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{ RCSid $Id: klems_half.cal,v 1.4 2018/08/26 05:33:46 greg Exp $ } |
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{ |
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Compute interior bin for half Klems BSDF basis (0-72) |
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Returns -1 for wrong-side rays |
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|
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Modified from klems_full.cal |
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|
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7/18/2014 G. Ward |
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} |
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DEGREE : PI/180; |
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Acos(x) : if(x-1, 0, if(-1-x, PI, acos(x))) / DEGREE; |
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posangle(a) : if(-a, a + 2*PI, a) / DEGREE; |
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Atan2(y,x) : posangle(atan2(y,x)); |
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|
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khpola(r) : select(r, 6.5, 19.5, 32.5, 45.5, 58.5, 71.5, 90); |
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khnaz(r) : select(r, 1, 8, 12, 16, 20, 12, 8); |
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khaccum(r) : if(r-.5, khnaz(r) + khaccum(r-1), 0); |
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khfindrow(r, pol) : if(r-khpola(0)+.5, r, |
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if(pol-khpola(r), khfindrow(r+1, pol), r) ); |
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|
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khazn(azi,inc) : if((360-.5*inc)-azi, floor((azi+.5*inc)/inc), 0); |
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|
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khbin2(pol,azi) = if(pol-90, -1, |
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select(khfindrow(1, pol), |
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khazn(azi,360/khnaz(1)), |
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khaccum(1) + khazn(azi,360/khnaz(2)), |
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khaccum(2) + khazn(azi,360/khnaz(3)), |
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khaccum(3) + khazn(azi,360/khnaz(4)), |
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khaccum(4) + khazn(azi,360/khnaz(5)), |
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khaccum(5) + khazn(azi,360/khnaz(6)), |
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khaccum(6) + khazn(azi,360/khnaz(7)) |
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) ); |
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|
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RHS = 1; { set to -1 for left-handed system } |
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|
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khbin(Nx,Ny,Nz,Ux,Uy,Uz) = khbin2(Acos(-Dx*Nx-Dy*Ny-Dz*Nz), |
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Atan2(-Dx*Ux-Dy*Uy-Dz*Uz + (Nx*Dx+Ny*Dy+Nz*Dz)*(Nx*Ux+Ny*Uy+Nz*Uz), |
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-RHS*(Dx*(Uy*Nz-Uz*Ny) + Dy*(Uz*Nx-Ux*Nz) + Dz*(Ux*Ny-Uy*Nx)))); |
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|
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Nkhbins : khaccum(khnaz(0)); { Number of bins for one elevation } |
