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|
/*
* Copyright 2011-2016 Blender Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
CCL_NAMESPACE_BEGIN
/* Most of the code is based on the supplemental implementations from https://eheitzresearch.wordpress.com/240-2/. */
/* === GGX Microfacet distribution functions === */
/* Isotropic GGX microfacet distribution */
ccl_device_forceinline float D_ggx(float3 wm, float alpha)
{
wm.z *= wm.z;
alpha *= alpha;
float tmp = (1.0f - wm.z) + alpha * wm.z;
return alpha / max(M_PI_F * tmp*tmp, 1e-7f);
}
/* Anisotropic GGX microfacet distribution */
ccl_device_forceinline float D_ggx_aniso(const float3 wm, const float2 alpha)
{
float slope_x = -wm.x/alpha.x;
float slope_y = -wm.y/alpha.y;
float tmp = wm.z*wm.z + slope_x*slope_x + slope_y*slope_y;
return 1.0f / max(M_PI_F * tmp*tmp * alpha.x*alpha.y, 1e-7f);
}
/* Sample slope distribution (based on page 14 of the supplemental implementation). */
ccl_device_forceinline float2 mf_sampleP22_11(const float cosI, const float2 randU)
{
if(cosI > 0.9999f || fabsf(cosI) < 1e-6f) {
const float r = sqrtf(randU.x / max(1.0f - randU.x, 1e-7f));
const float phi = M_2PI_F * randU.y;
return make_float2(r*cosf(phi), r*sinf(phi));
}
const float sinI = sqrtf(1.0f - cosI*cosI);
const float tanI = sinI/cosI;
const float projA = 0.5f * (cosI + 1.0f);
if(projA < 0.0001f)
return make_float2(0.0f, 0.0f);
const float A = 2.0f*randU.x*projA / cosI - 1.0f;
float tmp = A*A-1.0f;
if(fabsf(tmp) < 1e-7f)
return make_float2(0.0f, 0.0f);
tmp = 1.0f / tmp;
const float D = safe_sqrtf(tanI*tanI*tmp*tmp - (A*A-tanI*tanI)*tmp);
const float slopeX2 = tanI*tmp + D;
const float slopeX = (A < 0.0f || slopeX2 > 1.0f/tanI)? (tanI*tmp - D) : slopeX2;
float U2;
if(randU.y >= 0.5f)
U2 = 2.0f*(randU.y - 0.5f);
else
U2 = 2.0f*(0.5f - randU.y);
const float z = (U2*(U2*(U2*0.27385f-0.73369f)+0.46341f)) / (U2*(U2*(U2*0.093073f+0.309420f)-1.0f)+0.597999f);
const float slopeY = z * sqrtf(1.0f + slopeX*slopeX);
if(randU.y >= 0.5f)
return make_float2(slopeX, slopeY);
else
return make_float2(slopeX, -slopeY);
}
/* Visible normal sampling for the GGX distribution (based on page 7 of the supplemental implementation). */
ccl_device_forceinline float3 mf_sample_vndf(const float3 wi, const float2 alpha, const float2 randU)
{
const float3 wi_11 = normalize(make_float3(alpha.x*wi.x, alpha.y*wi.y, wi.z));
const float2 slope_11 = mf_sampleP22_11(wi_11.z, randU);
const float3 cossin_phi = safe_normalize(make_float3(wi_11.x, wi_11.y, 0.0f));
const float slope_x = alpha.x*(cossin_phi.x * slope_11.x - cossin_phi.y * slope_11.y);
const float slope_y = alpha.y*(cossin_phi.y * slope_11.x + cossin_phi.x * slope_11.y);
kernel_assert(isfinite(slope_x));
return normalize(make_float3(-slope_x, -slope_y, 1.0f));
}
/* === Phase functions: Glossy and Glass === */
/* Phase function for reflective materials. */
ccl_device_forceinline float3 mf_sample_phase_glossy(const float3 wi, float3 *weight, const float3 wm)
{
return -wi + 2.0f * wm * dot(wi, wm);
}
ccl_device_forceinline float3 mf_eval_phase_glossy(const float3 w, const float lambda, const float3 wo, const float2 alpha)
{
if(w.z > 0.9999f)
return make_float3(0.0f, 0.0f, 0.0f);
const float3 wh = normalize(wo - w);
if(wh.z < 0.0f)
return make_float3(0.0f, 0.0f, 0.0f);
float pArea = (w.z < -0.9999f)? 1.0f: lambda*w.z;
const float dotW_WH = dot(-w, wh);
if(dotW_WH < 0.0f)
return make_float3(0.0f, 0.0f, 0.0f);
float phase = max(0.0f, dotW_WH) * 0.25f / max(pArea * dotW_WH, 1e-7f);
if(alpha.x == alpha.y)
phase *= D_ggx(wh, alpha.x);
else
phase *= D_ggx_aniso(wh, alpha);
return make_float3(phase, phase, phase);
}
/* Phase function for dielectric transmissive materials, including both reflection and refraction according to the dielectric fresnel term. */
ccl_device_forceinline float3 mf_sample_phase_glass(const float3 wi, const float eta, const float3 wm, const float randV, bool *outside)
{
float cosI = dot(wi, wm);
float f = fresnel_dielectric_cos(cosI, eta);
if(randV < f) {
*outside = true;
return -wi + 2.0f * wm * cosI;
}
*outside = false;
float inv_eta = 1.0f/eta;
float cosT = -safe_sqrtf(1.0f - (1.0f - cosI*cosI) * inv_eta*inv_eta);
return normalize(wm*(cosI*inv_eta + cosT) - wi*inv_eta);
}
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)
{
if(w.z > 0.9999f)
return make_float3(0.0f, 0.0f, 0.0f);
float pArea = (w.z < -0.9999f)? 1.0f: lambda*w.z;
float v;
if(wo_outside) {
const float3 wh = normalize(wo - w);
if(wh.z < 0.0f)
return make_float3(0.0f, 0.0f, 0.0f);
const float dotW_WH = dot(-w, wh);
v = fresnel_dielectric_cos(dotW_WH, eta) * max(0.0f, dotW_WH) * D_ggx(wh, alpha.x) * 0.25f / (pArea * dotW_WH);
}
else {
float3 wh = normalize(wo*eta - w);
if(wh.z < 0.0f)
wh = -wh;
const float dotW_WH = dot(-w, wh), dotWO_WH = dot(wo, wh);
if(dotW_WH < 0.0f)
return make_float3(0.0f, 0.0f, 0.0f);
float temp = dotW_WH + eta*dotWO_WH;
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);
}
return make_float3(v, v, v);
}
/* === Utility functions for the random walks === */
/* Smith Lambda function for GGX (based on page 12 of the supplemental implementation). */
ccl_device_forceinline float mf_lambda(const float3 w, const float2 alpha)
{
if(w.z > 0.9999f)
return 0.0f;
else if(w.z < -0.9999f)
return -0.9999f;
const float inv_wz2 = 1.0f / max(w.z*w.z, 1e-7f);
const float2 wa = make_float2(w.x, w.y)*alpha;
float v = sqrtf(1.0f + dot(wa, wa) * inv_wz2);
if(w.z <= 0.0f)
v = -v;
return 0.5f*(v - 1.0f);
}
/* Height distribution CDF (based on page 4 of the supplemental implementation). */
ccl_device_forceinline float mf_invC1(const float h)
{
return 2.0f * saturate(h) - 1.0f;
}
ccl_device_forceinline float mf_C1(const float h)
{
return saturate(0.5f * (h + 1.0f));
}
/* Masking function (based on page 16 of the supplemental implementation). */
ccl_device_forceinline float mf_G1(const float3 w, const float C1, const float lambda)
{
if(w.z > 0.9999f)
return 1.0f;
if(w.z < 1e-5f)
return 0.0f;
return powf(C1, lambda);
}
/* Sampling from the visible height distribution (based on page 17 of the supplemental implementation). */
ccl_device_forceinline bool mf_sample_height(const float3 w, float *h, float *C1, float *G1, float *lambda, const float U)
{
if(w.z > 0.9999f)
return false;
if(w.z < -0.9999f) {
*C1 *= U;
*h = mf_invC1(*C1);
*G1 = mf_G1(w, *C1, *lambda);
}
else if(fabsf(w.z) >= 0.0001f) {
if(U > 1.0f - *G1)
return false;
if(*lambda >= 0.0f) {
*C1 = 1.0f;
}
else {
*C1 *= powf(1.0f-U, -1.0f / *lambda);
}
*h = mf_invC1(*C1);
*G1 = mf_G1(w, *C1, *lambda);
}
return true;
}
/* === PDF approximations for the different phase functions. ===
* As explained in bsdf_microfacet_multi_impl.h, using approximations with MIS still produces an unbiased result. */
/* Approximation for the albedo of the single-scattering GGX distribution,
* the missing energy is then approximated as a diffuse reflection for the PDF. */
ccl_device_forceinline float mf_ggx_albedo(float r)
{
float albedo = 0.806495f*expf(-1.98712f*r*r) + 0.199531f;
albedo -= ((((((1.76741f*r - 8.43891f)*r + 15.784f)*r - 14.398f)*r + 6.45221f)*r - 1.19722f)*r + 0.027803f)*r + 0.00568739f;
return saturate(albedo);
}
ccl_device_inline float mf_ggx_transmission_albedo(float a, float ior)
{
if(ior < 1.0f) {
ior = 1.0f/ior;
}
a = saturate(a);
ior = clamp(ior, 1.0f, 3.0f);
float I_1 = 0.0476898f*expf(-0.978352f*(ior-0.65657f)*(ior-0.65657f)) - 0.033756f*ior + 0.993261f;
float R_1 = (((0.116991f*a - 0.270369f)*a + 0.0501366f)*a - 0.00411511f)*a + 1.00008f;
float I_2 = (((-2.08704f*ior + 26.3298f)*ior - 127.906f)*ior + 292.958f)*ior - 287.946f + 199.803f/(ior*ior) - 101.668f/(ior*ior*ior);
float R_2 = ((((5.3725f*a -24.9307f)*a + 22.7437f)*a - 3.40751f)*a + 0.0986325f)*a + 0.00493504f;
return saturate(1.0f + I_2*R_2*0.0019127f - (1.0f - I_1)*(1.0f - R_1)*9.3205f);
}
ccl_device_forceinline float mf_ggx_pdf(const float3 wi, const float3 wo, const float alpha)
{
float D = D_ggx(normalize(wi+wo), alpha);
float lambda = mf_lambda(wi, make_float2(alpha, alpha));
float singlescatter = 0.25f * D / max((1.0f + lambda) * wi.z, 1e-7f);
float multiscatter = wo.z * M_1_PI_F;
float albedo = mf_ggx_albedo(alpha);
return albedo*singlescatter + (1.0f - albedo)*multiscatter;
}
ccl_device_forceinline float mf_ggx_aniso_pdf(const float3 wi, const float3 wo, const float2 alpha)
{
float D = D_ggx_aniso(normalize(wi+wo), alpha);
float lambda = mf_lambda(wi, alpha);
float singlescatter = 0.25f * D / max((1.0f + lambda) * wi.z, 1e-7f);
float multiscatter = wo.z * M_1_PI_F;
float albedo = mf_ggx_albedo(sqrtf(alpha.x*alpha.y));
return albedo*singlescatter + (1.0f - albedo)*multiscatter;
}
ccl_device_forceinline float mf_glass_pdf(const float3 wi, const float3 wo, const float alpha, const float eta)
{
bool reflective = (wi.z*wo.z > 0.0f);
float wh_len;
float3 wh = normalize_len(wi + (reflective? wo : (wo*eta)), &wh_len);
if(wh.z < 0.0f)
wh = -wh;
float3 r_wi = (wi.z < 0.0f)? -wi: wi;
float lambda = mf_lambda(r_wi, make_float2(alpha, alpha));
float D = D_ggx(wh, alpha);
float fresnel = fresnel_dielectric_cos(dot(r_wi, wh), eta);
float multiscatter = fabsf(wo.z * M_1_PI_F);
if(reflective) {
float singlescatter = 0.25f * D / max((1.0f + lambda) * r_wi.z, 1e-7f);
float albedo = mf_ggx_albedo(alpha);
return fresnel * (albedo*singlescatter + (1.0f - albedo)*multiscatter);
}
else {
float singlescatter = fabsf(dot(r_wi, wh)*dot(wo, wh) * D * eta*eta / max((1.0f + lambda) * r_wi.z * wh_len*wh_len, 1e-7f));
float albedo = mf_ggx_transmission_albedo(alpha, eta);
return (1.0f - fresnel) * (albedo*singlescatter + (1.0f - albedo)*multiscatter);
}
}
/* === Actual random walk implementations, one version of mf_eval and mf_sample per phase function. === */
#define MF_NAME_JOIN(x,y) x ## _ ## y
#define MF_NAME_EVAL(x,y) MF_NAME_JOIN(x,y)
#define MF_FUNCTION_FULL_NAME(prefix) MF_NAME_EVAL(prefix, MF_PHASE_FUNCTION)
#define MF_PHASE_FUNCTION glass
#define MF_MULTI_GLASS
#include "kernel/closure/bsdf_microfacet_multi_impl.h"
#define MF_PHASE_FUNCTION glossy
#define MF_MULTI_GLOSSY
#include "kernel/closure/bsdf_microfacet_multi_impl.h"
ccl_device void bsdf_microfacet_multi_ggx_blur(ShaderClosure *sc, float roughness)
{
MicrofacetBsdf *bsdf = (MicrofacetBsdf*)sc;
bsdf->alpha_x = fmaxf(roughness, bsdf->alpha_x);
bsdf->alpha_y = fmaxf(roughness, bsdf->alpha_y);
}
/* === Closure implementations === */
/* Multiscattering GGX Glossy closure */
ccl_device int bsdf_microfacet_multi_ggx_common_setup(MicrofacetBsdf *bsdf)
{
bsdf->alpha_x = clamp(bsdf->alpha_x, 1e-4f, 1.0f);
bsdf->alpha_y = clamp(bsdf->alpha_y, 1e-4f, 1.0f);
bsdf->extra->color.x = saturate(bsdf->extra->color.x);
bsdf->extra->color.y = saturate(bsdf->extra->color.y);
bsdf->extra->color.z = saturate(bsdf->extra->color.z);
bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x);
bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y);
bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z);
return SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_NEEDS_LCG;
}
ccl_device int bsdf_microfacet_multi_ggx_aniso_setup(MicrofacetBsdf *bsdf)
{
if(is_zero(bsdf->T))
bsdf->T = make_float3(1.0f, 0.0f, 0.0f);
bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_ID;
return bsdf_microfacet_multi_ggx_common_setup(bsdf);
}
ccl_device int bsdf_microfacet_multi_ggx_aniso_fresnel_setup(MicrofacetBsdf *bsdf, const ShaderData *sd)
{
if(is_zero(bsdf->T))
bsdf->T = make_float3(1.0f, 0.0f, 0.0f);
bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_FRESNEL_ID;
float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior);
float F = average(interpolate_fresnel_color(sd->I, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0));
bsdf->sample_weight *= F;
return bsdf_microfacet_multi_ggx_common_setup(bsdf);
}
ccl_device int bsdf_microfacet_multi_ggx_setup(MicrofacetBsdf *bsdf)
{
bsdf->alpha_y = bsdf->alpha_x;
bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_ID;
return bsdf_microfacet_multi_ggx_common_setup(bsdf);
}
ccl_device int bsdf_microfacet_multi_ggx_fresnel_setup(MicrofacetBsdf *bsdf, const ShaderData *sd)
{
bsdf->alpha_y = bsdf->alpha_x;
bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_FRESNEL_ID;
float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior);
float F = average(interpolate_fresnel_color(sd->I, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0));
bsdf->sample_weight *= F;
return bsdf_microfacet_multi_ggx_common_setup(bsdf);
}
ccl_device int bsdf_microfacet_multi_ggx_refraction_setup(MicrofacetBsdf *bsdf)
{
bsdf->alpha_y = bsdf->alpha_x;
bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_ID;
return bsdf_microfacet_multi_ggx_common_setup(bsdf);
}
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) {
*pdf = 0.0f;
return make_float3(0.0f, 0.0f, 0.0f);
}
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) {
const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc;
if(bsdf->alpha_x*bsdf->alpha_y < 1e-7f) {
return make_float3(0.0f, 0.0f, 0.0f);
}
bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_MULTI_GGX_FRESNEL_ID);
bool is_aniso = (bsdf->alpha_x != bsdf->alpha_y);
float3 X, Y, Z;
Z = bsdf->N;
if(is_aniso)
make_orthonormals_tangent(Z, bsdf->T, &X, &Y);
else
make_orthonormals(Z, &X, &Y);
float3 localI = make_float3(dot(I, X), dot(I, Y), dot(I, Z));
float3 localO = make_float3(dot(omega_in, X), dot(omega_in, Y), dot(omega_in, Z));
if(is_aniso)
*pdf = mf_ggx_aniso_pdf(localI, localO, make_float2(bsdf->alpha_x, bsdf->alpha_y));
else
*pdf = mf_ggx_pdf(localI, localO, bsdf->alpha_x);
return mf_eval_glossy(localI, localO, true, bsdf->extra->color, bsdf->alpha_x, bsdf->alpha_y, lcg_state, bsdf->ior, use_fresnel, bsdf->extra->cspec0);
}
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)
{
const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc;
float3 X, Y, Z;
Z = bsdf->N;
if(bsdf->alpha_x*bsdf->alpha_y < 1e-7f) {
*omega_in = 2*dot(Z, I)*Z - I;
*pdf = 1e6f;
*eval = make_float3(1e6f, 1e6f, 1e6f);
#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_SINGULAR;
}
bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_MULTI_GGX_FRESNEL_ID);
bool is_aniso = (bsdf->alpha_x != bsdf->alpha_y);
if(is_aniso)
make_orthonormals_tangent(Z, bsdf->T, &X, &Y);
else
make_orthonormals(Z, &X, &Y);
float3 localI = make_float3(dot(I, X), dot(I, Y), dot(I, Z));
float3 localO;
*eval = mf_sample_glossy(localI, &localO, bsdf->extra->color, bsdf->alpha_x, bsdf->alpha_y, lcg_state, bsdf->ior, use_fresnel, bsdf->extra->cspec0);
if(is_aniso)
*pdf = mf_ggx_aniso_pdf(localI, localO, make_float2(bsdf->alpha_x, bsdf->alpha_y));
else
*pdf = mf_ggx_pdf(localI, localO, bsdf->alpha_x);
*eval *= *pdf;
*omega_in = X*localO.x + Y*localO.y + Z*localO.z;
#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;
}
/* Multiscattering GGX Glass closure */
ccl_device int bsdf_microfacet_multi_ggx_glass_setup(MicrofacetBsdf *bsdf)
{
bsdf->alpha_x = clamp(bsdf->alpha_x, 1e-4f, 1.0f);
bsdf->alpha_y = bsdf->alpha_x;
bsdf->ior = max(0.0f, bsdf->ior);
bsdf->extra->color.x = saturate(bsdf->extra->color.x);
bsdf->extra->color.y = saturate(bsdf->extra->color.y);
bsdf->extra->color.z = saturate(bsdf->extra->color.z);
bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_ID;
return SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_NEEDS_LCG;
}
ccl_device int bsdf_microfacet_multi_ggx_glass_fresnel_setup(MicrofacetBsdf *bsdf, const ShaderData *sd)
{
bsdf->alpha_x = clamp(bsdf->alpha_x, 1e-4f, 1.0f);
bsdf->alpha_y = bsdf->alpha_x;
bsdf->ior = max(0.0f, bsdf->ior);
bsdf->extra->color.x = saturate(bsdf->extra->color.x);
bsdf->extra->color.y = saturate(bsdf->extra->color.y);
bsdf->extra->color.z = saturate(bsdf->extra->color.z);
bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x);
bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y);
bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z);
bsdf->type = CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_FRESNEL_ID;
float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior);
float F = average(interpolate_fresnel_color(sd->I, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0));
bsdf->sample_weight *= F;
return SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_NEEDS_LCG;
}
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) {
const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc;
if(bsdf->alpha_x*bsdf->alpha_y < 1e-7f) {
return make_float3(0.0f, 0.0f, 0.0f);
}
float3 X, Y, Z;
Z = bsdf->N;
make_orthonormals(Z, &X, &Y);
float3 localI = make_float3(dot(I, X), dot(I, Y), dot(I, Z));
float3 localO = make_float3(dot(omega_in, X), dot(omega_in, Y), dot(omega_in, Z));
*pdf = mf_glass_pdf(localI, localO, bsdf->alpha_x, bsdf->ior);
return mf_eval_glass(localI, localO, false, bsdf->extra->color, bsdf->alpha_x, bsdf->alpha_y, lcg_state, bsdf->ior, false, bsdf->extra->color);
}
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) {
const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc;
if(bsdf->alpha_x*bsdf->alpha_y < 1e-7f) {
return make_float3(0.0f, 0.0f, 0.0f);
}
bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_FRESNEL_ID);
float3 X, Y, Z;
Z = bsdf->N;
make_orthonormals(Z, &X, &Y);
float3 localI = make_float3(dot(I, X), dot(I, Y), dot(I, Z));
float3 localO = make_float3(dot(omega_in, X), dot(omega_in, Y), dot(omega_in, Z));
*pdf = mf_glass_pdf(localI, localO, bsdf->alpha_x, bsdf->ior);
return mf_eval_glass(localI, localO, true, bsdf->extra->color, bsdf->alpha_x, bsdf->alpha_y, lcg_state, bsdf->ior, use_fresnel, bsdf->extra->cspec0);
}
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__
float3 dRdx, dRdy, dTdx, dTdy;
#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;
}
}
bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_FRESNEL_ID);
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, use_fresnel, bsdf->extra->cspec0);
*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
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