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surface veins( float Ks=.5, Kd=.5, Ka=1, roughness=.1, Freq=3, Iter=2; color specularcolor=1 ) #define udn(x,lo,hi) (smoothstep(.25, .75, noise(x)) * ((hi) - (lo)) + (lo)) { normal Nf; vector V; color Csnew; float n1, x; float n2 = 0; /* define colors for spline */ color pink = (1.0, 0.855, 0.725); color blue = (0.5, 0.2, 1.0); /* calculate itterations of noise pattern */ for (x=1;x<=Iter;x+=1){ n1= smoothstep(.4,.6,noise(s*Freq*x,t*Freq*x)); /*enhance contrast in noise pattern & fill white with black*/ n2 = clamp (n2 + (smoothstep(0,(.09*x),n1) - smoothstep ((.1*x),(.2*x),n1)),0,1); } Csnew = spline(n2, pink, pink, blue, red, red); Nf = faceforward( normalize(N), I ); V = -normalize(I); Oi = Os; Ci = Os * ( Csnew * (Ka*ambient() + Kd*diffuse(Nf)) + specularcolor * Ks * specular(Nf,V,roughness) ); } |