RGB_to_HSV C code

RGB_to_HSV.c

// r, g, b 값은 0 ~ 1 사이
// h = [0,360], s = [0,1], v = [0,1]
// if s == 0, then h = -1 (undefined)
void RGBtoHSV( float r, float g, float b, float *h, float *s, float *v )
{	
	float min, max, delta;
	min = MIN( r, g, b );
	max = MAX( r, g, b );
	*v = max; // v
	delta = max - min;
	if( max != 0 )
	*s = delta / max; // s
	else {
		// r = g = b = 0 // s = 0, v is undefined
		*s = 0;
		*h = -1;
		return;
	}
	if( r == max )
		*h = ( g - b ) / delta; // between yellow & magenta
	else if( g == max )
		*h = 2 + ( b - r ) / delta; // between cyan & yellow
	else
		*h = 4 + ( r - g ) / delta; // between magenta & cyan
	
	*h *= 60; // degrees
	
	if( *h < 0 )
		*h += 360;
}