data from the geometric operation unit 1 (step 1). The drawing processor 4 reads the Z value from the Z buffer 5 based on the X and Y coordinate values of the pixels in the polygon (step 2).
[0043]
The drawing processing unit 4 refers to the flag value of the polygon data to determine whether or not to use depth information (step 3). If the drawing processing unit 4 determines that the flag value is 1 in step 3, the rendering processing unit 4 performs rendering processing by the Z buffer method with the polygon data input from the geometric operation unit 1 and the original picture data having no directivity. Become. The drawing processing unit 4 adds the offset Z value of the depth information memory 3 corresponding to the Z value of the pixel (step 4). The processing shown in Step 3 and Step 4 is a precondition for accurately performing the hidden surface processing of the polygon including the original picture data having no directivity.
[0044]
The drawing processing unit 4 compares the Z value of the pixel obtained by adding the offset Z value of the depth information memory 3 corresponding to the pixel Z value in step 4 with the value of the Z buffer 5 (step 5). If the drawing processing unit 4 determines in step 5 that the Z value of the pixel <the value of the Z buffer 5, the drawing processing unit 4 executes the processing of step 6. That is, the drawing processing unit 4 writes the Z value of the pixel in the Z buffer 5. The drawing processing unit 4 reads out pixel data constituting original picture data having no directivity corresponding to the pixel from the texture memory 2 and writes it into the frame buffer 6 (step 6).
[0045]
On the other hand, if the drawing processing unit 4 determines in step 5 that the pixel Z value> = the value of the Z buffer 5, the drawing processing unit 4 proceeds to step 7 without performing the processing in step 6. That is, the drawing processing unit 4 determines whether or not all the pixels of the polygon have been processed (step 7). If the drawing processing unit 4 determines in step 7 that all the pixels have not been processed, the drawing processing unit 4 returns to step 2 and executes the processing from step 2 described above. If the drawing processing unit 4 determines that all the pixels have been processed in step 7, the routine ends.
[0046]
On the other hand, if it is determined in step 3 that the flag value is 0, the rendering processing unit 4 does not execute the process of step 4, that is, the Z value and Z of the pixel to which the offset Z value of the depth information memory 3 is not added. The values in the buffer 5 are compared (step 5). This corresponds to general texture mapping for expressing the texture of an object.
In addition, since the process after step 5 is mentioned above, description is abbreviate | omitted.
[0047]
In the above-described embodiment, the calculation process in step 4 has been described as simply adding the offset Z value stored in the depth information memory 3 to the Z value of the pixel. However, the present invention is not limited to this, and a predetermined constant may be multiplied and added to the Z value constituting the pixel data. As a result, the same result can be obtained as when a plurality of original picture data having no directivity are stored by reducing the memory capacity.
[0048]
The above-described processing shown in Step 3 to Step 4 shown in FIG. 2 may be performed prior to other processing as an independent routine. This is because at the stage of creating a program, the polygons to which non-directive original picture data is pasted are determined, and if judged on a polygon basis, the judgment process can be reduced compared to judging on a pixel basis. It is.
[0049]
Note that the rendering processing described with reference to FIG. 2 may be realized by an integrated circuit. In that case, the processing is performed in parallel from Step 1 to Step 2 and Step 5 to Step 7 shown in FIG. 2 by dividing the polygon data to be processed in Step 4 shown in FIG. 2 and the polygon data not to be processed in Step 4. Circuit configuration. As a result, it can be executed at a higher speed than the processing by the software described with reference to FIG.
[0050]
In the above-described embodiment, the processing in step 6 has been described as writing the original picture data read from the texture memory 2 into the frame memory 6 as it is. However, the present invention is not limited to this, and the original picture data read from the texture memory 2 may be subjected to bilinear interpolation or trilinear interpolation and then written to the frame memory 6.
[0051]
FIG. 4 is a schematic diagram showing a display state of an image synthesized by the image synthesizing apparatus according to the present embodiment. Specifically, an example in which an image composition apparatus according to the present embodiment is used to synthesize and display an original picture having no directivity and a wall surface of a building, which is an example of a polygon, is shown. Compared with the conventional display example shown in FIG. 5, the display example shown in FIG. 4 realistically displays the three-dimensional intersection state between the explosion pattern and the wall surface of the building.
[0052]
In addition, as described above, the drawing apparatus according to the present embodiment is a three-dimensional effect, column, or explosion pattern that is three-dimensional compared to the conventional example described with reference to FIG. A solid object such as smoke or smoke, but it is possible to display a certain object with a small number of polygons regardless of the viewing direction, and to realistically display a three-dimensional intersection of the original picture data and polygons with no directivity did it.
[0053]
Furthermore, the present invention may store a program for realizing the functions of the above-described embodiments in a storage medium, and read and execute the program stored in the recording medium using a computer. As the recording medium, a floppy disk, a hard disk, a magneto-optical disk, or a CD-ROM can be used.
[0054]
【The invention's effect】
As described above, the present invention is a three-dimensional object such as an explosion or smoke. However, when combining an object of a fixed shape with a normal polygon regardless of the viewing direction, such as an effect or a pillar in which the viewing direction is determined, coordinate calculation is performed. Since the processing is not complicated, it is possible to provide a drawing apparatus, a drawing method, and a recording medium with reduced geometric calculation costs.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of an image composition apparatus of the present invention. FIG. 2 is a flowchart showing a rendering process in software in the rendering apparatus according to the embodiment. ) Is a schematic diagram showing an original picture representing an explosion pattern, and FIG. 3B is a schematic diagram showing depth data corresponding to pixel data constituting the original picture shown in FIG. 3A. FIG. 5 is a schematic diagram showing a display state of an image synthesized by an image synthesizing apparatus in a form. FIG. 5 is a conventional display example of displaying a polygon or sprite with a texture pasted in a 3D space.
DESCRIPTION OF SYMBOLS 1 Geometric operation part 2 Drawing process part 3 Texture memory 4 Depth information memory 5 Z buffer 6 Frame buffer 7 Display part

Claims (5)

In a drawing apparatus that performs rendering processing including hidden surface processing by comparing the Z value of pixel data generated by polygon calculation from polygon data and the Z value read from the Z buffer, the flag value attached to the polygon data And an offset determining means for determining whether or not to add an offset Z value, and reading the offset Z value corresponding to the Z value of the pixel data from the depth information memory, and calculating the offset Z value to the Z value of the pixel data And an offset calculating means that writes the Z value of the pixel data into a Z buffer and reads the pixel data from a texture memory and writes it into a frame buffer according to the result of the size comparison. Drawing device to do.    2. The drawing apparatus according to claim 1, wherein depth data corresponding to each pixel constituting the original picture data stored in the texture memory is set as an offset Z value. The original picture data drawing apparatus according to claim 1 or claim 2, characterized in that it comprises a source picture data with no directivity. A reading step of reading a Z value from a Z buffer based on X and Y coordinate data of pixels constituting polygon data, and a comparing step of comparing the Z value read from the Z buffer with the Z value of the pixel; An offset determination step for determining whether to add an offset Z value according to a flag value attached to the polygon data in a drawing method including a step of writing a Z value to the Z buffer according to a result of the comparison step If, reads the offset Z value corresponding to the Z value of the pixel from the depth information memory, writing the offset calculating step of calculating the offset Z value to the Z value of the pixel, the Z value of the pixel in the Z buffer, and The pixel data constituting the original picture data corresponding to the pixel is stored in the texture memory. Drawing method characterized by comprising the steps of: writing into the frame buffer is read out. A recording medium storing a program capable of constructing the drawing method according to claim 4 in a computer system.

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