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greg |
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{ RCSid $Id$ } |
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{ |
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Approximated triple-glazing model using BRTDfunc. |
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void BRTDfunc glaze3 |
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10 |
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sr_red sr_grn sr_blu |
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st_red st_grn st_blu |
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0 0 0 |
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glass3.cal |
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0 |
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18 0 0 0 0 0 0 0 0 0 |
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rfspc gfspc bfspc |
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rbspc gbspc bbspc |
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rtspc gtspc btspc |
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where: |
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rfspc, gfspc, bfspc - front specular RGB at normal |
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rbspc, gbspc, bbspc - back specular RGB at normal |
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rtspc, gtspc, btspc - transmitted RGB at normal |
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You can use the first 9 arguments to get diffuse components, |
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but the glazing model won't work very well if you do. |
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Also, if the transmission plus reflection on either side |
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adds up to greater than 1.0, you will be violating physics. |
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G.Ward for LBNL |
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} |
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Rexp : -2.5; { exponent found to work well for Fresnel } |
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Tsr = CrP*arg(16); |
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Tsg = CgP*arg(17); |
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Tsb = CbP*arg(18); |
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{ specular flux transfer, front } |
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Sfr = arg(10) + Tsr; |
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Sfg = arg(11) + Tsg; |
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Sfb = arg(12) + Tsb; |
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{ specular flux transfer, back } |
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Sbr = arg(13) + Tsr; |
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Sbg = arg(14) + Tsg; |
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Sbb = arg(15) + Tsb; |
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{ Fresnel reflection estimator for triple-glazing } |
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FresR = exp(Rexp*abs(RdotP)) - exp(Rexp); |
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specAdj(s) = s + (1-s)*FresR; |
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{ Specular reflection, front & back } |
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sr_red = specAdj(if(Rdot, arg(10) , arg(13))); |
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sr_grn = specAdj(if(Rdot, arg(11) , arg(14))); |
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sr_blu = specAdj(if(Rdot, arg(12) , arg(15))); |
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{ Specular transmission } |
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st_red = if(Rdot, Sfr, Sbr) - sr_red; |
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st_grn = if(Rdot, Sfg, Sbg) - sr_grn; |
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st_blu = if(Rdot, Sfb, Sbb) - sr_blu; |
