| 1 |
greg |
2.1 |
{ SCCSid "$SunId$ LBL" } |
| 2 |
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| 3 |
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{ |
| 4 |
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Interpolate triangle-mesh values using barycentric coordinates. |
| 5 |
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| 6 |
greg |
2.2 |
A1 = Major axis (0==X, 1==Y, 2==Z) |
| 7 |
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A2 through A7 = Transformation for barycentric system |
| 8 |
greg |
2.1 |
and: |
| 9 |
greg |
2.2 |
A8 through A16 = Surface normal perturbation matrix |
| 10 |
greg |
2.1 |
or: |
| 11 |
greg |
2.2 |
A8 through A13 = Lookup in 2-dimensional pattern or texture |
| 12 |
greg |
2.1 |
} |
| 13 |
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{ Compute barycentric coordinates } |
| 14 |
greg |
2.2 |
bu = select(arg(1)+1, Py, Pz, Px); |
| 15 |
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bv = select(arg(1)+1, Pz, Px, Py); |
| 16 |
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a = bu*arg( 2) + bv*arg( 3) + arg( 4); |
| 17 |
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b = bu*arg( 5) + bv*arg( 6) + arg( 7); |
| 18 |
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c = 1 - a - b; |
| 19 |
greg |
2.1 |
{ Compute variables } |
| 20 |
greg |
2.2 |
v1 = a*arg( 8) + b*arg( 9) + c*arg(10); |
| 21 |
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v2 = a*arg(11) + b*arg(12) + c*arg(13); |
| 22 |
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v3 = a*arg(14) + b*arg(15) + c*arg(16); |
| 23 |
greg |
2.1 |
{ Surface normal perturbation } |
| 24 |
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nf = 1/sqrt(v1*v1 + v2*v2 + v3*v3); |
| 25 |
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dx = v1*nf - Nx; |
| 26 |
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dy = v2*nf - Ny; |
| 27 |
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dz = v3*nf - Nz; |
| 28 |
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{ Lookup table index } |
| 29 |
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u = v1; |
| 30 |
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v = v2; |
