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root/radiance/ray/src/util/reinhartb.cal
Revision: 2.6
Committed: Fri Mar 27 18:58:06 2015 UTC (9 years ago) by greg
Branch: MAIN
CVS Tags: rad5R4, rad5R2, rad5R0, rad5R1, rad5R3, HEAD
Changes since 2.5: +4 -2 lines
Log Message:
Hopeful fix to bugs in genBSDF due to lack of left-handed coordinates

File Contents

# User Rev Content
1 greg 2.6 { RCSid $Id: reinhartb.cal,v 2.5 2014/08/26 18:56:19 greg Exp $ }
2 greg 2.1 {
3     Compute Reinhart high-density sky patch bin (rbin)
4    
5     MF - Subdivision value (usually a power of two)
6     Dx,Dy,Dz - Incident direction (normalized, towards surface face)
7 greg 2.3 rNx,rNy,rNz - Surface normal (normalized, away from surface)
8 greg 2.1 Ux,Uy,Uz - Up direction vector (does not need to be normalized)
9    
10     Modified from reinhart.cal
11    
12     July 2014 G. Ward
13     }
14     { Useful factors and functions }
15     DEGREE : PI/180;
16 greg 2.2 Asin(x) : if(x-1, PI/2, if(-1-x, -PI/2, asin(x))) / DEGREE;
17     posangle(a) : if(-a, a + 2*PI, a) / DEGREE;
18 greg 2.1 Atan2(y,x) : posangle(atan2(y,x));
19    
20     { Default to Tregenza sky }
21     MF = 1;
22 greg 2.6 { Set to -1 for left-handed coordinate system }
23     RHS = 1;
24 greg 2.1 { Default axis orientation (+Y == north) }
25 greg 2.5 rNx = 0; rNy = 0; rNz = -1;
26 greg 2.1 Ux = 0; Uy = 1; Uz = 0;
27     { Compute oriented axis angles }
28 greg 2.3 inc_dz = -Dx*rNx-Dy*rNy-Dz*rNz;
29 greg 2.6 inc_rx = -RHS*(Dx*(Uy*rNz-Uz*rNy) + Dy*(Uz*rNx-Ux*rNz) + Dz*(Ux*rNy-Uy*rNx));
30 greg 2.5 inc_ry = Dx*Ux+Dy*Uy+Dz*Uz + inc_dz*(rNx*Ux+rNy*Uy+rNz*Uz);
31 greg 2.1
32 greg 2.4 r_alt = Asin(inc_dz);
33 greg 2.2 r_azi = Atan2(inc_rx,inc_ry);
34 greg 2.1
35     alpha = 90/(MF*7 + .5); { Separation between rows in degrees }
36     { Number of patches per row }
37     tnaz(r) : select(r, 30, 30, 24, 24, 18, 12, 6);
38     rnaz(r) = if(r-(7*MF-.5), 1, MF*tnaz(floor((r+.5)/MF) + 1));
39    
40     raccum(r) = if(r-.5, rnaz(r-1) + raccum(r-1), 0);
41    
42     r_row = floor(r_alt/alpha);
43    
44     r_inc = 360/rnaz(r_row);
45    
46     r_azn = if(359.9999-.5*r_inc - r_azi, floor((r_azi +.5*r_inc)/r_inc), 0);
47    
48     { Final bin value, -1 for "ground" }
49     rbin = if (r_alt, raccum(r_row) + r_azn, -1);
50    
51     Nrbins = raccum(7*MF+1); { total number of bins }