forked from bartvdbraak/blender
Brecht Van Lommel
a29807cd63
* Volume multiple importace sampling support to combine equiangular and distance sampling, for both homogeneous and heterogeneous volumes. * Branched path "Sample All Direct Lights" and "Sample All Indirect Lights" now apply to volumes as well as surfaces. Implementation note: For simplicity this is all done with decoupled ray marching, the only case we do not use decoupled is for distance only sampling with one light sample. The homogeneous case should still compile on the GPU because it only requires fixed size storage, but the heterogeneous case will be trickier to get working.
266 lines
7.3 KiB
C
266 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,
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LightSample *ls, Ray *ray, BsdfEval *eval, bool *is_lamp,
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int bounce, int transparent_bounce)
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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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{
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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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#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, 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, 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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