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https://github.com/isometimes/rpi4-osdev
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59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
#include "wgt.h"
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#include "include/mem.h"
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void wbezier (tpolypoint *rawpts, short numraw, tpolypoint *curvepts, short numcurve)
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/* Bezier curve algorithm submitted to us by Claude Morais */
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{
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double *combi;
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double deltat, temp;
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double prod,quot;
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double sumx,sumy;
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short tmp, count;
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combi = malloc (sizeof(double)*numraw);
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numraw--;
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deltat = 1.0 / (numcurve - 1);
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combi[0] = combi[numraw] = 1.0;
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for (tmp = 0; tmp <= (numraw - 2); tmp++)
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combi[tmp + 1] = (combi[tmp] * (numraw - tmp)) / (tmp + 1);
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for (count = 0; count < numcurve; count++)
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{
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if ((temp = count*deltat) <= 0.5)
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{
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quot = prod = 1.0 - temp;
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for (tmp = 1; tmp < numraw; tmp++)
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prod *= quot;
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quot = temp / quot;
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sumx = rawpts[numraw].x;
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sumy = rawpts[numraw].y;
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for (tmp = numraw - 1; tmp >= 0; tmp--)
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{
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sumx = combi[tmp]* rawpts[tmp].x + quot* sumx;
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sumy = combi[tmp]* rawpts[tmp].y + quot* sumy;
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}
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}
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else
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{
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quot = prod = temp;
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for (tmp = 1; tmp < numraw; tmp++)
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prod *= quot;
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quot = (1.0 - temp) / quot;
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sumx = rawpts[0].x;
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sumy = rawpts[0].y;
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for (tmp = 1; tmp <= numraw; tmp++)
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{
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sumx = combi[tmp]* rawpts[tmp].x + quot* sumx;
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sumy = combi[tmp]* rawpts[tmp].y + quot* sumy;
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}
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}
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curvepts[count].x = (sumx*prod);
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curvepts[count].y = (sumy*prod);
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}
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free (combi);
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}
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