JP2535814B2 - Mapping circuit of CRT display device - Google Patents

Description

The present invention relates to a mapping circuit of a CRT display device,
In particular, the present invention relates to a mapping circuit for performing so-called texture mapping, which maps an arbitrary image pattern onto a plane representing a three-dimensional figure on a CRT display.

[Conventional technology]

3 displayed on a CRT display device such as CAD
When an arbitrary image pattern, for example, a diagonal line is put on each surface of the three-dimensional figure, a method called texture mapping is used. When performing texture mapping, it is necessary to convert the image pattern pixel by pixel into coordinates on a plane representing a three-dimensional figure of a CRT display.

[Problems to be Solved by the Invention]

When texture mapping is performed in a conventional CRT display device, coordinate conversion is performed in pixel units by software processing in a host computer.
However, when the coordinate conversion is performed in pixel units, it is necessary to perform coordinate conversion for each pixel for displaying a three-dimensional figure, which results in a long processing time and a heavy load on the host computer. .

Therefore, a main object of the present invention is to provide a mapping circuit of a CRT display device capable of performing texture mapping in a terminal device by a hardware configuration, reducing the load on the host computer and increasing the processing speed. Is to provide.

[Means for solving the problem]

The mapping circuit of the CRT display device according to the present invention is C
It is represented by a polygon of a three-dimensional figure having x, y, z values as the vertex coordinate values on the RT display, and a two-dimensional polygon having u, v values as the vertex coordinate values corresponding to the polygon. A mapping circuit for mapping the image pattern stored in the passed image pattern memory, wherein a reference point after conversion of a three-dimensional figure and a reference point of a two-dimensional figure match and conversion of a three-dimensional figure Vertex computing means for determining each vertex of the two-dimensional polygon corresponding to each vertex of the polygon of the three-dimensional figure by using a transformation matrix whose subsequent reference vector matches the reference vector of the two-dimensional figure, and three-dimensional First vertex interpolation means for interpolating between the vertices of the polygon of the figure based on the increments in the x and z directions with respect to the increment in the y direction, and each of the polygons of the three-dimensional figure calculated by the vertex computing means. 2 corresponding to the vertex
Between the vertices interpolated by the first vertex interpolating means and the second vertex interpolating means for interpolating between the vertices of the dimensional polygon based on the increments in the u and v directions with respect to the increments in the y direction. Of the points, when the points existing on the same scan line in the CRT display are set as the start point and the end point, respectively, the first for interpolating between the start point and the end point based on the increment in the z direction with respect to the increment in the x direction. Among the points between the vertices interpolated by the start / end point interpolating means and the second vertex interpolating means, when the polygon points of the two-dimensional figure corresponding to the start point and the end point are set as the start point or the end point, these start and end points are set. Second start / end point interpolating means for interpolating the points based on the increments in the u and v directions with respect to the increment in the x direction, and between the start and end points in the two-dimensional polygon interpolated by the second start / end point interpolating means Add the coordinates of each point of Each of the start and end points in the polygon of the three-dimensional figure interpolated by the first start and end point interpolating means includes a reading means for reading the image pattern from the image pattern memory and a storage area corresponding to the display area of the CRT display. Of the coordinates of each point between, the coordinates corresponding to the display area of the CRT disc play are used as addresses, and a frame memory for storing the image pattern read from the reading means is provided.

[Action]

The mapping circuit of the CRT display device according to the present invention,
Corresponding to each vertex of a polygon of a three-dimensional figure having x, y, z values as coordinate values, each vertex of a two-dimensional polygon having u, v values as coordinate values is obtained, and Y between each vertex
Interpolation based on the increments in the x and z directions with respect to the increments in the direction, and the increments in the u and v directions with respect to the increments in the y direction between the vertices of the 2D polygon corresponding to the vertices of the polygon of the 3D figure. Among the points between the vertices of the polygon of the interpolated three-dimensional figure, the points existing on the same scan line on the CRT display are set as the start point and the end point, respectively. Interpolation based on the increment in the z direction with respect to the increment in the x direction, and among the points between the vertices of the interpolated two-dimensional figure, 2 corresponding to the start point and the end point
When the point of the polygon of the three-dimensional figure is the start point or the end point,
The start and end points are interpolated based on the increments in the u and v directions with respect to the increments in the x direction, and the image pattern is stored in the image pattern memory using the coordinates of each point between the start and end points in the interpolated two-dimensional polygon as an address. Of the coordinates of each point between the start and end points in the polygon of the read and interpolated three-dimensional figure, CR
The read image pattern is stored in the frame memory using the coordinates corresponding to the display area of the T display as an address.

〔Example〕

FIG. 1 is a schematic block diagram of an embodiment of the present invention. First, the configuration of an embodiment of the present invention will be described with reference to FIG. Although not shown, the host computer outputs data on each vertex of the polygon to be displayed in the three-dimensional space of the CRT display, reference point coordinates, reference vector, and normal vector, and the data displayed on the CRT display 3 Data on the reference point coordinates and the reference vector of the pixel array as an image pattern to be mapped to the polygon of the dimensional space are output. These data are given to the buffer 1 and stored.

The vertex coordinates (x, y, z) of the polygon of the three-dimensional figure stored in the buffer 1 are given to the ALU / multiplier 3, the ALU / divider 4, and the DDA 6. The polygonal reference point coordinates, reference vector, normal vector, and pixel array reference point coordinates and reference vector of the three-dimensional figure are given to the ALU / divider / multiplier 2. ALU / divider / multiplier 2
Is the normal vector of the polygon in the three-dimensional space is parallel to the depth direction of the three-dimensional space, that is, the Z-axis, and is the reference point coordinate and the reference vector on the pixel array and the reference point coordinate and the reference vector of the three-dimensional polygon. The conversion matrix M that matches is calculated. The conversion matrix M obtained by the ALU / divider / multiplier 2 is given to the ALU / multiplier 3.

The ALU / multiplier 3 multiplies each vertex coordinate (x, y, z) of the polygon of the three-dimensional figure by the transformation matrix M to obtain the corresponding coordinate (u, v) on the pixel array. . On the other hand, the ALU / divider 4 is based on the coordinates (x, y, z) of each vertex of the given three-dimensional figure, and the slope of the line connecting the vertices, that is, the increment Δx of x, z with respect to the increment 1 of y. , Δz is obtained. The ALU / divider 5 increments the line segment y by 1 when each vertex on the pixel array is connected based on the coordinates (u, v) on the pixel array obtained by the ALU / multiplier 3.
The increments Δu and Δv of u and v with respect to are obtained.

DDA6 interpolates the coordinates between the vertices of the three-dimensional figure, x ',
Find y ′ and z ′. Further, the DDA 7 interpolates the coordinates between the vertices on the pixel array to obtain u ', v'. The ALU / divider 9 interpolates the coordinates between the vertices, and when each of the interpolated points is used as a start point and an end point, an increment Δ of z with respect to the line segment 1 of x with respect to the line segment connecting the start point and the end point.
z'is to be obtained. The ALU / divider 10 finds the slope of the line segment connecting the start point and the end point on the pixel array, and increments u and v of Δu ′ and Δ with respect to an increment of x.
v'is obtained. DDA11 is to find the coordinates (x ″, y ″, z ″) by interpolating each point between the start point and the end point on the three-dimensional figure. DDA12 is also between the start point and the end point on the pixel array. Coordinates (u ″, v ″) obtained by interpolating each point of
Ask for.

The pixel array memory 15 stores a two-dimensional image pattern in advance. Pixel array memory controller 14
Uses the interpolated coordinates (u ″, v ″) obtained by the DDA 12 as an address to read the corresponding pixel from the pixel array memory 15 and give it to the frame memory controller 16. The interpolated coordinates (x ″, y ″, z ″) obtained by the DDA 11 are given to the frame memory controller 16. Then, the frame memory controller 16 addresses the interpolated coordinates (x ″, y ″, z ″). Then, the pixels read from the pixel array memory 15 are written in the frame memory 17. The pixels written in the frame memory 17 are displayed on a CRT display (not shown).

FIG. 2 is a flow chart for explaining the operation of the embodiment of the present invention, and FIGS. 3 and 4 are views for facilitating the understanding of the operation of the embodiment of the present invention.

Next, the specific operation of the embodiment of the present invention will be described with reference to FIGS. First, the image pattern of the two-dimensional figure 22 represented by the coordinate axes u and v as shown in FIG. 4 is mapped to the figure 21 in the three-dimensional space represented by the coordinate axes x, y and z as shown in FIG. It shall be. Three
The coordinates of the vertices of the two-dimensional figure 21 are A, B, C, D, the reference point is C, the reference vector is CD, and the vertices of the two-dimensional figure 22 are A ', B', C ', D'. Let C ′ be the point and C′D ′ be the reference vector. The data relating to these three-dimensional figures and the reference points and reference vectors of the two-dimensional figures are given from the host computer to the buffer 1 in step (abbreviated as SP in the figure) SP1. The buffer 1 stores these data and gives the coordinates of the vertices A, B, C and D of the three-dimensional figure 21 to the ALU / multiplier 3, ALU / divider 4 and DDA6. Further, among the data stored in the buffer 1, the reference point coordinates, the reference vector, and the normal vector of the three-dimensional figure 21 and the two-dimensional figure 22 are given to the ALU / divider / multiplier 2.

In step SP2, the ALU / divider / multiplier 2 determines that the converted normal vector of the three-dimensional figure 21 is parallel to the Z-axis and that the converted reference point C of the three-dimensional figure 21 and the two-dimensional figure 22. A conversion matrix M is calculated such that the reference point C'matches and the converted reference vector CD of the three-dimensional figure 21 matches the reference vector C'D 'of the two-dimensional figure 22. Here, the normal vector is a normal vector with respect to the polygonal surface of the three-dimensional figure. If two points on the polygon and the direction of the three-dimensional polygon are parallel to the screen surface and the two points of the two-dimensional polygon are associated with each other, the correspondence relationship with the remaining points is obtained. Can generate a matrix of This conversion matrix M is given to the ALU / multiplier 3. The AUL / multiplier 3 calculates the conversion matrix M according to the following equation.
And the vertex coordinates A, B, C, D of the three-dimensional figure 21 are multiplied to calculate the coordinates of the vertices A ', B', C ', D'on the two-dimensional figure 22.

On the other hand, the ALU / divider 4 finds the slope of the line segment connecting each of the vertices A, B, C, D in the three-dimensional figure 21 in step SP4. That is, the increments Δx and Δz in the x and z directions are obtained for one scan line sequentially scanned in the y direction, that is, for increment 1 in y. Similarly, in step SP5, the ALU / divider 5 finds the slope of the line segment connecting the vertices A ', B', C ', D'on the two-dimensional figure 22. That is, the increments Δu and Δv in the u and v directions are obtained for one scan line which is sequentially scanned in the y direction.

At step SP6, the DDA 6 determines the vertices of the three-dimensional figure 21 based on the slopes Δx and Δz obtained by the ALU / divider 4 and the coordinates of the vertices A, B, C, D stored in the buffer 1.
Coordinates are interpolated between A, B, C and D to obtain the coordinates (x ', y', z ') of each interpolated point. That is, the coordinates (x ', y', z ') of each interpolated point are obtained by x' = x + Δx y '= y + 1 z' = z + Δz. At this time, the calculated (x ′, y ′, z ′)
Becomes a new (x, y, z), and the above operation is repeated.
Then, the interpolated points are set as the start point and the end point of the scan line. For example, the point b1 interpolated between the vertices A and B
Is the starting point, and the point a1 which is the interpolation between the vertices A and D is the ending point.

On the other hand, in step SP6, the DDA 7 interpolates points (u ′, u ′ on the two-dimensional figure corresponding to the interpolated points on the three-dimensional figure).
v ′) is calculated. That is, the interpolation point (u ′, v ′) on the two-dimensional figure is obtained by u ′ = u + Δu v ′ = v + Δv. At this time, the obtained (u ′, v ′) becomes a new (u, v), and the above calculation is repeated. Then, the starting point b1 'and the ending point a1' on the two-dimensional figure 22 corresponding to the starting point b1 and the ending point a1 on the three-dimensional figure are set.

The controller 8 controls the above-mentioned ALU / dividers 4,5 and DDAs 6,7. And the above step SP
When the operations of 4 to SP6 are completed, the control of the control 8 is transferred to the controller 13 in step SP7.

In step SP8, the ALU / divider 9 finds the slope in order to interpolate the vector between each start point and each end point on the three-dimensional figure 21 found in step SP6. That is, for example, in order to interpolate between the end point a2 of the start point b of the three-dimensional figure 21, the increment Δ of z ′ is increased with respect to the increment of x ′.
Find z '. Also, ALU ... Divider 10 is a two-dimensional figure 22
A slope for interpolating between the start point and the end point in the above is calculated. That is, the increments Δu ′ and Δv ′ of u and v with respect to the increment 1 of x for determining the slope between the start point and the end point in the three-dimensional figure 21 are determined. Furthermore, in step SP9, the DDA 11 performs coordinate interpolation between each start point and each end point in the three-dimensional figure 21, and coordinates (x ″, y ″,
z ″) is calculated by the following arithmetic expression.

x ″ = x ′ + 1 y ″ = y ′ z ″ = z ′ + Δz ′ At this time, the obtained (x ″, y ″, z ″) becomes a new (x ′, y ′, z ′), and The operation of is repeated. DD
A12 interpolates points on the two-dimensional figure 22 corresponding to the interpolated points of the three-dimensional figure 21, and obtains the coordinates (u ″, v ″) of each point by the following arithmetic expression.

u ″ = u ′ + Δu ′ v ″ = v ′ + Δv ′ At this time, the obtained (u ″, v ″) is new (u ′,
v ′), and the above operation is repeated. The pixel array memory control unit 14 determines the two-dimensional figure in step SP10.
Based on the interpolated point (u ″, v ″) on 22, the corresponding image data is read from the pixel array memory 15 and given to the frame memory control 16. Frame memory control unit 16 is DD
Pixel array memory using the coordinates (x ″, y ″) of each point of the three-dimensional figure 21 obtained by A11 as an address
The image data read from 15 is written in the frame memory 17.

That is, the three-dimensional figure 21
And the two-dimensional figure 22 which is an image pattern are made to correspond to each other.
Image data can be written in the frame memory 17 while referring to the image pattern of the two-dimensional figure 22 at each point on the three-dimensional figure 21.

In step SP11, it is determined whether or not the interpolation from the start point to the end point of one vector has been completed. If not completed, the operations of steps SP9 and SP10 described above are repeated.
Then, in step SP12, it is determined whether or not the interpolation between all the vertices has been completed. That is, for example, the points between the vertices A and B of the three-dimensional figure 21 are interpolated, the interpolated points are set as the start points, the points between the vertices A and D are set as the end points, and the points between the start points and the end points are set. The above steps until interpolation
Repeat SP9 to SP11. Then, when the interpolation between the vertices A and B is completed, this time, the points between the vertices B and C are interpolated and each point is set as the start point, and the points interpolated between the vertices A and D are set as the end point. The points between the vertices D and C are set as the end points, and the points between the start points and the end points are sequentially interpolated.

〔The invention's effect〕

As described above, according to the present invention, the corresponding relationship between each vertex of the polygon of the three-dimensional figure and the image pattern of the two-dimensional figure is obtained, and the three-dimensional figure is formed by referring to the image pattern of the two-dimensional figure. Since it is painted out, the mapping circuit can be configured by the hardware configuration on the terminal device side. Therefore, unlike the prior art, it is not necessary to perform coordinate conversion on a pixel-by-pixel basis on the host computer side, so that the processing time can be shortened.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an embodiment of the present invention.
FIG. 2 is a flow chart for explaining the operation of the embodiment of the present invention. 3 and 4 are diagrams for facilitating the understanding of the operation of the embodiment of the present invention. In the figure, 1 is a buffer, 2 is an ALU / divider / multiplier, 3 is an ALU / multiplier, 4,5,9,10 is an ALU / divider, 6,7,1
Reference numerals 1 and 12 are DDAs, 8 and 13 are controllers, 14 is a pixel array memory control unit, 15 is a pixel array memory, 16 is a frame memory control unit, and 17 is a frame memory.

Claims (1)

(57) [Claims] 1. As coordinate values of vertices on a CRT display
A polygon of a three-dimensional figure having x, y, z values is stored in an image pattern memory represented by a two-dimensional polygon having u, v values as coordinate values of vertices corresponding to the polygon. A mapping circuit for mapping an image pattern that is present, wherein the reference point after conversion of the three-dimensional figure and the reference point of the two-dimensional figure match and the reference vector after conversion of the three-dimensional figure is Vertex calculating means for finding each vertex of the two-dimensional polygon corresponding to each vertex of the polygon of the three-dimensional figure by using a transformation matrix that matches the reference vector of the two-dimensional figure; First vertex interpolating means for interpolating between the vertices of the polygon based on the increments in the x and z directions with respect to the increments in the y direction, and for each vertex of the polygon of the three-dimensional figure obtained by the vertex computing means Of each vertex of the corresponding 2D polygon Second apex interpolating means for interpolating based on the increments in the u and v directions with respect to the y direction increments, among the points between the vertices interpolated by the first apex interpolating means, the CRT display First start / end point interpolating means for interpolating between the start and end points based on the increment in the z direction with respect to the increment in the x direction, when the points existing on the same scan line in the above are set as the start point and the end point, respectively. Among the points between the vertices interpolated by the two vertex interpolating means, when the point of the polygon of the two-dimensional figure corresponding to the start point and the end point is set as the start point or the end point, the distance between these start and end points is the x point. Second start / end point interpolating means for interpolating based on the increments in the u and v directions with respect to the increment in the direction, and of each point between the start and end points in the two-dimensional polygon interpolated by the second start / end point interpolating means. Coordinates The address includes a reading means for reading an image pattern from the image pattern memory, and a storage area corresponding to the display area of the CRT display, and is interpolated by the first start / end interpolation means.
A frame memory for storing the image pattern read from the reading means is provided with the coordinates corresponding to the display area of the CRT disc play among the coordinates of each point between the start and end points in the polygon of the dimensional figure as an address. , CRT display device mapping circuit.