Codegen improvements to surfaceshader mix operator #1104
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| const ShaderGenerator& shadergen = context.getShaderGenerator(); | ||
| shadergen.emitBlock(FUNCTION_DEFINITION, FilePath(), context, stage); |
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Material node is now responsible for composing the surfaceshader components into a single closure.
| const bool isBsdfOutput = singleOutput && singleOutput->getType() == Type::BSDF; | ||
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| if (isSurfaceShaderOutput) |
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This logic added here is a bit hacky with hard coded handling of surfaceshader and BSDF as output types. The reason for this is to keep supporting output of nodegraphs / documents that does not have a material node as the final output terminal (there are many exampels of this in out test suite).
For now this is hard coded here for surfaceshader and BSDF types. I have a plan for how to improve and generalize this, but it includes change to our Syntax and TypeSyntax classes that I think is too intrusive for 1.38.6. So I'll hold on this until 1.39.
| {"alpha", 1.0f}, | ||
| {"transmission", 0.0f} }; | ||
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| if (node->getCategory() == MIX_CATEGORY) |
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New logic for transparency detection of mixed surface shaders.
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Results for running the whole render testsuite: |
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This looks like a really worthwhile change, thanks @niklasharrysson!
…undation#1104) This change list improves the handling of surfaceshader mix operator in code generation. One notable change is for OSL shader generation, which now implements the surfaceshader type as a struct of separate BSDF, EDF and Opacity components, in order to simplify operations like mixing. Also adds new logic to HW transparency detection to support generations of GLSL shaders with transparency when mixing surface shaders.
This change list improves the handling of surfaceshader mix operator in code generation. One notable change is for OSL shader generation, which now implements the surfaceshader type as a struct of separate BSDF, EDF and Opacity components, in order to simplify operations like mixing.
Also adds new logic to HW transparency detection to support generations of GLSL shaders with transparency when mixing surface shaders.
Attached are some results of mixing surface shaders. There may be some additional changes need on GLSL side to match transparency results better with OSL when mixing shaders. This is left for a future change list to keep this reasonably small.
mix_shader.pdf