forked from bartvdbraak/blender
200 lines
6.7 KiB
C
200 lines
6.7 KiB
C
/*
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* Adapted from Open Shading Language with this license:
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*
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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, Blender Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Sony Pictures Imageworks nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef __BSDF_WESTIN_H__
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#define __BSDF_WESTIN_H__
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CCL_NAMESPACE_BEGIN
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/* WESTIN BACKSCATTER */
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__device void bsdf_westin_backscatter_setup(ShaderData *sd, ShaderClosure *sc, float roughness)
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{
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roughness = clamp(roughness, 1e-5f, 1.0f);
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float m_invroughness = 1.0f/roughness;
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sc->type = CLOSURE_BSDF_WESTIN_BACKSCATTER_ID;
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sd->flag |= SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_GLOSSY;
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sc->data0 = m_invroughness;
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}
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__device void bsdf_westin_backscatter_blur(ShaderClosure *sc, float roughness)
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{
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float m_invroughness = sc->data0;
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m_invroughness = min(1.0f/roughness, m_invroughness);
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sc->data0 = m_invroughness;
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}
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__device float3 bsdf_westin_backscatter_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
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{
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float m_invroughness = sc->data0;
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float3 N = sc->N;
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// pdf is implicitly 0 (no indirect sampling)
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float cosNO = dot(N, I);
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float cosNI = dot(N, omega_in);
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if(cosNO > 0 && cosNI > 0) {
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float cosine = dot(I, omega_in);
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*pdf = cosine > 0 ? (m_invroughness + 1) * powf(cosine, m_invroughness) : 0;
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*pdf *= 0.5f * M_1_PI_F;
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return make_float3 (*pdf, *pdf, *pdf);
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}
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return make_float3 (0, 0, 0);
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}
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__device float3 bsdf_westin_backscatter_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
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{
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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__device float bsdf_westin_backscatter_albedo(const ShaderClosure *sc, const float3 I)
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{
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return 1.0f;
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}
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__device int bsdf_westin_backscatter_sample(const ShaderClosure *sc, float3 Ng, float3 I, float3 dIdx, float3 dIdy, float randu, float randv, float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf)
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{
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float m_invroughness = sc->data0;
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float3 N = sc->N;
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float cosNO = dot(N, I);
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if(cosNO > 0) {
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#ifdef __RAY_DIFFERENTIALS__
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*domega_in_dx = dIdx;
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*domega_in_dy = dIdy;
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#endif
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float3 T, B;
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make_orthonormals (I, &T, &B);
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float phi = 2 * M_PI_F * randu;
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float cosTheta = powf(randv, 1 / (m_invroughness + 1));
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float sinTheta2 = 1 - cosTheta * cosTheta;
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float sinTheta = sinTheta2 > 0 ? sqrtf(sinTheta2) : 0;
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*omega_in = (cosf(phi) * sinTheta) * T +
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(sinf(phi) * sinTheta) * B +
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(cosTheta) * I;
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if(dot(Ng, *omega_in) > 0)
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{
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// common terms for pdf and eval
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float cosNI = dot(N, *omega_in);
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// make sure the direction we chose is still in the right hemisphere
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if(cosNI > 0)
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{
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*pdf = 0.5f * M_1_PI_F * powf(cosTheta, m_invroughness);
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*pdf = (m_invroughness + 1) * (*pdf);
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*eval = make_float3(*pdf, *pdf, *pdf);
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#ifdef __RAY_DIFFERENTIALS__
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// Since there is some blur to this reflection, make the
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// derivatives a bit bigger. In theory this varies with the
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// exponent but the exact relationship is complex and
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// requires more ops than are practical.
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*domega_in_dx *= 10.0f;
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*domega_in_dy *= 10.0f;
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#endif
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}
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}
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}
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return LABEL_REFLECT|LABEL_GLOSSY;
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}
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/* WESTIN SHEEN */
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__device void bsdf_westin_sheen_setup(ShaderData *sd, ShaderClosure *sc, float edginess)
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{
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sc->type = CLOSURE_BSDF_WESTIN_SHEEN_ID;
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sd->flag |= SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_GLOSSY;
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sc->data0 = edginess;
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}
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__device void bsdf_westin_sheen_blur(ShaderClosure *sc, float roughness)
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{
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}
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__device float3 bsdf_westin_sheen_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
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{
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float m_edginess = sc->data0;
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float3 N = sc->N;
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// pdf is implicitly 0 (no indirect sampling)
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float cosNO = dot(N, I);
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float cosNI = dot(N, omega_in);
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if(cosNO > 0 && cosNI > 0) {
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float sinNO2 = 1 - cosNO * cosNO;
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*pdf = cosNI * M_1_PI_F;
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float westin = sinNO2 > 0 ? powf(sinNO2, 0.5f * m_edginess) * (*pdf) : 0;
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return make_float3 (westin, westin, westin);
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}
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return make_float3 (0, 0, 0);
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}
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__device float3 bsdf_westin_sheen_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
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{
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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__device float bsdf_westin_sheen_albedo(const ShaderClosure *sc, const float3 I)
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{
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return 1.0f;
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}
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__device int bsdf_westin_sheen_sample(const ShaderClosure *sc, float3 Ng, float3 I, float3 dIdx, float3 dIdy, float randu, float randv, float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf)
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{
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float m_edginess = sc->data0;
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float3 N = sc->N;
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// we are viewing the surface from the right side - send a ray out with cosine
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// distribution over the hemisphere
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sample_cos_hemisphere(N, randu, randv, omega_in, pdf);
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if(dot(Ng, *omega_in) > 0) {
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// TODO: account for sheen when sampling
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float cosNO = dot(N, I);
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float sinNO2 = 1 - cosNO * cosNO;
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float westin = sinNO2 > 0 ? powf(sinNO2, 0.5f * m_edginess) * (*pdf) : 0;
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*eval = make_float3(westin, westin, westin);
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#ifdef __RAY_DIFFERENTIALS__
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// TODO: find a better approximation for the diffuse bounce
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*domega_in_dx = (2 * dot(N, dIdx)) * N - dIdx;
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*domega_in_dy = (2 * dot(N, dIdy)) * N - dIdy;
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*domega_in_dx *= 125.0f;
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*domega_in_dy *= 125.0f;
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#endif
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}
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else {
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pdf = 0;
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}
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return LABEL_REFLECT|LABEL_DIFFUSE;
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}
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CCL_NAMESPACE_END
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#endif /* __BSDF_WESTIN_H__ */
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