/* 
William Schilthuis
WilliamGS.com
http://www.sfdm.scad.edu/faculty/mkesson/vsfx319/index.html
spring 2009

Renderman Archive
ST Coloration

"Biohazard Symbol"

This surface defines a complex pattern with IF statements,
but calculates diffuse and specular lighting, allows for
manipulation of the pattern including loading a background image.

*/
surface
wgs_biohazard03(
				float Kd = 0.7; /* [0 1] Diffuse Coefficient*/
				float Ks = 0.8; /* [0 1] Specular Coefficient*/
				float roughness = 0.1; /* [0 1] Specular Spread*/
				color highlightcolor = (1.0,0.95,0.8); /* Specular Color*/
				string textr = ""; /* Background Image*/
				float trxbg = 0.0; /* [0 1] transparency background */
				color cola = color (0.0,0.0,0.0); /* BG color */
				color colb = color (0.9,0.1,0.1); /* outer circles */
				color colc = color (0.1,0.9,0.1); /* inner circle  */
				color cold = color (0.1,0.1,0.9); /* inner circle  */

				float c1ct = 3;   /* [0 16 1] circle1 count */
				float c1r = 0.18; /* [0.0 0.5] circle1 radius */
				float c1t = 0.2;  /* [0 1] circle1 tangent */
				float c1o = 0.0;  /* [-3.14159 3.14159] circle1 radial offset */

				float cio = 0.02;/* circle inner offset */

				float c2ct = 3;   /* [0 16 1] circle2 count */
				float c2r = 0.12; /* [0.0 0.5] circle1 radius */
				float c2t = 0.24; /* [0 1] circle2 tangent */
				float c2o = 0;  /* [-3.14159 3.14159] circle2 radial offset */
				)
{
color surfcolor = cola; //set initial surface color
Oi = Os * trxbg;     //set initial surface opacity

if(textr != "")
	surfcolor = texture(textr, s, 1 -t);
else
	surfcolor = cola;

normal n = normalize(N);
normal nf = faceforward( n, I);

float c1d = (1/c1ct)*2*PI; //circle1 theta (radial distribution)
float c2d = (1/c2ct)*2*PI; //circle1 theta (radial distribution)
float j; //define local count variable



// Outer Circles.
for (j = 0; j < c1ct; j += 1)
	{
	if(	
		((s-(0.5+sin(c1d*j)*c1t))
		*(s-(0.5+sin(c1d*j)*c1t)))+
		((t-(0.5+cos(c1d*j)*c1t))
		*(t-(0.5+cos(c1d*j)*c1t)))
		< c1r*0.25 &&
		((s-(0.5+sin(c2d*j+c2o)*c2t))
		*(s-(0.5+sin(c2d*j+c2o)*c2t)))+
		((t-(0.5+cos(c2d*j+c2o)*c2t))
		*(t-(0.5+cos(c2d*j+c2o)*c2t)))
		> c2r*0.25  &&
		((s-0.5)*(s-0.5))+((t-0.5)*(t-0.5))
		> c1r*0.01
		)
	surfcolor = colb;
	if(	
		((s-(0.5+sin(c1d*j)*c1t))
		*(s-(0.5+sin(c1d*j)*c1t)))+
		((t-(0.5+cos(c1d*j)*c1t))
		*(t-(0.5+cos(c1d*j)*c1t)))
			< c1r*0.25 &&
		((s-(0.5+sin(c2d*j+c2o)*c2t))
		*(s-(0.5+sin(c2d*j+c2o)*c2t)))+
		((t-(0.5+cos(c2d*j+c2o)*c2t))
		*(t-(0.5+cos(c2d*j+c2o)*c2t)))
			> c2r*0.25  &&
		((s-0.5)*(s-0.5))+((t-0.5)*(t-0.5))
			> c1r*0.01
		)
	Oi = Os;
	}	
// Inner division lines
for (j = 0; j < c1ct; j += 1)
	{
	if(	
		((s-(0.5+sin(c1d*j+PI)*(c1t+cio)))
		*(s-(0.5+sin(c1d*j+PI)*(c1t+cio))))+//bottom edge
		((t-(0.5+cos(c1d*j+PI)*(c1t+cio)))
		*(t-(0.5+cos(c1d*j+PI)*(c1t+cio)))) //bottom edge
			< c1r*0.25 &&
		((s-(0.5+sin(c1d*j+PI)*(c1t+cio*2)))
		*(s-(0.5+sin(c1d*j+PI)*(c1t+cio*2))))+//top edge
		((t-(0.5+cos(c1d*j+PI)*(c1t+cio*2)))
		*(t-(0.5+cos(c1d*j+PI)*(c1t+cio*2)))) //top edge
			> c1r*0.25
		)
	surfcolor = cola;
	if(	
		((s-(0.5+sin(c1d*j+PI)*(c1t+cio)))
		*(s-(0.5+sin(c1d*j+PI)*(c1t+cio))))+//bottom edge
		((t-(0.5+cos(c1d*j+PI)*(c1t+cio)))
		*(t-(0.5+cos(c1d*j+PI)*(c1t+cio)))) //bottom edge
			< c1r*0.25 &&
		((s-(0.5+sin(c1d*j+PI)*(c1t+cio*2)))
		*(s-(0.5+sin(c1d*j+PI)*(c1t+cio*2))))+//top edge
		((t-(0.5+cos(c1d*j+PI)*(c1t+cio*2)))
		*(t-(0.5+cos(c1d*j+PI)*(c1t+cio*2)))) //top edge
			> c1r*0.25
		)
	Oi = Os * trxbg;
	}		
	

// Inner Circle.
for (j = 0; j < c1ct; j += 1)
	{
	if(	
		((s-0.5)*(s-0.5))+((t-0.5)*(t-0.5))
		< c1r*0.20 &&
		((s-0.5)*(s-0.5))+((t-0.5)*(t-0.5))
		> c2r*0.15 &&
		((s-(0.5+sin(c2d*j+c2o)*c2t))
		*(s-(0.5+sin(c2d*j+c2o)*c2t)))+
		((t-(0.5+cos(c2d*j+c2o)*c2t))
		*(t-(0.5+cos(c2d*j+c2o)*c2t)))
		< c2r*0.20 
		)
	surfcolor = colb;
	if(	
		((s-0.5)*(s-0.5))+((t-0.5)*(t-0.5))
			< c1r*0.20 &&
		((s-0.5)*(s-0.5))+((t-0.5)*(t-0.5))
			> c2r*0.15 &&
		((s-(0.5+sin(c2d*j+c2o)*c2t))
		*(s-(0.5+sin(c2d*j+c2o)*c2t)))+
		((t-(0.5+cos(c2d*j+c2o)*c2t))
		*(t-(0.5+cos(c2d*j+c2o)*c2t)))
			< c2r*0.20 
		)
	Oi = Os;
	}


/* calculate the apparent surface color */
color diffusecolor = diffuse(nf) * Kd;
vector i = normalize(-I);
color speccolor = specular(nf, i, roughness) * highlightcolor * Ks;
Ci = Oi * Cs * surfcolor * (diffusecolor + speccolor);
}