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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 2012, 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_PHONG_RAMP_H__
#define __BSDF_PHONG_RAMP_H__
CCL_NAMESPACE_BEGIN
__device float3 bsdf_phong_ramp_get_color(const ShaderClosure *sc, const float3 colors[8], float pos)
{
int MAXCOLORS = 8;
float npos = pos * (float)(MAXCOLORS - 1);
int ipos = (int)npos;
if (ipos >= (MAXCOLORS - 1))
return colors[MAXCOLORS - 1];
float offset = npos - (float)ipos;
return colors[ipos] * (1.0f - offset) + colors[ipos+1] * offset;
}
__device int bsdf_phong_ramp_setup(ShaderClosure *sc)
{
sc->type = CLOSURE_BSDF_PHONG_RAMP_ID;
return SD_BSDF | SD_BSDF_HAS_EVAL | SD_BSDF_GLOSSY;
}
__device void bsdf_phong_ramp_blur(ShaderClosure *sc, float roughness)
{
}
__device float3 bsdf_phong_ramp_eval_reflect(const ShaderClosure *sc, const float3 colors[8], const float3 I, const float3 omega_in, float *pdf)
{
float m_exponent = sc->data0;
float cosNI = dot(sc->N, omega_in);
float cosNO = dot(sc->N, I);
if (cosNI > 0 && cosNO > 0) {
// reflect the view vector
float3 R = (2 * cosNO) * sc->N - I;
float cosRI = dot(R, omega_in);
if (cosRI > 0) {
float cosp = powf(cosRI, m_exponent);
float common = 0.5f * (float) M_1_PI_F * cosp;
float out = cosNI * (m_exponent + 2) * common;
*pdf = (m_exponent + 1) * common;
return bsdf_phong_ramp_get_color(sc, colors, cosp) * out;
}
}
return make_float3(0.0f, 0.0f, 0.0f);
}
__device float3 bsdf_phong_ramp_eval_transmit(const ShaderClosure *sc, const float3 colors[8], const float3 I, const float3 omega_in, float *pdf)
{
return make_float3(0.0f, 0.0f, 0.0f);
}
__device int bsdf_phong_ramp_sample(const ShaderClosure *sc, const float3 colors[8], 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)
{
float cosNO = dot(sc->N, I);
float m_exponent = sc->data0;
if (cosNO > 0) {
// reflect the view vector
float3 R = (2 * cosNO) * sc->N - I;
#ifdef __RAY_DIFFERENTIALS__
*domega_in_dx = (2 * dot(sc->N, dIdx)) * sc->N - dIdx;
*domega_in_dy = (2 * dot(sc->N, dIdy)) * sc->N - dIdy;
#endif
float3 T, B;
make_orthonormals (R, &T, &B);
float phi = 2 * M_PI_F * randu;
float cosTheta = powf(randv, 1 / (m_exponent + 1));
float sinTheta2 = 1 - cosTheta * cosTheta;
float sinTheta = sinTheta2 > 0 ? sqrtf(sinTheta2) : 0;
*omega_in = (cosf(phi) * sinTheta) * T +
(sinf(phi) * sinTheta) * B +
( cosTheta) * R;
if (dot(Ng, *omega_in) > 0.0f)
{
// common terms for pdf and eval
float cosNI = dot(sc->N, *omega_in);
// make sure the direction we chose is still in the right hemisphere
if (cosNI > 0)
{
float cosp = powf(cosTheta, m_exponent);
float common = 0.5f * M_1_PI_F * cosp;
*pdf = (m_exponent + 1) * common;
float out = cosNI * (m_exponent + 2) * common;
*eval = bsdf_phong_ramp_get_color(sc, colors, cosp) * out;
}
}
}
return LABEL_REFLECT|LABEL_GLOSSY;
}
CCL_NAMESPACE_END
#endif /* __BSDF_PHONG_RAMP_H__ */
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