{ RCSid $Id: klems_full.cal,v 1.3 2015/03/27 18:58:06 greg Exp $ } { Compute interior bin for (full) Klems BSDF basis (0-144) Returns -1 for wrong-side rays Modified from Tregenza.cal, which is similar but different 6/14/2009 G. Ward } DEGREE : PI/180; Acos(x) : if(x-1, 0, if(-1-x, PI, acos(x))) / DEGREE; posangle(a) : if(-a, a + 2*PI, a) / DEGREE; Atan2(y,x) : posangle(atan2(y,x)); kpola(r) : select(r, 5, 15, 25, 35, 45, 55, 65, 75, 90); knaz(r) : select(r, 1, 8, 16, 20, 24, 24, 24, 16, 12); kaccum(r) : if(r-.5, knaz(r) + kaccum(r-1), 0); kfindrow(r, pol) : if(r-kpola(0)+.5, r, if(pol-kpola(r), kfindrow(r+1, pol), r) ); kazn(azi,inc) : if((360-.5*inc)-azi, floor((azi+.5*inc)/inc), 0); kbin2(pol,azi) = if(pol-90, -1, select(kfindrow(1, pol), kazn(azi,360/knaz(1)), kaccum(1) + kazn(azi,360/knaz(2)), kaccum(2) + kazn(azi,360/knaz(3)), kaccum(3) + kazn(azi,360/knaz(4)), kaccum(4) + kazn(azi,360/knaz(5)), kaccum(5) + kazn(azi,360/knaz(6)), kaccum(6) + kazn(azi,360/knaz(7)), kaccum(7) + kazn(azi,360/knaz(8)), kaccum(8) + kazn(azi,360/knaz(9)) ) ); RHS = 1; { set to -1 for left-handed system } kbin(Nx,Ny,Nz,Ux,Uy,Uz) = kbin2(Acos(-Dx*Nx-Dy*Ny-Dz*Nz), Atan2(-Dx*Ux-Dy*Uy-Dz*Uz + (Nx*Dx+Ny*Dy+Nz*Dz)*(Nx*Ux+Ny*Uy+Nz*Uz), -RHS*(Dx*(Uy*Nz-Uz*Ny) + Dy*(Uz*Nx-Ux*Nz) + Dz*(Ux*Ny-Uy*Nx)))); kbinN = kbin(0,-1,0, 0,0,1); { North bins } kbinE = kbin(-1,0,0, 0,0,1); { East bins } kbinS = kbin(0,1,0, 0,0,1); { South bins } kbinW = kbin(1,0,0, 0,0,1); { West bins } kbinD = kbin(0,0,-1, 0,1,0); { Skylight bins } Nkbins : kaccum(knaz(0)); { Number of bins for one elevation }