forked from bartvdbraak/blender
d14e39622a
It uses an idea of accumulating all possible light reachable across the light path (without taking shadow blocked into account) and accumulating total shaded light across the path. Dividing second figure by first one seems to be giving good estimate of the shadow. In fact, to my knowledge, it's something really similar to what is happening in the denoising branch, so we are aligned here which is good. The workflow is following: - Create an object which matches real-life object on which shadow is to be catched. - Create approximate similar material on that object. This is needed to make indirect light properly affecting CG objects in the scene. - Mark object as Shadow Catcher in the Object properties. Ideally, after doing that it will be possible to render the image and simply alpha-over it on top of real footage.
347 lines
11 KiB
C
347 lines
11 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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ShaderData *emission_sd,
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LightSample *ls,
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ccl_addr_space PathState *state,
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float3 I,
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differential3 dI,
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float t,
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float time)
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{
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/* setup shading at emitter */
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float3 eval;
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int shader_flag = kernel_tex_fetch(__shader_flag, (ls->shader & SHADER_MASK)*SHADER_SIZE);
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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, emission_sd, &ray);
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path_state_modify_bounce(state, true);
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eval = shader_eval_background(kg, emission_sd, state, 0, SHADER_CONTEXT_EMISSION);
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path_state_modify_bounce(state, false);
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}
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else
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#endif
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if(shader_flag & SD_HAS_CONSTANT_EMISSION)
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{
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eval.x = __int_as_float(kernel_tex_fetch(__shader_flag, (ls->shader & SHADER_MASK)*SHADER_SIZE + 2));
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eval.y = __int_as_float(kernel_tex_fetch(__shader_flag, (ls->shader & SHADER_MASK)*SHADER_SIZE + 3));
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eval.z = __int_as_float(kernel_tex_fetch(__shader_flag, (ls->shader & SHADER_MASK)*SHADER_SIZE + 4));
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if((ls->prim != PRIM_NONE) && dot(ls->Ng, I) < 0.0f) {
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ls->Ng = -ls->Ng;
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}
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}
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else
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{
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shader_setup_from_sample(kg, emission_sd,
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ls->P, ls->Ng, I,
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ls->shader, ls->object, ls->prim,
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ls->u, ls->v, t, time, false, ls->lamp);
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ls->Ng = emission_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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path_state_modify_bounce(state, true);
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shader_eval_surface(kg, emission_sd, NULL, state, 0.0f, 0, SHADER_CONTEXT_EMISSION);
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path_state_modify_bounce(state, false);
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/* evaluate emissive closure */
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if(emission_sd->flag & SD_EMISSION)
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eval = shader_emissive_eval(kg, emission_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,
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ShaderData *sd,
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ShaderData *emission_sd,
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LightSample *ls,
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ccl_addr_space PathState *state,
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Ray *ray,
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BsdfEval *eval,
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bool *is_lamp,
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float rand_terminate)
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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,
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emission_sd,
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ls,
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state,
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-ls->D,
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dD,
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ls->t,
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sd->time);
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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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#ifdef __VOLUME__
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if(sd->prim != PRIM_NONE)
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shader_bsdf_eval(kg, sd, ls->D, eval, ls->pdf, ls->shader & SHADER_USE_MIS);
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else {
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float bsdf_pdf;
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shader_volume_phase_eval(kg, sd, ls->D, eval, &bsdf_pdf);
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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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}
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#else
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shader_bsdf_eval(kg, sd, ls->D, eval, ls->pdf, ls->shader & SHADER_USE_MIS);
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#endif
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bsdf_eval_mul3(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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eval->subsurface = make_float3(0.0f, 0.0f, 0.0f);
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}
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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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if(ls->shader & SHADER_EXCLUDE_SCATTER)
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eval->scatter = 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(kernel_data.integrator.light_inv_rr_threshold > 0.0f
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#ifdef __SHADOW_TRICKS__
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&& (state->flag & PATH_RAY_SHADOW_CATCHER) == 0
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#endif
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)
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{
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float probability = max3(fabs(bsdf_eval_sum(eval))) * kernel_data.integrator.light_inv_rr_threshold;
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if(probability < 1.0f) {
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if(rand_terminate >= probability) {
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return false;
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}
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bsdf_eval_mul(eval, 1.0f / probability);
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}
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}
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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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{
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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,
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ShaderData *emission_sd,
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ccl_addr_space PathState *state,
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Ray *ray,
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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) &&
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((state->flag & (PATH_RAY_GLOSSY|PATH_RAY_REFLECT)) == (PATH_RAY_GLOSSY|PATH_RAY_REFLECT))) ||
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((ls.shader & SHADER_EXCLUDE_TRANSMIT) && (state->flag & PATH_RAY_TRANSMIT)) ||
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((ls.shader & SHADER_EXCLUDE_SCATTER) && (state->flag & PATH_RAY_VOLUME_SCATTER)))
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continue;
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}
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#endif
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float3 L = direct_emissive_eval(kg,
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emission_sd,
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&ls,
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state,
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-ray->D,
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ray->dD,
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ls.t,
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ray->time);
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#ifdef __VOLUME__
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if(state->volume_stack[0].shader != SHADER_NONE) {
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/* shadow attenuation */
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Ray volume_ray = *ray;
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volume_ray.t = ls.t;
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float3 volume_tp = make_float3(1.0f, 1.0f, 1.0f);
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kernel_volume_shadow(kg, emission_sd, state, &volume_ray, &volume_tp);
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L *= volume_tp;
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}
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#endif
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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,
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ShaderData *emission_sd,
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ccl_addr_space PathState *state,
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ccl_addr_space 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) &&
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((state->flag & (PATH_RAY_GLOSSY|PATH_RAY_REFLECT)) == (PATH_RAY_GLOSSY|PATH_RAY_REFLECT))) ||
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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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((shader & SHADER_EXCLUDE_SCATTER) && (state->flag & PATH_RAY_VOLUME_SCATTER)))
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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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# ifdef __SPLIT_KERNEL__
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Ray priv_ray = *ray;
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shader_setup_from_background(kg, emission_sd, &priv_ray);
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# else
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shader_setup_from_background(kg, emission_sd, ray);
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# endif
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path_state_modify_bounce(state, true);
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float3 L = shader_eval_background(kg, emission_sd, state, state->flag, SHADER_CONTEXT_EMISSION);
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path_state_modify_bounce(state, false);
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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->P, 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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