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Support glTF material occlusion in hardware surface shaders #2940

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1 change: 1 addition & 0 deletions libraries/bxdf/gltf_pbr.mtlx
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Original file line number Diff line number Diff line change
Expand Up @@ -360,6 +360,7 @@
<input name="bsdf" type="BSDF" nodename="clearcoat_layer" />
<input name="edf" type="EDF" nodename="emission" />
<input name="opacity" type="float" nodename="opacity" />
<input name="occlusion" type="float" interfacename="occlusion" />
</surface>
<output name="out" type="surfaceshader" nodename="shader_constructor" />
</nodegraph>
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1 change: 1 addition & 0 deletions libraries/pbrlib/pbrlib_defs.mtlx
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Original file line number Diff line number Diff line change
Expand Up @@ -244,6 +244,7 @@
<input name="bsdf" type="BSDF" value="" doc="Distribution function for surface scattering." />
<input name="edf" type="EDF" value="" doc="Distribution function for surface emission." />
<input name="opacity" type="float" value="1.0" doc="Surface cutout opacity" />
<input name="occlusion" type="float" value="1.0" doc="Ambient occlusion factor applied to indirect lighting. A value of 1.0 means no occlusion." />
<input name="thin_walled" type="boolean" value="false" uniform="true" doc="Option to make the surface thin-walled." />
<output name="out" type="surfaceshader" />
</nodedef>
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34 changes: 24 additions & 10 deletions source/MaterialXGenHw/Nodes/HwSurfaceNode.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ namespace
const string INPUT_BSDF = "bsdf";
const string INPUT_EDF = "edf";
const string INPUT_OPACITY = "opacity";
const string INPUT_OCCLUSION = "occlusion";

} // anonymous namespace

Expand Down Expand Up @@ -45,6 +46,11 @@ const string& HwSurfaceNode::getOpacityInputName() const
return INPUT_OPACITY;
}

const string& HwSurfaceNode::getOcclusionInputName() const
{
return INPUT_OCCLUSION;
}

void HwSurfaceNode::createVariables(const ShaderNode&, GenContext& context, Shader& shader) const
{
// TODO:
Expand Down Expand Up @@ -123,7 +129,7 @@ void HwSurfaceNode::emitFunctionCall(const ShaderNode& node, GenContext& context
shadergen.emitLine(vec3+" V = normalize(" + HW::T_VIEW_POSITION + " - " + prefix + HW::T_POSITION_WORLD + ")", stage);
shadergen.emitLine(vec3+" P = " + prefix + HW::T_POSITION_WORLD, stage);
shadergen.emitLine(vec3+" L = "+vec3_zero, stage);
shadergen.emitLine("float occlusion = 1.0", stage);
shadergen.emitLine("float closureOcclusion = 1.0", stage);
shadergen.emitLineBreak(stage);

const string outColor = output->getVariable() + ".color";
Expand All @@ -146,7 +152,7 @@ void HwSurfaceNode::emitFunctionCall(const ShaderNode& node, GenContext& context
shadergen.emitComment("Shadow occlusion", stage);
if (context.getOptions().hwShadowMap)
{
shadergen.emitLine("occlusion = mx_shadow_occlusion(" + HW::T_SHADOW_MAP + ", " + HW::T_SHADOW_MATRIX + ", " + prefix + HW::T_POSITION_WORLD + ")", stage);
shadergen.emitLine("closureOcclusion = mx_shadow_occlusion(" + HW::T_SHADOW_MAP + ", " + HW::T_SHADOW_MATRIX + ", " + prefix + HW::T_POSITION_WORLD + ")", stage);
}
shadergen.emitLineBreak(stage);

Expand All @@ -164,11 +170,19 @@ void HwSurfaceNode::emitFunctionCall(const ShaderNode& node, GenContext& context
{
shadergen.emitLine("ambOccUv = "+vec2+"(ambOccUv.x, 1.0 - ambOccUv.y)", stage);
}
shadergen.emitLine("occlusion = mix(1.0, texture(" + HW::T_AMB_OCC_MAP + ", ambOccUv).x, " + HW::T_AMB_OCC_GAIN + ")", stage);
shadergen.emitLine("closureOcclusion = mix(1.0, texture(" + HW::T_AMB_OCC_MAP + ", ambOccUv).x, " + HW::T_AMB_OCC_GAIN + ")", stage);
}
else
{
shadergen.emitLine("occlusion = 1.0", stage);
shadergen.emitLine("closureOcclusion = 1.0", stage);
}
const ShaderInput* occlusionInput = node.getInput(getOcclusionInputName());
if (occlusionInput)
{
shadergen.emitLineBegin(stage);
shadergen.emitString("closureOcclusion *= ", stage);
shadergen.emitInput(occlusionInput, context, stage);
shadergen.emitLineEnd(stage);
}
shadergen.emitLineBreak(stage);

Expand All @@ -178,7 +192,7 @@ void HwSurfaceNode::emitFunctionCall(const ShaderNode& node, GenContext& context
// indirect lighting
if (bsdf->hasClassification(ShaderNode::Classification::BSDF_R))
{
shadergen.emitLine("ClosureData closureData = makeClosureData(CLOSURE_TYPE_INDIRECT, L, V, N, P, occlusion)", stage);
shadergen.emitLine("ClosureData closureData = makeClosureData(CLOSURE_TYPE_INDIRECT, L, V, N, P, closureOcclusion)", stage);
shadergen.emitFunctionCall(*bsdf, context, stage);
}
else
Expand All @@ -189,7 +203,7 @@ void HwSurfaceNode::emitFunctionCall(const ShaderNode& node, GenContext& context
}

shadergen.emitLineBreak(stage);
shadergen.emitLine(outColor + " += occlusion * " + bsdf->getOutput()->getVariable() + ".response", stage);
shadergen.emitLine(outColor + " += closureOcclusion * " + bsdf->getOutput()->getVariable() + ".response", stage);
shadergen.emitScopeEnd(stage);
shadergen.emitLineBreak(stage);
}
Expand All @@ -208,7 +222,7 @@ void HwSurfaceNode::emitFunctionCall(const ShaderNode& node, GenContext& context

if (edf->hasClassification(ShaderNode::Classification::EDF))
{
shadergen.emitLine("ClosureData closureData = makeClosureData(CLOSURE_TYPE_EMISSION, L, V, N, P, occlusion)", stage);
shadergen.emitLine("ClosureData closureData = makeClosureData(CLOSURE_TYPE_EMISSION, L, V, N, P, closureOcclusion)", stage);
shadergen.emitFunctionCall(*edf, context, stage);
}
else
Expand All @@ -234,7 +248,7 @@ void HwSurfaceNode::emitFunctionCall(const ShaderNode& node, GenContext& context
shadergen.emitComment("Calculate the BSDF transmission for viewing direction", stage);
if (bsdf->hasClassification(ShaderNode::Classification::BSDF_T) || bsdf->hasClassification(ShaderNode::Classification::VDF))
{
shadergen.emitLine("ClosureData closureData = makeClosureData(CLOSURE_TYPE_TRANSMISSION, L, V, N, P, occlusion)", stage);
shadergen.emitLine("ClosureData closureData = makeClosureData(CLOSURE_TYPE_TRANSMISSION, L, V, N, P, closureOcclusion)", stage);
shadergen.emitFunctionCall(*bsdf, context, stage);
}
else
Expand Down Expand Up @@ -299,7 +313,7 @@ void HwSurfaceNode::emitLightLoop(const ShaderNode& node, GenContext& context, S
shadergen.emitComment("Calculate the BSDF response for this light source", stage);
if (bsdf->hasClassification(ShaderNode::Classification::BSDF_R))
{
shadergen.emitLine("ClosureData closureData = makeClosureData(CLOSURE_TYPE_REFLECTION, L, V, N, P, occlusion)", stage);
shadergen.emitLine("ClosureData closureData = makeClosureData(CLOSURE_TYPE_REFLECTION, L, V, N, P, closureOcclusion)", stage);
shadergen.emitFunctionCall(*bsdf, context, stage);
}
else
Expand All @@ -317,7 +331,7 @@ void HwSurfaceNode::emitLightLoop(const ShaderNode& node, GenContext& context, S
shadergen.emitLineBreak(stage);

shadergen.emitComment("Clear shadow factor for next light", stage);
shadergen.emitLine("occlusion = 1.0", stage);
shadergen.emitLine("closureOcclusion = 1.0", stage);

shadergen.emitScopeEnd(stage);
shadergen.emitLineBreak(stage);
Expand Down
3 changes: 3 additions & 0 deletions source/MaterialXGenHw/Nodes/HwSurfaceNode.h
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Expand Up @@ -33,6 +33,9 @@ class MX_GENHW_API HwSurfaceNode : public HwImplementation

/// Return the name of the opacity input on the node.
virtual const string& getOpacityInputName() const;

/// Return the name of the occlusion input on the node.
virtual const string& getOcclusionInputName() const;
};

MATERIALX_NAMESPACE_END
Expand Down
28 changes: 28 additions & 0 deletions source/MaterialXTest/MaterialXGenGlsl/GenGlsl.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -125,6 +125,34 @@ TEST_CASE("GenShader: GLSL Light Shaders", "[genglsl]")
REQUIRE_NOTHROW(mx::HwShaderGenerator::bindLightShader(*spotLightShader, 66, context));
}

TEST_CASE("GenShader: GLSL glTF PBR Occlusion", "[genglsl]")
{
mx::FileSearchPath searchPath = mx::getDefaultDataSearchPath();
mx::DocumentPtr doc = mx::createDocument();
loadLibraries({ "libraries" }, searchPath, doc);
readFromXmlFile(doc, searchPath.find("resources/Materials/Examples/GltfPbr/gltf_pbr_default.mtlx"));

mx::NodeDefPtr surfaceDef = doc->getNodeDef("ND_surface");
REQUIRE(surfaceDef != nullptr);
REQUIRE(surfaceDef->getInput("occlusion") != nullptr);

mx::TypedElementPtr gltfPbr = doc->getNode("SR_default");
REQUIRE(gltfPbr != nullptr);

mx::GenContext context(mx::GlslShaderGenerator::create());
context.registerSourceCodeSearchPath(searchPath);
context.getShaderGenerator().registerTypeDefs(doc);

mx::ShaderPtr shader = context.getShaderGenerator().generate("gltfPbrOcclusion", gltfPbr, context);
REQUIRE(shader != nullptr);

const std::string& pixelSourceCode = shader->getSourceCode(mx::Stage::PIXEL);
REQUIRE(pixelSourceCode.find("float closureOcclusion = 1.0") != std::string::npos);
REQUIRE(pixelSourceCode.find("closureOcclusion *=") != std::string::npos);
REQUIRE(pixelSourceCode.find("makeClosureData(CLOSURE_TYPE_INDIRECT, L, V, N, P, closureOcclusion)") != std::string::npos);
REQUIRE(pixelSourceCode.find("float occlusion = 1.0") == std::string::npos);
}

#ifdef MATERIALX_BUILD_BENCHMARK_TESTS
TEST_CASE("GenShader: GLSL Performance Test", "[genglsl]")
{
Expand Down
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