ad35453cd1
Light groups are a type of pass that only contains lighting from a subset of light sources. They are created in the View layer, and light sources (lamps, objects with emissive materials and/or the environment) can be assigned to a group. Currently, each light group ends up generating its own version of the Combined pass. In the future, additional types of passes (e.g. shadowcatcher) might be getting their own per-lightgroup versions. The lightgroup creation and assignment is not Cycles-specific, so Eevee or external render engines could make use of it in the future. Note that Lightgroups are identified by their name - therefore, the name of the Lightgroup in the View Layer and the name that's set in an object's settings must match for it to be included. Currently, changing a Lightgroup's name does not update objects - this is planned for the future, along with other features such as denoising for light groups and viewing them in preview renders. Original patch by Alex Fuller (@mistaed), with some polishing by Lukas Stockner (@lukasstockner97). Differential Revision: https://developer.blender.org/D12871
117 lines
4.4 KiB
C
117 lines
4.4 KiB
C
/* SPDX-License-Identifier: Apache-2.0
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* Copyright 2011-2022 Blender Foundation */
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#pragma once
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#include "kernel/film/accumulate.h"
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#include "kernel/integrator/shader_eval.h"
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#include "kernel/light/light.h"
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#include "kernel/light/sample.h"
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CCL_NAMESPACE_BEGIN
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ccl_device_inline void integrate_light(KernelGlobals kg,
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IntegratorState state,
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ccl_global float *ccl_restrict render_buffer)
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{
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/* Setup light sample. */
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Intersection isect ccl_optional_struct_init;
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integrator_state_read_isect(kg, state, &isect);
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float3 ray_P = INTEGRATOR_STATE(state, ray, P);
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const float3 ray_D = INTEGRATOR_STATE(state, ray, D);
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const float ray_time = INTEGRATOR_STATE(state, ray, time);
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/* Advance ray beyond light. */
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/* TODO: can we make this more numerically robust to avoid reintersecting the
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* same light in some cases? Ray should not intersect surface anymore as the
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* object and prim ids will prevent self intersection. */
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const float3 new_ray_P = ray_P + ray_D * isect.t;
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INTEGRATOR_STATE_WRITE(state, ray, P) = new_ray_P;
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INTEGRATOR_STATE_WRITE(state, ray, t) -= isect.t;
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/* Set position to where the BSDF was sampled, for correct MIS PDF. */
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const float mis_ray_t = INTEGRATOR_STATE(state, path, mis_ray_t);
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ray_P -= ray_D * mis_ray_t;
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isect.t += mis_ray_t;
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INTEGRATOR_STATE_WRITE(state, path, mis_ray_t) = isect.t;
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LightSample ls ccl_optional_struct_init;
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const bool use_light_sample = light_sample_from_intersection(kg, &isect, ray_P, ray_D, &ls);
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if (!use_light_sample) {
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return;
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}
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/* Use visibility flag to skip lights. */
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#ifdef __PASSES__
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const uint32_t path_flag = INTEGRATOR_STATE(state, path, flag);
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if (ls.shader & SHADER_EXCLUDE_ANY) {
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if (((ls.shader & SHADER_EXCLUDE_DIFFUSE) && (path_flag & PATH_RAY_DIFFUSE)) ||
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((ls.shader & SHADER_EXCLUDE_GLOSSY) &&
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((path_flag & (PATH_RAY_GLOSSY | PATH_RAY_REFLECT)) ==
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(PATH_RAY_GLOSSY | PATH_RAY_REFLECT))) ||
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((ls.shader & SHADER_EXCLUDE_TRANSMIT) && (path_flag & PATH_RAY_TRANSMIT)) ||
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((ls.shader & SHADER_EXCLUDE_SCATTER) && (path_flag & PATH_RAY_VOLUME_SCATTER)))
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return;
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}
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#endif
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/* Evaluate light shader. */
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/* TODO: does aliasing like this break automatic SoA in CUDA? */
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ShaderDataTinyStorage emission_sd_storage;
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ccl_private ShaderData *emission_sd = AS_SHADER_DATA(&emission_sd_storage);
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float3 light_eval = light_sample_shader_eval(kg, state, emission_sd, &ls, ray_time);
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if (is_zero(light_eval)) {
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return;
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}
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/* MIS weighting. */
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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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const float mis_ray_pdf = INTEGRATOR_STATE(state, path, mis_ray_pdf);
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const float mis_weight = light_sample_mis_weight_forward(kg, mis_ray_pdf, ls.pdf);
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light_eval *= mis_weight;
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}
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/* Write to render buffer. */
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const float3 throughput = INTEGRATOR_STATE(state, path, throughput);
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kernel_accum_emission(kg, state, throughput * light_eval, render_buffer, ls.group);
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}
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ccl_device void integrator_shade_light(KernelGlobals kg,
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IntegratorState state,
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ccl_global float *ccl_restrict render_buffer)
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{
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PROFILING_INIT(kg, PROFILING_SHADE_LIGHT_SETUP);
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integrate_light(kg, state, render_buffer);
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/* TODO: we could get stuck in an infinite loop if there are precision issues
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* and the same light is hit again.
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*
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* As a workaround count this as a transparent bounce. It makes some sense
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* to interpret lights as transparent surfaces (and support making them opaque),
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* but this needs to be revisited. */
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uint32_t transparent_bounce = INTEGRATOR_STATE(state, path, transparent_bounce) + 1;
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INTEGRATOR_STATE_WRITE(state, path, transparent_bounce) = transparent_bounce;
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if (transparent_bounce >= kernel_data.integrator.transparent_max_bounce) {
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INTEGRATOR_PATH_TERMINATE(DEVICE_KERNEL_INTEGRATOR_SHADE_LIGHT);
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return;
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}
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else {
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INTEGRATOR_PATH_NEXT(DEVICE_KERNEL_INTEGRATOR_SHADE_LIGHT,
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DEVICE_KERNEL_INTEGRATOR_INTERSECT_CLOSEST);
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return;
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}
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/* TODO: in some cases we could continue directly to SHADE_BACKGROUND, but
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* probably that optimization is probably not practical if we add lights to
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* scene geometry. */
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}
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CCL_NAMESPACE_END
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