forked from bartvdbraak/blender
Brecht Van Lommel
a3abb020e3
Mostly this is making inlining match CUDA 7.5 in a few performance critical places. The end result is that performance is now better than before, possibly due to less register spilling or other CUDA 8.0 compiler improvements. On benchmarks scenes, there are 3% to 35% render time reductions. Stack memory usage is reduced a little too. Reviewed By: sergey Differential Revision: https://developer.blender.org/D2269
558 lines
18 KiB
C
558 lines
18 KiB
C
/*
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* Copyright 2011-2016 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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CCL_NAMESPACE_BEGIN
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/* Most of the code is based on the supplemental implementations from https://eheitzresearch.wordpress.com/240-2/. */
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/* === GGX Microfacet distribution functions === */
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/* Isotropic GGX microfacet distribution */
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ccl_device_forceinline float D_ggx(float3 wm, float alpha)
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{
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wm.z *= wm.z;
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alpha *= alpha;
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float tmp = (1.0f - wm.z) + alpha * wm.z;
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return alpha / max(M_PI_F * tmp*tmp, 1e-7f);
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}
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/* Anisotropic GGX microfacet distribution */
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ccl_device_forceinline float D_ggx_aniso(const float3 wm, const float2 alpha)
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{
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float slope_x = -wm.x/alpha.x;
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float slope_y = -wm.y/alpha.y;
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float tmp = wm.z*wm.z + slope_x*slope_x + slope_y*slope_y;
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return 1.0f / max(M_PI_F * tmp*tmp * alpha.x*alpha.y, 1e-7f);
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}
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/* Sample slope distribution (based on page 14 of the supplemental implementation). */
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ccl_device_forceinline float2 mf_sampleP22_11(const float cosI, const float2 randU)
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{
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if(cosI > 0.9999f || cosI < 1e-6f) {
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const float r = sqrtf(randU.x / (1.0f - randU.x));
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const float phi = M_2PI_F * randU.y;
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return make_float2(r*cosf(phi), r*sinf(phi));
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}
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const float sinI = sqrtf(1.0f - cosI*cosI);
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const float tanI = sinI/cosI;
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const float projA = 0.5f * (cosI + 1.0f);
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if(projA < 0.0001f)
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return make_float2(0.0f, 0.0f);
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const float A = 2.0f*randU.x*projA / cosI - 1.0f;
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float tmp = A*A-1.0f;
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if(fabsf(tmp) < 1e-7f)
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return make_float2(0.0f, 0.0f);
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tmp = 1.0f / tmp;
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const float D = safe_sqrtf(tanI*tanI*tmp*tmp - (A*A-tanI*tanI)*tmp);
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const float slopeX2 = tanI*tmp + D;
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const float slopeX = (A < 0.0f || slopeX2 > 1.0f/tanI)? (tanI*tmp - D) : slopeX2;
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float U2;
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if(randU.y >= 0.5f)
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U2 = 2.0f*(randU.y - 0.5f);
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else
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U2 = 2.0f*(0.5f - randU.y);
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const float z = (U2*(U2*(U2*0.27385f-0.73369f)+0.46341f)) / (U2*(U2*(U2*0.093073f+0.309420f)-1.0f)+0.597999f);
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const float slopeY = z * sqrtf(1.0f + slopeX*slopeX);
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if(randU.y >= 0.5f)
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return make_float2(slopeX, slopeY);
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else
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return make_float2(slopeX, -slopeY);
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}
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/* Visible normal sampling for the GGX distribution (based on page 7 of the supplemental implementation). */
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ccl_device_forceinline float3 mf_sample_vndf(const float3 wi, const float2 alpha, const float2 randU)
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{
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const float3 wi_11 = normalize(make_float3(alpha.x*wi.x, alpha.y*wi.y, wi.z));
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const float2 slope_11 = mf_sampleP22_11(wi_11.z, randU);
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const float2 cossin_phi = normalize(make_float2(wi_11.x, wi_11.y));
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const float slope_x = alpha.x*(cossin_phi.x * slope_11.x - cossin_phi.y * slope_11.y);
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const float slope_y = alpha.y*(cossin_phi.y * slope_11.x + cossin_phi.x * slope_11.y);
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kernel_assert(isfinite(slope_x));
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return normalize(make_float3(-slope_x, -slope_y, 1.0f));
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}
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/* === Phase functions: Glossy, Diffuse and Glass === */
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/* Phase function for reflective materials, either without a fresnel term (for compatibility) or with the conductive fresnel term. */
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ccl_device_forceinline float3 mf_sample_phase_glossy(const float3 wi, float3 *n, float3 *k, float3 *weight, const float3 wm)
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{
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if(n && k)
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*weight *= fresnel_conductor(dot(wi, wm), *n, *k);
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return -wi + 2.0f * wm * dot(wi, wm);
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}
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ccl_device_forceinline float3 mf_eval_phase_glossy(const float3 w, const float lambda, const float3 wo, const float2 alpha, float3 *n, float3 *k)
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{
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if(w.z > 0.9999f)
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return make_float3(0.0f, 0.0f, 0.0f);
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const float3 wh = normalize(wo - w);
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if(wh.z < 0.0f)
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return make_float3(0.0f, 0.0f, 0.0f);
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float pArea = (w.z < -0.9999f)? 1.0f: lambda*w.z;
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const float dotW_WH = dot(-w, wh);
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if(dotW_WH < 0.0f)
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return make_float3(0.0f, 0.0f, 0.0f);
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float phase = max(0.0f, dotW_WH) * 0.25f / max(pArea * dotW_WH, 1e-7f);
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if(alpha.x == alpha.y)
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phase *= D_ggx(wh, alpha.x);
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else
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phase *= D_ggx_aniso(wh, alpha);
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if(n && k) {
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/* Apply conductive fresnel term. */
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return phase * fresnel_conductor(dotW_WH, *n, *k);
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}
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return make_float3(phase, phase, phase);
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}
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/* Phase function for rough lambertian diffuse surfaces. */
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ccl_device_forceinline float3 mf_sample_phase_diffuse(const float3 wm, const float randu, const float randv)
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{
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float3 tm, bm;
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make_orthonormals(wm, &tm, &bm);
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float2 disk = concentric_sample_disk(randu, randv);
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return disk.x*tm + disk.y*bm + safe_sqrtf(1.0f - disk.x*disk.x - disk.y*disk.y)*wm;
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}
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ccl_device_forceinline float3 mf_eval_phase_diffuse(const float3 w, const float3 wm)
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{
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const float v = max(0.0f, dot(w, wm)) * M_1_PI_F;
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return make_float3(v, v, v);
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}
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/* Phase function for dielectric transmissive materials, including both reflection and refraction according to the dielectric fresnel term. */
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ccl_device_forceinline float3 mf_sample_phase_glass(const float3 wi, const float eta, const float3 wm, const float randV, bool *outside)
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{
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float cosI = dot(wi, wm);
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float f = fresnel_dielectric_cos(cosI, eta);
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if(randV < f) {
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*outside = true;
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return -wi + 2.0f * wm * cosI;
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}
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*outside = false;
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float inv_eta = 1.0f/eta;
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float cosT = -safe_sqrtf(1.0f - (1.0f - cosI*cosI) * inv_eta*inv_eta);
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return normalize(wm*(cosI*inv_eta + cosT) - wi*inv_eta);
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}
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ccl_device_forceinline float3 mf_eval_phase_glass(const float3 w, const float lambda, const float3 wo, const bool wo_outside, const float2 alpha, const float eta)
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{
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if(w.z > 0.9999f)
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return make_float3(0.0f, 0.0f, 0.0f);
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float pArea = (w.z < -0.9999f)? 1.0f: lambda*w.z;
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float v;
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if(wo_outside) {
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const float3 wh = normalize(wo - w);
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if(wh.z < 0.0f)
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return make_float3(0.0f, 0.0f, 0.0f);
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const float dotW_WH = dot(-w, wh);
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v = fresnel_dielectric_cos(dotW_WH, eta) * max(0.0f, dotW_WH) * D_ggx(wh, alpha.x) * 0.25f / (pArea * dotW_WH);
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}
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else {
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float3 wh = normalize(wo*eta - w);
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if(wh.z < 0.0f)
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wh = -wh;
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const float dotW_WH = dot(-w, wh), dotWO_WH = dot(wo, wh);
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if(dotW_WH < 0.0f)
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return make_float3(0.0f, 0.0f, 0.0f);
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float temp = dotW_WH + eta*dotWO_WH;
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v = (1.0f - fresnel_dielectric_cos(dotW_WH, eta)) * max(0.0f, dotW_WH) * max(0.0f, -dotWO_WH) * D_ggx(wh, alpha.x) / (pArea * temp * temp);
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}
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return make_float3(v, v, v);
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}
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/* === Utility functions for the random walks === */
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/* Smith Lambda function for GGX (based on page 12 of the supplemental implementation). */
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ccl_device_forceinline float mf_lambda(const float3 w, const float2 alpha)
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{
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if(w.z > 0.9999f)
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return 0.0f;
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else if(w.z < -0.9999f)
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return -0.9999f;
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const float inv_wz2 = 1.0f / max(w.z*w.z, 1e-7f);
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const float2 wa = make_float2(w.x, w.y)*alpha;
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float v = sqrtf(1.0f + dot(wa, wa) * inv_wz2);
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if(w.z <= 0.0f)
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v = -v;
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return 0.5f*(v - 1.0f);
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}
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/* Height distribution CDF (based on page 4 of the supplemental implementation). */
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ccl_device_forceinline float mf_invC1(const float h)
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{
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return 2.0f * saturate(h) - 1.0f;
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}
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ccl_device_forceinline float mf_C1(const float h)
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{
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return saturate(0.5f * (h + 1.0f));
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}
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/* Masking function (based on page 16 of the supplemental implementation). */
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ccl_device_forceinline float mf_G1(const float3 w, const float C1, const float lambda)
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{
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if(w.z > 0.9999f)
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return 1.0f;
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if(w.z < 1e-5f)
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return 0.0f;
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return powf(C1, lambda);
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}
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/* Sampling from the visible height distribution (based on page 17 of the supplemental implementation). */
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ccl_device_forceinline bool mf_sample_height(const float3 w, float *h, float *C1, float *G1, float *lambda, const float U)
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{
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if(w.z > 0.9999f)
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return false;
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if(w.z < -0.9999f) {
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*C1 *= U;
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*h = mf_invC1(*C1);
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*G1 = mf_G1(w, *C1, *lambda);
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}
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else if(fabsf(w.z) >= 0.0001f) {
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if(U > 1.0f - *G1)
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return false;
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if(*lambda >= 0.0f) {
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*C1 = 1.0f;
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}
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else {
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*C1 *= powf(1.0f-U, -1.0f / *lambda);
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}
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*h = mf_invC1(*C1);
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*G1 = mf_G1(w, *C1, *lambda);
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}
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return true;
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}
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/* === PDF approximations for the different phase functions. ===
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* As explained in bsdf_microfacet_multi_impl.h, using approximations with MIS still produces an unbiased result. */
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/* Approximation for the albedo of the single-scattering GGX distribution,
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* the missing energy is then approximated as a diffuse reflection for the PDF. */
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ccl_device_forceinline float mf_ggx_albedo(float r)
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{
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float albedo = 0.806495f*expf(-1.98712f*r*r) + 0.199531f;
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albedo -= ((((((1.76741f*r - 8.43891f)*r + 15.784f)*r - 14.398f)*r + 6.45221f)*r - 1.19722f)*r + 0.027803f)*r + 0.00568739f;
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return saturate(albedo);
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}
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ccl_device_forceinline float mf_ggx_pdf(const float3 wi, const float3 wo, const float alpha)
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{
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float D = D_ggx(normalize(wi+wo), alpha);
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float lambda = mf_lambda(wi, make_float2(alpha, alpha));
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float albedo = mf_ggx_albedo(alpha);
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return 0.25f * D / max((1.0f + lambda) * wi.z, 1e-7f) + (1.0f - albedo) * wo.z;
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}
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ccl_device_forceinline float mf_ggx_aniso_pdf(const float3 wi, const float3 wo, const float2 alpha)
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{
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return 0.25f * D_ggx_aniso(normalize(wi+wo), alpha) / ((1.0f + mf_lambda(wi, alpha)) * wi.z) + (1.0f - mf_ggx_albedo(sqrtf(alpha.x*alpha.y))) * wo.z;
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}
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ccl_device_forceinline float mf_diffuse_pdf(const float3 wo)
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{
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return M_1_PI_F * wo.z;
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}
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ccl_device_forceinline float mf_glass_pdf(const float3 wi, const float3 wo, const float alpha, const float eta)
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{
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float3 wh;
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float fresnel;
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if(wi.z*wo.z > 0.0f) {
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wh = normalize(wi + wo);
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fresnel = fresnel_dielectric_cos(dot(wi, wh), eta);
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}
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else {
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wh = normalize(wi + wo*eta);
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fresnel = 1.0f - fresnel_dielectric_cos(dot(wi, wh), eta);
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}
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if(wh.z < 0.0f)
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wh = -wh;
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float3 r_wi = (wi.z < 0.0f)? -wi: wi;
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return fresnel * max(0.0f, dot(r_wi, wh)) * D_ggx(wh, alpha) / ((1.0f + mf_lambda(r_wi, make_float2(alpha, alpha))) * r_wi.z) + fabsf(wo.z);
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}
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/* === Actual random walk implementations, one version of mf_eval and mf_sample per phase function. === */
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#define MF_NAME_JOIN(x,y) x ## _ ## y
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#define MF_NAME_EVAL(x,y) MF_NAME_JOIN(x,y)
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#define MF_FUNCTION_FULL_NAME(prefix) MF_NAME_EVAL(prefix, MF_PHASE_FUNCTION)
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#define MF_PHASE_FUNCTION glass
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#define MF_MULTI_GLASS
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#include "bsdf_microfacet_multi_impl.h"
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/* The diffuse phase function is not implemented as a node yet. */
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#if 0
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#define MF_PHASE_FUNCTION diffuse
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#define MF_MULTI_DIFFUSE
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#include "bsdf_microfacet_multi_impl.h"
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#endif
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#define MF_PHASE_FUNCTION glossy
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#define MF_MULTI_GLOSSY
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#include "bsdf_microfacet_multi_impl.h"
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ccl_device void bsdf_microfacet_multi_ggx_blur(ShaderClosure *sc, float roughness)
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{
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MicrofacetBsdf *bsdf = (MicrofacetBsdf*)sc;
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bsdf->alpha_x = fmaxf(roughness, bsdf->alpha_x);
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bsdf->alpha_y = fmaxf(roughness, bsdf->alpha_y);
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}
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/* === Closure implementations === */
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/* Multiscattering GGX Glossy closure */
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ccl_device int bsdf_microfacet_multi_ggx_common_setup(MicrofacetBsdf *bsdf)
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{
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bsdf->alpha_x = clamp(bsdf->alpha_x, 1e-4f, 1.0f);
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bsdf->alpha_y = clamp(bsdf->alpha_y, 1e-4f, 1.0f);
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bsdf->extra->color.x = saturate(bsdf->extra->color.x);
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bsdf->extra->color.y = saturate(bsdf->extra->color.y);
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bsdf->extra->color.z = saturate(bsdf->extra->color.z);
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bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_ID;
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return SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_NEEDS_LCG;
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}
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ccl_device int bsdf_microfacet_multi_ggx_aniso_setup(MicrofacetBsdf *bsdf)
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{
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if(is_zero(bsdf->T))
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bsdf->T = make_float3(1.0f, 0.0f, 0.0f);
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return bsdf_microfacet_multi_ggx_common_setup(bsdf);
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}
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ccl_device int bsdf_microfacet_multi_ggx_setup(MicrofacetBsdf *bsdf)
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{
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bsdf->alpha_y = bsdf->alpha_x;
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return bsdf_microfacet_multi_ggx_common_setup(bsdf);
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}
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ccl_device float3 bsdf_microfacet_multi_ggx_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf, ccl_addr_space uint *lcg_state) {
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*pdf = 0.0f;
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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_microfacet_multi_ggx_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf, ccl_addr_space uint *lcg_state) {
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const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc;
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if(bsdf->alpha_x*bsdf->alpha_y < 1e-7f) {
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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bool is_aniso = (bsdf->alpha_x != bsdf->alpha_y);
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float3 X, Y, Z;
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Z = bsdf->N;
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if(is_aniso)
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make_orthonormals_tangent(Z, bsdf->T, &X, &Y);
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else
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make_orthonormals(Z, &X, &Y);
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float3 localI = make_float3(dot(I, X), dot(I, Y), dot(I, Z));
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float3 localO = make_float3(dot(omega_in, X), dot(omega_in, Y), dot(omega_in, Z));
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if(is_aniso)
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*pdf = mf_ggx_aniso_pdf(localI, localO, make_float2(bsdf->alpha_x, bsdf->alpha_y));
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else
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*pdf = mf_ggx_pdf(localI, localO, bsdf->alpha_x);
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return mf_eval_glossy(localI, localO, true, bsdf->extra->color, bsdf->alpha_x, bsdf->alpha_y, lcg_state, NULL, NULL);
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}
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ccl_device int bsdf_microfacet_multi_ggx_sample(KernelGlobals *kg, 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, ccl_addr_space uint *lcg_state)
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{
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const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc;
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float3 X, Y, Z;
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Z = bsdf->N;
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if(bsdf->alpha_x*bsdf->alpha_y < 1e-7f) {
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*omega_in = 2*dot(Z, I)*Z - I;
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*pdf = 1e6f;
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*eval = make_float3(1e6f, 1e6f, 1e6f);
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return LABEL_REFLECT|LABEL_SINGULAR;
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}
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bool is_aniso = (bsdf->alpha_x != bsdf->alpha_y);
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if(is_aniso)
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make_orthonormals_tangent(Z, bsdf->T, &X, &Y);
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else
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make_orthonormals(Z, &X, &Y);
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float3 localI = make_float3(dot(I, X), dot(I, Y), dot(I, Z));
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float3 localO;
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*eval = mf_sample_glossy(localI, &localO, bsdf->extra->color, bsdf->alpha_x, bsdf->alpha_y, lcg_state, NULL, NULL);
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if(is_aniso)
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*pdf = mf_ggx_aniso_pdf(localI, localO, make_float2(bsdf->alpha_x, bsdf->alpha_y));
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else
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*pdf = mf_ggx_pdf(localI, localO, bsdf->alpha_x);
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*eval *= *pdf;
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*omega_in = X*localO.x + Y*localO.y + Z*localO.z;
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#ifdef __RAY_DIFFERENTIALS__
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*domega_in_dx = (2 * dot(Z, dIdx)) * Z - dIdx;
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*domega_in_dy = (2 * dot(Z, dIdy)) * Z - dIdy;
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#endif
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return LABEL_REFLECT|LABEL_GLOSSY;
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}
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/* Multiscattering GGX Glass closure */
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ccl_device int bsdf_microfacet_multi_ggx_glass_setup(MicrofacetBsdf *bsdf)
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{
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bsdf->alpha_x = clamp(bsdf->alpha_x, 1e-4f, 1.0f);
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bsdf->alpha_y = bsdf->alpha_x;
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bsdf->ior = max(0.0f, bsdf->ior);
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bsdf->extra->color.x = saturate(bsdf->extra->color.x);
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bsdf->extra->color.y = saturate(bsdf->extra->color.y);
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bsdf->extra->color.z = saturate(bsdf->extra->color.z);
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bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_ID;
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return SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_NEEDS_LCG;
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}
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ccl_device float3 bsdf_microfacet_multi_ggx_glass_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf, ccl_addr_space uint *lcg_state) {
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const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc;
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if(bsdf->alpha_x*bsdf->alpha_y < 1e-7f) {
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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float3 X, Y, Z;
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Z = bsdf->N;
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make_orthonormals(Z, &X, &Y);
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float3 localI = make_float3(dot(I, X), dot(I, Y), dot(I, Z));
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float3 localO = make_float3(dot(omega_in, X), dot(omega_in, Y), dot(omega_in, Z));
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*pdf = mf_glass_pdf(localI, localO, bsdf->alpha_x, bsdf->ior);
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return mf_eval_glass(localI, localO, false, bsdf->extra->color, bsdf->alpha_x, bsdf->alpha_y, lcg_state, bsdf->ior);
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}
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ccl_device float3 bsdf_microfacet_multi_ggx_glass_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf, ccl_addr_space uint *lcg_state) {
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const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc;
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|
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if(bsdf->alpha_x*bsdf->alpha_y < 1e-7f) {
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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|
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float3 X, Y, Z;
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Z = bsdf->N;
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make_orthonormals(Z, &X, &Y);
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|
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float3 localI = make_float3(dot(I, X), dot(I, Y), dot(I, Z));
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float3 localO = make_float3(dot(omega_in, X), dot(omega_in, Y), dot(omega_in, Z));
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|
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*pdf = mf_glass_pdf(localI, localO, bsdf->alpha_x, bsdf->ior);
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return mf_eval_glass(localI, localO, true, bsdf->extra->color, bsdf->alpha_x, bsdf->alpha_y, lcg_state, bsdf->ior);
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}
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ccl_device int bsdf_microfacet_multi_ggx_glass_sample(KernelGlobals *kg, 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, ccl_addr_space uint *lcg_state)
|
|
{
|
|
const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc;
|
|
|
|
float3 X, Y, Z;
|
|
Z = bsdf->N;
|
|
|
|
if(bsdf->alpha_x*bsdf->alpha_y < 1e-7f) {
|
|
float3 R, T;
|
|
#ifdef __RAY_DIFFERENTIALS__
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|
float3 dRdx, dRdy, dTdx, dTdy;
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#endif
|
|
bool inside;
|
|
float fresnel = fresnel_dielectric(bsdf->ior, Z, I, &R, &T,
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
dIdx, dIdy, &dRdx, &dRdy, &dTdx, &dTdy,
|
|
#endif
|
|
&inside);
|
|
|
|
*pdf = 1e6f;
|
|
*eval = make_float3(1e6f, 1e6f, 1e6f);
|
|
if(randu < fresnel) {
|
|
*omega_in = R;
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
*domega_in_dx = dRdx;
|
|
*domega_in_dy = dRdy;
|
|
#endif
|
|
return LABEL_REFLECT|LABEL_SINGULAR;
|
|
}
|
|
else {
|
|
*omega_in = T;
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
*domega_in_dx = dTdx;
|
|
*domega_in_dy = dTdy;
|
|
#endif
|
|
return LABEL_TRANSMIT|LABEL_SINGULAR;
|
|
}
|
|
}
|
|
|
|
make_orthonormals(Z, &X, &Y);
|
|
|
|
float3 localI = make_float3(dot(I, X), dot(I, Y), dot(I, Z));
|
|
float3 localO;
|
|
|
|
*eval = mf_sample_glass(localI, &localO, bsdf->extra->color, bsdf->alpha_x, bsdf->alpha_y, lcg_state, bsdf->ior);
|
|
*pdf = mf_glass_pdf(localI, localO, bsdf->alpha_x, bsdf->ior);
|
|
*eval *= *pdf;
|
|
|
|
*omega_in = X*localO.x + Y*localO.y + Z*localO.z;
|
|
if(localO.z*localI.z > 0.0f) {
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
*domega_in_dx = (2 * dot(Z, dIdx)) * Z - dIdx;
|
|
*domega_in_dy = (2 * dot(Z, dIdy)) * Z - dIdy;
|
|
#endif
|
|
return LABEL_REFLECT|LABEL_GLOSSY;
|
|
}
|
|
else {
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
float cosI = dot(Z, I);
|
|
float dnp = max(sqrtf(1.0f - (bsdf->ior * bsdf->ior * (1.0f - cosI*cosI))), 1e-7f);
|
|
*domega_in_dx = -(bsdf->ior * dIdx) + ((bsdf->ior - bsdf->ior * bsdf->ior * cosI / dnp) * dot(dIdx, Z)) * Z;
|
|
*domega_in_dy = -(bsdf->ior * dIdy) + ((bsdf->ior - bsdf->ior * bsdf->ior * cosI / dnp) * dot(dIdy, Z)) * Z;
|
|
#endif
|
|
|
|
return LABEL_TRANSMIT|LABEL_GLOSSY;
|
|
}
|
|
}
|
|
|
|
CCL_NAMESPACE_END
|