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{ SCCSid "$SunId$ LBL" } |
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|
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{ |
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Coordinate computations for mkillum output. |
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|
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For the spherical case, A1-A3 is the value at the positive pole, |
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A4-A6 is the value at the negative pole, and A7 is the pole influence: |
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|
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il_alt - Altitude (1 to -1) for spherical coordinates |
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il_azi - Azimuth (0 to 2*PI) for sphere |
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|
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For the hemispherical case, A1-A3 and A4 are the pole value and |
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influence, respectively, and A5-A13 are the unit vectors for the |
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hemisphere's coordinate system: |
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|
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il_alth - Altitude (1 to 0) for hemispherical coordinates |
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il_azih - Azimuth (0 to 2*PI) for hemisphere |
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} |
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|
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norm_rad(r) : if( r, r, r+2*PI ); |
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{ sphere coordinates } |
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il_alt = Dz; |
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il_azi = norm_rad(atan2(Dy, Dx)); |
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|
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s_val(v, vN, vS) = noneg(if( il_alt-A7, |
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linterp((il_alt-A7)/(1-A7), v, vN), |
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if ( -il_alt-A7, |
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linterp((-il_alt-A7)/(1-A7), v, vS), |
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v ), |
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v )); |
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{ sphere values } |
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s_red(r,g,b) = s_val(r, A1, A4); |
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s_grn(r,g,b) = s_val(g, A2, A5); |
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s_blu(r,g,b) = s_val(b, A3, A6); |
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s_gry(r,g,b) = s_val(grey(r,g,b), grey(A1,A2,A3), grey(A4,A5,A6)); |
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|
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{ hemisphere coordinates } |
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il_alth = sq(-Dx*arg(11)-Dy*arg(12)-Dz*arg(13)); |
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il_azih = norm_rad(atan2(-Dx*arg(8)-Dy*arg(9)-Dz*arg(10), |
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-Dx*arg(5)-Dy*arg(6)-Dz*arg(7))); |
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|
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h_val(v, vN) = noneg(if( il_alth-A4, linterp((il_alth-A4)/(1-A4), v, vN), v )); |
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{ hemisphere values } |
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h_red(r,g,b) = h_val(r, A1); |
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h_grn(r,g,b) = h_val(g, A2); |
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h_blu(r,g,b) = h_val(b, A3); |
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h_gry(r,g,b) = h_val(grey(r,g,b), grey(A1,A2,A3)); |
