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
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
/*
* Copyright 2011-2013 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
*/
CCL_NAMESPACE_BEGIN
ccl_device_inline bool shadow_blocked(KernelGlobals *kg, PathState *state, Ray *ray, float3 *shadow)
{
*shadow = make_float3(1.0f, 1.0f, 1.0f);
if(ray->t == 0.0f)
return false;
Intersection isect;
#ifdef __HAIR__
bool result = scene_intersect(kg, ray, PATH_RAY_SHADOW_OPAQUE, &isect, NULL, 0.0f, 0.0f);
#else
bool result = scene_intersect(kg, ray, PATH_RAY_SHADOW_OPAQUE, &isect);
#endif
#ifdef __TRANSPARENT_SHADOWS__
if(result && kernel_data.integrator.transparent_shadows) {
/* transparent shadows work in such a way to try to minimize overhead
* in cases where we don't need them. after a regular shadow ray is
* cast we check if the hit primitive was potentially transparent, and
* only in that case start marching. this gives on extra ray cast for
* the cases were we do want transparency.
*
* also note that for this to work correct, multi close sampling must
* be used, since we don't pass a random number to shader_eval_surface */
if(shader_transparent_shadow(kg, &isect)) {
float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
float3 Pend = ray->P + ray->D*ray->t;
int bounce = state->transparent_bounce;
#ifdef __VOLUME__
PathState ps = *state;
#endif
for(;;) {
if(bounce >= kernel_data.integrator.transparent_max_bounce) {
return true;
}
else if(bounce >= kernel_data.integrator.transparent_min_bounce) {
/* todo: get random number somewhere for probabilistic terminate */
#if 0
float probability = average(throughput);
float terminate = 0.0f;
if(terminate >= probability)
return true;
throughput /= probability;
#endif
}
#ifdef __HAIR__
if(!scene_intersect(kg, ray, PATH_RAY_SHADOW_TRANSPARENT, &isect, NULL, 0.0f, 0.0f)) {
#else
if(!scene_intersect(kg, ray, PATH_RAY_SHADOW_TRANSPARENT, &isect)) {
#endif
#ifdef __VOLUME__
/* attenuation for last line segment towards light */
if(ps.volume_stack[0].shader != SHADER_NO_ID)
throughput *= kernel_volume_get_shadow_attenuation(kg, &ps, ray);
#endif
*shadow *= throughput;
return false;
}
if(!shader_transparent_shadow(kg, &isect))
return true;
#ifdef __VOLUME__
/* attenuation between last surface and next surface */
if(ps.volume_stack[0].shader != SHADER_NO_ID) {
Ray segment_ray = *ray;
segment_ray.t = isect.t;
throughput *= kernel_volume_get_shadow_attenuation(kg, &ps, &segment_ray);
}
#endif
/* setup shader data at surface */
ShaderData sd;
shader_setup_from_ray(kg, &sd, &isect, ray, state->bounce+1);
/* attenuation from transparent surface */
if(!(sd.flag & SD_HAS_ONLY_VOLUME)) {
shader_eval_surface(kg, &sd, 0.0f, PATH_RAY_SHADOW, SHADER_CONTEXT_SHADOW);
throughput *= shader_bsdf_transparency(kg, &sd);
}
/* move ray forward */
ray->P = ray_offset(sd.P, -sd.Ng);
if(ray->t != FLT_MAX)
ray->D = normalize_len(Pend - ray->P, &ray->t);
#ifdef __VOLUME__
/* exit/enter volume */
kernel_volume_stack_enter_exit(kg, &sd, ps.volume_stack);
#endif
bounce++;
}
}
}
#ifdef __VOLUME__
else if(!result && state->volume_stack[0].shader != SHADER_NO_ID) {
/* apply attenuation from current volume shader */
*shadow *= kernel_volume_get_shadow_attenuation(kg, state, ray);
}
#endif
#endif
return result;
}
CCL_NAMESPACE_END
|