research.m1stereo.tv/gitweb/ - melted/blob - src/modules/effectv/utils.c

   1 /*
   2  * EffecTV - Realtime Digital Video Effector
   3  * Copyright (C) 2001-2006 FUKUCHI Kentaro
   4  *
   5  * utils.c: utilities
   6  *
   7  */
   8
   9 #include <math.h>
  10 #include "utils.h"
  11
  12 /*
  13  * HSI color system utilities
  14  */
  15 static int itrunc(double f)
  16 {
  17         int i;
  18
  19         i=(int)f;
  20         if(i<0)i=0;
  21         if(i>255)i=255;
  22         return i;
  23 }
  24
  25 void HSItoRGB(double H, double S, double I, int *r, int *g, int *b)
  26 {
  27         double T,Rv,Gv,Bv;
  28
  29         Rv=1+S*sin(H-2*M_PI/3);
  30         Gv=1+S*sin(H);
  31         Bv=1+S*sin(H+2*M_PI/3);
  32         T=255.999*I/2;
  33         *r=itrunc(Rv*T);
  34         *g=itrunc(Gv*T);
  35         *b=itrunc(Bv*T);
  36 }
  37
  38 /*
  39  * fastrand - fast fake random number generator
  40  * Warning: The low-order bits of numbers generated by fastrand()
  41  *          are bad as random numbers. For example, fastrand()%4
  42  *          generates 1,2,3,0,1,2,3,0...
  43  *          You should use high-order bits.
  44  */
  45 #ifdef __DARWIN__
  46 static
  47 #endif
  48 unsigned int fastrand_val;
  49
  50 unsigned int fastrand(void)
  51 {
  52         return (fastrand_val=fastrand_val*1103515245+12345);
  53 }
  54
  55 void fastsrand(unsigned int seed)
  56 {
  57         fastrand_val = seed;
  58 }