/* CLF.sl */
/* Author: Jeremy S. De Bonet    jsd@ai.mit.edu */
/*
 * CLFShade() : Shades a surface to look like a chain link fence
 * CLFDisp() :  Displaces a surface to match the CLFShade shading
 */

float SemiSinWave(float x,m,d)
{	
	float ret;

	if (abs(x-m)>d)
		ret= 0;
	else
		ret= sin((x-m)/d);

	return ret;
}



surface
CLFShade(float rDensity = 1)
{
	float tt,ss;
	float rAccum;
	float SpFq=6.28*rDensity;
	float rPeriod = 1/rDensity;

	tt=mod(t, rPeriod);
	ss=mod(s, rPeriod);
	
	rAccum =Gaussian(tt,.35*(abs(cos(ss*SpFq)+.7)),.05);
	rAccum+=Gaussian(tt,1-.35*(abs(cos(ss*SpFq)+.7)),.05);

	
	Ci=mix( color(0,0,0), Cs, rAccum); 

	Oi = 1;

}

displacement
CLFDisp(float rDensity = 1)
{
	float tt,ss;
	float rAccum;
	float SpFq=6.28*rDensity;
	float rPeriod = 1/rDensity;

	tt=mod(t, rPeriod);
	ss=mod(s, rPeriod);
	

	rAccum =SemiSinWave(tt,.35*(abs(cos(ss*SpFq)+.7)),.05) * cos(mod(ss,.5)*SpFq);
	rAccum-=SemiSinWave(tt,1-.35*(abs(cos(ss*SpFq)+.7)),.05) *(1- cos(mod(ss,.5)*SpFq));
	
	P+=normalize(N)*rAccum*.05;

	N=calculatenormal(P);
}