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greg |
1.3 |
{ RCSid $Id: aniso.cal,v 1.2 2018/12/01 02:06:04 greg Exp $ } |
2 |
greg |
1.1 |
{ Ward-Geisler-Moroder-Duer anisotropic BSDF model } |
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{ Final 5 real arguments are alpha_x and alpha_y roughnesses and Up vector } |
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ax = arg(AC-4); { ax is roughness in Up orientation } |
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ay = arg(AC-3); |
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9 |
greg |
1.3 |
arefl(hx,hy,hz) = Exp(-(hx*hx/(ax*ax) + hy*hy/(ay*ay))/(hz*hz)) * |
10 |
greg |
1.1 |
(hx*hx + hy*hy + hz*hz) / |
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(PI*ax*ay*hz*hz*hz*hz); |
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13 |
greg |
1.3 |
axmit(hx,hy,hz) = Exp(-(hx*hx/(ax*ax) + hy*hy/(ay*ay))/(hz*hz)) / |
14 |
greg |
1.1 |
(4*PI*ax*ay); |
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16 |
greg |
1.2 |
dobsdf(sdx,sdy,sdz) = if(sdz, arefl(Idx+sdx, Idy+sdy, Idz+sdz), |
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axmit(Idx+sdx, Idy+sdy, Idz-sdz) / sqrt(-sdz*Idz) ); |
18 |
greg |
1.1 |
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19 |
greg |
1.2 |
absdf(ox,oy,oz) = dobsdf(Ldx(ox,oy,oz), Ldy(ox,oy,oz), Ldz(ox,oy,oz)); |