forked from bartvdbraak/blender
d632ef7c66
Precision of the fast functions seems to be enough in there and since the code was heavily using inverse trigonometric functions this change gives few percent speedup on Victor's hair. From the tests files from ctests storage doesn't have any meaningful difference, hair on Victor is all below 4% absolute error and only few pixels are exceeding 1% absolute difference. In any case, let it be as it is currently so it allows us to have fast math file in sources for it's further evaluation and possible usage in other areas as well.
286 lines
9.3 KiB
C
286 lines
9.3 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_HAIR_H__
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#define __BSDF_HAIR_H__
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CCL_NAMESPACE_BEGIN
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ccl_device void bsdf_hair_reflection_blur(ShaderClosure *sc, float roughness)
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{
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}
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ccl_device void bsdf_hair_transmission_blur(ShaderClosure *sc, float roughness)
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{
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}
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ccl_device int bsdf_hair_reflection_setup(ShaderClosure *sc)
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{
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sc->type = CLOSURE_BSDF_HAIR_REFLECTION_ID;
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sc->data0 = clamp(sc->data0, 0.001f, 1.0f);
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sc->data1 = clamp(sc->data1, 0.001f, 1.0f);
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return SD_BSDF|SD_BSDF_HAS_EVAL;
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}
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ccl_device int bsdf_hair_transmission_setup(ShaderClosure *sc)
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{
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sc->type = CLOSURE_BSDF_HAIR_TRANSMISSION_ID;
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sc->data0 = clamp(sc->data0, 0.001f, 1.0f);
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sc->data1 = clamp(sc->data1, 0.001f, 1.0f);
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return SD_BSDF|SD_BSDF_HAS_EVAL;
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}
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ccl_device float3 bsdf_hair_reflection_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
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{
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#ifdef __HAIR__
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float offset = sc->data2;
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float3 Tg = sc->T;
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#else
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float offset = 0.0f;
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float3 Tg = make_float3(1.0f, 0.0f, 0.0f);
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#endif
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float roughness1 = sc->data0;
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float roughness2 = sc->data1;
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float Iz = dot(Tg, I);
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float3 locy = normalize(I - Tg * Iz);
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//float3 locx = cross(locy, Tg);
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float theta_r = M_PI_2_F - fast_acosf(Iz);
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float omega_in_z = dot(Tg, omega_in);
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float3 omega_in_y = normalize(omega_in - Tg * omega_in_z);
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float theta_i = M_PI_2_F - fast_acosf(omega_in_z);
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float cosphi_i = dot(omega_in_y, locy);
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if(M_PI_2_F - fabsf(theta_i) < 0.001f || cosphi_i < 0.0f) {
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*pdf = 0.0f;
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return make_float3(*pdf, *pdf, *pdf);
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}
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float roughness1_inv = 1.0f / roughness1;
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float roughness2_inv = 1.0f / roughness2;
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float phi_i = fast_acosf(cosphi_i) * roughness2_inv;
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phi_i = fabsf(phi_i) < M_PI_F ? phi_i : M_PI_F;
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float costheta_i = fast_cosf(theta_i);
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float a_R = fast_atan2f(((M_PI_2_F + theta_r) * 0.5f - offset) * roughness1_inv, 1.0f);
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float b_R = fast_atan2f(((-M_PI_2_F + theta_r) * 0.5f - offset) * roughness1_inv, 1.0f);
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float theta_h = (theta_i + theta_r) * 0.5f;
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float t = theta_h - offset;
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float phi_pdf = fast_cosf(phi_i * 0.5f) * 0.25f * roughness2_inv;
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float theta_pdf = roughness1 / (2 * (t*t + roughness1*roughness1) * (a_R - b_R)* costheta_i);
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*pdf = phi_pdf * theta_pdf;
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return make_float3(*pdf, *pdf, *pdf);
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}
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ccl_device float3 bsdf_hair_transmission_eval_reflect(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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ccl_device float3 bsdf_hair_reflection_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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ccl_device float3 bsdf_hair_transmission_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
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{
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#ifdef __HAIR__
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float offset = sc->data2;
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float3 Tg = sc->T;
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#else
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float offset = 0.0f;
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float3 Tg = make_float3(1.0f, 0.0f, 0.0f);
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#endif
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float roughness1 = sc->data0;
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float roughness2 = sc->data1;
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float Iz = dot(Tg, I);
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float3 locy = normalize(I - Tg * Iz);
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//float3 locx = cross(locy, Tg);
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float theta_r = M_PI_2_F - fast_acosf(Iz);
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float omega_in_z = dot(Tg, omega_in);
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float3 omega_in_y = normalize(omega_in - Tg * omega_in_z);
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float theta_i = M_PI_2_F - fast_acosf(omega_in_z);
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float phi_i = fast_acosf(dot(omega_in_y, locy));
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if(M_PI_2_F - fabsf(theta_i) < 0.001f) {
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*pdf = 0.0f;
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return make_float3(*pdf, *pdf, *pdf);
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}
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float costheta_i = fast_cosf(theta_i);
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float roughness1_inv = 1.0f / roughness1;
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float a_TT = fast_atan2f(((M_PI_2_F + theta_r)/2 - offset) * roughness1_inv, 1.0f);
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float b_TT = fast_atan2f(((-M_PI_2_F + theta_r)/2 - offset) * roughness1_inv, 1.0f);
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float c_TT = 2 * fast_atan2f(M_PI_2_F / roughness2, 1.0f);
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float theta_h = (theta_i + theta_r) / 2;
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float t = theta_h - offset;
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float phi = fabsf(phi_i);
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float p = M_PI_F - phi;
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float theta_pdf = roughness1 / (2 * (t*t + roughness1 * roughness1) * (a_TT - b_TT)*costheta_i);
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float phi_pdf = roughness2 / (c_TT * (p * p + roughness2 * roughness2));
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*pdf = phi_pdf * theta_pdf;
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return make_float3(*pdf, *pdf, *pdf);
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}
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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)
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{
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#ifdef __HAIR__
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float offset = sc->data2;
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float3 Tg = sc->T;
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#else
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float offset = 0.0f;
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float3 Tg = make_float3(1.0f, 0.0f, 0.0f);
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#endif
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float roughness1 = sc->data0;
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float roughness2 = sc->data1;
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float Iz = dot(Tg, I);
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float3 locy = normalize(I - Tg * Iz);
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float3 locx = cross(locy, Tg);
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float theta_r = M_PI_2_F - fast_acosf(Iz);
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float roughness1_inv = 1.0f / roughness1;
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float a_R = fast_atan2f(((M_PI_2_F + theta_r) * 0.5f - offset) * roughness1_inv, 1.0f);
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float b_R = fast_atan2f(((-M_PI_2_F + theta_r) * 0.5f - offset) * roughness1_inv, 1.0f);
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float t = roughness1 * tanf(randu * (a_R - b_R) + b_R);
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float theta_h = t + offset;
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float theta_i = 2 * theta_h - theta_r;
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float costheta_i, sintheta_i;
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fast_sincosf(theta_i, &sintheta_i, &costheta_i);
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float phi = 2 * safe_asinf(1 - 2 * randv) * roughness2;
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float phi_pdf = fast_cosf(phi * 0.5f) * 0.25f / roughness2;
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float theta_pdf = roughness1 / (2 * (t*t + roughness1*roughness1) * (a_R - b_R)*costheta_i);
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float sinphi, cosphi;
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fast_sincosf(phi, &sinphi, &cosphi);
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*omega_in =(cosphi * costheta_i) * locy -
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(sinphi * costheta_i) * locx +
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( sintheta_i) * Tg;
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//differentials - TODO: find a better approximation for the reflective bounce
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#ifdef __RAY_DIFFERENTIALS__
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*domega_in_dx = 2 * dot(locy, dIdx) * locy - dIdx;
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*domega_in_dy = 2 * dot(locy, dIdy) * locy - dIdy;
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#endif
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*pdf = fabsf(phi_pdf * theta_pdf);
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if(M_PI_2_F - fabsf(theta_i) < 0.001f)
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*pdf = 0.0f;
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*eval = make_float3(*pdf, *pdf, *pdf);
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return LABEL_REFLECT|LABEL_GLOSSY;
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}
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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)
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{
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#ifdef __HAIR__
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float offset = sc->data2;
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float3 Tg = sc->T;
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#else
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float offset = 0.0f;
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float3 Tg = make_float3(1.0f, 0.0f, 0.0f);
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#endif
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float roughness1 = sc->data0;
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float roughness2 = sc->data1;
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float Iz = dot(Tg, I);
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float3 locy = normalize(I - Tg * Iz);
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float3 locx = cross(locy, Tg);
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float theta_r = M_PI_2_F - fast_acosf(Iz);
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float roughness1_inv = 1.0f / roughness1;
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float a_TT = fast_atan2f(((M_PI_2_F + theta_r)/2 - offset) * roughness1_inv, 1.0f);
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float b_TT = fast_atan2f(((-M_PI_2_F + theta_r)/2 - offset) * roughness1_inv, 1.0f);
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float c_TT = 2 * fast_atan2f(M_PI_2_F / roughness2, 1.0f);
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float t = roughness1 * tanf(randu * (a_TT - b_TT) + b_TT);
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float theta_h = t + offset;
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float theta_i = 2 * theta_h - theta_r;
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float costheta_i, sintheta_i;
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fast_sincosf(theta_i, &sintheta_i, &costheta_i);
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float p = roughness2 * tanf(c_TT * (randv - 0.5f));
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float phi = p + M_PI_F;
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float theta_pdf = roughness1 / (2 * (t*t + roughness1*roughness1) * (a_TT - b_TT) * costheta_i);
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float phi_pdf = roughness2 / (c_TT * (p * p + roughness2 * roughness2));
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float sinphi, cosphi;
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fast_sincosf(phi, &sinphi, &cosphi);
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*omega_in =(cosphi * costheta_i) * locy -
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(sinphi * costheta_i) * locx +
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( sintheta_i) * Tg;
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//differentials - TODO: find a better approximation for the transmission bounce
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#ifdef __RAY_DIFFERENTIALS__
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*domega_in_dx = 2 * dot(locy, dIdx) * locy - dIdx;
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*domega_in_dy = 2 * dot(locy, dIdy) * locy - dIdy;
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#endif
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*pdf = fabsf(phi_pdf * theta_pdf);
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if(M_PI_2_F - fabsf(theta_i) < 0.001f) {
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*pdf = 0.0f;
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}
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*eval = make_float3(*pdf, *pdf, *pdf);
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kernel_assert(dot(locy, *omega_in) < 0.0f);
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return LABEL_GLOSSY;
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}
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CCL_NAMESPACE_END
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#endif /* __BSDF_HAIR_H__ */
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