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UnrealEngine/Engine/Source/ThirdParty/MaterialX/MaterialX-1.38.10/source/MaterialXGenGlsl/Nodes/LightNodeGlsl.cpp
2025-05-18 13:04:45 +08:00

98 lines
3.5 KiB
C++

//
// Copyright Contributors to the MaterialX Project
// SPDX-License-Identifier: Apache-2.0
//
#include <MaterialXGenGlsl/Nodes/LightNodeGlsl.h>
#include <MaterialXGenShader/Shader.h>
MATERIALX_NAMESPACE_BEGIN
namespace
{
const string LIGHT_DIRECTION_CALCULATION =
"vec3 L = light.position - position;\n"
"float distance = length(L);\n"
"L /= distance;\n"
"result.direction = L;\n";
} // anonymous namespace
LightNodeGlsl::LightNodeGlsl() :
_callEmission(HwShaderGenerator::ClosureContextType::EMISSION)
{
// Emission context
_callEmission.addArgument(Type::EDF, ClosureContext::Argument(Type::VECTOR3, "light.direction"));
_callEmission.addArgument(Type::EDF, ClosureContext::Argument(Type::VECTOR3, "-L"));
}
ShaderNodeImplPtr LightNodeGlsl::create()
{
return std::make_shared<LightNodeGlsl>();
}
void LightNodeGlsl::createVariables(const ShaderNode&, GenContext& context, Shader& shader) const
{
ShaderStage& ps = shader.getStage(Stage::PIXEL);
// Create uniform for intensity, exposure and direction
VariableBlock& lightUniforms = ps.getUniformBlock(HW::LIGHT_DATA);
lightUniforms.add(Type::FLOAT, "intensity", Value::createValue<float>(1.0f));
lightUniforms.add(Type::FLOAT, "exposure", Value::createValue<float>(0.0f));
lightUniforms.add(Type::VECTOR3, "direction", Value::createValue<Vector3>(Vector3(0.0f, 1.0f, 0.0f)));
const GlslShaderGenerator& shadergen = static_cast<const GlslShaderGenerator&>(context.getShaderGenerator());
shadergen.addStageLightingUniforms(context, ps);
}
void LightNodeGlsl::emitFunctionCall(const ShaderNode& node, GenContext& context, ShaderStage& stage) const
{
DEFINE_SHADER_STAGE(stage, Stage::PIXEL)
{
const GlslShaderGenerator& shadergen = static_cast<const GlslShaderGenerator&>(context.getShaderGenerator());
shadergen.emitBlock(LIGHT_DIRECTION_CALCULATION, FilePath(), context, stage);
shadergen.emitLineBreak(stage);
const ShaderInput* edfInput = node.getInput("edf");
const ShaderNode* edf = edfInput->getConnectedSibling();
if (edf)
{
context.pushClosureContext(&_callEmission);
shadergen.emitFunctionCall(*edf, context, stage);
context.popClosureContext();
shadergen.emitLineBreak(stage);
shadergen.emitComment("Apply quadratic falloff and adjust intensity", stage);
shadergen.emitLine("result.intensity = " + edf->getOutput()->getVariable() + " / (distance * distance)", stage);
const ShaderInput* intensity = node.getInput("intensity");
const ShaderInput* exposure = node.getInput("exposure");
shadergen.emitLineBegin(stage);
shadergen.emitString("result.intensity *= ", stage);
shadergen.emitInput(intensity, context, stage);
shadergen.emitLineEnd(stage);
// Emit exposure adjustment only if it matters
if (exposure->getConnection() || (exposure->getValue() && exposure->getValue()->asA<float>() != 0.0f))
{
shadergen.emitLineBegin(stage);
shadergen.emitString("result.intensity *= pow(2, ", stage);
shadergen.emitInput(exposure, context, stage);
shadergen.emitString(")", stage);
shadergen.emitLineEnd(stage);
}
}
else
{
shadergen.emitLine("result.intensity = vec3(0.0)", stage);
}
}
}
MATERIALX_NAMESPACE_END