JPH05210744A - Device and method for plotting computer graphics - Google Patents

Abstract

PURPOSE:To rapidly plot three-dimensional graphics. CONSTITUTION:A plotter for executing plotting processing by a graphic processor capable of simultaneously writing n pixels in a frame memory 21 as one processing unit is provided with a pixel setting part 11 for extracting data for one processing unit including n pixels, or all stored pixels when all the pixels are <= n pixels from a plotting data storing part 4, a pixel storing part 9 for storing data for one processing unit, a plotting pixel length judging part 12 for judging pixel length stored in the storing part 4, and a mask forming part 15 for forming a mask to mask a data part other than pixels to be plotted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing apparatus and a drawing method for drawing data to be drawn in a frame memory in three-dimensional computer graphics.

Although three-dimensional computer graphics are used in various fields such as animation and simulation, it is necessary to draw realistic depiction at high speed.
Therefore, development of a high-speed three-dimensional computer graphics device is desired.

[0003]

2. Description of the Related Art FIG. 6 shows a conventional three-dimensional computer graphics drawing method. In the figure, reference numeral 110 denotes a new graphic, which represents the graphic currently being drawn. 111
Represents an old figure that has already been drawn and stored in the frame memory. Reference numeral 112 represents drawing target data of a new figure, and 1-pixel data is composed of position, color, color inclination, Z value, Z value inclination, and the like.
In the figure, black circles are pixels to be drawn, and white circles are pixels outside the drawing area (hereinafter the same).

A drawing data holding unit 113 holds drawing target data. Reference numeral 114 denotes a drawing processing unit that performs drawing processing on the pixels held in the drawing data holding unit 113. A Z buffer 115 holds the Z value of a pixel. 1
Reference numeral 16 denotes a pixel holding unit, which is a drawing data holding unit 11
The number of pixels taken out by each processing unit (the number of pixels that can be written at one time, for example, 4 pixels) from 3 is held. Reference numeral 117 denotes a Z value holding unit that holds the Z value of the pixel set in the pixel holding unit 116.

Reference numeral 120 is a processing pixel length determination unit,
The pixel length (1 span) of the drawing target data held in the drawing data holding unit 113 is determined, and the pixel processing number (4 pixels or 1 pixel) is determined.

Reference numeral 121 denotes a pixel length calculation unit, which initially determines that the pixel is 15 pixels (the number of pixels of the drawing target data 112) in the figure. Then, after extracting 4 pixels, 11 pixels are determined. Reference numeral 122 denotes a 4-pixel processing instruction unit, which is a pixel length calculation unit 12
When the calculation result of 1 is, for example, 4 pixels or more, 4 pixel processing is instructed. Reference numeral 123 denotes a 1-pixel processing instructing unit, which instructs processing for each pixel when the calculation result of the pixel length calculating unit 121 is 4 pixels or less. Reference numeral 124 denotes a pixel setting unit that takes out 4 pixels or 1 pixel at a time from the drawing data holding unit 113 and sets them in the pixel holding unit 116.

Reference numeral 125 is a Z value comparison unit, which is used for the Z of the old figure.
The value (Z value stored in the Z buffer 115) is compared with the Z value of the new figure held in the Z value holding unit 117. Reference numeral 126 is a Z value updating unit, which is a Z value comparing unit 1
The Z buffer 115 is updated based on the comparison result of 25.

Numeral 127 is a mask generation unit, and according to the comparison result of the Z value comparison unit 125, for example, if the Z value of the new figure is smaller than the Z value of the old figure, the value "1" is set at the bit position of the corresponding mask. Is set and the Z value of the new figure is the Z of the old figure.
If it is larger than the value, the value "0" is set in the bit position of the corresponding mask.

Reference numeral 128 denotes a frame memory writing unit, which if the value of the mask 130 is a value (“1”) that indicates updating of the frame memory, sets the corresponding pixel held in the pixel holding unit 116 to the frame memory. When the value is written in 131 and the value of the mask 130 is a value (“0”) indicating that the frame memory is not updated, the corresponding frame memory 131 is not updated.

Reference numeral 130 denotes a mask, which is a Z value comparison unit 12
Based on the comparison result of No. 5, a mask for determining whether to update the frame memory 131 with the pixel of the new figure or to keep the pixel value of the old figure is generated. For example, when the Z value of the new figure is smaller than the Z value of the old figure (when the new figure is closer to the viewpoint than the old figure), the value "1" that indicates to update the frame memory 131 with the pixel value of the new figure. Is set and the Z value of the new figure is the Z of the old figure.
When it is larger than the value (when the new figure is farther from the viewpoint than the old figure), the value "0" is set to instruct not to update the value in the frame memory 131.

Reference numeral 131 is a frame memory for expanding the pixels to be displayed on the display. 132
Is a display for displaying the drawing developed in the frame memory on the screen.

FIG. 7 is a flow (1) of the conventional drawing method. FIG. 8 is a flow (2) of the conventional drawing method, which is a continuation of the flow (1) (FIG. 7) of the conventional drawing method. Figure 7,
The flow of the figure will be described according to the parenthesized numbers in FIG. If necessary, refer to FIG.

(1) The pixel setting unit 124 sets the value of the pixel (4 pixels) to be drawn as the pixel holding unit 1.
Set to 16. (2) Z value holding unit 1 for the Z value of the drawing target pixel
Set to 17.

(3) The processed pixel length determination unit 120 calculates the pixel length. If the pixel length is 4 or more, the process proceeds to (4), and if it is less than 4 or less, the process proceeds to FIG. 8 (S). (4) The Z value comparison unit 125 is the Z buffer 1 for each pixel.
The Z value of 15 and the Z value of the Z value holding unit 117 are compared.

(5) Z buffer 11 for Z value of 4 pixels
Store to 5. That is, the Z value of the comparison result of the Z value comparison unit 125 is written in the Z buffer 115. (6), (7) Store the pixel value of the frame memory 131 (4 pixels). That is, if the Z value of the drawing data of the new figure is smaller than the Z value of the old figure as a result of the comparison by the Z value comparing section 125, the mask generating section 127 sets "1" to the mask 130. If the Z value held in the Z buffer is smaller than the Z value held in the Z value holding unit 117, “0” is set in the mask 130.

The frame memory writing unit 128 has the pixels and masks 13 set in the pixel holding unit 116.
Compare 0, write the pixel value for which “1” is set in the mask 130 to the frame memory 131, and update it.
Pixels set to "0" do not update the pixel value written in the frame memory.

(8) The pixel length calculation unit 121 decrements the pixel length by 4 (subtracts 4 from the held value). (9) The pixel setting unit 124 sets the value of the next pixel (4 pixels) to be drawn in the pixel holding unit 116.

(10) The pixel setting unit 124 sets the Z value of the next pixel (4 pixels) to be drawn as the Z value holding unit 1.
Set it to 17 and repeat the following process (3). Next, (3)
In FIG. 8, a flow in the case where the processed pixel length determination unit 120 determines that the pixel length is less than 4 will be described with reference to FIG.

(11) It is determined whether the pixel length calculated by the pixel length calculation unit 121 is> 0 (positive). If positive
Proceed to (12), and if not positive, the process ends. (12) The pixel length calculation unit 121 decrements the pixel length by 1.

(13), (14) The Z value comparison unit 125 sets the Z value of one pixel from the Z buffer 115. The Z value of the pixel to be drawn is compared with the Z value of the Z buffer. As a result, if the Z value of the drawing target pixel is smaller than the Z value of the Z buffer, the pixel is a drawing target pixel and the process proceeds to (15). If the Z value of the drawing target pixel is larger than the Z value of the Z buffer, it is not the drawing target pixel, and therefore the processing from (11) is repeated.

(15) If the Z value of the pixel to be drawn is smaller than the Z value of the Z buffer, the frame memory writing unit 128 writes the pixel value in the frame memory 131 (in the case of processing for each pixel, the mask 130 Generation control is not performed).

(16) The Z value updating unit 126 calculates the Z of the comparison result.
Store the value in the Z buffer and update.

[0023]

In the above-described conventional drawing processing, when the span pixel length is equal to or longer than the processing unit (4 pixels), high speed drawing is possible, but the span pixel length is equal to the processing unit (4 pixels). In the following cases, it was necessary to compare Z values pixel by pixel and draw in the frame memory, so the drawing speed was slow.

It is an object of the present invention to provide a drawing device and a drawing method capable of drawing three-dimensional graphics at high speed even when the number of pixels included in one span is less than a processing unit (for example, 4 pixels). ..

[0025]

According to the present invention, even if the number of pixels in one span is less than a processing unit (for example, 4 pixels), the mask generation control of the CPU is used, and data other than pixels is used as the processing unit data. If there is data, that part is masked so that it cannot be written to the frame memory, and even in such a case, it is possible to write to the frame memory in processing units.

FIG. 1 shows the basic configuration of the present invention. In FIG. 1, 1 represents a drawing target figure. Reference numeral 2 is drawing target data. In the drawing target figure 1, A, B, and C are pixels given as input (position as a pixel value,
It has colors, color gradients, Z values, Z value gradients, etc.). The pixel value of the point D is calculated from the pixel values of the points A and B. Further, the pixel value of the point E is calculated from the pixel values of the points A and C. The pixel value of the pixel between the points D and E in the drawing target data 2 is calculated from the pixel values of the points D and E.

Reference numeral 3 is a drawing data input unit for inputting drawing target data 2. A drawing data holding unit 4 holds the drawing target data 2. 5
Indicates a processing unit that can be processed by the CPU with one access, and the figure shows a case of 4 pixels as an example (hereinafter, the case of 4 pixels will be described). Reference numeral 6 denotes a drawing unnecessary portion, which represents data other than the drawing target data (pixels) included in the processing unit.

Reference numeral 7 denotes a Z buffer, which is the Z of the old graphic (the graphic of the pixel currently written in the frame memory).
It holds a value. A Z value holding unit 8 holds the Z value of the new figure (drawing target data).

A drawing processing unit 10 performs drawing processing for writing the pixels held in the drawing data holding unit 4 into the frame memory. Reference numeral 11 denotes a pixel setting unit, which extracts a processing unit (4 pixels) from the pixels held in the drawing data holding unit 4,
The pixel value is set in the pixel holding unit 9 and the Z value holding unit 8 is set.
To set the Z value. Reference numeral 12 is a drawing pixel length determination unit, which is stored in the drawing data storage unit 1
The pixel length of the span is calculated. A Z value comparison unit 13 compares the Z value held in the Z buffer 7 and the Z value held in the Z value holding unit 8 for each pixel. A Z value updating unit 14 updates the Z buffer 7.

Reference numeral 15 denotes a mask generation unit, which determines the Z value of the pixel held in the pixel holding unit 9 based on the Z value comparison result of the Z value comparison unit 13 from the Z value held in the Z buffer 7. If it is larger, a value “0” that prohibits writing to the frame buffer is set in the mask 20 and the Z value of the pixel held in the pixel holding unit 9 is smaller than the Z value held in the Z buffer 7. Is mask 2
Value "1" that allows writing to the frame buffer to 0
Is to be set. Further, based on the determination result of the drawing pixel length determining unit 12, the mask generating unit 15 determines that the mask 20 is used when the processing unit includes data other than pixels (the drawing unnecessary portion 6 in the drawing data holding unit 4). A value "0" that prohibits writing to the frame memory 21 is set in that portion of the.

Reference numeral 16 denotes a frame memory writing unit which masks the pixels held in the pixel holding unit 9 with a mask 2
0 is referred to and the writing process is performed in the frame memory 21. Reference numeral 21 is a frame memory.

[0032]

In the basic configuration shown in the figure, the operation when the number of pixels held in the drawing data holding unit 4 is the processing unit (for example, 4 pixels) or more is the same as that in the conventional technique (FIG. 6). Is omitted.

A case where the number of pixels held in the drawing data holding unit 4 is 4 pixels or less in the basic configuration of the drawing will be described with reference to an example shown in the figure (two pixels).
The pixel holding unit 9 holds two pixels as illustrated. The Z values of the two pixels held in the pixel holding unit 9 are smaller than the corresponding Z values stored in the Z buffer 7. As a result, the value “1” is written in the mask 20 corresponding to the pixel held in the corresponding drawing data holding unit 4.

The drawing pixel length judgment unit 12 judges that the drawing target data is 2 pixels, and the mask generation unit 15
To notify. The mask generation unit 15 writes a write-inhibit mask “0” to the portion (drawing unnecessary portion 6) that should not be written in the frame memory based on the designated pixel length.
To set.

The frame memory writing unit 16 refers to the mask 20 for the data of the pixels of the pixel holding unit 9 and the unnecessary portion, and writes the pixels whose writing is not prohibited in the frame memory.

(Note that the operation of the basic configuration of FIG. 1 will be described in detail in the description of FIG. 5.)

[0037]

FIG. 2 shows an embodiment of the system configuration of the present invention.
In the figure, reference numeral 30 denotes a main processor, which performs processing of the entire system. Reference numeral 31 is a main storage unit, and 32 is a graphics processor, which performs drawing processing. Reference numeral 33 is a drawing processing means for performing writing processing to the frame memory by the graphics processor 32. Reference numeral 34 is a frame memory, 35 is a display, 36 is a disk control unit, and 37 is a disk device for storing drawing data, drawing results and the like. Reference numeral 38 is an input control unit, and 39 is an input device, which is a keyboard, a mouse, a tablet, or the like.

FIG. 3 shows an embodiment of the Z value comparison processing and mask of the present invention. Figure (a) shows the Z value comparison process. In the figure, (A) is a Z buffer, which is composed of four 32-bit registers 40, 41, 42, 43. Each register has a Z value of 4 pixels (OldZ
1, OldZ2, OldZ3, OldZ4) are stored.

(B) is a Z value holding unit, which is composed of four 32-bit registers like the Z buffer. Z value of drawing target data in each register (NewZ1, NewZ2, NewZ3, NewZ4)
Is stored.

(C) represents a register for storing the comparison result by the Z value comparison unit, and is composed of four 32-bit registers like the Z buffer. The Z value of the Z buffer (A) and the Z value holding unit (B) are compared pixel by pixel by the Z value comparison instruction (compare), and the smaller one of the comparison result Z values (StoreZ1, StoreZ2, StoreZ).
3, StoreZ4) is stored. Then, a pixel drawing mask is set in the control register in the graphics processor according to the comparison result of the Z values.

FIG. 3B shows an embodiment of the mask. In the figure, (D) is a pixel holding unit, which is composed of four 32-bit registers 50, 51, 52, and 53, each of which has a pixel value (Pixel1, Pixel2, Pi).
xel3, Pixel4) are retained.

(E) is a control register (32 bits) in the graphics processor, which uses 24 to 31 bits as a mask and can control up to 8 pixels. As a result of the Z value comparison instruction, a mask is set in the mask 55 of the control register (E) (the 24th bit becomes the mask of the first pixel).

FIG. 4 shows a mask embodiment for data other than pixel data according to the present invention. (a) shows an example of drawing target data. Write 4 pixels to the frame buffer with 4 pixels as the processing unit. Reference numeral 60 indicates a case where the drawing target data is 2 pixels and the processing unit includes data other than pixels for 2 pixels.

(B) shows an embodiment of a mask outside the drawing target area. In the figure, 61 is a control register (32 bits), which uses 24 to 31 bits as a mask (same as the control register (E) in FIG. 3). 6
2 shows an example of a mask for the drawing target data 60 in FIG.

Reference numeral 63 is a mask bit set for a pixel which is a drawing target by the Z value comparison command, and 64 is a mask bit which prohibits drawing in an area which is not a drawing target.

According to the present invention, of data (pixels) held in the pixel holding unit (data written in pixels and portions outside the drawing area) that are not prohibited from being written in the frame memory by the mask, Only the frame memory store instruction writes to the frame memory, and data other than pixels is prohibited by the mask and is not written to the frame memory.

The flow of the drawing processing means of the present invention will be described with reference to FIG. Refer to FIG. 1 and FIG. 3 as needed. (1) The pixel setting unit (Fig. 1 (1)) stores the value of the pixel (4 pixels) that is the drawing target in the pixel holding unit (Fig. 1).
(9), set in Fig. 3 (D).

(Hereinafter, in the reference numerals, the numerals are the reference numerals of FIG. 1 and the alphabets are the reference numerals of FIG. 3.) (2) The pixel setting unit is a Z value (4 pixels Minute) is set in the Z value holding unit (8, B).

(3) The drawing pixel length determination unit (12) determines whether the pixel length is 4 or more in one span. If it is 4 or more, proceed to (4). If it is 4 or less, proceed to (11). (4) The Z value comparison unit (13) compares the Z value of the Z buffer (7, A) with the Z value of the Z value holding unit (8, C), and the smaller Z value is the Z value comparison result. (C) is obtained. Then, the mask generation unit (15) determines the mask (20, E) based on the comparison result of the Z values.
To generate mask bits.

(5) The Z value updating unit (14) stores the Z value comparison result (C) in the Z buffer (7, A). (6) The frame memory writing unit (16) stores a pixel value of a pixel held in the pixel holding unit (9, D) for which writing is not prohibited by the mask (20, E) in the frame memory ( Write in 21).

(7) Count the Z buffer and frame memory addresses. (8) The drawing pixel length determination unit (12) decrements the pixel length (subtracts 4 from the pixel length held in the pixel holding unit (9, D)).

(9) The pixel setting unit (11) sets the value of the pixel (4 pixels) to be drawn in the pixel holding unit (9, D). (10) The pixel setting unit (11) sets the Z value of the pixel (4 pixels) that is the drawing target in the Z value holding unit (8, E), and repeats the processing from (3).

(11) The Z value comparison unit (13) compares the Z values with the Z value comparison instruction, and the mask generation unit (15) uses the mask value (20) of the control register (E) based on the comparison result of the Z values. , Fig. 3
A mask bit is generated in (55)). Furthermore, since the pixel length of one span is 4 or less, the mask generation unit (15)
Is a mask portion (20, FIG. 3 (5) of the control register (E).
5)) Set the write-inhibit bit value to the bits not subject to drawing.

(12) The frame memory writing unit (16) sets the write inhibit bit value in the mask portion (20, FIG. 3 (55)) of the control register (E) among the pixels of the pixel holding unit (9, D). Write the pixel value corresponding to the unmarked bit to the frame memory (21).

(13) Write the Z value of the Z value comparison result (C) in the Z buffer (7, A).

[0056]

According to the present invention, in three-dimensional graphics drawing, processing such as Z value comparison and writing to the frame memory can be performed in units of a plurality of pixels, so that the drawing speed is increased. It

Therefore, the drawing efficiency in three-dimensional graphics can be significantly improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention.

FIG. 2 is a diagram showing a system configuration example of the present invention.

FIG. 3 is a diagram showing an embodiment of a Z value comparison process and a mask of the present invention.

FIG. 4 is a diagram showing a mask embodiment for data other than pixel data of the present invention.

FIG. 5 is a diagram showing a flow of drawing processing means of the present invention.

FIG. 6 is a diagram showing a conventional three-dimensional computer graphics rendering method.

FIG. 7 is a diagram showing a flow (1) of a conventional drawing method.

FIG. 8 is a diagram showing a flow (2) of a conventional drawing method.

[Explanation of symbols]

 1: Drawing target figure 2: Drawing target data 3: Drawing data input part 4: Drawing data holding part 5: Processing unit 6: Drawing unnecessary part 7: Z buffer 8: Z value holding part 9: Pixel holding part 10: Drawing processing Means 11: Pixel setting unit 12: Drawing pixel length determination unit 13: Z value comparison unit 14: Z value updating unit 15: Mask generation unit 16: Frame memory writing unit 20: Mask 21: Frame memory

Claims (3)

[Claims] 1. A drawing data holding drawing target data (2) in a drawing device which performs drawing processing by a graphics processor capable of writing n pixels at a time into a frame memory (21) with n pixels as one processing unit. Includes the holding unit (4) and n pixels from the drawing data holding unit (4), or all held pixels if the number of pixels held in the drawing data holding unit (4) is less than n pixels A pixel setting unit (11) that extracts data for one processing unit and n extracted from the pixel setting unit (11)
A pixel holding unit (9) holding pixels or data for one processing unit, a frame memory (21) into which a pixel to be drawn is written from the pixels held in the pixel holding unit (9), and a drawing data holding unit ( 4) The drawing pixel length judgment unit (12) that judges the pixel length held in the pixel holding unit based on the judgment results of the drawing pixel length judgment unit (12)
A computer graphics, comprising: a mask generation unit (15) for generating a mask for masking a data portion other than a drawing target pixel in the data for one processing unit held in (9). Drawing device. 2. A drawing data which holds drawing target data (2) in a drawing method in which drawing processing is performed by a graphics processor capable of writing n pixels at a time into a frame memory (21) with n pixels as one processing unit. Includes the holding unit (4) and n pixels from the drawing data holding unit (4), or all held pixels if the number of pixels held in the drawing data holding unit (4) is less than n pixels A pixel setting unit (11) that extracts data for one processing unit and n extracted from the pixel setting unit (11)
A pixel holding unit (9) holding pixels or data for one processing unit, a frame memory (21) into which a pixel to be drawn is written from the pixels held in the pixel holding unit (9), and a drawing data holding unit ( 4) The drawing pixel length judging unit (12) for judging the pixel length held in, and the processing unit held in the pixel holding unit (9) from the judgment result of the drawing pixel length judging unit (12) The data part other than the drawing target pixel of the minute data is masked, and the writing to the frame memory (21) is performed by masking the n pixels held in the pixel holding unit (9) or the data for one processing unit. A drawing method in computer graphics, characterized in that only non-inhibited pixels are written to the frame memory (21). 3. A Z-buffer (7) for holding a Z value of a pixel being drawn, and a Z of drawing target data according to claim 1, wherein the drawing device draws a three-dimensional figure.
It is provided with a Z value holding unit (8) for holding values and a Z value comparing unit (13) for comparing the Z value of the Z buffer (7) and the Z value of the Z value holding unit (8) for each pixel. The generation unit (15) has a Z value comparison unit (1
A mask (20) is generated based on the result of 3), and
A drawing device in computer graphics, characterized in that a mask is generated based on a comparison result of a drawing pixel length determination unit (12).