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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_HAIR_H__
#define __BSDF_HAIR_H__
CCL_NAMESPACE_BEGIN
ccl_device void bsdf_hair_reflection_blur(ShaderClosure *sc, float roughness)
{
}
ccl_device void bsdf_hair_transmission_blur(ShaderClosure *sc, float roughness)
{
}
ccl_device int bsdf_hair_reflection_setup(ShaderClosure *sc)
{
sc->type = CLOSURE_BSDF_HAIR_REFLECTION_ID;
sc->data0 = clamp(sc->data0, 0.001f, 1.0f);
sc->data1 = clamp(sc->data1, 0.001f, 1.0f);
return SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_GLOSSY;
}
ccl_device int bsdf_hair_transmission_setup(ShaderClosure *sc)
{
sc->type = CLOSURE_BSDF_HAIR_TRANSMISSION_ID;
sc->data0 = clamp(sc->data0, 0.001f, 1.0f);
sc->data1 = clamp(sc->data1, 0.001f, 1.0f);
return SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_GLOSSY;
}
ccl_device float3 bsdf_hair_reflection_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
{
#ifdef __HAIR__
float offset = sc->data2;
float3 Tg = sc->T;
#else
float offset = 0.0f;
float3 Tg = make_float3(1.0f, 0.0f, 0.0f);
#endif
float roughness1 = sc->data0;
float roughness2 = sc->data1;
float Iz = dot(Tg, I);
float3 locy = normalize(I - Tg * Iz);
//float3 locx = cross(locy, Tg);
float theta_r = M_PI_2_F - safe_acosf(Iz);
float omega_in_z = dot(Tg, omega_in);
float3 omega_in_y = normalize(omega_in - Tg * omega_in_z);
float theta_i = M_PI_2_F - safe_acosf(omega_in_z);
float cosphi_i = dot(omega_in_y, locy);
if(M_PI_2_F - fabsf(theta_i) < 0.001f || cosphi_i < 0.0f) {
*pdf = 0.0f;
return make_float3(*pdf, *pdf, *pdf);
}
float phi_i = safe_acosf(cosphi_i) / roughness2;
phi_i = fabsf(phi_i) < M_PI_F ? phi_i : M_PI_F;
float costheta_i = cosf(theta_i);
float a_R = atan2f(((M_PI_2_F + theta_r) * 0.5f - offset) / roughness1, 1.0f);
float b_R = atan2f(((-M_PI_2_F + theta_r) * 0.5f - offset) / roughness1, 1.0f);
float theta_h = (theta_i + theta_r) * 0.5f;
float t = theta_h - offset;
float phi_pdf = cosf(phi_i * 0.5f) * 0.25f / roughness2;
float theta_pdf = roughness1 / (2 * (t*t + roughness1*roughness1) * (a_R - b_R)* costheta_i);
*pdf = phi_pdf * theta_pdf;
return make_float3(*pdf, *pdf, *pdf);
}
ccl_device float3 bsdf_hair_transmission_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_hair_reflection_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 float3 bsdf_hair_transmission_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
{
#ifdef __HAIR__
float offset = sc->data2;
float3 Tg = sc->T;
#else
float offset = 0.0f;
float3 Tg = make_float3(1.0f, 0.0f, 0.0f);
#endif
float roughness1 = sc->data0;
float roughness2 = sc->data1;
float Iz = dot(Tg, I);
float3 locy = normalize(I - Tg * Iz);
//float3 locx = cross(locy, Tg);
float theta_r = M_PI_2_F - safe_acosf(Iz);
float omega_in_z = dot(Tg, omega_in);
float3 omega_in_y = normalize(omega_in - Tg * omega_in_z);
float theta_i = M_PI_2_F - safe_acosf(omega_in_z);
float phi_i = safe_acosf(dot(omega_in_y, locy));
if(M_PI_2_F - fabsf(theta_i) < 0.001f) {
*pdf = 0.0f;
return make_float3(*pdf, *pdf, *pdf);
}
float costheta_i = cosf(theta_i);
float a_TT = atan2f(((M_PI_2_F + theta_r)/2 - offset) / roughness1, 1.0f);
float b_TT = atan2f(((-M_PI_2_F + theta_r)/2 - offset) / roughness1, 1.0f);
float c_TT = 2 * atan2f(M_PI_2_F / roughness2, 1.0f);
float theta_h = (theta_i + theta_r) / 2;
float t = theta_h - offset;
float phi = fabsf(phi_i);
float p = M_PI_F - phi;
float theta_pdf = roughness1 / (2 * (t*t + roughness1 * roughness1) * (a_TT - b_TT)*costheta_i);
float phi_pdf = roughness2 / (c_TT * (p * p + roughness2 * roughness2));
*pdf = phi_pdf * theta_pdf;
return make_float3(*pdf, *pdf, *pdf);
}
ccl_device int bsdf_hair_reflection_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)
{
#ifdef __HAIR__
float offset = sc->data2;
float3 Tg = sc->T;
#else
float offset = 0.0f;
float3 Tg = make_float3(1.0f, 0.0f, 0.0f);
#endif
float roughness1 = sc->data0;
float roughness2 = sc->data1;
float Iz = dot(Tg, I);
float3 locy = normalize(I - Tg * Iz);
float3 locx = cross(locy, Tg);
float theta_r = M_PI_2_F - safe_acosf(Iz);
float a_R = atan2f(((M_PI_2_F + theta_r) * 0.5f - offset) / roughness1, 1.0f);
float b_R = atan2f(((-M_PI_2_F + theta_r) * 0.5f - offset) / roughness1, 1.0f);
float t = roughness1 * tanf(randu * (a_R - b_R) + b_R);
float theta_h = t + offset;
float theta_i = 2 * theta_h - theta_r;
float costheta_i = cosf(theta_i);
float sintheta_i = sinf(theta_i);
float phi = 2 * safe_asinf(1 - 2 * randv) * roughness2;
float phi_pdf = cosf(phi * 0.5f) * 0.25f / roughness2;
float theta_pdf = roughness1 / (2 * (t*t + roughness1*roughness1) * (a_R - b_R)*costheta_i);
*omega_in =(cosf(phi) * costheta_i) * locy -
(sinf(phi) * costheta_i) * locx +
( sintheta_i) * Tg;
//differentials - TODO: find a better approximation for the reflective bounce
#ifdef __RAY_DIFFERENTIALS__
*domega_in_dx = 2 * dot(locy, dIdx) * locy - dIdx;
*domega_in_dy = 2 * dot(locy, dIdy) * locy - dIdy;
#endif
*pdf = fabsf(phi_pdf * theta_pdf);
if(M_PI_2_F - fabsf(theta_i) < 0.001f)
*pdf = 0.0f;
*eval = make_float3(*pdf, *pdf, *pdf);
if(dot(locy, *omega_in) < 0.0f) {
return LABEL_REFLECT|LABEL_TRANSMIT|LABEL_GLOSSY;
}
return LABEL_REFLECT|LABEL_GLOSSY;
}
ccl_device int bsdf_hair_transmission_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)
{
#ifdef __HAIR__
float offset = sc->data2;
float3 Tg = sc->T;
#else
float offset = 0.0f;
float3 Tg = make_float3(1.0f, 0.0f, 0.0f);
#endif
float roughness1 = sc->data0;
float roughness2 = sc->data1;
float Iz = dot(Tg, I);
float3 locy = normalize(I - Tg * Iz);
float3 locx = cross(locy, Tg);
float theta_r = M_PI_2_F - safe_acosf(Iz);
float a_TT = atan2f(((M_PI_2_F + theta_r)/2 - offset) / roughness1, 1.0f);
float b_TT = atan2f(((-M_PI_2_F + theta_r)/2 - offset) / roughness1, 1.0f);
float c_TT = 2 * atan2f(M_PI_2_F / roughness2, 1.0f);
float t = roughness1 * tanf(randu * (a_TT - b_TT) + b_TT);
float theta_h = t + offset;
float theta_i = 2 * theta_h - theta_r;
float costheta_i = cosf(theta_i);
float sintheta_i = sinf(theta_i);
float p = roughness2 * tanf(c_TT * (randv - 0.5f));
float phi = p + M_PI_F;
float theta_pdf = roughness1 / (2 * (t*t + roughness1*roughness1) * (a_TT - b_TT) * costheta_i);
float phi_pdf = roughness2 / (c_TT * (p * p + roughness2 * roughness2));
*omega_in =(cosf(phi) * costheta_i) * locy -
(sinf(phi) * costheta_i) * locx +
( sintheta_i) * Tg;
//differentials - TODO: find a better approximation for the transmission bounce
#ifdef __RAY_DIFFERENTIALS__
*domega_in_dx = 2 * dot(locy, dIdx) * locy - dIdx;
*domega_in_dy = 2 * dot(locy, dIdy) * locy - dIdy;
#endif
*pdf = fabsf(phi_pdf * theta_pdf);
if(M_PI_2_F - fabsf(theta_i) < 0.001f) {
*pdf = 0.0f;
}
*eval = make_float3(*pdf, *pdf, *pdf);
if(dot(locy, *omega_in) < 0.0f)
return LABEL_TRANSMIT|LABEL_GLOSSY;
return LABEL_GLOSSY;
}
CCL_NAMESPACE_END
#endif /* __BSDF_HAIR_H__ */
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