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/*
* 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/integrator/integrator_shade_volume.h"
#include "kernel/integrator/integrator_volume_stack.h"
#include "kernel/integrator/integrator_shader_eval.h"
CCL_NAMESPACE_BEGIN
ccl_device_inline bool shadow_intersections_has_remaining(const uint num_hits)
{
return num_hits >= INTEGRATOR_SHADOW_ISECT_SIZE;
}
#ifdef __TRANSPARENT_SHADOWS__
ccl_device_inline float3 integrate_transparent_surface_shadow(KernelGlobals kg,
IntegratorShadowState state,
const int hit)
{
PROFILING_INIT(kg, PROFILING_SHADE_SHADOW_SURFACE);
/* TODO: does aliasing like this break automatic SoA in CUDA?
* Should we instead store closures separate from ShaderData?
*
* TODO: is it better to declare this outside the loop or keep it local
* so the compiler can see there is no dependency between iterations? */
ShaderDataTinyStorage shadow_sd_storage;
ccl_private ShaderData *shadow_sd = AS_SHADER_DATA(&shadow_sd_storage);
/* Setup shader data at surface. */
Intersection isect ccl_optional_struct_init;
integrator_state_read_shadow_isect(state, &isect, hit);
Ray ray ccl_optional_struct_init;
integrator_state_read_shadow_ray(kg, state, &ray);
shader_setup_from_ray(kg, shadow_sd, &ray, &isect);
/* Evaluate shader. */
if (!(shadow_sd->flag & SD_HAS_ONLY_VOLUME)) {
shader_eval_surface<KERNEL_FEATURE_NODE_MASK_SURFACE_SHADOW>(
kg, state, shadow_sd, NULL, PATH_RAY_SHADOW);
}
# ifdef __VOLUME__
/* Exit/enter volume. */
shadow_volume_stack_enter_exit(kg, state, shadow_sd);
# endif
/* Compute transparency from closures. */
return shader_bsdf_transparency(kg, shadow_sd);
}
# ifdef __VOLUME__
ccl_device_inline void integrate_transparent_volume_shadow(KernelGlobals kg,
IntegratorShadowState state,
const int hit,
const int num_recorded_hits,
ccl_private float3 *ccl_restrict
throughput)
{
PROFILING_INIT(kg, PROFILING_SHADE_SHADOW_VOLUME);
/* TODO: deduplicate with surface, or does it not matter for memory usage? */
ShaderDataTinyStorage shadow_sd_storage;
ccl_private ShaderData *shadow_sd = AS_SHADER_DATA(&shadow_sd_storage);
/* Setup shader data. */
Ray ray ccl_optional_struct_init;
integrator_state_read_shadow_ray(kg, state, &ray);
/* Modify ray position and length to match current segment. */
const float start_t = (hit == 0) ? 0.0f :
INTEGRATOR_STATE_ARRAY(state, shadow_isect, hit - 1, t);
const float end_t = (hit < num_recorded_hits) ?
INTEGRATOR_STATE_ARRAY(state, shadow_isect, hit, t) :
ray.t;
ray.P += start_t * ray.D;
ray.t = end_t - start_t;
shader_setup_from_volume(kg, shadow_sd, &ray);
const float step_size = volume_stack_step_size(
kg, [=](const int i) { return integrator_state_read_shadow_volume_stack(state, i); });
volume_shadow_heterogeneous(kg, state, &ray, shadow_sd, throughput, step_size);
}
# endif
ccl_device_inline bool integrate_transparent_shadow(KernelGlobals kg,
IntegratorShadowState state,
const uint num_hits)
{
/* Accumulate shadow for transparent surfaces. */
const uint num_recorded_hits = min(num_hits, INTEGRATOR_SHADOW_ISECT_SIZE);
for (uint hit = 0; hit < num_recorded_hits + 1; hit++) {
/* Volume shaders. */
if (hit < num_recorded_hits || !shadow_intersections_has_remaining(num_hits)) {
# ifdef __VOLUME__
if (!integrator_state_shadow_volume_stack_is_empty(kg, state)) {
float3 throughput = INTEGRATOR_STATE(state, shadow_path, throughput);
integrate_transparent_volume_shadow(kg, state, hit, num_recorded_hits, &throughput);
if (is_zero(throughput)) {
return true;
}
INTEGRATOR_STATE_WRITE(state, shadow_path, throughput) = throughput;
}
# endif
}
/* Surface shaders. */
if (hit < num_recorded_hits) {
const float3 shadow = integrate_transparent_surface_shadow(kg, state, hit);
const float3 throughput = INTEGRATOR_STATE(state, shadow_path, throughput) * shadow;
if (is_zero(throughput)) {
return true;
}
INTEGRATOR_STATE_WRITE(state, shadow_path, throughput) = throughput;
INTEGRATOR_STATE_WRITE(state, shadow_path, transparent_bounce) += 1;
INTEGRATOR_STATE_WRITE(state, shadow_path, rng_offset) += PRNG_BOUNCE_NUM;
}
/* Note we do not need to check max_transparent_bounce here, the number
* of intersections is already limited and made opaque in the
* INTERSECT_SHADOW kernel. */
}
if (shadow_intersections_has_remaining(num_hits)) {
/* There are more hits that we could not recorded due to memory usage,
* adjust ray to intersect again from the last hit. */
const float last_hit_t = INTEGRATOR_STATE_ARRAY(state, shadow_isect, num_recorded_hits - 1, t);
const float3 ray_P = INTEGRATOR_STATE(state, shadow_ray, P);
const float3 ray_D = INTEGRATOR_STATE(state, shadow_ray, D);
INTEGRATOR_STATE_WRITE(state, shadow_ray, P) = ray_offset(ray_P + last_hit_t * ray_D, ray_D);
INTEGRATOR_STATE_WRITE(state, shadow_ray, t) -= last_hit_t;
}
return false;
}
#endif /* __TRANSPARENT_SHADOWS__ */
ccl_device void integrator_shade_shadow(KernelGlobals kg,
IntegratorShadowState state,
ccl_global float *ccl_restrict render_buffer)
{
PROFILING_INIT(kg, PROFILING_SHADE_SHADOW_SETUP);
const uint num_hits = INTEGRATOR_STATE(state, shadow_path, num_hits);
#ifdef __TRANSPARENT_SHADOWS__
/* Evaluate transparent shadows. */
const bool opaque = integrate_transparent_shadow(kg, state, num_hits);
if (opaque) {
INTEGRATOR_SHADOW_PATH_TERMINATE(DEVICE_KERNEL_INTEGRATOR_SHADE_SHADOW);
return;
}
#endif
if (shadow_intersections_has_remaining(num_hits)) {
/* More intersections to find, continue shadow ray. */
INTEGRATOR_SHADOW_PATH_NEXT(DEVICE_KERNEL_INTEGRATOR_SHADE_SHADOW,
DEVICE_KERNEL_INTEGRATOR_INTERSECT_SHADOW);
return;
}
else {
kernel_accum_light(kg, state, render_buffer);
INTEGRATOR_SHADOW_PATH_TERMINATE(DEVICE_KERNEL_INTEGRATOR_SHADE_SHADOW);
return;
}
}
CCL_NAMESPACE_END
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