/*
 * curlyball
 *
 * DESCRIPTION:
 *   Fun sin() curve mixed with balls
 *
 * PARAMETERS:
 *   Ka, Kd, Ks, roughness, specularcolor - work just like the plastic shader
 *   wirecolor, ballcolor, wirewidth, repeat value
 * AUTHOR: Nick Meshes
 *
 *
 *
 * The RenderMan (R) Interface Procedures and RIB Protocol are:
 *     Copyright 1988, 1989, Pixar.  All rights reserved.
 * RenderMan (R) is a registered trademark of Pixar.
 */

surface curlyball(
	float Ka = 0.5, Kd = 0.4, Ks = 0.2;
	float roughness = 0.05;
	color specularcolor = 1;
	color wirecolor = color(0.937255, 0.447059, 0.752941);
	color ballcolor = color(0.643137, 0.180392, 0.87451);
	float wirewidth = 2.5;
	float repeat = 4;
)
{
	float xpart = mod(xcomp(P), repeat);
	float ypart = mod(ycomp(P), repeat);
	float zpart = mod(zcomp(P), repeat);
	point thisp;

	setxcomp(thisp, xpart);
	setycomp(thisp, ypart);
	setzcomp(thisp, zpart);

	float besty = cos(xpart);
	float bestz = sin(xpart);

	point bestp;
	setxcomp(bestp, xpart);
	setycomp(bestp, besty);
	setzcomp(bestp, bestz);
	point distance = thisp - bestp;
	float len = length(distance);
	
	if (len < (wirewidth/2)){
		Cs = wirecolor;
		Os = len/wirewidth;
	}

	point nextp;
	setxcomp(nextp, repeat/2);
	setycomp(nextp, repeat/2);
	setycomp(nextp, repeat/2);
	
	distance = thisp - nextp;
	len = length(distance);
	if (len < repeat){
		Cs = ballcolor;
		Os = 1;
	}
	normal Nf = faceforward (normalize(N),I);
	Oi = Os;
    	Ci = Os * ( Cs * (Ka*ambient() + Kd*diffuse(Nf)) +
		specularcolor * Ks*specular(Nf,-normalize(I),roughness));

}