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//DISABLE_TEST:SIMPLE: -target cuda -line-directive-mode none
// Verify that we can output a cuda device function with [CudaDeviceExport].
// Disabled until we have FileCheck.
//////////////////////////////////////////////////////////////////////////
// Lambda GGX
//////////////////////////////////////////////////////////////////////////
[CudaDeviceExport]
[BackwardDifferentiable]
float lambdaGGX(const float alphaSqr, const float cosTheta)
{
const float SPECULAR_EPSILON = 1e-4f;
float _cosTheta = clamp(cosTheta, SPECULAR_EPSILON, 1.0f - SPECULAR_EPSILON);
float cosThetaSqr = _cosTheta * _cosTheta;
float tanThetaSqr = (1.0 - cosThetaSqr) / cosThetaSqr;
return 0.5f * (sqrt(1.0f + alphaSqr * tanThetaSqr) - 1.0f);
}
[CudaDeviceExport]
void lambdaGGX_bwd(inout DifferentialPair<float> alphaSqr, inout DifferentialPair<float> cosTheta, const float d_out)
{
__bwd_diff(lambdaGGX)(alphaSqr, cosTheta, d_out);
}
//////////////////////////////////////////////////////////////////////////
// Masking Smith
//////////////////////////////////////////////////////////////////////////
[CudaDeviceExport]
[BackwardDifferentiable]
float maskingSmithGGXCorrelated(const float alphaSqr, const float cosThetaI, const float cosThetaO)
{
float lambdaI = lambdaGGX(alphaSqr, cosThetaI);
float lambdaO = lambdaGGX(alphaSqr, cosThetaO);
return 1.0f / (1.0f + lambdaI + lambdaO);
}
[CudaDeviceExport]
void maskingSmithGGXCorrelated_bwd(inout DifferentialPair<float> alphaSqr,
inout DifferentialPair<float> cosThetaI,
inout DifferentialPair<float> cosThetaO,
const float d_out)
{
__bwd_diff(maskingSmithGGXCorrelated)(alphaSqr, cosThetaI, cosThetaO, d_out);
}
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