d9bc8f189c
This patch adds a CMake option "WITH_CYCLES_DEBUG" which builds cycles with a feature that allows debugging/selecting the direct-light sampling strategy. The same option may later be used to add other debugging features that could affect performance in release builds. The three options are: * Forward path tracing (e.g., via BSDF or phase function) * Next-event estimation * Multiple importance sampling combination of the previous two methods Such a feature is useful for debugging light different sampling, evaluation, and pdf methods (e.g., for light sources and BSDFs). Differential Revision: https://developer.blender.org/D13152
129 lines
4.8 KiB
C
129 lines
4.8 KiB
C
/*
|
|
* Copyright 2011-2021 Blender Foundation
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include "kernel/film/accumulate.h"
|
|
#include "kernel/integrator/shader_eval.h"
|
|
#include "kernel/light/light.h"
|
|
#include "kernel/light/sample.h"
|
|
|
|
CCL_NAMESPACE_BEGIN
|
|
|
|
ccl_device_inline void integrate_light(KernelGlobals kg,
|
|
IntegratorState state,
|
|
ccl_global float *ccl_restrict render_buffer)
|
|
{
|
|
/* Setup light sample. */
|
|
Intersection isect ccl_optional_struct_init;
|
|
integrator_state_read_isect(kg, state, &isect);
|
|
|
|
float3 ray_P = INTEGRATOR_STATE(state, ray, P);
|
|
const float3 ray_D = INTEGRATOR_STATE(state, ray, D);
|
|
const float ray_time = INTEGRATOR_STATE(state, ray, time);
|
|
|
|
/* Advance ray beyond light. */
|
|
/* TODO: can we make this more numerically robust to avoid reintersecting the
|
|
* same light in some cases? */
|
|
const float3 new_ray_P = ray_offset(ray_P + ray_D * isect.t, ray_D);
|
|
INTEGRATOR_STATE_WRITE(state, ray, P) = new_ray_P;
|
|
INTEGRATOR_STATE_WRITE(state, ray, t) -= isect.t;
|
|
|
|
/* Set position to where the BSDF was sampled, for correct MIS PDF. */
|
|
const float mis_ray_t = INTEGRATOR_STATE(state, path, mis_ray_t);
|
|
ray_P -= ray_D * mis_ray_t;
|
|
isect.t += mis_ray_t;
|
|
INTEGRATOR_STATE_WRITE(state, path, mis_ray_t) = mis_ray_t + isect.t;
|
|
|
|
LightSample ls ccl_optional_struct_init;
|
|
const bool use_light_sample = light_sample_from_intersection(kg, &isect, ray_P, ray_D, &ls);
|
|
|
|
if (!use_light_sample) {
|
|
return;
|
|
}
|
|
|
|
/* Use visibility flag to skip lights. */
|
|
#ifdef __PASSES__
|
|
const uint32_t path_flag = INTEGRATOR_STATE(state, path, flag);
|
|
|
|
if (ls.shader & SHADER_EXCLUDE_ANY) {
|
|
if (((ls.shader & SHADER_EXCLUDE_DIFFUSE) && (path_flag & PATH_RAY_DIFFUSE)) ||
|
|
((ls.shader & SHADER_EXCLUDE_GLOSSY) &&
|
|
((path_flag & (PATH_RAY_GLOSSY | PATH_RAY_REFLECT)) ==
|
|
(PATH_RAY_GLOSSY | PATH_RAY_REFLECT))) ||
|
|
((ls.shader & SHADER_EXCLUDE_TRANSMIT) && (path_flag & PATH_RAY_TRANSMIT)) ||
|
|
((ls.shader & SHADER_EXCLUDE_SCATTER) && (path_flag & PATH_RAY_VOLUME_SCATTER)))
|
|
return;
|
|
}
|
|
#endif
|
|
|
|
/* Evaluate light shader. */
|
|
/* TODO: does aliasing like this break automatic SoA in CUDA? */
|
|
ShaderDataTinyStorage emission_sd_storage;
|
|
ccl_private ShaderData *emission_sd = AS_SHADER_DATA(&emission_sd_storage);
|
|
float3 light_eval = light_sample_shader_eval(kg, state, emission_sd, &ls, ray_time);
|
|
if (is_zero(light_eval)) {
|
|
return;
|
|
}
|
|
|
|
/* MIS weighting. */
|
|
if (!(path_flag & PATH_RAY_MIS_SKIP)) {
|
|
/* multiple importance sampling, get regular light pdf,
|
|
* and compute weight with respect to BSDF pdf */
|
|
const float mis_ray_pdf = INTEGRATOR_STATE(state, path, mis_ray_pdf);
|
|
const float mis_weight = light_sample_mis_weight_forward(kg, mis_ray_pdf, ls.pdf);
|
|
light_eval *= mis_weight;
|
|
}
|
|
|
|
/* Write to render buffer. */
|
|
const float3 throughput = INTEGRATOR_STATE(state, path, throughput);
|
|
kernel_accum_emission(kg, state, throughput * light_eval, render_buffer);
|
|
}
|
|
|
|
ccl_device void integrator_shade_light(KernelGlobals kg,
|
|
IntegratorState state,
|
|
ccl_global float *ccl_restrict render_buffer)
|
|
{
|
|
PROFILING_INIT(kg, PROFILING_SHADE_LIGHT_SETUP);
|
|
|
|
integrate_light(kg, state, render_buffer);
|
|
|
|
/* TODO: we could get stuck in an infinite loop if there are precision issues
|
|
* and the same light is hit again.
|
|
*
|
|
* As a workaround count this as a transparent bounce. It makes some sense
|
|
* to interpret lights as transparent surfaces (and support making them opaque),
|
|
* but this needs to be revisited. */
|
|
uint32_t transparent_bounce = INTEGRATOR_STATE(state, path, transparent_bounce) + 1;
|
|
INTEGRATOR_STATE_WRITE(state, path, transparent_bounce) = transparent_bounce;
|
|
|
|
if (transparent_bounce >= kernel_data.integrator.transparent_max_bounce) {
|
|
INTEGRATOR_PATH_TERMINATE(DEVICE_KERNEL_INTEGRATOR_SHADE_LIGHT);
|
|
return;
|
|
}
|
|
else {
|
|
INTEGRATOR_PATH_NEXT(DEVICE_KERNEL_INTEGRATOR_SHADE_LIGHT,
|
|
DEVICE_KERNEL_INTEGRATOR_INTERSECT_CLOSEST);
|
|
return;
|
|
}
|
|
|
|
/* TODO: in some cases we could continue directly to SHADE_BACKGROUND, but
|
|
* probably that optimization is probably not practical if we add lights to
|
|
* scene geometry. */
|
|
}
|
|
|
|
CCL_NAMESPACE_END
|