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/*
* Adapted from Open Shading Language with this license:
*
* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
* All Rights Reserved.
*
* Modifications Copyright 2011, Blender Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Sony Pictures Imageworks nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __BSDF_DIFFUSE_H__
#define __BSDF_DIFFUSE_H__
CCL_NAMESPACE_BEGIN
typedef ccl_addr_space struct DiffuseBsdf {
SHADER_CLOSURE_BASE;
float3 N;
} DiffuseBsdf;
/* DIFFUSE */
ccl_device int bsdf_diffuse_setup(DiffuseBsdf *bsdf)
{
bsdf->type = CLOSURE_BSDF_DIFFUSE_ID;
return SD_BSDF|SD_BSDF_HAS_EVAL;
}
ccl_device bool bsdf_diffuse_merge(const ShaderClosure *a, const ShaderClosure *b)
{
const DiffuseBsdf *bsdf_a = (const DiffuseBsdf*)a;
const DiffuseBsdf *bsdf_b = (const DiffuseBsdf*)b;
return (isequal_float3(bsdf_a->N, bsdf_b->N));
}
ccl_device float3 bsdf_diffuse_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
{
const DiffuseBsdf *bsdf = (const DiffuseBsdf*)sc;
float3 N = bsdf->N;
float cos_pi = fmaxf(dot(N, omega_in), 0.0f) * M_1_PI_F;
*pdf = cos_pi;
return make_float3(cos_pi, cos_pi, cos_pi);
}
ccl_device float3 bsdf_diffuse_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
{
return make_float3(0.0f, 0.0f, 0.0f);
}
ccl_device int bsdf_diffuse_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)
{
const DiffuseBsdf *bsdf = (const DiffuseBsdf*)sc;
float3 N = bsdf->N;
// distribution over the hemisphere
sample_cos_hemisphere(N, randu, randv, omega_in, pdf);
if(dot(Ng, *omega_in) > 0.0f) {
*eval = make_float3(*pdf, *pdf, *pdf);
#ifdef __RAY_DIFFERENTIALS__
// TODO: find a better approximation for the diffuse bounce
*domega_in_dx = (2 * dot(N, dIdx)) * N - dIdx;
*domega_in_dy = (2 * dot(N, dIdy)) * N - dIdy;
#endif
}
else
*pdf = 0.0f;
return LABEL_REFLECT|LABEL_DIFFUSE;
}
/* TRANSLUCENT */
ccl_device int bsdf_translucent_setup(DiffuseBsdf *bsdf)
{
bsdf->type = CLOSURE_BSDF_TRANSLUCENT_ID;
return SD_BSDF|SD_BSDF_HAS_EVAL;
}
ccl_device float3 bsdf_translucent_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
{
return make_float3(0.0f, 0.0f, 0.0f);
}
ccl_device float3 bsdf_translucent_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
{
const DiffuseBsdf *bsdf = (const DiffuseBsdf*)sc;
float3 N = bsdf->N;
float cos_pi = fmaxf(-dot(N, omega_in), 0.0f) * M_1_PI_F;
*pdf = cos_pi;
return make_float3 (cos_pi, cos_pi, cos_pi);
}
ccl_device int bsdf_translucent_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)
{
const DiffuseBsdf *bsdf = (const DiffuseBsdf*)sc;
float3 N = bsdf->N;
// we are viewing the surface from the right side - send a ray out with cosine
// distribution over the hemisphere
sample_cos_hemisphere (-N, randu, randv, omega_in, pdf);
if(dot(Ng, *omega_in) < 0) {
*eval = make_float3(*pdf, *pdf, *pdf);
#ifdef __RAY_DIFFERENTIALS__
// TODO: find a better approximation for the diffuse bounce
*domega_in_dx = -((2 * dot(N, dIdx)) * N - dIdx);
*domega_in_dy = -((2 * dot(N, dIdy)) * N - dIdy);
#endif
}
else {
*pdf = 0;
}
return LABEL_TRANSMIT|LABEL_DIFFUSE;
}
CCL_NAMESPACE_END
#endif /* __BSDF_DIFFUSE_H__ */
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