JPH09330422A - Three-dimensional graphic displaying method and system therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tree-dimensional graphic really displayed without caring about a plotting order even when plural translucent graphics are superposed. SOLUTION: This system is provided with a transparent plane memory 18 storing the opacity of a plotted object. A graphic processor 16 updates a plotting pattern (the number and the positions of plotting pixels) in an area to plot from the opacity on the transparent plane 18 and the opacity of a graphic to draw in, and manages it on a private memory. In addition, when the coordinate (x, y) of graphpic data transferred from CPU 11 corresponds to the plotting position of the updated plotting pattern, the pixel of the coordinate (x, y) on a frame memory 14 is plotted. Plotting patterns in an area where graphics are superposed are generated so as not to be superimposed with the plotting pattern of an existent plotting pattern, and a value Z comparing processing using a Z buffer 17 is executed for every plotted pixel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional graphic display system, and more particularly to a display control method for handling a plurality of semi-transparent stereo models.

[0002]

2. Description of the Related Art As a semi-transparent display method for a three-dimensional model,
Blending method and screen door method are used. For details on these methods, refer to "3D Computer Graphics (Eihachiro Nakamae; Shokoido Co., Ltd .; P164).
−166) ”and“ PEX Protocol Specification Version
5.2 (Supervised by X Consortium; P10) ”and so on.

In the blending method, when the hidden surface is erased by comparing the depth information (Z value) of the Z buffer, the opaque figure in the back is drawn first with respect to the semitransparent figure in the front. As a result, the opaque figure in the back is displayed so that it can be seen through the translucent figure.

In the screen door method, pixels to be drawn are thinned out to be semitransparent, and a figure at a distant position is watermarked to display a three-dimensional model. In the pixel thinning process, a tile pattern that determines pixels to be drawn according to the transparency of the figure is prepared, and the figure is drawn according to this tile pattern.

FIG. 2 is a conceptual diagram for explaining a translucent display using a screen door system. Here, the semi-transparent object 2
1 is, for example, a figure having a transmittance of 50%, which is an opaque object
Located in front of. At this time, the opaque object 22 at the back
The hidden surface 23 must be transparent and visible depending on the transmissivity of the semi-transparent object 21.

For this reason, the semi-transparent pattern 24 for drawing the hidden surface 23 is determined, and only the pixels at the positions blackened in the pattern are drawn, and the other pixels are not drawn.
For example, the semitransparent pattern 24 is defined so that only half the pattern area of pixels is drawn so that the translucency of the semitransparent object 21 is 50%. When the translucency of the semitransparent object 21 is 25%, 3/4 pixels of the area of the pattern are drawn, and the remaining 1/4 pixels are not drawn.

In the screen door method, even if the Z-buffer method is used for hidden surface removal, it is possible to realize semi-transparent display without paying attention to the drawing order in order to determine whether to draw in pixel units.

[0008]

In the conventional blending method, it is necessary to draw an opaque figure first and then draw a transparent figure in the latter half of the figure. If the drawing order is not changed according to the depth information of the object, the stereoscopic figure must be changed. There is a problem that the context and brightness of the model cannot be displayed correctly.

Further, in the conventional screen door system, the translucent pattern is fixed due to the transmittance,
There is a problem that only the figure drawn after the semi-transparent object is displayed, which is different from the actual appearance.

As shown in FIG. 3, a plurality of semi-transparent objects 31, 3 are provided.
2 exists, the semi-transparent object 31 and the semi-transparent object 32
If both have a transmittance of 50%, the overlapping area 3
The transmittance of 3 is 25%. However, since the two semi-transparent patterns are the same, the semi-transparent pattern 34 with respect to the overlapping region 33 becomes a pattern for drawing half the pixel of the area and does not reflect the original transmittance of 25%.

An object of the present invention is to overcome the problems of the prior art, and to realize a three-dimensional figure without paying attention to the drawing order of a plurality of semitransparent figures while using the hidden surface elimination method using a Z buffer. It is to provide a graphic display control method and a display system that can be described in FIG.

[0012]

The above object is to generate a drawing pattern according to transparency information of a semi-transparent figure to be drawn when displaying a three-dimensional figure including a plurality of semi-transparent figures, and to provide the figure pattern data. In the three-dimensional graphic display method of drawing in the frame memory when the drawing coordinate corresponds to the drawing pixel position of the drawing pattern, the figure being drawn in the transparent plane memory corresponding to the pixel position of the frame memory one-to-one. Transparency information is stored for each figure or area by overlapping, and new transparency information after drawing is calculated from the transparency information of the target semi-transparent figure to be drawn and the transparency information of the corresponding area read from the transparent plane memory. This is achieved by determining the drawing pattern of the target graphic based on this new transparency information.

The drawing pattern in the overlapping area of the target figure is the drawing pixel number obtained by subtracting the drawing pixel number of the existing drawing pattern already drawn from the drawing pixel number on the drawing pattern calculated from the new transparency information. It is characterized in that a drawing pixel is set at a position which does not or hardly overlaps the drawing position of the existing drawing pattern.

The transparency information is opacity (1-transmittance)
And the new opacity (New) corresponding to the transparency information.
DstNT) is calculated by the equation (1), and the corresponding area of the transparent plane memory is updated with the new opacity after drawing.

[0015]

[Formula 2] NewDstNT = OldDstNT + (1- OldDstNT) x SrcNT (1) where OldDstNT: opacity of the already drawn semi-transparent figure (overlapping area), SrcNT: non-existence of the figure to be written It is the transmittance.

When the drawing pattern is composed of n × n pixels (n is an integer of 2 or more), the position of the drawing coordinate of the target figure on the drawing pattern is obtained by the remainder system of n, and the obtained position is the drawing position. Drawing is performed in the frame memory at the time corresponding to the drawing pixel position of the pattern.

The drawing pixel position of the drawing pattern is
When the numbers 1 to n are arbitrarily given in random order to the pixels of the drawing pattern, a value obtained by multiplying the number of pixels of the drawing pattern by the new opacity to -1 is set as a start number, and the numbers are in ascending order. The number of drawing pixels is selected and determined.

The Z coordinate value of the drawing coordinate given by the graphic data is compared with the Z value on the Z buffer at the coordinate, and when the former is large (in the front direction), it is drawn in the frame memory according to the drawing pattern. The Z coordinate value after drawing is stored in the Z buffer.

According to the present invention, when semi-transparent display is performed using the hidden surface elimination method using the Z buffer method, it is not necessary to rearrange the drawing order of the figures according to the position in the depth direction.
And when multiple translucent objects are displayed overlapping,
Since semi-transparent display can be performed according to the transmittance of the overlapped portion, realistic graphic display can be realized.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of a three-dimensional graphic display device according to an embodiment of the present invention. For the three-dimensional graphic data stored in the main memory 12, the CPU 11 performs processing such as coordinate conversion and brightness calculation for determining the color of the graphic.

The graphic processor 16 receives the graphic data for which the coordinate conversion and the brightness calculation have been performed, calculates the drawing position on the frame memory 14, and writes the calculated color (brightness) for each pixel therein. In addition, the depth information (Z coordinate) of the figure after the coordinate conversion is changed to the Z buffer 17
Write one pixel at a time. At this time, the Z value already written (destination Z) and the Z value to be written
The values (source Z) are compared, and the values in the Z buffer 17 and the frame memory 14 are updated only when the source Z is greater than or equal to the destination Z.

As a result, the model of the three-dimensional figure displayed on the CRT 15 via the frame memory 14 is displayed in front of the screen (the Z coordinate is large) when a plurality of models overlap each other. Will be. Therefore, the Z buffer 17 always holds the Z coordinate of the graphic currently displayed.

The transparent plane memory 18 is a buffer that holds the opacity of a figure as transparency information, and corresponds to the frame memory 14 on a one-to-one basis. Like the Z-buffer 17, it is written by the graphics processor 16.

The private memory (PM) 20 holds a drawing pattern (also called a tile pattern).
The graphic processor 16 determines the drawing pixel position of the drawing pattern according to the opacity of the transparent plane 18,
Drawing is performed in the frame memory 14 according to the drawing pattern.

FIG. 4 is an explanatory diagram showing the function of the transparent plane memory. Semi-transparent figures 41 and 42 and opaque figure 4
The positional relationship of 3 in the Z direction is from the front in the descending order of the Z value, and the semitransparent graphic 42> the semitransparent graphic 41> the opaque graphic 43.
Becomes In addition, the drawing order of the figures is the opaque figure 43,
The semi-transparent graphic 42 and the semi-transparent graphic 41 are in this order.

In this case, the hidden surface of the opaque figure 43 causes a portion to be displayed through the semitransparent figures 41 and 42, and can be seen through on the back side according to the transparency of the semitransparent figures 41 and 42. Assuming that the translucency of the semi-transparent figures 41 and 42 is 0.5, the transmissivity of the area 45 where they overlap is 0.25.
And becomes more opaque than the non-overlapping areas.

The opacity which is the transparency information of this embodiment is
Opacity OldDs of translucent figures that have already been drawn
tNT, opacity SrcN of the figure to be written
T, opacity NewDstN of the figure displayed as a result
Let T be the relationship of equation (1).

[0028]

## EQU00003 ## NewDstNT = OldDstNT + (1-OldDstNT) * SrcNT (1) This is similar to the fact that the colors become darker as the translucent cellophane overlaps. That is, when the semi-transparent objects overlap, the opacity increases as they overlap, and the transparency decreases as the opacity approaches 1.0.

Opacity Sr of the figure to be written
cNT is the transmittance α given when drawing the figure.
Therefore, it is determined as 1-α. The opacity NewDstNT written in the transparent plane 18 is calculated by the graphic processor 16 for each pixel from the equation (1). If the number of bits of the transparent plane 18 is 8 bits, 0.0 to
A plane value in which an opacity of 1.0 is mapped by an integer value of 0 to 255 is written.

Here, the opaque graphic 43 and the semi-transparent graphic 41
Consider a case in which the semi-transparent graphic 42 is newly drawn when is already drawn as shown in FIG. Translucent figure 4
Areas 46, 47 of the transparent plane 18 corresponding to 1, 42
The region 48 where they overlap holds the opacity calculated by the equations (4) and (5), which is the same as the equation (1).

The opacity NewDstNT of the areas 46 and 47 where there is no overlap is the initial value of the transparent plane 18.
If OldDstNT = 0.0 (transparent), area 4
Since SrcNT of 6,47 is 0.5, it can be obtained as shown in Formula 4.

[0032]

[Formula 4] NewDstNT ₄₆ = NewDstNT ₄₇ = 0.0 + (1.0-
0.0) × 0.5 = 0.5 The plane value is 255 × (1-NewDstNT) = 12
It becomes 7.

The NewDstNT ₄₈ in the region ₄₈ where the regions 46 and 47 overlap each other has an opacity OldDD in the region 46.
stNT = 0.5, opacity SrcNT = in area 47 =
Since it is 0.5, it can be obtained as in Expression 5.

[0034]

[Equation 5] NewDstNT ₄₈ = 0.5 + (1.0-0.5) ×
0.5 = 0.75 The plane value is 255 × (1−0.75) = 63.
Becomes

Next, the opacity New obtained as described above
A pixel area written in the frame memory 14 using DstNT will be described. Here, focusing on a partial region 45 (4 × 4 pixels) of the region 44 in which the figures 41 and 42 overlap, the opacity of the region 44 is 0.75 from the equation 5, so that the background is 25% transparent. It is natural that the figure 43 can be seen through.

Therefore, using the same method as the screen door method, only 8 pixels out of 16 pixels in the area 45 are drawn (hatched portion), and 4 pixels (white portion) which are not drawn are the pixels of the background (opaque figure 43). Is displayed. That is, the number of pixels to be drawn and the pixel position on the drawing pattern are determined based on NewDstNT of the transparent plane 18, and the area 45 is drawn in the frame memory 14 according to this drawing pattern.

As described above, the drawing pattern is dynamically changed by the graphics processor 16 from the combination of the opacity of the graphic already drawn and the opacity of the graphic to be written, and the private memory 2
0 is stored in the drawing pattern management table.

To determine the pixel position of the drawing pattern, a remainder system of n corresponding to the number of pixels n × n of the drawing pattern is used. FIG. 5 shows the concept of the coset system of 4. The upper left is the origin (0,0) of the frame memory 14 (corresponding to the screen), the position is determined by the coset system of 4, and (0,0) = 1,
(0,1) = 8 ,. . . , (3, 3) = 7, the pixel numbers are arbitrarily given in no particular order. However, it is desirable to assign numbers that are as close as possible so that they are not adjacent to each other.

By using the pixel number of the drawing pattern set in this way, the pixel number is obtained by the equation (3) for the coordinates (x, y) of the graphic data input for drawing thereafter.

[0040]

## EQU00006 ## Pixel number = (mod4 (X), mod4 (Y)) (3) where mod4 (i) is the remainder of the integer i divided by 4. For example, the coordinate (5,3) is (mod4
(5), mod4 (3)) = (1,3), and the coordinates (1,
The pixel number of 3) is 6. Also, the coordinates (6, 5) are (mod4 (6), mod4 (5)) = (2, 1),
Pixel number = 13.

By the way, NewDst obtained by the equation 1
NT indicates the ratio of the number of display pixels of the semitransparent graphic after newly drawn. Therefore, the destination opacity (OldD) already written on the transparent plane 18 is
stNT) and the source opacity (SrcNT) of the figure to be written, the number of drawing pixels of the drawing pattern to be newly written is calculated by the equation (4).

[0042]

[Equation 7] PixelNum = PatternNum × NewDstNT × (SrcNT / (OldDstNT + SrcNT)) (4) where PixelNum is the number of pixels to be newly written (drawing pixel number), and PatternNum is the total number of drawing pattern pixels used for drawing. is there.

FIG. 6 is an explanatory view conceptually showing the procedure of generating a drawing pattern. Drawing pattern is 4x4, and opacity (OldDstNT) 0.25 on the transparent plane.
A procedure for newly writing a figure with an opacity of 0.5 in the figure area in which is written will be described.

The drawing pattern 61 of the already written figure draws the positions of pixel numbers 0, 1, 2, and 3 with the number of drawing pixels = 4. Drawing pattern 62 of newly written figure
Is combined with the pattern 61, a pattern 63 after the drawing of a new figure is generated. Here, the number of drawing pixels of the pattern 63 is new opacity (0.625) × the total number of pixels of the pattern (16) = 10.

Therefore, in the drawing pattern 62, the number of drawing pixels (PixelNum) is 6 (= 10-4), and the pattern 6 is used.
A position that does not overlap with the drawing position of 1 is selected as a drawing pixel. By the way, the starting number of the drawing pixel position (StartPixel)
Is calculated by Equation (5), and the end number (EndPixel) is calculated by Equation (6).

[0046]

## EQU00008 ## StartPixel = (NewDstNT.times.PatternNum) -PixelNum (5) EndPixel = StartPixel + NewDstNT.times.PatternNum-1 (6) where PatternNum is the total number of pixels in the drawing pattern.

In this example, the start number is 4 and the end number is 9.
Therefore, the drawing pattern 62 having the drawing positions of the pixel numbers 4, 5, 6, 7, 8, and 9 is determined.

As a result, the destination pattern 6
1 and the drawing pixel position of the source pattern 62 do not overlap. Therefore, the new destination pattern 63
Is the number of drawing pixels that faithfully reflects the opacity as a result of overlapping the pattern 61 and the pattern 62.

Here, if the pixel number of the coordinate (x, y) of the graphic data according to the equation (3) falls within the range of the start number and the end number, the pixel of the coordinate (x, y) of the frame memory 14 is determined. It is drawn with the brightness value from the CRT.

FIG. 7 shows the format of the drawing pattern management table. The drawing pattern generated as described above is managed by the drawing pattern management table and stored in the private memory 20.

NewDs is stored in the drawing pattern management table.
tNT, OldDstNT, SrcNT, StartP
pixel, EndPixel, PixelNum and P
Each value of alternNum is set, and equation (1) and
It is updated according to the calculation of Expressions (4) to (6).

Next, the case where a large number of semi-transparent figures overlap will be described. FIG. 8 shows the positional relationship of many figures viewed in parallel with the Z axis. Here, the translucent figures 41 and 42 are shown in FIG.
Similarly, the semi-transparent graphic 81 is displayed in front of the overlapping area 45. Figure 81 has an opacity of 0.8
And is located at Z = d ₀ .

When the semi-transparent graphic 81 is displayed in the relationship shown in the figure, the opacity of the area 82 where the graphic 81 and the area 45 overlap is 0.95 from the equation (1). That is, the transparency of the area 82 is only 5%, and the figure overlapping behind Z = d ₀ is hardly visible. In this way, when a large number of semi-transparent figures are overlapped and the opacity that is almost invisible is integrated, and the number of written pixels is recalculated by Formula 4, the number becomes 1 or less, which is meaningless.

Therefore, in the present embodiment, when the opacity exceeds a certain threshold value, it is considered that only the opaque figure is drawn in the area, and the transparent plane is reset to 0. , Reduce the number of calculations.

FIG. 9 shows a flow chart of a schematic process of the graphics processor according to the present embodiment. First, the transparent plane 18 is initialized to an initial value of 0.0 (S91). Then, it is checked whether or not all the graphics forming one screen have been drawn (S92), and if not finished, the process proceeds.

Next, it is checked whether the target graphic to be drawn is translucent or opaque (S93). If it is opaque, the Z value in the Z buffer 17 is compared. Drawing is performed in the memory 14, and the Z value is updated at this time (S94). On the other hand, in the case of semi-transparency, the drawing pattern is updated as follows and the drawing pattern is used to perform drawing processing in the frame memory 14 (S95).

FIG. 10 shows a flow chart of the drawing process using the drawing pattern. First, the source opacity (SrcNT) of the semi-transparent graphic to be drawn is set in the drawing pattern management table (S101). After that, this source opacity is used in the drawing process of this figure. And
It is checked whether or not the drawing of all pixels of the target graphic to be drawn is completed (S102), and if not completed, the process proceeds.

Next, the opacity of the overlapping area where the target graphic overlaps is read from the transparent plane (S103). This value is the destination opacity (OldDstNT)
Is equivalent to Here, the read opacity of the transparent plane is the current Old on the drawing pattern management table.
It is determined whether it is the same as DstNT, that is, the opacity of the drawing pattern currently in use (S10).
4) If they are the same, the process immediately proceeds to S106. If they are not the same, the OldDstNT of the drawing pattern management table is updated (S105), and then the process proceeds to S106.

FIG. 11 shows a flow chart of the drawing pattern management table updating process (S105). First, the opacity read from the transparent plane is set in OldDstNT of the drawing pattern management table (S1051). Further, the source opacity of the target graphic to be drawn is set in SrcNT of the drawing pattern management table, and the new opacity NewDstNT is calculated according to the equation (1).
(S1052).

Next, using these values, the number of pixels (PixelNum) to be drawn in the drawing pattern is calculated by the equation (4) (S1053). In addition, the start number (StartPixel) and end number (En
dPixel) is calculated by the equations (5) and (6) (S10).
54). Finally, the new opacity (NewDstNT) on the drawing pattern management table, the drawing pixel start number (StartPixel),
Drawing pixel end number (EndPixel), number of drawing pixels (PixelNu
m) is updated (S1055).

In step S106, the pixel number is obtained from the drawing coordinate (x, y) after the coordinate conversion passed as the graphic data. That is, for coordinates (x, y), mod4
The pixel number is obtained from (x) and mod4 (y). The calculated pixel numbers are the start pixel number (StartPixel) and end pixel number (EndtPixe) of the drawing pattern management table.
It is determined whether or not it is included between 1), that is, the drawing position on the drawing pattern (S107). If it is the pixel number of the drawing position, the luminance value based on the graphic data is drawn in the pixel of the coordinate (x, y) on the frame memory 14, and the Z value of the coordinate is written in the Z buffer 17 (S10).
8).

In S107, if the pixel number is not the drawing target, the process immediately proceeds to the next step, and the new opacity (New
It is checked whether DstNT) is larger than a threshold value (for example, 0.9) (S109), and if larger, the new opacity is set to 0 (S110). Then, the new opacity (NewDstNT) is written in the corresponding position of the transparent plane 18 (S1).
11), the process returns to step S102.

FIG. 12 shows a flow chart of the drawing process (S108) of the frame memory and Z buffer. First, it is determined whether the Z value of the drawing target pixel is equal to or larger than the Z value of the corresponding coordinate on the Z buffer (S1081). If so, the target draws the brightness value in the frame memory (S108).
2) Also, the Z of the drawing target pixel is placed at the same coordinates in the Z buffer.
A value is written (S1083). On the other hand, Z of the drawing target pixel
If the value is small, no drawing is done.

As described above, the Z-value comparison processing according to the present embodiment is performed in pixel units when graphics overlap. As described above, the drawing of each pixel does not overlap the drawing pixel position of the existing drawing pattern, or is determined by the drawing pattern that is determined so as not to overlap as much as possible. Absent. Therefore, even when the hidden surface elimination method using the Z buffer is used, the user can easily create a program without paying attention to the drawing order of the figures.

[0065]

According to the present invention, when semi-transparent display is performed using the hidden surface elimination method using the Z buffer method, it is not necessary to rearrange the drawing order of figures in the order of positions in the depth direction. , Easy to use.

Furthermore, when a plurality of semi-transparent figures are displayed in an overlapping manner, it is possible to perform realistic semi-transparent display that faithfully reflects the transparency information between the overlapping figures.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a three-dimensional graphic display system according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of translucent display using a screen door system.

FIG. 3 is an explanatory diagram showing a problem of translucent display using a screen door system.

FIG. 4 is an explanatory diagram showing a relative relationship between a drawing pattern of an overlapping region of a plurality of semi-transparent figures and a transparent plane holding an opacity for each region.

FIG. 5 is an explanatory diagram of a remainder system of 4 which determines a drawing pattern and its pixel number.

FIG. 6 is an explanatory diagram conceptually showing a procedure for generating a drawing pattern.

FIG. 7 is a format diagram of a drawing pattern management table.

FIG. 8 is an explanatory view when a plurality of figures overlap each other in the Z-axis direction.

FIG. 9 is a schematic flowchart of drawing processing by the graphic processor.

FIG. 10 is a flowchart of a drawing pattern generation (update) and a drawing process using the drawing pattern.

FIG. 11 is a flowchart of a drawing pattern update process.

FIG. 12 is a flowchart of drawing processing including Z value comparison processing (hidden surface removal) using the Z buffer method.

[Explanation of symbols]

11 ... CPU, 12 ... Main memory, 14 ... Frame memory, 15 ... CRT, 16 ... Graphic processor, 1
7 ... Z buffer, 18 ... Transparent plane memory, 20 ... Private memory, 41 ... Semi-transparent figure, 42 ... Semi-transparent figure, 43 ... Opaque figure.

Claims (8)

[Claims] 1. When displaying a three-dimensional figure including a plurality of semi-transparent figures, a drawing pattern is generated according to transparency information of the semi-transparent figure to be drawn, and drawing coordinates given by the figure data are drawn in the drawing pattern. In the three-dimensional graphic display method of drawing in the frame memory when it corresponds to the pixel position, the transparency information of the figure being drawn is displayed in the transparent plane memory corresponding to the pixel position of the frame memory by the figure and its duplication. The new transparency information after drawing is calculated from the transparency information of the target semi-transparent figure to be drawn and the transparency information of the corresponding area read from the transparent plane memory, which is stored in each area, and based on this new transparency information A three-dimensional graphic display method characterized by determining a drawing pattern of a target figure. 2. The drawing pattern in the overlapping area of the target graphic according to claim 1, wherein the drawing pixel number of the existing drawing pattern already drawn from the drawing pixel number on the drawing pattern calculated from the new transparency information. The three-dimensional graphic display method is characterized in that a drawing pixel is a position that does not or hardly overlaps the drawing position of the existing drawing pattern with the drawing pixel number obtained by subtracting. 3. The opacity according to claim 1, wherein the transparency information is an opacity (1-transmittance), and a new opacity (NewDstN) corresponding to the new transparency information.
T) is calculated by the equation (1), and the corresponding area of the transparent plane memory is updated with the new opacity after drawing, which is a three-dimensional graphic display method. [Formula 1] NewDstNT = OldDstNT + (1- OldDstNT) x SrcNT (1) where OldDstNT: opacity of the already drawn semi-transparent graphic (overlapping area), SrcNT: non-transparency of the target graphic to be written It is the transmittance. 4. The drawing pattern according to claim 1, wherein when the drawing pattern consists of n × n pixels (n is an integer of 2 or more), the position of the drawing coordinate of the target graphic on the drawing pattern is n. A three-dimensional graphic display method of drawing in a frame memory when the position obtained by the coset system corresponds to the drawing position of the drawing pattern. 5. The drawing position of the drawing pattern according to claim 4, wherein when each pixel of the drawing pattern is given a random number 1 to n Multiply by the transmittance-
A three-dimensional graphic display method, characterized in that a value that is 1 is used as a start number, and the drawing pixels are selected in ascending order of the numbers. 6. The Z-coordinate value of the drawing coordinate given by the graphic data and the Z-value on the Z-buffer at the coordinate are compared with each other, and the former is larger (front side). Direction), and the Z coordinate value after drawing is stored in the Z buffer according to the drawing pattern, and the Z coordinate value after drawing is stored in the Z buffer. 7. A memory for storing graphic data, a CPU for obtaining drawing coordinates and brightness values thereof from the graphic data, a frame memory for storing the display graphic data, and a brightness value of the drawing coordinates as a pattern for use. In a three-dimensional graphic display system including a graphics processor that draws in a frame memory according to the above, in an area of an existing semi-transparent graphic that is being drawn and corresponds to a pixel position of the frame memory in a one-to-one manner or in an overlapping area thereof. The graphics processor includes a transparent plane memory that stores transparency information for each area and a private memory that stores a drawing pattern for each area.
A three-dimensional graphic display system, wherein a drawing pattern of an overlapping area to be drawn is generated from transparency information of a semi-transparent drawing to be drawn and transparency information of an existing translucent figure or an overlapping area where the drawing overlaps. 8. The Z buffer for storing depth information of a display graphic in pixel units according to claim 7, wherein the graphics processor has a Z coordinate value of the drawing coordinates larger than a corresponding Z value on the Z buffer. Sometimes a three-dimensional graphic display system configured to draw in a frame memory.