JPS62205479A - Specific graphic generating circuit of crt display device - Google Patents

Abstract

PURPOSE:To eliminate the need for the repeating calculation of adding and multiplying and to increase processing speed by multiplying the data of determinant data to display a specific graphic and the determinant data for converting an image for enlargement and reduction and generating specific graphic data. CONSTITUTION:An ALU 21 prepares a determinant B for generating a circular graphic based upon circular graphic central coordinates and radius in a segment buffer 1. A matrix multiplier 38 multiplies a matrix for converting an image and the formula B stored at a matrix stack memory 37. Further, the ALU 21 makes a circular graphic approximate to a polygon, the value of an argument thetaof respective peaks is counted by an address counter 24, the address of a look-up table memory 23 is designated and the values of sintheta and costheta are read. These are stored to registers 32 and 33. Based upon the multiplying result of these values and the matrix, the multiplier 38 executes the calculation concerning respective peaks, when the calculation is completed, the calculating result is stored to an FIFO 39 and outputted to a clip processor.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a special figure generation circuit for a CRT display device, and particularly for a graphic display, in which, for example, the center coordinates (XO, yo) and radius r of a circle are stored in a segment buffer. The present invention relates to a special figure generation circuit for a CRT display device that displays an enlarged or reduced circular figure on a CRT display based on its center coordinates and radius.

[Prior Art] FIG. 4 is a schematic block diagram of a conventional graphic display device, FIG. TS5 is a flow diagram for explaining the operation of generating a circular figure by the conventional graphic display device, and FIG. FIG. 3 is a diagram showing an example of polygonal approximation of a circular figure to ten triangles.

First, with reference to FIGS. 4 to 6, the operation of generating special graphics using a conventional graphic display device will be described. Special shapes that can be displayed on a graphic display device include circles, elliptical arcs, fans, Bezier curves, and B-subline curves.

Here, it is assumed that a circular figure as shown in FIG. 6 is generated. When generating a circle represented by center coordinates (XO, )'0) and radius r as shown in FIG. 6, this circle is approximated by a polygon. That is, if a circle is approximated to, for example, an m:gon, the number of vertices n will be 12, and the minimum reference angle θ will be 36
It becomes 0/12-300. The segment processor 2 is provided with a look-up table, and each value of sin θ and COS θ is stored in advance in this look-up table. segment processor 2
is the center coordinate (XO
, )'0) and radius r is divided as described above to obtain the argument angle θ, and the values of sin θ and cos θ are determined by referring to the lookup table.

And the segment processor 2 is XO+r*cosθ
is given to the image transformation processor 3. Furthermore, the segment processor 2 converts yo+r*sinθ into the image transformation processor 3.
give to The image conversion processor 3 determines whether θ has reached 360°. That is, it is determined whether the circular figure has been approximated to a ten-triangular polygon. If θ is not 360°, θ is set to 30°, the lookup table is again referred to, the values of stnθ and cosθ are determined, and the following operations are performed in the same manner as described above. In other words, the segment processor 2 and the image transformation processor 3 transform the circular figure into θ
Calculation is performed every -30° to approximate the circular figure to a ten-triangular polygon.

[Problems to be Solved by the Invention] In the above-mentioned conventional graphic display device,
If polygonal approximation is used to generate a circular figure, the number of multiplications and additions will be extremely large, and the generation processing speed for generating a special figure will be extremely slow. This has the disadvantage that it adversely affects the main processing of the CPU after the special figure is generated, slowing down the overall processing speed.

Therefore, the main object of the present invention is to provide a special figure generation circuit for a CRT display device that can generate special figures at high speed and improve the overall processing speed.

[Means for Solving the Problems] The present invention is a special figure generation circuit for generating special figures such as circles and ellipses to be displayed on a CRT display device, which generates determinant data representing the special figures. A first determinant data output means for outputting, a second determinant data output means for outputting data representing a determinant for image transformation necessary for enlarging or reducing a special figure, and a method for multiplying these determinants. and a multiplication means for outputting data representing the special figure after image conversion.

[Operation] The special figure generation circuit of the CRT display device of the present invention outputs data representing the special figure after image conversion by multiplying the determinant representing the special figure by the image conversion determinant. Therefore, it is not necessary to repeatedly perform multiplication and addition as in the conventional method, and the processing speed can be increased.

[Embodiment of the Invention] FIG. 2 is a concrete block diagram of an embodiment of the invention. First, the configuration of an embodiment of the present invention will be described with reference to FIG. The same segment buffer 1 as shown in FIG. 4 is used, and stores the center coordinates (xo, yo) and radius r of the special figure. Segment processor 20 includes an ALU 21, an ALU register group 22, a lookup table memory 23, and an address counter 24. The ALU 21 performs logical operations on data provided from the segment buffer 1 and outputs the result to the data bus 40. The ALU cash register group 22 stores manually entered data via the data bus 40, and
This will be given to U21. The lookup table memory 23 stores in advance various values of sin θ and cos θ for approximating a circle to a polygon as shown in FIG. 6 described above. The address counter 24 specifies each address in the lookup table memory 23.

The image conversion processor 30 inputs F I FO 31 and X on the input side.
It is composed of a register 32, a Y register 33, a 2 register 34, a command register 35, a stack address counter 36, a matrix stack memory 37, a matrix multiplier 38, and an output side FIFO 39. FIFO
31 is for sequentially storing data output from the ALU 21 or data read from the look-up table memory 23 from the beginning and sequentially reading it from the beginning;
The X register 32 stores X coordinate data, the X register 33 stores Y coordinate data, the Z register 34 stores Z coordinate data for three-dimensional processing, and the command register 35 stores various commands. remember.

Stack address counter 36 specifies the respective addresses of A matrix array 371, B matrix array 372, and C matrix array 373 included in matrix stack memory 37. A matrix array 371 and B matrix array 372 store matrix data applied via data bus 40 and provide it to 7 matrix multiplier 38. C
The matrix array 373 has the function of providing matrix data input from the data bus 40 to the matrix multiplier 38 and outputting the matrix data multiplied by the matrix multiplier 38 to the data bus 40.

The matrix multiplier 38 includes A matrix array 371, B
Matrix array 372 and C matrix array 37
Matrix data given from 3 and X register 3
2. It has a function that allows multiplication with vectors given from X register 33 and Z register 34, multiplication between matrices, or output as is without performing any multiplication. For this purpose, the matrix multiplier 38 includes:
a flag 41 for indicating whether the multiplication is between matrices or between a matrix and a vector;
Flag 43 indicating three-dimensional or two-dimensional multiplication
is given.

Further, the matrix multiplier 38 outputs a flag 42 when the multiplication is completed. The result of multiplication by the matrix multiplier 38 is given to the FIFO 39 on the output side. FIFO
The multiplication result stored in 39 is given to clip processor 4 or display processor 5 shown in FIG.

FIG. 1 is a flowchart for explaining the specific operation of an embodiment of the present invention.

Next, with reference to FIG. 1 and FIG. 2, a specific operation of an embodiment of the present invention will be described.

The ALU 21 generates a determinant B for generating a circular figure as shown in the following equation (1) based on the circular figure center coordinates (Xo, yo) and the radius r stored in the segment buffer 1.
Create.

Further, an image conversion matrix is stored in advance in the A matrix array 371, and the matrix multiplier 38
According to the following equation (2), the image conversion matrix stored in the A matrix array 371 is multiplied by the circular figure generation matrix B stored in the B matrix array 373.

Furthermore, the ALU 21 approximates a circular figure to a polygon, and in order to perform calculations on each vertex, the value of the argument angle θ of each vertex is counted by the address scalator 24, and the address of the lookup table memory 23 is specified. , sin θ and COS θ are read from the lookup table memory 23. The values of sin θ and COS θ read from the lookup table memory 23 are stored in the FIFO 31, and based on the output of the FIFO 31, the values of sin θ and COS θ are stored in the X register 32.
sin θ is stored in the X register 33, and COS θ is stored in the X register 33. Matrix multiplier 38 is X register 32
The following equation (3) is multiplied based on sin θ stored in , COS θ stored in the X register 33, and the aforementioned matrix.

(x+)+rcosθ, 310+rsfl'lθ) [Image transformation Marixco...(
3) The matrix multiplier 38 determines whether or not the calculation for each vertex has been completed, and if it has not been completed, the matrix multiplier 38 performs the matrix calculation based on the above-mentioned equation (3) again. When the calculation for each vertex is completed, the calculation result is stored in the FIFO 39 on the output side and output to the clip processor 4.

As described above, according to this embodiment, a matrix for generating a circular figure is created based on the center coordinates (xo, yo) and the radius of the circular figure, and this matrix is multiplied by the image transformation matrix, The multiplication result and sinθ and COSθ
A circular figure can be generated by repeatedly multiplying the vector by the number of vertices, so the processing speed is faster compared to generating a circular figure by repeating addition and multiplication as shown in Figure 5 above. You can improve.

FIG. 3 is a diagram showing a B-spline curve as an example of a special figure.

Next, an example of displaying a B-spline curve on a CRT display will be described. As shown in FIG. 3, the B-spline curve is a curve that does not pass through the control points P1 to P7, but has continuous tangent vectors and curvatures in the vicinity of each control point. To generate such a spline curve, use the following equation (4) or (
6) It is necessary to calculate the expression.

In conventional graphic display devices, the above-mentioned (
The calculations of equations 4) to 6 are performed by the CPU. However, if the matrix multiplier 38 is used to calculate the -spline curve, the processing speed can be further improved. That is, if the above-mentioned equations (4) to (6) are expressed by matrix operations, the equations (7) and (8) are expressed as
) can be expressed by the formula.

” To multiply each of the two series of matrixes A and B, store matrix A in the A matrix array 371 and input matrix B to the B matrix array 372. Then, the matrix multiplier 38 calculates the following equation (9) A matrix multiplication represented by is performed.

After the matrix multiplier 38 performs the multiplication according to equation (9) above, the multiplication result is stored in the C matrix array 373. The multiplication results stored in this C matrix array 373 are transferred to the ALU register group 2 via the data bus 40.
Stored in 2. ALU21 is ALU register group 22
Based on the calculation results stored in , the calculations of the following equations (10) to (12) are performed to obtain x, y, and z.

X−Xo +X+ + X2 + Xa −(
10) Y-Y6 + Y+ + Y2 + Y3
...(11) Z=Z(1+zl +Zz +Zs
-(12) Based on the X, Y, and Z thus determined, a spline curve as shown in FIG. 3 can be displayed on the CRT display.

[Effects of the Invention] As described above, according to the present invention, data representing a special figure is multiplied by data representing a determinant representing a special figure and data representing a determinant for image transformation for enlargement or reduction. , it is no longer necessary to repeatedly perform addition and multiplication as in the conventional case, and the processing speed can be increased and the throughput of the entire apparatus can be improved.

[Brief explanation of drawings]

FIG. 1 is a flowchart for explaining the specific operation of an embodiment of the present invention. FIG. 2 is a concrete block diagram of an embodiment of the present invention. FIG. 3 is a diagram showing a B-spline curve as an example of a special figure. FIG. 4 is a schematic block diagram of a conventional graphic display device. FIG. 5 is a flowchart illustrating the operation of generating a circular figure using a conventional graphic display device. FIG. 6 is a diagram showing an example of polygonal approximation of a circular figure to ten triangles. In the figure, 1 is a segment buffer, 4 is a clip processor, 5 is a display processor, 20 is a segment processor, 21 is an ALU, 22 is an ALU register group, 2
3 is a lookup table memory, 24 is an address counter, 30 is an image conversion processor, 31.32 is a FIFo
, 32 is an X register, 33 is an X register, 34 is a Z register, 35 is a command register, 36 is a stack address counter, 37 is a matrix stack memory, and 38 is a matrix multiplier. Figure 1 Figure 3 Figure 2 Figure 4 Figure 6 Figure 5

Claims (1)

[Scope of Claims] A special figure generation circuit for generating special figures such as circles and ellipses to be displayed on a CRT display device, comprising: a first matrix that outputs determinant data representing the special figure; formula data output means; second determinant data output means for outputting data representing a determinant for image transformation for enlarging or reducing the special figure; and a determinant output from the first determinant data output means. and a determinant for image transformation outputted from the second determinant data output means, and outputs data representing the special figure after image transformation. generation circuit.