rgb.c

convert RGB to HSV, full

//mozne hodnoty promennych: h = <0,360>  , s = <0,255>, v = <0,255>   
// rgb jsou komparacni registry PWM kanalu
#define r	OCR1A
#define g 	OCR2
#define b   	OCR1B
// --------------------------- konverze HSV do RGB -----------------
void HSVtoRGB(unsigned int h, unsigned char s, unsigned char v )
{
	long q,t,p,f;
	unsigned char i;

	if(s = = 0)  {
	    r = g = b = v;  
	    return;
	}

	 i =  h / 60;
               f =  h % 60;	
	 p =  ((v * (255 - s)) / 255) ;
	 q =  ((v * (15049 - s * f)) / 15049);
	 t =  ((v * (15049 - s * (59 - f))) / 15049);

	switch(i)   {
	   case 0: r = v ;g = t ;b = p ;break;
	   case 1: r = q ;g = v ;b = p ;break;
	   case 2: r = p ;g = v ;b = t ;break;
	   case 3: r = p ;g = q ;b = v ;break;
	   case 4:	r = t ;g = p ;b = v ;break;
	   default:r = v ;g = p ;b = q ;break; 
	}
}