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/* SPDX-License-Identifier: BSD-3-Clause
*
* Adapted from Open Shading Language
* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
* All Rights Reserved.
*
* Modifications Copyright 2011-2022 Blender Foundation. */
#pragma once
CCL_NAMESPACE_BEGIN
ccl_device void bsdf_transparent_setup(ccl_private ShaderData *sd,
const Spectrum weight,
uint32_t path_flag)
{
/* Check cutoff weight. */
float sample_weight = fabsf(average(weight));
if (!(sample_weight >= CLOSURE_WEIGHT_CUTOFF)) {
return;
}
if (sd->flag & SD_TRANSPARENT) {
sd->closure_transparent_extinction += weight;
/* Add weight to existing transparent BSDF. */
for (int i = 0; i < sd->num_closure; i++) {
ccl_private ShaderClosure *sc = &sd->closure[i];
if (sc->type == CLOSURE_BSDF_TRANSPARENT_ID) {
sc->weight += weight;
sc->sample_weight += sample_weight;
break;
}
}
}
else {
sd->flag |= SD_BSDF | SD_TRANSPARENT;
sd->closure_transparent_extinction = weight;
if (path_flag & PATH_RAY_TERMINATE) {
/* In this case the number of closures is set to zero to disable
* all others, but we still want to get transparency so increase
* the number just for this. */
sd->num_closure_left = 1;
}
/* Create new transparent BSDF. */
ccl_private ShaderClosure *bsdf = closure_alloc(
sd, sizeof(ShaderClosure), CLOSURE_BSDF_TRANSPARENT_ID, weight);
if (bsdf) {
bsdf->sample_weight = sample_weight;
bsdf->N = sd->N;
}
else if (path_flag & PATH_RAY_TERMINATE) {
sd->num_closure_left = 0;
}
}
}
ccl_device Spectrum bsdf_transparent_eval_reflect(ccl_private const ShaderClosure *sc,
const float3 I,
const float3 omega_in,
ccl_private float *pdf)
{
*pdf = 0.0f;
return zero_spectrum();
}
ccl_device Spectrum bsdf_transparent_eval_transmit(ccl_private const ShaderClosure *sc,
const float3 I,
const float3 omega_in,
ccl_private float *pdf)
{
*pdf = 0.0f;
return zero_spectrum();
}
ccl_device int bsdf_transparent_sample(ccl_private const ShaderClosure *sc,
float3 Ng,
float3 I,
float3 dIdx,
float3 dIdy,
float randu,
float randv,
ccl_private Spectrum *eval,
ccl_private float3 *omega_in,
ccl_private float3 *domega_in_dx,
ccl_private float3 *domega_in_dy,
ccl_private float *pdf)
{
// only one direction is possible
*omega_in = -I;
#ifdef __RAY_DIFFERENTIALS__
*domega_in_dx = -dIdx;
*domega_in_dy = -dIdy;
#endif
*pdf = 1;
*eval = one_spectrum();
return LABEL_TRANSMIT | LABEL_TRANSPARENT;
}
CCL_NAMESPACE_END
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