69 lines
1.5 KiB
C
69 lines
1.5 KiB
C
#include <windows.h>
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#include <math.h>
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#include <GL/gl.h>
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#include "sscommon.h"
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/******************************Public*Routine******************************\
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* HsvToRgb
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* HSV to RGB color space conversion. From pg. 593 of Foley & van Dam.
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*/
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void
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ss_HsvToRgb(float h, float s, float v, RGBA *color )
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{
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float i, f, p, q, t;
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// set alpha value, so caller doesn't have to worry about undefined value
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color->a = 1.0f;
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if (s == 0.0f) // assume h is undefined
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color->r = color->g = color->b = v;
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else {
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if (h >= 360.0f)
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h = 0.0f;
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h = h / 60.0f;
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i = (float) floor(h);
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f = h - i;
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p = v * (1.0f - s);
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q = v * (1.0f - (s * f));
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t = v * (1.0f - (s * (1.0f - f)));
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switch ((int)i) {
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case 0:
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color->r = v;
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color->g = t;
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color->b = p;
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break;
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case 1:
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color->r = q;
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color->g = v;
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color->b = p;
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break;
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case 2:
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color->r = p;
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color->g = v;
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color->b = t;
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break;
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case 3:
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color->r = p;
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color->g = q;
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color->b = v;
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break;
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case 4:
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color->r = t;
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color->g = p;
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color->b = v;
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break;
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case 5:
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color->r = v;
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color->g = p;
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color->b = q;
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break;
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default:
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break;
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}
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}
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}
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