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{ SCCSid "$SunId$ LBL" } |
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{ |
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Initialization file for Radiance. |
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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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Ix, Iy, Iz - world i unit vector |
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Jx, Jy, Jz - world j unit vector |
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Kx, Ky, Kz - world k unit vector |
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arg(n) - real arguments, arg(0) is count |
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|
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For brdf functions, the following are also available: |
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NxP, NyP, NzP - perturbed surface normal |
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RdotP - perturbed ray dot product |
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CrP, CgP, CbP - perturbed material color |
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|
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Library functions: |
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if(a, b, c) - if a positive, return b, else c |
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select(N, a1, a2, ..) - return aN |
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sqrt(x) - square root function |
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sin(x), cos(x), tan(x), |
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asin(x), acos(x), |
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atan(x), atan2(y,x) - standard trig functions |
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|
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floor(x), ceil(x) - g.l.b. & l.u.b. |
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exp(x), log(x), log10(x) - exponent and log functions |
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erf(z), erfc(z) - error functions |
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rand(x) - pseudo-random function (0 to 1) |
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hermite(p0,p1,r0,r1,t) - 1-dimensional hermite polynomial |
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noise3(x,y,z), noise3a(x,y,z), |
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noise3b(x,y,z), noise3c(x,y,z) - noise function with gradient (-1 to 1) |
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|
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fnoise3(x,y,z) - fractal noise function (-1 to 1) |
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} |
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{ Backward compatibility } |
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AC = arg(0); |
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A1 = arg(1); A2 = arg(2); A3 = arg(3); A4 = arg(4); A5 = arg(5); |
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A6 = arg(6); A7 = arg(7); A8 = arg(8); A9 = arg(9); A10 = arg(10); |
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|
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{ Forward compatibility (?) } |
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D(i) = select(i, Dx, Dy, Dz); |
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N(i) = select(i, Nx, Ny, Nz); |
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P(i) = select(i, Px, Py, Pz); |
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noise3d(i,x,y,z) = select(i, noise3a(x,y,z), noise3b(x,y,z), noise3c(x,y,z)); |
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|
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{ More robust versions of library functions } |
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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-100, 0, exp(x)); |
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Sqrt(x) : if(x, sqrt(x), 0); |
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|
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{ Useful constants } |
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PI : 3.14159265358979323846; |
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DEGREE : PI/180; |
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FTINY : 1e-7; |
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|
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{ Useful functions } |
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and(a,b) : if( a, b, a ); |
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or(a,b) : if( a, a, b ); |
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not(a) : if( a, -1, 1 ); |
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abs(x) : if( x, x, -x ); |
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sgn(x) : if( x, 1, if(-x, -1, 0) ); |
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sq(x) : x*x; |
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max(a,b) : if( a-b, a, b ); |
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min(a,b) : if( a-b, b, a ); |
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inside(a,x,b) : and(x-a,b-x); |
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frac(x) : x - floor(x); |
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mod(n,d) : n - floor(n/d)*d; |
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tri(n,d) : abs( d - mod(n-d,2*d) ); |
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linterp(t,p0,p1) : (1-t)*p0 + t*p1; |
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noop(v) = v; |
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clip(v) = bound(0,v,1); |
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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) = 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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v1(3)*v2(1) - v1(1)*v2(3), |
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v1(1)*v2(2) - v1(2)*v2(1)); |
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fade(near_val,far_val,dist) = far_val + |
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if (16-dist, (near_val-far_val)/(1+dist*dist), 0); |
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bezier(p1, p2, p3, p4, t) = p1 * (1+t*(-3+t*(3-t))) + |
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p2 * 3*t*(1+t*(-2+t)) + |
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p3 * 3*t*t*(1-t) + |
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p4 * t*t*t ; |
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bspline(pp, p0, p1, pn, t) = pp * (1/6+t*(-.5+t*(.5-1/6*t))) + |
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p0 * (2/3+t*t*(-1+.5*t)) + |
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p1 * (1/6+t*(.5+t*(.5-.5*t))) + |
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pn * (1/6*t*t*t) ; |
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|
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turbulence(x,y,z,s) = if( s-1.01, 0, abs(noise3(x/s,y/s,z/s)*s) + |
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turbulence(x,y,z,2*s) ); |
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turbulencea(x,y,z,s) = if( s-1.01, 0, |
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sgn(noise3(x/s,y/s,z/s))*noise3a(x/s,y/s,z/s) + |
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turbulencea(x,y,z,2*s) ); |
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turbulenceb(x,y,z,s) = if( s-1.01, 0, |
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sgn(noise3(x/s,y/s,z/s))*noise3b(x/s,y/s,z/s) + |
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turbulenceb(x,y,z,2*s) ); |
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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 origin in XY-plane } |
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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); |
