JPH11144079A - Processor and method for image processing and recording medium where image processing program thereof is recorded - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processor and method for image processing which performs a processing for lighting from a light source through a simplified arithmetic processing for some area of a polygon. SOLUTION: A Z value of a polygon positioned on the inner side of a viewpoint about a pixel in a lighting polygon and a Z value of a position on the front side are stored in a couple of lighting memories 30 and 32. When a drawing polygon is processed, it is determined whether or not each pixel is positioned in a lighting object by using the Z values in the lighting memories 30 and 32. When the pixel of the drawing polygon is positioned in the lighting object, its luminance value is increased and image data such as color data is stored in a pixel memory 26. The pixel memory 26 is stored with image data of pixels of one frame and an image is displayed on a display screen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus using a computer, and more specifically to an image processing apparatus capable of more realistically expressing light irradiation (writing) from a light source to a polygon, and an image processing apparatus for the same. The present invention relates to a method and a recording medium on which the image processing program is recorded.

[0002]

2. Description of the Related Art In image processing, the effect of irradiating (lighting) light from a light source onto a polygon can be achieved by a flat shading method for uniformly increasing the luminance of one polygon or by setting the luminance at each vertex of the polygon. A Gouraud shading method or the like for obtaining the luminance in a polygon by interpolating from the luminance of the vertex is known. The former case is a process in which the brightness of all the pixels in one polygon is increased, and the latter case is a process in which the brightness changes between vertices in one polygon at a constant slope. Therefore, with these processing methods, it is not possible to produce a lighting effect as if, for example, a spotlight was illuminated in an arbitrary area within the polygon.

Conventionally, as a method of expressing a lighting effect on a still image, an inner product of a normal vector for each pixel in a polygon and a light source vector from the pixel to a light source is calculated, and the inner product is calculated according to the inner product value. There is a method of correcting the luminance of each pixel. According to this method, the luminance can be set independently for each pixel.

[0004]

However, according to such a method, it is necessary to obtain an inner product value for each pixel, the amount of calculation using a computer becomes large, and it is necessary to process a moving image in real time. Is extremely difficult. In particular, since the calculation of the inner product value involves multiplication and division, the time required for the calculation is considerably long when a general-purpose computer that is currently widely used is used.

In the case of a game device or a simulation device, it is necessary to perform image processing in real time in response to an input signal input by a player or an operator. Therefore, in such a field, it is difficult to apply the above-described lighting method performed on still images.

It is an object of the present invention to provide an image processing apparatus, an image processing method, and a recording medium on which an image processing program is recorded, which can easily perform a process of giving an effect of light irradiation (writing) to an image. To provide.

Further, an object of the present invention is to provide an image processing apparatus, an image processing method, and a processing program capable of performing, in real time, a process of giving an effect of lighting (writing) from a moving light source to a moving image or the like. To provide a recording medium on which is recorded.

Further, an object of the present invention is to provide an image which can easily perform special processing such as a shading effect for lowering the brightness of an arbitrary region on an image and a clipping effect for inhibiting the display of polygons in an arbitrary region. It is to provide a processing device and the like.

[0009]

According to the present invention, a lighting object consisting of an area to be irradiated with light is added, and a lighting polygon constituting the lighting object is generated together with a normal drawing polygon. And
The Z value of the polygon located on the far side from the viewpoint and the Z value of the polygon located on the near side with respect to the pixels in the lighting polygon are respectively stored in a pair of lighting memories. Thereafter, at the time of drawing processing of the drawing polygon, it is determined whether or not each pixel is located in the riding object based on the Z values in the pair of writing memories. Specifically, it is determined whether or not it is located between the Z values of the writing memory. When the pixels of the drawing polygon are located in the lighting object, for example, a lighting process for increasing the luminance value is performed, and the processed image data such as color data is stored in the pixel memory. The pixel memory stores image data of pixels for one frame, and an image is displayed on a display screen according to the image data of the pixel memory.

According to the above method, a lighting object corresponding to a light source is added, and it is necessary to process a Z value of a lighting polygon constituting the lighting object. However, it is determined whether or not to increase the luminance value for each pixel. This is merely a comparison of the Z values, and the amount of calculation is significantly reduced as compared with the case where a conventional inner product value is obtained. Therefore, an image processing apparatus that performs image processing by such a method can give the effect of light irradiation from a moving light source to a moving image or the like in real time.

Further, when there are a plurality of light sources, the above-mentioned pair of writing memories is provided for each light source, and it is determined whether or not the pixel of the polygon to be drawn has the Z value sandwiched between the pair of writing memories. By making the determination, the lighting process can be performed by the same method.

In addition, the present invention is not limited to a lighting object, and can easily perform a shading process using a shading object, or perform a clipping process on a partial area using a clipping object.

In order to achieve the above object, according to the present invention, polygons including coordinate data and color data in a display screen are given to polygons constituting an object, and polygons in each polygon are given according to the coordinate data. In an image processing device that performs a pixel rendering process, the polygon includes a rendering target polygon on which the rendering process is performed and a writing polygon that forms a writing object in a target region of the writing process, and the image processing device includes: A first writing memory in which the Z value of a pixel in the writing polygon positioned on the near side of the display screen in the writing polygon is written; and a pixel in the writing polygon positioned on the back side of the display screen in the lighting polygon Second writer to which the Z value of is written A pixel memory in which color data of a pixel displayed on the display screen is written, and a Z value of a pixel in the polygon to be drawn is obtained from the coordinate data. And a drawing processing unit that performs a lighting process for increasing the luminance value on the color data of the pixel when the pixel data is located between the Z values in the writing memory, and writes the color data subjected to the lighting process to the pixel memory. Features.

According to the above-described image processing apparatus, a simple Z-value comparison between the two Z-values of the writing memory storing the Z-values of the writing polygons constituting the writing object and the Z-values of the pixels of the polygon to be rendered is being performed. Through the calculation, it can be determined whether or not the lighting effect should be given.

In order to achieve the above object, according to the present invention, polygons including coordinate data and color data in a display screen are given to polygons constituting an object, and polygons in each polygon are given according to the coordinate data. In the image processing method for performing a pixel rendering process, the polygon includes a rendering target polygon on which the rendering process is performed and a lighting polygon that forms a lighting object in a target region of the lighting process, and the image processing method includes: When the data of the writing polygon is given, the Z value of the pixel in the writing polygon is obtained from the coordinate data, and the Z value of the pixel of the writing polygon located on the near side and the back side of the display screen is calculated. Writing points to be written in the first and second writing memories Gon drawing step, and when the data of the drawing target polygon is given, the Z value of the pixel in the drawing target polygon is obtained from the coordinate data, and the Z value of the pixel is stored in the first and second writing memories. A writing process for increasing the luminance value of the color data of the pixel when the pixel data is located between the Z values, and writing the polygon data to the pixel memory. .

According to the above-described image processing method, both the writing polygon and the polygon to be drawn are processed as polygons. In the case of the writing polygon, the drawing process is to write the Z value into the writing memory. The image processing in such a case is to determine whether or not to perform the lighting process by using the Z value of the pixel, and if necessary, to increase the brightness and write it to the pixel memory.
Therefore, a lighting effect can be given to a predetermined area of the polygon by a simple arithmetic processing.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to the embodiment.

FIG. 1 is a diagram showing an example of a lighting effect. In this example, light from a light source 10 having directivity located on the right side is applied to the object 12 on the stairs to which the handrail is attached. Lighting (irradiation) from a light source is performed on a part of the polygons 13, 14, and 15 constituting the staircase object 12, and the brightness of the region 16 indicated by oblique lines in the drawing increases. When the position and direction of the light source change, the lighting area changes according to the shape of the object.

FIG. 2 is a view for explaining a lighting object in the present embodiment. In the example of FIG. 1, when the light from the light source 10 is radiated in a conical shape (cone shape), a cone-shaped lighting object 20 including an area irradiated with the light is defined. The lighting object 20 is handled in the same manner as a normal object. That is, in the example of FIG. 2, the conical lighting object 20 indicated by the thick line is constituted by a plurality of planar polygons forming a polygonal pyramid. Then, it is determined whether or not the pixels of the polygons 13, 14, and 15 constituting the staircase object 12 when viewed from the viewpoint are located in the lighting object 20.

FIG. 3 is a diagram for explaining a writing memory for facilitating determination as to whether or not a pixel of a polygon is located in the lighting object 20. FIG.
2 shows the distribution of the Z values of the pixels in the writing polygon located on the horizontal line of the display screen of FIG. With respect to the viewpoint in FIG. 2, the lighting object 20 is composed of a near-side polygon having a normal vector in a direction toward the viewpoint and a back-side polygon having a normal vector in a direction opposite to the viewpoint. That is, it is composed of a writing polygon located on the back side and a lighting polygon located on the front side with respect to the viewpoint.

FIG. 3A shows the distribution of the Z value of the lighting polygon located on the far side when viewed from the viewpoint. On the other hand, FIG. 3B shows the distribution of the Z value of the lighting polygon located on the near side as viewed from the viewpoint. That is, when a straight line passes through the lighting object 20 from the viewpoint, the straight line is inserted inside the lighting object 20 on the near side and goes outside on the far side. Therefore, the lighting polygon located on the back side is Z
The value is large, and the lighting polygon located on the near side has a small Z value. Therefore, the distribution in FIG. 3A shows the shape on the opposite side to the viewpoint of the lighting object.
The distribution (b) shows the shape of the lighting object on the viewpoint side.

In the present embodiment, in the processing of the writing polygon constituting the writing object 20, a first writing memory (FIG. 3B) for storing the Z value of the front side writing polygon and a back side of the first side are stored. A second writing memory (FIG. 3A) for storing the Z value of the writing polygon is created. Thereafter, in the rendering process for each pixel of the rendering polygon, it is determined whether or not the Z value of the pixel is a value between the Z values of both memories. If the Z value of the pixel is a value between the Z values of both memories, it is determined that the pixel being rendered is located in the lighting object, and the image data whose luminance value has been increased is equivalent to one frame. Write to the pixel memory of

The determination as to whether a front-side writing polygon to be written to the first writing memory or a back-side writing polygon to be written to the second writing memory is made by comparing, for example, the Z value as described above. be able to. Here, it is assumed that the lighting object is a convex object.
That is, a convex object is an object that intersects at two points or intersects at one point when it intersects with an arbitrary straight line.

As another method, a normal vector of the writing polygon is obtained, and if the Z value of the normal vector is positive, the writing polygon is located on the back side, and the Z value is stored in the second writing memory. If the Z value of the normal vector is negative, it is determined that the writing polygon is located on the near side and the Z value is a polygon to be written in the first writing memory.

FIG. 4 is an overall configuration diagram of the image processing apparatus according to the present embodiment. In this example, as an image processing unit of a game device, a simulation device, or the like, a CPU 22 that obtains three-dimensional coordinate values of a polygon to be displayed in accordance with an operation input, and performs a perspective transformation of the three-dimensional coordinate values into display screen coordinates, A rendering engine 24 which receives polygon data from the CPU 22 and performs a rendering process according to the attribute of the polygon; a pixel memory 26, a Z value memory 28, and a first writing memory connected to the rendering engine 24 via a memory bus 30 and a second writing memory 32. A display device 34 is connected to the drawing engine 24, and image data is given from a pixel memory 26 in which image data for each pixel of one frame is stored, and an image is displayed.

FIG. 5 is a diagram showing a configuration example of polygon data according to the present embodiment. This example shows a data configuration that can form both a normal drawing polygon and a writing polygon that forms a lighting object. First, the polygon attribute data P10 has any one of (1) a non-lighting reference polygon, (2) a lighting reference polygon, (3) a front lighting polygon, and (4) a back lighting polygon. Furthermore, the vertex coordinates V0, V1, V2 of the polygon are included in the polygon data.
Having. Specifically, two-dimensional coordinates (X0, Y0), (X1, Y1), (X2, Y
2) and Z value Z indicating the depth in each display screen
0, Z1, and Z2. The polygon data includes color data (color data). The example of the color data shown in FIG. 5 is data indicating a single color. In the case of more complex color data, for example, color data for each vertex, texture data to be pasted on the polygon surface, and the like are included.

The above-mentioned polygon attributes will be further described. (1) A non-lighting polygon refers to a drawing in which the normal vector of the polygon has a direction opposite to that of the light source and does not need a lighting effect. This is the target polygon. For example, it is a polygon of a portion that becomes a shadow from a light source. In the case of such a polygon, it is not necessary to provide a lighting effect even if the polygon is located in the lighting object. Accordingly, polygons that do not require a lighting effect are given this attribute by the CPU. This polygon is simply subjected to a drawing process, and the data is written in the pixel memory 26 and the Z value memory 28.

Next, (2) the writing reference polygon is a polygon to be rendered which requires a lighting effect. For example, the polygon whose normal vector is directed to the light source 10 side is the polygon such as the polygons 13, 14, and 15 constituting the steps shown in FIG. This attribute is also given from the CPU 22 side. For lighting reference polygons,
A determination is made as to whether the pixel memory 26 is located within the lighting object or not.
The data is written to the value memory 28.

The lighting polygons constituting the lighting object are divided into (3) a front side lighting polygon and (4) a back side lighting polygon.
This dividing method is as described above. In this example, the CPU 22 already divides the image and gives each attribute as a polygon attribute P10. In the case of a writing polygon, the Z value data is written in the writing memories 30 and 32.

FIG. 6 is a flowchart of an example of image processing involving lighting processing. An outline of the processing will be described along the steps shown in the flowchart. CPU 22
Performs a geometric operation in a three-dimensional space according to an input operation signal input by a player or an operator to obtain three-dimensional coordinates of polygons in a screen, and performs perspective transformation to display screen coordinates (S
10). Then, the polygon data shown in FIG. 5 is sequentially provided to the drawing engine 24 for each polygon. Normally, the lighting polygon in one frame is given first. For the given writing polygon, the rendering engine 24 performs, for example, raster scanning of the polygon and performs an interpolation operation from the Z value of the vertex to obtain a Z value for each pixel.
Write to 0,32. If the attribute of the polygon provided by the CPU 22 is a front-side writing polygon, the Z value Z1 is stored in the first writing memory 30. If the attribute is a back-side writing polygon, the Z-value Z1 is stored in the second lighting 32. The Z value Z2 is stored.

Next, from the CPU 22 to the drawing engine 24
Is given polygon data of the drawing polygon. Among the drawing polygons, the Z value for each pixel obtained by raster scanning or the like for the polygon for which a lighting effect needs to be given is replaced with the Z values Z1, Z in the writing memory.
Then, it is determined whether or not the Z value of the pixel is located between the two Z values (S14). As a result of the determination, if the Z value of the pixel is located between the two Z values, a lighting process for correcting the color data to color data when the luminance value is increased is performed, and the data is used as image data. The data is written to the corresponding pixel area of the pixel memory 26 (S16). The above steps S14 and S16
This is performed for all the pixels in the drawing polygon, and also for all the drawing polygons.

Incidentally, for example, infinite data is written in the Z value memory 28 as an initial value. Then, a comparison with the Z value of the pixel of the polygon to be drawn is performed. If the Z value of the pixel being processed is small, it is determined that the pixel is located on the near side, and the image data is written to the pixel memory 26. The Z value of the pixel is newly written to the Z value memory. By using the Z value memory 28,
Even if rendering polygons are given to the rendering engine at random, only the image data of the pixels to be displayed is written to the pixel memory 26.

When the drawing process for all the polygons in one frame is completed, the image data written in the pixel memory 26 is read out, given to the display device, and the image subjected to the lighting process is displayed (S18).

The above is an example of image processing involving lighting processing. As is clear from the above description, in addition to the drawing processing for each pixel in a polygon, which has been conventionally performed in general, a processing step of drawing a writing polygon in a writing memory, Is simply added. Moreover, the added processing differs from the calculation of the inner product value and the like, and involves only a simple operation.

FIG. 7 is a diagram showing a detailed configuration of the drawing engine. Parts corresponding to those in FIG. 4 are denoted by the same reference numerals. As described above, the CPU 22 performs a geometric operation such as vertex coordinate conversion of all polygons, and converts the perspectively transformed polygon data into two-dimensional coordinates on the display screen using the drawing command D.
1 is given to the drawing engine 24. A memory 23 such as a ROM and a RAM is used when the CPU 22 performs arithmetic processing and program control.

The drawing engine 24 performs drawing of a writing polygon on a writing memory and drawing of a drawing polygon on a pixel memory and a Z-value memory. First, a timing control unit 241 for the entire drawing process is provided in the drawing engine 24. The drawing command D1 from the CPU 22 is input to the CPU bus interface unit 242. The input drawing command D1 is stored in the drawing command latch unit 243 until drawing processing of the polygon is completed. The drawing command analysis unit 244 analyzes the drawing command D1, and analyzes the four types of polygon attributes shown in FIG.

Further, the ridge processing unit 245 generates one-line data D2 for raster-scanning the polygon. Specifically, the two-dimensional coordinates and the Z value of the viewpoint S and the end point E of one line along the ridge line connecting the vertices of the polygon are obtained by the interpolation calculation method based on the vertex data. FIG.
FIG. 1 is a diagram illustrating the raster scan. For triangular polygons, edges R01 and R02 at vertices 0, 1, 2
The coordinate values of the upper point S and the point E are represented by the respective internal division ratios t1,
It is obtained by an interpolation operation using t2, t3, and t4.
As a result, the coordinates of the start point S (SxSySz) and the end point (ExEyEz) of one line are obtained. Then, the line issuing unit 247 sets the coordinate values of the start point S and the end point E as one-line data D2,
Give 5

In the line processing unit 25, the ridge line issuing unit 2
The drawing process of the pixels in the line generated in 46 is performed. Each pixel in the line is obtained by interpolating the coordinate data at the start point S and the end point E by the internal division ratio. The line data latch unit 251 stores the given data for one line until the drawing processing for one line is completed. The Z value calculator 252 obtains the Z value of each pixel by interpolating the Z values Sz and Ez of the start point S and the end point E according to the internal division ratio.

The Z value comparing section 253 of the Z value memory compares the Z value of the pixel being processed with the Z value of the pixel to be drawn already stored in the Z value memory 28. The comparison here is the same as a drawing process using a general Z-value buffer, and using the fact that the Z-value of the pixel located in the foreground is the smallest, it is determined whether or not the pixel is a pixel to be displayed. This is performed by comparing with the Z value in the Z value memory.

On the other hand, the Z value comparison unit 2 of the writing memory
At 54, different processing is performed according to the attribute of the polygon being processed. That is, if the polygon being processed is a non-lighting reference polygon, the processing in the Z value comparison unit 254 is not performed. If the polygon being processed is a lighting reference polygon, the Z value of the pixel being processed and the Z values Z1, Z stored in the lighting memories 30, 32
2 is compared. Z1 <Z value of pixel under processing <Z2
, The luminance value of the pixel is increased.
If the polygon being processed is the front side writing polygon, the Z value of the pixel being processed is stored in the first writing memory 30. If the polygon being processed is the back side writing polygon, the Z value of the pixel being processed is stored. The value is stored in the second writing memory 32.

The Z memory interface unit 255
The interface with the value memory 28 is performed, and the writing memory interface unit 256 interfaces with the writing memories 30 and 32.

The pixel drawing permission determining unit 257 determines whether or not to draw a pixel being processed and whether or not to increase the brightness when drawing, and also increases the brightness of the pixels in the writing area. Do. This judgment,
The processing will be described later in detail. The above is the line processing unit 25
It is a structure of.

Further, the drawing engine 24 is provided with a pixel data determination unit 248. The pixel data determination unit 248 finally determines the pixel memory 26 based on the drawing permission signal output from the pixel drawing permission determination unit 257.
Determine the data to be written to That is, when the pixel of the lighting reference polygon being processed is located in the lighting object, processing for increasing the brightness of the polygon color is performed. Otherwise, the polygon color of the pixel is written to the pixel memory 26 as it is. As described above, the pixel data D9 subjected to the lighting process is stored in the pixel memory 26 via the pixel memory interface unit 27. Further, the display pixel readout unit 35 superimposes the pixel data in the pixel memory 26 on the synchronizing signal for, for example, a video signal in the display control unit 26 and provides the image signal D10 to the television receiver 34 as a display device.

FIG. 8 is a detailed flowchart of the processing in the drawing engine of FIG. FIG. 9 is a detailed flowchart of the processing in the line processing unit in the drawing engine. FIG. 10 is a diagram showing transition of data in the writing memory and the pixel memory. Detailed processing will be described according to flowcharts with reference to FIGS.

In drawing one frame, FIG.
As shown in FIG. 0 (a), in the writing memories 1 and 2, a Z value of infinity ∞ is written as an initial value in an area corresponding to each pixel. Also, the pixel memory 2
6 shows the transparent data T in each of the areas corresponding to the pixels.
Is written. These memories preferably have a storage area for each pixel. In order to reduce the memory area, a storage area can be allocated every several pixels.

First, the CPU bus interface unit 24
2 obtains the drawing command data D1 from the CPU 22. This drawing command D1 includes the polygon data shown in FIG. Then, the drawing command latch unit 243
(S40). Drawing command latch unit 243
Is determined by the drawing command analysis unit 244 (S41). In the case of writing non-reference polygon drawing, the writing switch is turned off and both the writing memory 1 switch and the writing memory 2 switch are turned off. Turn off (S42, S4
3). These switches are realized by, for example, flags in a register. In the case of a writing reference polygon, the writing switch is turned on and the writing memory switch is turned off (S44, S45). Further, in the case of the front side writing polygon, the lighting switch is turned on, the switch of the writing memory 1 is turned on, and the switch of the writing memory 2 is turned off (S46, S47). In the case of the back side writing polygon, the switch of the writing memory 2 is turned on (S48, S49).

Next, in the ridge processing unit 245, the coordinates of the start point S and the end point E of the ridge are obtained by interpolation from the vertex coordinates of the polygon included in the drawing command D1 (S50). As shown in FIG. 11, this generates coordinate data for one line. This one line of data D
2 is given to the line processing unit 25, and processing according to the attribute of the polygon determined by the command analysis unit is performed (S51). This process is shown in detail in FIG.

When the above processing is completed for all the lines of the polygon (S52), the processing for one polygon is completed. After the processing for all the polygons in one frame is completed, the display of the frame is performed.

FIG. 9 shows detailed processing in the line drawing unit after the line drawing unit is activated in step S51 of FIG. As shown in FIG. 11, the processing is sequentially performed on the pixels on one line from the start point S to the end point E on the ridge line. One line data is input by the line data latch unit 251 and latched until the processing for one line is completed (S53). Therefore, the coordinates (X, Y) on the screen for each pixel are calculated by the interpolation calculation by the Z value calculation unit 252 (S54). Further, the Z coordinate for each pixel is calculated in the same manner (S55).

If the polygon being processed is a writing polygon, one of the writing memory switches is turned on (S56, S58), so that the Z value comparison unit 254 outputs the corresponding writing memory via the interface unit 256. 30 and 32 indicate the Z of the pixel.
The value is written in the area corresponding to the (X, Y) coordinates in the memory (S57, S59). This is the end of the processing for the lighting polygon.

FIG. 10B shows an example of data in the writing memory at this time. In this example, the Z value of the writing polygon on the near side and the Z value of the writing polygon on the back side are stored in pixels P = 3 to 6 of both writing memories, respectively.

When the polygon being processed is a drawing polygon, the writing memory switches are both off (S56, S58), and the Z value Z 'corresponding to the coordinates (X, Y) is calculated by the Z value comparing unit 253. It is read from the Z value memory 28 (S60). Then, the Z value Z ′ is compared with the Z value Z of the pixel being processed, and if Z <Z ′, it is determined that the pixel being processed is a pixel to be drawn in front of the pixel (S61). ). In that case, the pixel drawing permission determining unit 257 writes a new Z value Z in the Z value memory 28 and updates it (S62).

Further, the lighting switch is turned on (S6).
In the case of 3), since it is a lighting reference polygon,
The determination whether the lighting process is necessary is made by the Z value
4 and the pixel drawing permission determining unit 257. Specifically, the Z value comparison unit 254 reads the respective Z values Z1 and Z2 from the writing memories 1 and 2 (S64,
S65), when the Z value of the pixel being processed is the two Z values Z1 and Z2
Is determined (S66). If the pixel is located between the two Z values Z1 and Z2, it means that the pixel being processed is located within the lighting object, and the pixel data determination unit 248 calculates the pixel color from the polygon data and the luminance value. Is performed (S68).

For example, as shown by the bold line in FIG. 10C, the normal polygons to be drawn are pixels P = 2 to P =
If the drawing is performed up to 7, the Z value Z of the corresponding pixel is compared with the Z values stored in the writing memories 30 and 32. As a result, pixel P = 2, 3, 7
Is determined to be located outside the lighting object, and the color data C is written to the pixel memory 26 as pixel data as it is. Further, for the pixel P = 4.5.6, it is determined that it is located in the lighting object, and the data CC whose luminance value has been increased with respect to the color data is written to the pixel memory 26 as pixel data (S69). ).

When the lighting switch is off (S63), the polygon is, for example, a polygon oriented in a position or a direction from a light source to a shadow and is a non-lighting reference polygon. It is calculated from the polygon data (S67).
No processing of the lighting effect is performed. And finally,
The data is written to the pixel memory 26 (S6
9).

As described above, first, the drawing processing is performed on the writing polygon, and the Z is stored in the writing memory.
After the value has been written, the drawing processing of the drawing target polygon is performed. In this case, the writing reference polygon is compared with the Z value of the writing memory, and in the case of a writing target polygon, a process of increasing the brightness value is performed. To determine whether a pixel is to be displayed or not, as usual, using the Z value memory, only the color data of the pixel having the foremost Z value is written to the pixel memory (frame memory) as pixel data.

FIG. 12 is a diagram showing a case where a plurality of light sources are included in one frame and a plurality of lighting objects are present. In FIG. 12, the light sources 10A and 10A
B has lighting objects 20A and 20B. In this example, lighting object 2
0A is located closer to the screen. In such a case, if an object obtained by combining both the lighting objects is set as a lighting object, the shape may not be a convex object but a concave object. In such a case, there is a possibility that a process of increasing the luminance value is performed on a pixel located between the two Z values of the writing memory even though the convex portion is not irradiated with light.

Therefore, in this embodiment, when a plurality of light sources are present, a pair of lighting memories is allocated to each lighting object. FIG. 13 is a diagram showing the writing memories (FIGS. 13 (1) to (4)) assigned to the lighting objects 20A and 20B in the case of the example of FIG. As in the case of FIG. 3, the Z values at pixels on a certain horizontal line of the display screen are indicated by thick lines. The dashed line indicates the opposite Z value of the same lighting object.

As described above, by providing a pair of lighting memories for each lighting object, the lighting object can always be handled as a convex object. Therefore, the lighting process for a plurality of light sources can be easily performed on an extension of the above process.

[Example of Process for Providing Effects Other than Lighting Effect] In the above-described embodiment, the lighting object region for the light source is subjected to lighting processing such as increasing the luminance value after that as a region to be irradiated with light. . However, it is also possible to give an effect other than lighting by using the determination as to whether or not the Z value of the pixel being processed is located within an arbitrary object.

FIG. 14 is a diagram for explaining a case where shading processing is performed on a partial surface of a polygon using a shading object. The example of FIG.
This is an example in the case where there is an object 100 that blocks the light. For example, due to the presence of the light source 10 having no directivity, polygons in the screen are subjected to a process of uniformly increasing the luminance value. However, due to the presence of the shield 100, a shading area 120, which is a shadow thereof, is generated on the polygons 111, 112, and 113 of the steps. In order to generate the shading area 120, the shading object 110 based on the same concept as the above-described lighting object is used.

That is, a shading object 110 formed by the light source 10 and the shield 100 is generated by the CPU, and a shading polygon constituting the shading object is generated. In the subsequent processing, as in the case of the lighting object described above, the Z values of the front and rear shading polygons are stored in a pair of shading memories. A determination is made as to whether it falls between the Z values of both shading memories. If the pixel falls within the range, shading processing such as lowering the luminance value of the pixel is performed.

Therefore, by adding an attribute called a shading polygon and adding a shading memory, a shading effect can be given to a partial area on the polygon surface by the same simple arithmetic processing as in the case of a lighting object.

FIG. 15 is a diagram showing an example of a three-dimensional clipping object. In the example of FIG. 15, a process of partially displaying the internal state of the object using the three-dimensional clipping object is performed. FIG. 15A shows an example in which bookshelf objects are displayed. Polygons 131, 132, 133 that make up the bookshelf object
Is not visible from the screen of FIG.

Therefore, in this embodiment, for example, a spherical three-dimensional clipping object is introduced. The three-dimensional clipping object is not drawn in the pixel memory like the lighting object, and the Z value on the far side and the Z value on the near side are stored in a pair of clipping memories. If the pixel being processed for the drawing polygon is located between the Z values of the clipping memory, a clipping process of not writing any data in the pick cell memory is performed on the pixel. That is, this is a process in which pixels located in the three-dimensional clipping object are not drawn. As a result, the position where the clipping object is present is displayed with a scrambled effect. By the clipping process, the Z value of the pixel is not written in the Z value memory.

In FIG. 15B, since the polygon at the position of the spherical three-dimensional clipping object 130 (not shown) is not displayed, the polygons 131 and 1 are used in this example.
32 is hidden, and the inner side of the polygon 133 is displayed. Such an effect is used, for example, when there is a request to display the inside of a desired part while maintaining the appearance in a residential building. In addition, the processing can be performed by simple arithmetic processing as in the case of the above-described lighting object.

As described above, the present invention is not limited to the lighting effect processing using a lighting object, but is also applied to a shading effect processing using a shading object, a clipping processing for partially removing using a three-dimensional clipping object, and the like. be able to. Each pair of memories stores the Z value, determines whether or not the drawing polygon is located between those Z values, and increases the luminance value for the pixels located between them. By performing corresponding processing such as lowering the value or not drawing, the drawing processing can be easily performed.

[Example of General-Purpose Computer] FIG. 16 is a configuration diagram of an image processing apparatus when the above-described image processing is performed using a general-purpose computer. When image processing is performed using a general-purpose computer, image processing calculations are performed according to a program stored in a recording medium. Therefore, the general-purpose computer operates as a computer dedicated to image processing by storing the image processing program in a computer-readable recording medium. The image processing program causes a computer to execute the procedures described in the flowcharts and the like.

In the example shown in FIG. 16, the CPU 23
The AM 231 and the ROM 232 storing the game program and the image processing program are connected to the bus 236.
The input / output unit 233 connected to the bus 236 is connected to an operation unit 234 operated by an operator, and inputs an operation signal. For image processing, a Z-value memory 28 and lighting memories 30 and 32 are provided.
6 is connected. The pixel memory 26, which is a frame memory, is also connected to the bus 236, and is also connected to an external display device.

In this example, the image processing program is a ROM
232, but besides, an external CD
From a recording medium 235 such as a ROM or a magnetic tape to a RAM 2
An image processing program can be installed in the server 31.

In the above-described embodiment, the determination as to whether or not the pixel is a pixel to be displayed is made by using the Z value memory 28. However, in the case where the drawing polygons are already sorted and supplied in descending order of the Z value, they are supplied. Does not require the Z-value memory 28.

[0072]

As described above, according to the present invention, the lighting object is used for the light source, and the writing memory for storing the Z values of the lighting objects on the near side and the back side of the screen is provided. By determining whether or not the pixel is located between the Z values of the pair of writing memories, it is possible to give a lighting process such as increasing the luminance value to some pixels in the polygon. Therefore, with little hardware and simple arithmetic processing without making significant changes to the conventional drawing circuit,
Lighting processing, which was conventionally difficult, can be performed.

Further, according to the present invention, a pair of memories corresponding to the shading objects and the clipping objects are provided in the same way as the above-mentioned lighting objects, and the near side and the back side of the respective shading objects and the clipping objects are provided in these memories. Is written, and when a pixel to be drawn is located between the two Z values, a corresponding process can be performed. Therefore, shading processing and clipping processing of an arbitrary area can be provided by adding simple hardware and simple arithmetic processing.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a lighting effect.

FIG. 2 is a diagram illustrating a lighting object according to the embodiment.

FIG. 3 is a diagram illustrating a writing memory.

FIG. 4 is an overall configuration diagram of an image processing apparatus according to the embodiment.

FIG. 5 is a diagram illustrating a configuration example of polygon data according to the embodiment;

FIG. 6 is a flowchart illustrating an example of image processing involving lighting processing.

FIG. 7 is a diagram showing a detailed configuration of a drawing engine.

FIG. 8 is a detailed flowchart of the processing in the drawing engine of FIG. 7;

FIG. 9 is a detailed flowchart of processing in a line processing unit in the drawing engine.

FIG. 10 is a diagram showing transition of data in a writing memory and a pixel memory.

FIG. 11 is a diagram illustrating a raster scan.

FIG. 12 is a diagram illustrating a case where a plurality of lighting objects exist.

FIG. 13 is a diagram showing a writing memory assigned to each of the writing objects 20A and 20B.

FIG. 14 is a diagram illustrating a case where shading processing is performed on a partial surface of a polygon using a shading object.

FIG. 15 is a diagram illustrating an example of a three-dimensional clipping object.

FIG. 16 is a configuration diagram of an image processing apparatus when performing image processing using a general-purpose computer.

[Explanation of symbols]

 Reference Signs List 10 light source 20 lighting object 24 drawing processing unit, drawing engine 26 pixel memory 28 Z value memory 30, 32 writing memory 34 display device 110 shading object 130 clipping object

Claims (9)

[Claims] 1. An image processing apparatus which is provided with polygon data including coordinate data and color data in a display screen for a polygon constituting an object, and performs drawing processing of pixels in each polygon in accordance with the coordinate data. The polygon has a drawing target polygon on which the drawing process is performed and a lighting polygon that constitutes a writing object of a target region of the lighting process.The image processing apparatus includes, in the writing polygon, a front side of the display screen. A first writing memory in which a Z value of a pixel in a located writing polygon is written; and a second writing memory in which a Z value of a pixel in a writing polygon positioned at the far side of the display screen among the writing polygons is written. Displayed on the display screen A pixel memory in which color data of a pixel to be written is written; and a Z value of a pixel in the polygon to be drawn is determined from the coordinate data, and a Z value of the pixel is between a Z value in the first and second writing memories. An image processing device comprising: a rendering processing unit that performs a lighting process for increasing the luminance value on the color data of the pixel when the pixel data is located in the pixel data and writes the color data subjected to the lighting process to the pixel memory. 2. The drawing processing unit according to claim 1, wherein when the data of the writing polygon is given, the drawing processing unit obtains a Z value of a pixel in the writing polygon from the coordinate data, and determines a Z value of the pixel. An image processing apparatus for writing in a first or second writing memory. 3. The rendering target polygon according to claim 1, wherein the rendering target polygon further comprises a writing target polygon and a non-writing target polygon. The writing process is performed according to the Z value of the pixel in the pixel, and when the rendering target polygon is a non-writing target polygon, the color data of the pixel is written to the pixel memory without performing the lighting process. Image processing device. 4. The method according to claim 1, wherein a plurality of pairs of the first and second lighting polygons are provided corresponding to a plurality of lighting objects.
The image processing apparatus, wherein the drawing processing unit compares the Z value of a pixel in the drawing target polygon with the Z value in the plurality of pairs of first and second writing polygons. 5. An image processing method wherein polygon data including coordinate data and color data in a display screen is given to a polygon constituting an object, and a drawing process of a pixel in each polygon is performed according to the coordinate data. The polygon has a drawing target polygon on which the drawing processing is performed and a lighting polygon that constitutes a writing object of a target area of the lighting processing.The image processing method includes the steps of: The Z value of the pixel in the writing polygon is obtained from the coordinate data, and the Z value of the pixel of the writing polygon located on the near side and the back side of the display screen is stored in the corresponding first and second writing memories. A writing polygon drawing process to be written; Given the data of the gon, the Z value of a pixel in the polygon to be drawn is obtained from the coordinate data, and the Z value of the pixel is located between the Z values in the first and second writing memories. In that case, a lighting process for increasing the luminance value is performed on the color data of the pixel,
A rendering target polygon rendering step of writing the lighting-processed color data into a pixel memory. 6. Polygon data including coordinate data and color data in a display screen is given to polygons constituting an object, and an image processing program for drawing a pixel in each polygon in accordance with the coordinate data is recorded. In the machine-readable recording medium described above, the polygon has a drawing target polygon on which the drawing process is performed and a writing polygon constituting a writing object in a target region of the writing process, and the image processing program includes: Is given, the Z value of the pixel in the writing polygon is obtained from the coordinate data, and the Z value of the pixel of the writing polygon located on the near side and the back side of the display screen is corresponding to the first value. And a line to be written into the second writing memory. A drawing polygon drawing procedure, and when data of the drawing target polygon is given, a Z value of a pixel in the drawing target polygon is obtained from the coordinate data, and the Z value of the pixel is stored in the first and second writing memories. Performing lighting processing to increase the luminance value on the color data of the pixel when the pixel is located between the Z values in
A recording medium storing an image processing program for causing a computer to execute a rendering target polygon rendering procedure for writing the lighting-processed color data into a pixel memory. 7. An image processing apparatus which is provided with polygon data including coordinate data and color data in a display screen for polygons constituting an object, and performs drawing processing of pixels in each polygon in accordance with the coordinate data. The polygon includes a drawing target polygon on which the drawing processing is performed and a special processing polygon that forms a special processing object in a target area of the special processing. The image processing apparatus includes: A first special processing memory in which the Z value of a pixel in the special processing polygon positioned on the near side is written, and a Z value of a pixel in the special processing polygon positioned on the back side of the display screen among the special processing polygons A second special processing memory to be written, and a pixel to which color data of a pixel displayed on the display screen is written. A cell memory, a Z value of a pixel in the polygon to be drawn is obtained from the coordinate data, and if the Z value of the pixel is located between the Z values in the first and second special processing memories, And a drawing processing unit for performing a special process on the color data. 8. The image processing apparatus according to claim 7, wherein the special processing is shading processing for lowering a luminance value, and the special processing object is a shading object that forms a shadow on a light source. 9. The special process according to claim 7, wherein the special process is a process in which color data of a pixel located in the special process object is not written in the pixel memory. An image processing apparatus, wherein the image processing apparatus is a clipping polygon that prohibits polygon drawing.