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{ RCSid $Id: klems_int.cal,v 1.1 2009/06/14 20:07:59 greg Exp $ } |
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{ |
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Compute interior bin for (full) Klems BSDF basis |
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|
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Modified from Tregenza.cal, which is similar but different |
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|
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6/14/2009 G. Ward |
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} |
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DEGREE : PI/180; |
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Acos(x) : 1/DEGREE * if(x-1, 0, if(-1-x, 0, acos(x))); |
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posangle(a) : if(-a, a + 2*PI, a); |
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Atan2(y,x) : 1/DEGREE * posangle(atan2(y,x)); |
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kpola(r) : select(r, 5, 15, 25, 35, 45, 55, 65, 75, 90); |
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knaz(r) : select(r, 1, 8, 16, 20, 24, 24, 24, 16, 12); |
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kaccum(r) : if(r-.5, knaz(r) + kaccum(r-1), 0); |
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kfindrow(r, pol) : if(r-kpola(0)+.5, r, |
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if(pol-kpola(r), kfindrow(r+1, pol), r) ); |
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kazn(azi,inc) : if(azi-(360-.5*inc), 0, floor((azi+.5*inc)/inc)); |
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kbin2(pol,azi) = select(kfindrow(1, pol), |
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kazn(azi,360/knaz(1)), |
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kaccum(1) + kazn(azi,360/knaz(2)), |
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kaccum(2) + kazn(azi,360/knaz(3)), |
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kaccum(3) + kazn(azi,360/knaz(4)), |
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kaccum(4) + kazn(azi,360/knaz(5)), |
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kaccum(5) + kazn(azi,360/knaz(6)), |
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kaccum(6) + kazn(azi,360/knaz(7)), |
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kaccum(7) + kazn(azi,360/knaz(8)), |
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kaccum(8) + kazn(azi,360/knaz(9)) |
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); |
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kbin(Nx,Ny,Nz,Ux,Uy,Uz) = kbin2(Acos(-Dx*Nx-Dy*Ny-Dz*Nz), |
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Atan2(-Dx*Ux-Dy*Uy-Dz*Uz, |
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-Dx*(Ny*Uz-Nz*Uy) - Dy*(Nz*Ux-Nx*Uz) - Dz*(Nx*Uy-Ny*Ux))); |
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kbinN = kbin(0,1,0, 0,0,1); { North bins } |
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kbinE = kbin(1,0,0, 0,0,1); { East bins } |
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kbinS = kbin(0,-1,0, 0,0,1); { South bins } |
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kbinW = kbin(-1,0,0, 0,0,1); { West bins } |
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kbinU = kbin(0,0,1, 0,1,0); { "Up" bins for skylights } |
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Nkbins : kaccum(knaz(0)); { total number of bins } |
