Weizhen Huang
543bf28fb1
wi is the viewing direction, and wo is the illumination direction. Under this notation, BSDF sampling always samples from wi and outputs wo, which is consistent with most of the papers and mitsuba. This order is reversed compared with PBRT, although PBRT also traces from the camera.
62 lines
1.7 KiB
C++
62 lines
1.7 KiB
C++
/* SPDX-License-Identifier: BSD-3-Clause
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*
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* Adapted from Open Shading Language
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* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
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* All Rights Reserved.
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*
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* Modifications Copyright 2011-2022 Blender Foundation. */
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#pragma once
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CCL_NAMESPACE_BEGIN
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/* REFLECTION */
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ccl_device int bsdf_reflection_setup(ccl_private MicrofacetBsdf *bsdf)
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{
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bsdf->type = CLOSURE_BSDF_REFLECTION_ID;
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return SD_BSDF;
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}
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ccl_device Spectrum bsdf_reflection_eval(ccl_private const ShaderClosure *sc,
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const float3 wi,
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const float3 wo,
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ccl_private float *pdf)
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{
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*pdf = 0.0f;
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return zero_spectrum();
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}
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ccl_device int bsdf_reflection_sample(ccl_private const ShaderClosure *sc,
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float3 Ng,
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float3 wi,
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float randu,
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float randv,
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ccl_private Spectrum *eval,
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ccl_private float3 *wo,
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ccl_private float *pdf,
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ccl_private float *eta)
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{
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ccl_private const MicrofacetBsdf *bsdf = (ccl_private const MicrofacetBsdf *)sc;
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float3 N = bsdf->N;
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*eta = bsdf->ior;
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// only one direction is possible
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float cosNI = dot(N, wi);
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if (cosNI > 0) {
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*wo = (2 * cosNI) * N - wi;
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if (dot(Ng, *wo) > 0) {
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/* Some high number for MIS. */
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*pdf = 1e6f;
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*eval = make_spectrum(1e6f);
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}
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}
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else {
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*pdf = 0.0f;
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*eval = zero_spectrum();
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}
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return LABEL_REFLECT | LABEL_SINGULAR;
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}
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CCL_NAMESPACE_END
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