surface
pianotexmap(
	float Ka=1, Kd=1, Ks=0, roughness=.25;
	color specularcolor = 1)
{	
	string texname ="newkey.tif"
	uniform float ssize, tsize;	
	varying vector Nf, NI;
	varying point PP,O,X,Y,Z,NN;
	varying color ctx;
	Nf = faceforward( normalize(N), I);
	ctx = float texture(texname [0]);
 	Ci = (Ka*ambient() + Kd*diffuse(Nf)) * ctx;
	if (Ks != 0.0)
	{
		NI = normalize(-I);
		Ci += Ks*specularcolor*specular(Nf,NI,roughness);	
	}	
Oi = Os;	
Ci = Ci * Oi;
}