blender/intern/cycles/kernel/closure/bsdf_transparent.h
Weizhen Huang cc93b7f5a4 Refactor: Cycles: Separate shader flags and runtime flags
We are running out of bits. Split the original `ShaderDataFlag` into
`ShaderRuntimeFlag`, which is determined by closures in the shader and
set up during rendering, and `ShaderDataFlag`, which is the same for the
whole shader graph and hence determined during shader compilation

The size of `ShaderData` did not change due to padding

Pull Request: https://projects.blender.org/blender/blender/pulls/161856
2026-07-27 19:31:18 +02:00

88 lines
2.6 KiB
C

/* SPDX-FileCopyrightText: 2009-2010 Sony Pictures Imageworks Inc., et al. All Rights Reserved.
* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
*
* SPDX-License-Identifier: BSD-3-Clause
*
* Adapted code from Open Shading Language. */
#pragma once
#include "kernel/types.h"
#include "kernel/closure/alloc.h"
CCL_NAMESPACE_BEGIN
ccl_device void bsdf_transparent_setup(ccl_private ShaderData *sd,
const Spectrum weight,
const uint32_t path_flag)
{
/* Check cutoff weight. */
const float sample_weight = fabsf(average(weight));
if (!(sample_weight >= CLOSURE_WEIGHT_CUTOFF)) {
return;
}
sd->closure_transparent_extinction += weight;
if (sd->runtime_flag & SR_TRANSPARENT) {
/* 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->runtime_flag |= SR_BSDF | SR_TRANSPARENT;
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(const ccl_private ShaderClosure * /*sc*/,
const float3 /*wi*/,
const float3 /*wo*/,
ccl_private float *pdf)
{
*pdf = 0.0f;
return zero_spectrum();
}
ccl_device int bsdf_transparent_sample(const ccl_private ShaderClosure * /*sc*/,
const float3 /*Ng*/,
const float3 wi,
ccl_private Spectrum *eval,
ccl_private float3 *wo,
ccl_private float *pdf)
{
// only one direction is possible
*wo = -wi;
/* Some high number for MIS. */
*pdf = 1e6f;
*eval = one_spectrum() * 1e6f;
return LABEL_TRANSMIT | LABEL_TRANSPARENT;
}
CCL_NAMESPACE_END