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https://github.com/blender/blender
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cc93b7f5a4
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
73 lines
2.5 KiB
C
73 lines
2.5 KiB
C
/* SPDX-FileCopyrightText: 2011-2024 Blender Foundation
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*
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* SPDX-License-Identifier: Apache-2.0 */
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#pragma once
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#include "kernel/types.h"
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#include "kernel/closure/volume_util.h"
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CCL_NAMESPACE_BEGIN
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/* FOURNIER-FORAND CLOSURE */
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struct FournierForandVolume {
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SHADER_CLOSURE_VOLUME_BASE;
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/* Precomputed coefficients, based on B and IOR */
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float c1, c2, c3;
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};
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static_assert(sizeof(ShaderVolumeClosure) >= sizeof(FournierForandVolume),
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"FournierForandVolume is too large!");
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ccl_device int volume_fournier_forand_setup(ccl_private FournierForandVolume *volume,
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float B,
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float IOR)
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{
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volume->type = CLOSURE_VOLUME_FOURNIER_FORAND_ID;
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/* clamp backscatter fraction to avoid delta function */
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B = min(fabsf(B), 0.5f - 1e-3f);
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IOR = max(IOR, 1.0f + 1e-3f);
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const float3 coeffs = phase_fournier_forand_coeffs(B, IOR);
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volume->c1 = coeffs.x;
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volume->c2 = coeffs.y;
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volume->c3 = coeffs.z;
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return SR_SCATTER;
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}
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ccl_device Spectrum volume_fournier_forand_eval(const ccl_private ShaderData *sd,
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const ccl_private ShaderVolumeClosure *svc,
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const float3 wo,
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ccl_private float *pdf)
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{
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const ccl_private FournierForandVolume *volume = (const ccl_private FournierForandVolume *)svc;
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const float3 coeffs = make_float3(volume->c1, volume->c2, volume->c3);
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/* note that wi points towards the viewer */
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const float cos_theta = dot(-sd->wi, wo);
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*pdf = phase_fournier_forand(cos_theta, coeffs);
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return make_spectrum(*pdf);
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}
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ccl_device int volume_fournier_forand_sample(const ccl_private ShaderData *sd,
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const ccl_private ShaderVolumeClosure *svc,
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const float2 rand,
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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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const ccl_private FournierForandVolume *volume = (const ccl_private FournierForandVolume *)svc;
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const float3 coeffs = make_float3(volume->c1, volume->c2, volume->c3);
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/* note that wi points towards the viewer and so is used negated */
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*wo = phase_fournier_forand_sample(-sd->wi, coeffs, rand, pdf);
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*eval = make_spectrum(*pdf); /* perfect importance sampling */
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return LABEL_VOLUME_SCATTER;
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}
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CCL_NAMESPACE_END
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