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
1.5 KiB
C
62 lines
1.5 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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/* BACKGROUND CLOSURE */
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ccl_device void background_setup(ccl_private ShaderData *sd, const Spectrum weight)
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{
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if (sd->flag & SD_EMISSION) {
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sd->closure_emission_background += weight;
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}
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else {
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sd->flag |= SD_EMISSION;
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sd->closure_emission_background = weight;
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}
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}
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/* EMISSION CLOSURE */
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ccl_device void emission_setup(ccl_private ShaderData *sd, const Spectrum weight)
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{
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if (sd->flag & SD_EMISSION) {
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sd->closure_emission_background += weight;
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}
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else {
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sd->flag |= SD_EMISSION;
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sd->closure_emission_background = weight;
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}
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}
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/* return the probability distribution function in the direction wi,
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* given the parameters and the light's surface normal. This MUST match
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* the PDF computed by sample(). */
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ccl_device float emissive_pdf(const float3 Ng, const float3 wi)
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{
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float cosNI = fabsf(dot(Ng, wi));
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return (cosNI > 0.0f) ? 1.0f : 0.0f;
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}
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ccl_device void emissive_sample(
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const float3 Ng, float randu, float randv, ccl_private float3 *wi, ccl_private float *pdf)
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{
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/* todo: not implemented and used yet */
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}
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ccl_device Spectrum emissive_simple_eval(const float3 Ng, const float3 wi)
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{
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float res = emissive_pdf(Ng, wi);
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return make_spectrum(res);
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}
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CCL_NAMESPACE_END
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