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Initialization file for Radiance. |
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4/14/86 |
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} |
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{ |
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The following are predefined: |
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Dx, Dy, Dz - ray direction |
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Nx, Ny, Nz - surface normal |
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Px, Py, Pz - intersection point |
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T - distance from start |
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Ts - single ray (shadow) distance |
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Rdot - ray dot product |
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S - world scale |
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Tx, Ty, Tz - world origin |
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bound(a,x,b) : if(a-x, a, if(x-b, b, x)); |
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Acos(x) : acos(bound(-1,x,1)); |
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Asin(x) : asin(bound(-1,x,1)); |
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Exp(x) : if(-x-60, 0, exp(x)); |
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Atan2(y,x) : if(x*x+y*y, atan2(y,x), 0); |
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Exp(x) : if(-x-100, 0, exp(x)); |
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Sqrt(x) : if(x, sqrt(x), 0); |
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{ Useful constants } |
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noop(v) = v; |
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clip(v) = bound(0,v,1); |
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noneg(v) = max(0,v); |
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red(r,g,b) = r; |
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green(r,g,b) = g; |
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blue(r,g,b) = b; |
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grey(r,g,b) = .3*r + .59*g + .11*b; |
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noneg(v) = if(v,v,0); |
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red(r,g,b) = if(r,r,0); |
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green(r,g,b) = if(g,g,0); |
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blue(r,g,b) = if(b,b,0); |
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grey(r,g,b) = noneg(.263*r + .655*g + .082*b); |
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clip_r(r,g,b) = bound(0,r,1); |
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clip_g(r,g,b) = bound(0,g,1); |
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clip_b(r,g,b) = bound(0,b,1); |
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clipgrey(r,g,b) = bound(0,grey(r,g,b),1); |
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clipgrey(r,g,b) = min(grey(r,g,b),1); |
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dot(v1,v2) : v1(1)*v2(1) + v1(2)*v2(2) + v1(3)*v2(3); |
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cross(i,v1,v2) : select(i, v1(2)*v2(3) - v1(3)*v2(2), |
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turbulencec(x,y,z,s) = if( s-1.01, 0, |
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sgn(noise3(x/s,y/s,z/s))*noise3c(x/s,y/s,z/s) + |
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turbulencec(x,y,z,2*s) ); |
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{ Normal distribution from uniform range (0,1) } |
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un2`private(t) : t - (2.515517+t*(.802853+t*.010328))/ |
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(1+t*(1.432788+t*(.189269+t*.001308))) ; |
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un1`private(p) : un2`private(sqrt(-2*log(p))) ; |
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unif2norm(p) : if( .5-p, -un1`private(p), un1`private(1-p) ) ; |
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nrand(x) = unif2norm(rand(x)); |
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{ Local (u,v) coordinates for planar surfaces } |
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crosslen`private = Nx*Nx + Ny*Ny; |
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{ U is distance from projected Z-axis } |
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U = if( crosslen`private - FTINY, |
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(Py*Nx - Px*Ny)/crosslen`private, |
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Px); |
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{ V is defined so that N = U x V } |
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V = if( crosslen`private - FTINY, |
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Pz - Nz*(Px*Nx + Py*Ny)/crosslen`private, |
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Py); |