1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
|
/* SPDX-License-Identifier: Apache-2.0
* Copyright 2011-2022 Blender Foundation */
#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 to new start distance. */
INTEGRATOR_STATE_WRITE(state, ray, tmin) = intersection_t_offset(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, ls.group);
}
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(kg, state, DEVICE_KERNEL_INTEGRATOR_SHADE_LIGHT);
return;
}
else {
integrator_path_next(kg,
state,
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
|
