86 lines
2.5 KiB
C
86 lines
2.5 KiB
C
/* SPDX-FileCopyrightText: 2009-2010 Sony Pictures Imageworks Inc., et al. All Rights Reserved.
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* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Adapted code from Open Shading Language. */
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#pragma once
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CCL_NAMESPACE_BEGIN
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ccl_device void bsdf_transparent_setup(ccl_private ShaderData *sd,
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const Spectrum weight,
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uint32_t path_flag)
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{
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/* Check cutoff weight. */
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float sample_weight = fabsf(average(weight));
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if (!(sample_weight >= CLOSURE_WEIGHT_CUTOFF)) {
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return;
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}
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if (sd->flag & SD_TRANSPARENT) {
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sd->closure_transparent_extinction += weight;
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/* Add weight to existing transparent BSDF. */
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private ShaderClosure *sc = &sd->closure[i];
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if (sc->type == CLOSURE_BSDF_TRANSPARENT_ID) {
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sc->weight += weight;
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sc->sample_weight += sample_weight;
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break;
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}
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}
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}
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else {
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sd->flag |= SD_BSDF | SD_TRANSPARENT;
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sd->closure_transparent_extinction = weight;
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if (path_flag & PATH_RAY_TERMINATE) {
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/* In this case the number of closures is set to zero to disable
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* all others, but we still want to get transparency so increase
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* the number just for this. */
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sd->num_closure_left = 1;
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}
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/* Create new transparent BSDF. */
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ccl_private ShaderClosure *bsdf = closure_alloc(
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sd, sizeof(ShaderClosure), CLOSURE_BSDF_TRANSPARENT_ID, weight);
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if (bsdf) {
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bsdf->sample_weight = sample_weight;
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bsdf->N = sd->N;
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}
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else if (path_flag & PATH_RAY_TERMINATE) {
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sd->num_closure_left = 0;
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}
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}
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}
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ccl_device Spectrum bsdf_transparent_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_transparent_sample(ccl_private const ShaderClosure *sc,
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float3 Ng,
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float3 wi,
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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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{
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// only one direction is possible
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*wo = -wi;
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/* Some high number for MIS. */
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*pdf = 1e6f;
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*eval = one_spectrum() * 1e6f;
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return LABEL_TRANSMIT | LABEL_TRANSPARENT;
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}
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CCL_NAMESPACE_END
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