| 3 |
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{ |
| 4 |
|
Initialization file for Radiance. |
| 5 |
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|
| 6 |
– |
4/14/86 |
| 7 |
– |
} |
| 8 |
– |
|
| 9 |
– |
{ |
| 6 |
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The following are predefined: |
| 7 |
|
|
| 8 |
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Dx, Dy, Dz - ray direction |
| 130 |
|
turbulencec(x,y,z,s) = if( s-1.01, 0, |
| 131 |
|
sgn(noise3(x/s,y/s,z/s))*noise3c(x/s,y/s,z/s) + |
| 132 |
|
turbulencec(x,y,z,2*s) ); |
| 133 |
+ |
|
| 134 |
+ |
{ Normal distribution from uniform range (0,1) } |
| 135 |
+ |
|
| 136 |
+ |
un2`private(t) : t - (2.515517+t*(.802853+t*.010328))/ |
| 137 |
+ |
(1+t*(1.432788+t*(.189269+t*.001308))) ; |
| 138 |
+ |
un1`private(p) : un2`private(sqrt(log(1/p/p))) ; |
| 139 |
+ |
|
| 140 |
+ |
unif2norm(p) : if( .5-p, un1`private(p), -un1`private(1-p) ) ; |
| 141 |
+ |
|
| 142 |
+ |
nrand(x) = unif2norm(rand(x)); |
| 143 |
+ |
|
| 144 |
+ |
{ Local (u,v) coordinates for planar surfaces } |
| 145 |
+ |
crosslen`private = Nx*Nx + Ny*Ny; |
| 146 |
+ |
{ U is distance from origin in XY-plane } |
| 147 |
+ |
U = if( crosslen`private - FTINY, |
| 148 |
+ |
(Py*Nx - Px*Ny)/crosslen`private, |
| 149 |
+ |
Px); |
| 150 |
+ |
{ V is defined so that N = U x V } |
| 151 |
+ |
V = if( crosslen`private - FTINY, |
| 152 |
+ |
Pz - Nz*(Px*Nx + Py*Ny)/crosslen`private, |
| 153 |
+ |
Py); |
