5152c7c152
For transparency, volume and light intersection rays, adjust these distances rather than the ray start position. This way we increment the start distance by the smallest possible float increment to avoid self intersections, and be sure it works as the distance compared to be will be exactly the same as before, due to the ray start position and direction remaining the same. Fix T98764, T96537, hair ray tracing precision issues. Differential Revision: https://developer.blender.org/D15455
108 lines
3.9 KiB
C
108 lines
3.9 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 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(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(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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