81 lines
2.3 KiB
C
81 lines
2.3 KiB
C
/*
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* Sample program to illustrate EGA/VGA line drawing routines.
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*
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* Compiled with Borland C++
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*
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* By Michael Abrash
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*/
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#include <dos.h>
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#include "regs.h"
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#define GRAPHICS_MODE 0x10
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#define TEXT_MODE 0x03
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#define BIOS_VIDEO_INT 0x10
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#define X_MAX 640 /* working screen width */
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#define Y_MAX 348 /* working screen height */
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extern void EVGALine();
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/*
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* Subroutine to draw a rectangle full of vectors, of the specified
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* length and color, around the specified rectangle center.
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*/
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void VectorsUp(XCenter, YCenter, XLength, YLength, Color)
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int XCenter, YCenter; /* center of rectangle to fill */
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int XLength, YLength; /* distance from center to edge
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of rectangle */
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int Color; /* color to draw lines in */
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{
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int WorkingX, WorkingY;
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/* Lines from center to top of rectangle */
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WorkingX = XCenter - XLength;
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WorkingY = YCenter - YLength;
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for ( ; WorkingX < ( XCenter + XLength ); WorkingX++ )
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EVGALine(XCenter, YCenter, WorkingX, WorkingY, Color);
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/* Lines from center to right of rectangle */
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WorkingX = XCenter + XLength - 1;
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WorkingY = YCenter - YLength;
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for ( ; WorkingY < ( YCenter + YLength ); WorkingY++ )
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EVGALine(XCenter, YCenter, WorkingX, WorkingY, Color);
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/* Lines from center to bottom of rectangle */
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WorkingX = XCenter + XLength - 1;
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WorkingY = YCenter + YLength - 1;
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for ( ; WorkingX >= ( XCenter - XLength ); WorkingX-- )
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EVGALine(XCenter, YCenter, WorkingX, WorkingY, Color);
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/* Lines from center to left of rectangle */
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WorkingX = XCenter - XLength;
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WorkingY = YCenter + YLength - 1;
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for ( ; WorkingY >= ( YCenter - YLength ); WorkingY-- )
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EVGALine(XCenter, YCenter, WorkingX, WorkingY, Color );
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}
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/*
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* Sample program to draw four rectangles full of lines.
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*/
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void main()
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{
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char temp;
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/* Set graphics mode */
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USES_REGS;
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_AX = GRAPHICS_MODE;
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geninterrupt(BIOS_VIDEO_INT);
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/* Draw each of four rectangles full of vectors */
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VectorsUp(X_MAX / 4, Y_MAX / 4, X_MAX / 4, Y_MAX / 4, 1);
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VectorsUp(X_MAX * 3 / 4, Y_MAX / 4, X_MAX / 4, Y_MAX / 4, 2);
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VectorsUp(X_MAX / 4, Y_MAX * 3 / 4, X_MAX / 4, Y_MAX / 4, 3);
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VectorsUp(X_MAX * 3 / 4, Y_MAX * 3 / 4, X_MAX / 4, Y_MAX / 4, 4);
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/* Wait for the enter key to be pressed */
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scanf("%c", &temp);
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/* Back to text mode */
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_AX = TEXT_MODE;
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geninterrupt(BIOS_VIDEO_INT);
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}
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