86 lines
1.5 KiB
C++
86 lines
1.5 KiB
C++
#include <windows.h>
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static void __inline DrawPixel(int color, unsigned char *fb)
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{
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int a=*fb;
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a+=color;
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if (a>255)a=255;
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*fb=(unsigned char)a;
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}
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// based on abrash's wu antialiasing routine
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void line(unsigned char *fb, int X0, int Y0, int X1, int Y1, int w, int h)
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{
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unsigned int ErrorAdj=0, ErrorAcc;
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int DeltaX, DeltaY, XDir=1;
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if (Y0 > Y1)
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{
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int t = Y0; Y0 = Y1; Y1 = t;
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t = X0; X0 = X1; X1 = t;
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}
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DeltaY = Y1 - Y0;
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DeltaX = X1 - X0;
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if (DeltaX < 0)
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{
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XDir = -1;
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DeltaX = -DeltaX;
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}
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if (DeltaY > DeltaX) {
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ErrorAcc = (X0&0xffff);
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Y0>>=16;
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X0>>=16;
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DeltaY += 65535;
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DeltaY >>= 16;
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if (DeltaY) ErrorAdj = DeltaX/DeltaY;
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fb+=Y0*w+X0;
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while (DeltaY-- >= 0) {
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if (X0 > 0 && Y0 >= 0 && X0 < w-1 && Y0 < h)
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{
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int Weighting = ErrorAcc >> 10;
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DrawPixel(Weighting^63,fb);
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DrawPixel(Weighting,fb+XDir);
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}
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ErrorAcc += ErrorAdj;
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if (ErrorAcc >= 65536) {
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X0 += XDir;
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fb += XDir;
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ErrorAcc -= 65536;
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}
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fb+=w;
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Y0++;
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}
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}
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else
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{
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ErrorAcc = (Y0&0xffff);
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X0>>=16;
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Y0>>=16;
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DeltaX += 65535;
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DeltaX >>= 16;
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if (DeltaX) ErrorAdj = DeltaY/DeltaX;
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fb+=Y0*w+X0;
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while (DeltaX-- >= 0) {
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if (Y0 >= 0 && Y0 < h-1 && X0 >= 0 && X0 < w)
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{
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int Weighting = ErrorAcc >> 10;
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DrawPixel(Weighting^63,fb);
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DrawPixel(Weighting,fb+w);
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}
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ErrorAcc += ErrorAdj;
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if (ErrorAcc >= 65536) {
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Y0++;
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fb+=w;
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ErrorAcc-=65536;
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}
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fb+=XDir;
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X0+=XDir;
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}
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}
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} |