JP3027777B2 - Drawing apparatus and drawing method in computer graphics - Google Patents

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 depictions 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 drawing method of three-dimensional computer graphics. In the figure, reference numeral 110 denotes a new figure, which is a figure currently being drawn. 111
Represents an old graphic which has already been rendered and stored in the frame memory. Reference numeral 112 denotes drawing target data of a new figure, and data of one pixel is composed of a position, a color, a gradient of a color, a Z value, a gradient of a Z value, and the like.
In the figure, black circles represent pixels to be rendered, and white circles represent pixels outside the rendering area (the same applies hereinafter).

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

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

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

Reference numeral 125 denotes a Z-value comparison unit, which is a Z-value comparison unit for the old figure.
The value (the 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 denotes a Z value updating unit, which is a Z value comparing unit 1
The updating process of the Z buffer 115 is performed based on the comparison result of 25.

Reference numeral 127 denotes a mask generation unit. 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 Z
If the value is larger than the value, the value "0" is set to the bit position of the corresponding mask.

Reference numeral 128 denotes a frame memory writing unit. If the value of the mask 130 is a value (“1”) instructing updating of the frame memory, the corresponding pixel held in the pixel holding unit 116 is stored in the frame memory. If 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 comparing unit 12
Based on the comparison result of No. 5, a mask for determining whether to update the frame memory 131 with the pixels of the new figure or to keep the pixel values of the old figure as it is is generated. For example, when the Z value of the new graphic is smaller than the Z value of the old graphic (when the new graphic is closer to the viewpoint than the old graphic), a value “1” indicating that the frame memory 131 is updated with the pixel values of the new graphic. Is set, and the Z value of the new figure is Z
If the value is larger than the value (when the new graphic is farther from the viewpoint than the old graphic), a value “0” is set to instruct not to update the value of the frame memory 131.

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

FIG. 7 is a flowchart (1) of a conventional drawing method. FIG. 8 shows the flow (2) of the conventional drawing method, which is a continuation of the flow (1) (FIG. 7) of the conventional drawing method. FIG.
The flow of the figure will be described according to the bracket numbers in FIG. Refer to FIG. 6 as necessary.

(1) The pixel setting unit 124 stores the value of the pixel (four pixels) to be drawn in the pixel holding unit 1
Set to 16. (2) The Z value of the pixel to be drawn is stored in the Z value holding unit 1
Set to 17.

(3) The processing pixel length determination unit 120 calculates the pixel length. If the pixel length is 4 or more, the process proceeds to (4). If the pixel length is less than 4, the process proceeds to FIG. (4) The Z value comparison unit 125 operates in the Z buffer 1
The Z value of 15 and the Z value of the Z value holding unit 117 are compared.

(5) Z buffer 11 of 4-pixel Z value
5 is stored. That is, the Z value of the comparison result of the Z value comparison unit 125 is written to the Z buffer 115. (6), (7) Store the pixel value in the frame memory 131 (4 pixels). That is, if the Z value of the drawing data of the new graphic is smaller than the Z value of the old graphic as a result of the comparison by the Z value comparing unit 125, the mask generation unit 127 sets “1” to the mask. If the Z value stored in the Z buffer is smaller than the Z value stored in the Z value storage unit 117, “0” is set in the mask.

The frame memory writing section 128 stores the pixels set in the pixel holding section 116 and the mask 13
0 is compared, and the pixel value in which “1” is set in the mask 130 is written to the frame memory 131 and updated.
Pixels for which “0” is set do not update the pixel values written in the frame memory.

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

(10) The pixel setting unit 124 stores the Z value of the next pixel (four pixels) to be drawn in the Z value holding unit 1
17 and (3) The following processing is repeated. Next, (3)
8, the flow when the processing 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, end the processing. (12) The pixel length calculation unit 121 decrements the pixel length by one.

(13), (14) The Z value comparator 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 pixel to be rendered is smaller than the Z value of the Z buffer, the pixel is the pixel to be rendered, and the process proceeds to (15). If the Z value of the pixel to be rendered is larger than the Z value of the Z buffer, the pixel is not a pixel to be rendered, and 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 frame 130 No generation control is performed).

(16) The Z value updating unit 126 calculates the Z
The value is stored in the Z buffer and updated.

[0023]

In the above-described conventional drawing processing, high-speed drawing can be performed when the pixel length of the span is longer than the processing unit (4 pixels), but the pixel length of the span is equal to the processing unit (4 pixels). In the following cases, it was necessary to compare the Z values one pixel at a time and draw in the frame memory, so that the drawing speed was slow.

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

[0025]

According to the present invention, even when the number of pixels in one span becomes equal to or 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 for the data of the processing unit. If data is present, that portion 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, reference numeral 1 denotes a drawing target graphic. Reference numeral 2 denotes drawing target data. In the drawing target graphic 1, A, B, and C are pixels given as inputs (positions as pixel values,
Color, slope of color, Z value, slope of Z value, etc.). The pixel value at point D is calculated from the pixel values at points A and B. Further, the pixel value of point E is calculated from the pixel values of 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 denotes a drawing data input unit for inputting drawing target data 2. Reference numeral 4 denotes a drawing data holding unit, which holds drawing target data 2. 5
Indicates a processing unit that can be processed by the CPU in one access, and the figure shows a case of four pixels as an example (the case of four pixels will be described below). 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 buffer of the old graphic (the graphic of the pixel currently written in the frame memory).
It holds the value. Reference numeral 8 denotes a Z value holding unit which holds the Z value of a new figure (drawing target data).

Reference numeral 10 denotes a drawing processing means for performing a drawing process for writing the pixels held in the drawing data holding unit 4 into the frame memory. A pixel setting unit 11 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.
Is set to the Z value. Reference numeral 12 denotes a drawing pixel length determining unit, which is stored in the drawing data holding unit 4.
This is for calculating the pixel length of the span. Reference numeral 13 denotes a Z value comparison unit which compares the Z value held in the Z buffer 7 with the Z value held in the Z value holding unit 8 for each pixel. Reference numeral 14 denotes a Z value updating unit for updating the Z buffer 7.

Numeral 15 denotes a mask generation unit which, based on the Z value comparison result of the Z value comparison unit 13, changes the Z value of the pixel held in the pixel holding unit 9 from the Z value held in the Z buffer 7. If the value is larger, the mask 20 is set to a value “0” that prohibits writing to the frame buffer, and if 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 the mask 2
A value "1" that allows writing to the frame buffer to 0
Is set. Further, based on the determination result of the rendering pixel length determination unit 12, the mask generation unit 15 determines whether the mask 20 is required if the processing unit includes data other than pixels (the rendering unnecessary part 6 in the rendering data holding unit 4). Is set to a value "0" that prohibits writing to the frame memory 21.

Reference numeral 16 denotes a frame memory writing unit which masks the pixels held in the pixel holding unit 9 with a mask 2.
The write processing is performed on the frame memory 21 with reference to 0. 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 equal to or larger than the processing unit (for example, 4 pixels) is the same as that in the case of the conventional technique (FIG. 6). Is omitted.

The case where the number of pixels held in the drawing data holding unit 4 is 4 pixels or less in the basic configuration shown in FIG.
The pixel holding unit 9 holds two pixels as shown. It is assumed that 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, a 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 determining unit 12 determines that the data to be drawn is two pixels, and the mask generating unit 15
Notify. The mask generation unit 15 writes a write-protection mask “0” for a part that does not need to be written to the frame memory (unnecessary part 6) based on the specified pixel length.
Set.

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

(The operation of the basic configuration in 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 denotes a main storage unit, and 32 denotes a graphics processor, which performs a drawing process. Reference numeral 33 denotes drawing processing means, which performs writing processing to the frame memory by the graphics processor 32. 34 is a frame memory, 35 is a display, 36 is a disk controller, and 37 is a disk device, which stores drawing data, drawing results, and the like. Reference numeral 38 denotes an input control unit, and reference numeral 39 denotes an input device, such as a keyboard, a mouse, and a tablet.

FIG. 3 shows an embodiment of the Z value comparison processing and mask of the present invention. FIG. 7A shows the Z value comparison processing. In the figure, (A) is a Z buffer, which is composed of four 32-bit registers 40, 41, 42 and 43. A 4-pixel Z value (OldZ) is stored in each register.
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. The Z value of the drawing target data (NewZ1, NewZ2, NewZ3, NewZ4) is stored in each register.
Is stored.

FIG. 4C shows a register for storing the result of comparison by the Z-value comparison unit, which is composed of four 32-bit registers like the Z buffer. The Z value of the Z buffer (A) and the Z value of the Z value holding unit (B) are compared for each pixel by a Z value comparison instruction (compare), and the smaller Z value of the comparison result (StoreZ1, StoreZ2, StoreZ) is compared.
3, StoreZ4) are stored. Then, a pixel drawing mask is set in a control register in the graphics processor according to the result of the comparison 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 held.

(E) is a control register (32 bits) in the graphics processor, which can control up to 8 pixels by using 24-31 bits as a mask. 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 is a mask of the first pixel).

FIG. 4 shows an embodiment of a mask 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 denotes a case where the drawing target data is two pixels, and the processing unit includes data other than two pixels.

(B) shows an embodiment of the mask outside the drawing target area. In the figure, reference numeral 61 denotes a control register (32 bits) which uses 24-31 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 denotes a mask bit set for a pixel to be rendered by the Z value comparison command, and 64 denotes a mask bit for inhibiting rendering of an area not to be rendered.

According to the present invention, data (pixels) which is not prohibited from being written into the frame memory by the mask among the data (data written in the pixel and the portion outside the drawing area) held in the pixel holding unit. Only the data is written to the frame memory by the frame memory store instruction, and the data other than the pixel is prohibited by the mask and is not written to the frame memory.

Referring to FIG. 5, the flow of the drawing processing means of the present invention will be described. Refer to FIG. 1 and FIG. 3 as necessary. (1) The pixel setting unit (FIG. 1 (1)) stores the value of the pixel (4 pixels) to be drawn in the pixel holding unit (FIG. 1 (1)).
(9), set as shown in FIG.

(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 sets the Z value (4 pixels) Min) is set in the Z value holding unit (8, B).

(3) The drawing pixel length determining unit (12) determines whether the pixel length is 4 or more in one span. If it is 4 or more, proceed to (4), and 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 compares the smaller Z value with the Z value comparison result. (C) is obtained. Then, based on the comparison result of the Z value, the mask generation unit (15) sets the mask (20, E)
To generate a mask bit.

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

(7) Count 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 section (11) sets the value of the pixel (4 pixels) to be drawn in the pixel holding section (9, D). (10) The pixel setting unit (11) sets the Z value of the pixel (4 pixels) to be drawn 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 according to the Z value comparison command, and the mask generation unit (15) uses the mask value (20) of the control register (E) based on the Z value comparison result. , FIG.
A mask bit is generated in (55)). Further, since the pixel length of one span is 4 or less, the mask generation unit (15)
Is the mask portion (20, FIG. 3 (5) of the control register (E).
5) A write inhibit bit value is set for bits that are not to be drawn in step 5).

(12) The frame memory writing unit (16) sets the write inhibit bit value in the mask part (20, FIG. 3 (55)) of the control register (E) among the pixels of the pixel holding unit (9, D). The pixel value corresponding to the bit that has not been written is written to the frame memory (21).

(13) The Z value of the Z value comparison result (C) is written to the Z buffer (7, A).

[0056]

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

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

[Brief description of the 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 according to the present invention.

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

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

FIG. 6 is a diagram illustrating a conventional three-dimensional computer graphics drawing 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 unit 4: Drawing data holding unit 5: Processing unit 6: Drawing unnecessary part 7: Z buffer 8: Z value holding unit 9: Pixel holding unit 10: Drawing processing Means 11: Pixel setting unit 12: Drawing pixel length determination unit 13: Z value comparison unit 14: Z value update unit 15: Mask generation unit 16: Frame memory writing unit 20: Mask 21: Frame memory

Claims (2)

(57) [Claims] 1. Drawing data for holding pixels to be drawn
Extraction of n pixels from the holding unit and the drawing data holding unit
And the pixel setting section to be set in the pixel holding section
A pixel that holds the pixels extracted from the image data storage
Xel storage unit and Z value of pixel drawn on the screen
And the Z value of the pixel to be drawn.
Holding Z value and the pixel
Z buffer holding Z value, Z value and Z value of Z buffer
A Z value comparison unit that compares the Z value of the holding unit for each pixel;
Hide pixels that are not displayed on the screen according to the Z value comparison result
Mask generation unit that generates a mask
Write the pixels to be drawn to the frame memory
3D graphics rendering device with
The target of the drawing process held in the drawing data holding unit
Includes a writing pixel length determination unit determines the number of pixels, of the object to be drawn processed held by the drawing data holding unit
Draw pixels that the number of pixels is less than n pixels
When the length determination unit determines, the mask generation unit performs a drawing process.
Pixels in the pixel holder based on the number of pixels
Generate a mask to remove unnecessary data for drawing other than files
Remove unnecessary data for drawing by mask
Write the pixels to be drawn to the frame memory
A drawing device in computer graphics , characterized by the following . 2. A pixel to be drawn is stored in a drawing data holding unit.
Hold and extract n pixels at a time from drawing data storage
To the pixel holding section, and
Pixel to store the x value of xel in Z buffer and draw
Is stored in the Z value storage unit, and
The Z value of the cell is compared with the Z value of the drawing process, and the Z value
The pixels stored in the pixel storage unit according to the comparison result
Generates a mask that hides pixels that are not displayed on the screen among cells
Out of the pixel holder and through the mask
Write the pixels to be drawn to the frame memory
In the method of drawing three-dimensional graphics to be drawn in
The number of pixels is determined, and the drawing processing target held in the drawing data
If the number of pixels is determined to be less than n Pikuse Le
, Based on the number of pixels to be rendered
Eliminate unnecessary data for drawing other than pixels in the holding unit
Generate a mask and remove unnecessary data for drawing with the mask
And write the pixels to be drawn to the frame memory.
And a drawing method in computer graphics.