/*
 * noise2(): surface shader giving a color based on a
 * common noise function
 */

surface
noise2(	float 	octaves		= 4.00,
		lacunarity	= 2.00,
		scale		= 3.00,
		brightness	= 0.45,
		contrast	= 5.00 )
{

	float i, size;
	float sum;

    	sum = 0.0;
    	size = scale;
    	
    	for (i=0; i < octaves; i+=1)
    	{
    		sum += (0.5 - abs(0.5 - (noise(s*size, t*size)))) / size;
    		/*sum += (0.5 - (noise(s*size, t*size))) / size;*/
    		size *= lacunarity;
    	}
	
	sum = ((sum + (brightness - 0.5)) * contrast) + 0.5;
    	Ci = color sum;
}