/* displacement map based on color information from a texture */
/* file */
displacement
mapper1(float 	Km = 0.1,
				redchannel = 0;
		string  texname = "")
{
float	hump1 = 0, hump2 = 1 , red, green, blue;

/* Breaks the texture file into separate rgb channels */
red    = texture(texname[0]);
green  = texture(texname[1]);
blue   = texture(texname[2]);

normal n = normalize(N);


/* this tests for the amount of red within each pixel and then */
/* "bumps" accordingly. */
if(red >= redchannel && green >= 0 && blue >= 0)
		hump1 = 1;

/* this tests for white values and doesn't allow for it tp "bump" */
if(red == 1.0 && green == 1.0 && blue == 1.0)
		hump2 = 0;
		
/* multiples all of the hump values together and either bumps or */
/* doesn't */
P = P - n * hump1 * hump2  * Km;
N = calculatenormal(P);
}