forked from bartvdbraak/blender
Brecht Van Lommel
c806a8ce96
Probably will not be noticed in most scenes. This helps reduce noise when you have multiple lamps with MIS enabled, at the cost of some performance, but from testing some scenes this seems better.
268 lines
7.3 KiB
C
268 lines
7.3 KiB
C
/*
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* Copyright 2011-2013 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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/* Direction Emission */
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ccl_device_noinline float3 direct_emissive_eval(KernelGlobals *kg,
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LightSample *ls, float3 I, differential3 dI, float t, float time, int bounce, int transparent_bounce)
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{
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/* setup shading at emitter */
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ShaderData sd;
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float3 eval;
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#ifdef __BACKGROUND_MIS__
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if(ls->type == LIGHT_BACKGROUND) {
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Ray ray;
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ray.D = ls->D;
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ray.P = ls->P;
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ray.t = 1.0f;
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#ifdef __OBJECT_MOTION__
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ray.time = time;
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#endif
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ray.dP = differential3_zero();
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ray.dD = dI;
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shader_setup_from_background(kg, &sd, &ray, bounce+1, transparent_bounce);
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eval = shader_eval_background(kg, &sd, 0, SHADER_CONTEXT_EMISSION);
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}
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else
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#endif
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{
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shader_setup_from_sample(kg, &sd, ls->P, ls->Ng, I, ls->shader, ls->object, ls->prim, ls->u, ls->v, t, time, bounce+1, transparent_bounce);
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ls->Ng = sd.Ng;
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/* no path flag, we're evaluating this for all closures. that's weak but
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* we'd have to do multiple evaluations otherwise */
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shader_eval_surface(kg, &sd, 0.0f, 0, SHADER_CONTEXT_EMISSION);
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/* evaluate emissive closure */
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if(sd.flag & SD_EMISSION)
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eval = shader_emissive_eval(kg, &sd);
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else
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eval = make_float3(0.0f, 0.0f, 0.0f);
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}
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eval *= ls->eval_fac;
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return eval;
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}
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ccl_device_noinline bool direct_emission(KernelGlobals *kg, ShaderData *sd, int lindex,
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float randt, float randu, float randv, Ray *ray, BsdfEval *eval,
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bool *is_lamp, int bounce, int transparent_bounce)
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{
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LightSample ls;
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#ifdef __BRANCHED_PATH__
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if(lindex != LAMP_NONE) {
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/* sample position on a specified light */
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light_select(kg, lindex, randu, randv, sd->P, &ls);
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}
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else
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#endif
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{
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/* sample a light and position on int */
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light_sample(kg, randt, randu, randv, sd->time, sd->P, &ls);
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}
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if(ls.pdf == 0.0f)
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return false;
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/* todo: implement */
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differential3 dD = differential3_zero();
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/* evaluate closure */
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float3 light_eval = direct_emissive_eval(kg, &ls, -ls.D, dD, ls.t, sd->time, bounce, transparent_bounce);
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if(is_zero(light_eval))
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return false;
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/* evaluate BSDF at shading point */
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float bsdf_pdf;
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#ifdef __VOLUME__
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if(sd->prim != PRIM_NONE)
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shader_bsdf_eval(kg, sd, ls.D, eval, &bsdf_pdf);
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else
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shader_volume_phase_eval(kg, sd, ls.D, eval, &bsdf_pdf);
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#else
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shader_bsdf_eval(kg, sd, ls.D, eval, &bsdf_pdf);
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#endif
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if(ls.shader & SHADER_USE_MIS) {
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/* multiple importance sampling */
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float mis_weight = power_heuristic(ls.pdf, bsdf_pdf);
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light_eval *= mis_weight;
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}
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bsdf_eval_mul(eval, light_eval/ls.pdf);
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#ifdef __PASSES__
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/* use visibility flag to skip lights */
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if(ls.shader & SHADER_EXCLUDE_ANY) {
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if(ls.shader & SHADER_EXCLUDE_DIFFUSE)
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eval->diffuse = make_float3(0.0f, 0.0f, 0.0f);
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if(ls.shader & SHADER_EXCLUDE_GLOSSY)
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eval->glossy = make_float3(0.0f, 0.0f, 0.0f);
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if(ls.shader & SHADER_EXCLUDE_TRANSMIT)
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eval->transmission = make_float3(0.0f, 0.0f, 0.0f);
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}
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#endif
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if(bsdf_eval_is_zero(eval))
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return false;
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if(ls.shader & SHADER_CAST_SHADOW) {
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/* setup ray */
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bool transmit = (dot(sd->Ng, ls.D) < 0.0f);
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ray->P = ray_offset(sd->P, (transmit)? -sd->Ng: sd->Ng);
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if(ls.t == FLT_MAX) {
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/* distant light */
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ray->D = ls.D;
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ray->t = ls.t;
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}
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else {
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/* other lights, avoid self-intersection */
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ray->D = ray_offset(ls.P, ls.Ng) - ray->P;
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ray->D = normalize_len(ray->D, &ray->t);
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}
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ray->dP = sd->dP;
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ray->dD = differential3_zero();
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}
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else {
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/* signal to not cast shadow ray */
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ray->t = 0.0f;
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}
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/* return if it's a lamp for shadow pass */
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*is_lamp = (ls.prim == PRIM_NONE && ls.type != LIGHT_BACKGROUND);
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return true;
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}
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/* Indirect Primitive Emission */
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ccl_device_noinline float3 indirect_primitive_emission(KernelGlobals *kg, ShaderData *sd, float t, int path_flag, float bsdf_pdf)
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{
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/* evaluate emissive closure */
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float3 L = shader_emissive_eval(kg, sd);
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#ifdef __HAIR__
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if(!(path_flag & PATH_RAY_MIS_SKIP) && (sd->flag & SD_USE_MIS) && (sd->type & PRIMITIVE_ALL_TRIANGLE)) {
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#else
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if(!(path_flag & PATH_RAY_MIS_SKIP) && (sd->flag & SD_USE_MIS)) {
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#endif
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/* multiple importance sampling, get triangle light pdf,
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* and compute weight with respect to BSDF pdf */
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float pdf = triangle_light_pdf(kg, sd->Ng, sd->I, t);
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float mis_weight = power_heuristic(bsdf_pdf, pdf);
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return L*mis_weight;
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}
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return L;
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}
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/* Indirect Lamp Emission */
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ccl_device_noinline bool indirect_lamp_emission(KernelGlobals *kg, PathState *state, Ray *ray, float3 *emission)
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{
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bool hit_lamp = false;
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*emission = make_float3(0.0f, 0.0f, 0.0f);
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for(int lamp = 0; lamp < kernel_data.integrator.num_all_lights; lamp++) {
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LightSample ls;
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if(!lamp_light_eval(kg, lamp, ray->P, ray->D, ray->t, &ls))
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continue;
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#ifdef __PASSES__
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/* use visibility flag to skip lights */
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if(ls.shader & SHADER_EXCLUDE_ANY) {
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if(((ls.shader & SHADER_EXCLUDE_DIFFUSE) && (state->flag & PATH_RAY_DIFFUSE)) ||
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((ls.shader & SHADER_EXCLUDE_GLOSSY) && (state->flag & PATH_RAY_GLOSSY)) ||
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((ls.shader & SHADER_EXCLUDE_TRANSMIT) && (state->flag & PATH_RAY_TRANSMIT)))
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continue;
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}
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#endif
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float3 L = direct_emissive_eval(kg, &ls, -ray->D, ray->dD, ls.t, ray->time, state->bounce, state->transparent_bounce);
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if(!(state->flag & PATH_RAY_MIS_SKIP)) {
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/* multiple importance sampling, get regular light pdf,
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* and compute weight with respect to BSDF pdf */
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float mis_weight = power_heuristic(state->ray_pdf, ls.pdf);
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L *= mis_weight;
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}
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*emission += L;
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hit_lamp = true;
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}
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return hit_lamp;
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}
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/* Indirect Background */
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ccl_device_noinline float3 indirect_background(KernelGlobals *kg, PathState *state, Ray *ray)
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{
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#ifdef __BACKGROUND__
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int shader = kernel_data.background.surface_shader;
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/* use visibility flag to skip lights */
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if(shader & SHADER_EXCLUDE_ANY) {
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if(((shader & SHADER_EXCLUDE_DIFFUSE) && (state->flag & PATH_RAY_DIFFUSE)) ||
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((shader & SHADER_EXCLUDE_GLOSSY) && (state->flag & PATH_RAY_GLOSSY)) ||
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((shader & SHADER_EXCLUDE_TRANSMIT) && (state->flag & PATH_RAY_TRANSMIT)) ||
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((shader & SHADER_EXCLUDE_CAMERA) && (state->flag & PATH_RAY_CAMERA)))
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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/* evaluate background closure */
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ShaderData sd;
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shader_setup_from_background(kg, &sd, ray, state->bounce+1, state->transparent_bounce);
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float3 L = shader_eval_background(kg, &sd, state->flag, SHADER_CONTEXT_EMISSION);
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#ifdef __BACKGROUND_MIS__
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/* check if background light exists or if we should skip pdf */
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int res = kernel_data.integrator.pdf_background_res;
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if(!(state->flag & PATH_RAY_MIS_SKIP) && res) {
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/* multiple importance sampling, get background light pdf for ray
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* direction, and compute weight with respect to BSDF pdf */
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float pdf = background_light_pdf(kg, ray->D);
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float mis_weight = power_heuristic(state->ray_pdf, pdf);
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return L*mis_weight;
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}
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#endif
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return L;
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#else
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return make_float3(0.8f, 0.8f, 0.8f);
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#endif
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}
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CCL_NAMESPACE_END
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