s t    c o l o r a t i o n

These images show the results of using the RenderMan Shading Language (RSL) to write a variety of special effects surface shaders. The notes and RSL code accompanying each image explain how each effect was achieved.

Cross

if(s > .25 && s < .75 || t > .25 && t < .75)
	surfcolor = color(0.2,0.4,1.0);
			

Center Square

if(s > .25 && s < .75 && t > .25 && t < .75)
	surfcolor = color(0.2,0.4,1.0);
			

Diagonal

if(s+t>1)
	surfcolor = color(0.2,0.4,1.0);
			

Circle

if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.10)
	surfcolor = color(0.2,0.4,1.0);
			

Quadrant Arc

if((s*s)+(t*t)>1)
	surfcolor = color(0.2,0.4,1.0);
			

Crescent

if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.2 && (s-.45)*(s-.45)+(t-.45)*(t-.45)>.19)
	surfcolor = color(0.2,0.4,1.0);
			

Bull's Eye

if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.3)
	surfcolor = color(0.2,0.4,1.0);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.25)
	surfcolor = color(1,.6,0);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.2)
	surfcolor = color(0.2,0.4,1.0);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.15)
	surfcolor = color(1,.6,0);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.1)
	surfcolor = color(0.2,0.4,1.0);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.05)
	surfcolor = color(1,.6,0);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.01)
	surfcolor = color(0.2,0.4,1.0);
			

Partially Shaded Mighty Eightball

if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.26 && (s-.45)*(s-.45)+(t-.45)*(t-.45)>.16)
		surfcolor = color(0);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.24 && (s-.45)*(s-.45)+(t-.45)*(t-.45)>.16)
		surfcolor = color(0.05);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.22 && (s-.45)*(s-.45)+(t-.45)*(t-.45)>.16)
		surfcolor = color(0.1);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.2 && (s-.45)*(s-.45)+(t-.45)*(t-.45)>.16)
		surfcolor = color(0.15);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.18 && (s-.45)*(s-.45)+(t-.45)*(t-.45)>.16)
		surfcolor = color(0.2);
if((s-.5)*(s-.5)+(t-.5)*(t-.5)<.16 && (s-.45)*(s-.45)+(t-.45)*(t-.45)>.16)
		surfcolor = color(0.25);
if((s-.4)*(s-.4)+(t-.3)*(t-.3)<.015)
		surfcolor = color(.175);
if((s-.4)*(s-.4)+(t-.3)*(t-.3)<.0075)
		surfcolor = color(1);
if((s-.4)*(s-.4)+(t-.55)*(t-.55)<.025)
		surfcolor = color(.175);
if((s-.4)*(s-.4)+(t-.55)*(t-.55)<.015)
		surfcolor = color(1);
			

These three movies show how a simple noise modifier can create interesting results

The equation below can be implemented to add noise to st patterns.



float value = (noise(  (s- sfocus) * sfreq, (t- tfocus) * tfreq) - 0.5) * amp;
					
float ss = s + value;
float tt = t + value;