0c9ce4ba4f
it is difficult to keep in mind when MIS weight is needed, better to handle this logic in the lower-level functions. This reduces code duplication in many places.
100 lines
3.4 KiB
C
100 lines
3.4 KiB
C
/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
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*
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* SPDX-License-Identifier: Apache-2.0 */
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#pragma once
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#include "kernel/film/light_passes.h"
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#include "kernel/integrator/surface_shader.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(state, &isect);
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guiding_record_light_surface_segment(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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const uint32_t path_flag = INTEGRATOR_STATE(state, path, flag);
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const float3 N = INTEGRATOR_STATE(state, path, mis_origin_n);
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/* Advance ray to new start distance. */
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INTEGRATOR_STATE_WRITE(state, ray, tmin) = intersection_t_offset(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(
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kg, &isect, ray_P, ray_D, N, path_flag, &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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if (!is_light_shader_visible_to_path(ls.shader, path_flag)) {
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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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Spectrum 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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const float mis_weight = light_sample_mis_weight_forward_lamp(kg, state, path_flag, &ls, ray_P);
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/* Write to render buffer. */
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guiding_record_surface_emission(kg, state, light_eval, mis_weight);
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film_write_surface_emission(kg, state, light_eval, mis_weight, 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(kg, state, 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(kg,
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state,
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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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