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agiofws@celeron3~/extracted/effectv-0.3.11
$more utils.c 
/*
 * EffecTV - Realtime Digital Video Effector
 * Copyright (C) 2001-2006 FUKUCHI Kentaro
 *
 * utils.c: utilities
 *
 */

#include <math.h>
#include "EffecTV.h"
#include "utils.h"

int utils_init(void)
{
        yuv_init();
        if(image_init())
                return -1;
        return 0;
}

void utils_end(void)
{
        image_end();
}

/*
 * HSI color system utilities
 */
static int trunc(double f)
{
        int i;

        i=(int)f;
        if(i<0)i=0;
        if(i>255)i=255;
        return i;
}

void HSItoRGB(double H, double S, double I, int *r, int *g, int *b)
{
        double T,Rv,Gv,Bv;

        Rv=1+S*sin(H-2*M_PI/3);
        Gv=1+S*sin(H);
        Bv=1+S*sin(H+2*M_PI/3);
        T=255.999*I/2;
        *r=trunc(Rv*T);
        *g=trunc(Gv*T);
        *b=trunc(Bv*T);
}

/*
 * fastrand - fast fake random number generator
 * Warning: The low-order bits of numbers generated by fastrand()
 *          are bad as random numbers. For example, fastrand()%4
 *          generates 1,2,3,0,1,2,3,0...
 *          You should use high-order bits.
 */
unsigned int fastrand_val;

unsigned int fastrand(void)
{
        return (fastrand_val=fastrand_val*1103515245+12345);
}

void fastsrand(unsigned int seed)
{
        fastrand_val = seed;
}