forked from bartvdbraak/blender
234 lines
6.0 KiB
C
234 lines
6.0 KiB
C
/*
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* Copyright 2011, Blender Foundation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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CCL_NAMESPACE_BEGIN
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/* Direction Emission */
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__device float3 direct_emissive_eval(KernelGlobals *kg, float rando,
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LightSample *ls, float u, float v, float3 I, float t, float time)
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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.dx = make_float3(0.0f, 0.0f, 0.0f);
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ray.dP.dy = make_float3(0.0f, 0.0f, 0.0f);
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#ifdef __CAMERA_MOTION__
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ray.time = time;
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#endif
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shader_setup_from_background(kg, &sd, &ray);
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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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#ifdef __HAIR__
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if(ls->type == LIGHT_STRAND)
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shader_setup_from_sample(kg, &sd, ls->P, ls->Ng, I, ls->shader, ls->object, ls->prim, u, v, t, time, ls->prim);
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else
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#endif
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shader_setup_from_sample(kg, &sd, ls->P, ls->Ng, I, ls->shader, ls->object, ls->prim, u, v, t, time);
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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, rando, 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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shader_release(kg, &sd);
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return eval;
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}
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__device bool direct_emission(KernelGlobals *kg, ShaderData *sd, int lindex,
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float randt, float rando, float randu, float randv, Ray *ray, BsdfEval *eval,
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bool *is_lamp)
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{
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LightSample ls;
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#ifdef __NON_PROGRESSIVE__
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if(lindex != -1) {
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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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/* evaluate closure */
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float3 light_eval = direct_emissive_eval(kg, rando, &ls, randu, randv, -ls.D, ls.t, sd->time);
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if(is_zero(light_eval))
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return false;
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/* todo: use visbility flag to skip lights */
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/* evaluate BSDF at shading point */
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float bsdf_pdf;
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shader_bsdf_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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bsdf_eval_mul(eval, light_eval/ls.pdf);
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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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}
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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 == ~0);
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return true;
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}
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/* Indirect Primitive Emission */
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__device 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_SAMPLE_AS_LIGHT) && (sd->segment == ~0)) {
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#else
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if(!(path_flag & PATH_RAY_MIS_SKIP) && (sd->flag & SD_SAMPLE_AS_LIGHT)) {
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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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__device bool indirect_lamp_emission(KernelGlobals *kg, Ray *ray, int path_flag, float bsdf_pdf, float randt, float3 *emission)
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{
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LightSample ls;
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int lamp = lamp_light_eval_sample(kg, randt);
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if(lamp == ~0)
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return false;
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if(!lamp_light_eval(kg, lamp, ray->P, ray->D, ray->t, &ls))
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return false;
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/* todo: missing texture coordinates */
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float u = 0.0f;
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float v = 0.0f;
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float3 L = direct_emissive_eval(kg, 0.0f, &ls, u, v, -ray->D, ls.t, ray->time);
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if(!(path_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(bsdf_pdf, ls.pdf);
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L *= mis_weight;
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}
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*emission = L;
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return true;
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}
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/* Indirect Background */
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__device float3 indirect_background(KernelGlobals *kg, Ray *ray, int path_flag, float bsdf_pdf)
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{
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#ifdef __BACKGROUND__
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/* evaluate background closure */
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ShaderData sd;
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shader_setup_from_background(kg, &sd, ray);
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float3 L = shader_eval_background(kg, &sd, path_flag, SHADER_CONTEXT_EMISSION);
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shader_release(kg, &sd);
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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(!(path_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(bsdf_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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