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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
|
/*
* 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
#if defined(__BRANCHED_PATH__) || defined(__SUBSURFACE__)
/* branched path tracing: connect path directly to position on one or more lights and add it to L */
ccl_device void kernel_branched_path_surface_connect_light(KernelGlobals *kg, RNG *rng,
ShaderData *sd, PathState *state, float3 throughput, float num_samples_adjust, PathRadiance *L, bool sample_all_lights)
{
#ifdef __EMISSION__
/* sample illumination from lights to find path contribution */
if(!(sd->flag & SD_BSDF_HAS_EVAL))
return;
Ray light_ray;
BsdfEval L_light;
bool is_lamp;
#ifdef __OBJECT_MOTION__
light_ray.time = sd->time;
#endif
if(sample_all_lights) {
/* lamp sampling */
for(int i = 0; i < kernel_data.integrator.num_all_lights; i++) {
int num_samples = ceil_to_int(num_samples_adjust*light_select_num_samples(kg, i));
float num_samples_inv = num_samples_adjust/(num_samples*kernel_data.integrator.num_all_lights);
RNG lamp_rng = cmj_hash(*rng, i);
if(kernel_data.integrator.pdf_triangles != 0.0f)
num_samples_inv *= 0.5f;
for(int j = 0; j < num_samples; j++) {
float light_u, light_v;
path_branched_rng_2D(kg, &lamp_rng, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
LightSample ls;
light_select(kg, i, light_u, light_v, sd->P, &ls, false);
if(direct_emission(kg, sd, &ls, &light_ray, &L_light, &is_lamp, state->bounce, state->transparent_bounce)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, throughput*num_samples_inv, &L_light, shadow, num_samples_inv, state->bounce, is_lamp);
}
}
}
}
/* mesh light sampling */
if(kernel_data.integrator.pdf_triangles != 0.0f) {
int num_samples = ceil_to_int(num_samples_adjust*kernel_data.integrator.mesh_light_samples);
float num_samples_inv = num_samples_adjust/num_samples;
if(kernel_data.integrator.num_all_lights)
num_samples_inv *= 0.5f;
for(int j = 0; j < num_samples; j++) {
float light_t = path_branched_rng_1D(kg, rng, state, j, num_samples, PRNG_LIGHT);
float light_u, light_v;
path_branched_rng_2D(kg, rng, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
/* only sample triangle lights */
if(kernel_data.integrator.num_all_lights)
light_t = 0.5f*light_t;
LightSample ls;
light_sample(kg, light_t, light_u, light_v, sd->time, sd->P, &ls, false);
if(direct_emission(kg, sd, &ls, &light_ray, &L_light, &is_lamp, state->bounce, state->transparent_bounce)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, throughput*num_samples_inv, &L_light, shadow, num_samples_inv, state->bounce, is_lamp);
}
}
}
}
}
else {
/* sample one light at random */
float light_t = path_state_rng_1D(kg, rng, state, PRNG_LIGHT);
float light_u, light_v;
path_state_rng_2D(kg, rng, state, PRNG_LIGHT_U, &light_u, &light_v);
LightSample ls;
light_sample(kg, light_t, light_u, light_v, sd->time, sd->P, &ls, false);
/* sample random light */
if(direct_emission(kg, sd, &ls, &light_ray, &L_light, &is_lamp, state->bounce, state->transparent_bounce)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, throughput*num_samples_adjust, &L_light, shadow, num_samples_adjust, state->bounce, is_lamp);
}
}
}
#endif
}
/* branched path tracing: bounce off or through surface to with new direction stored in ray */
ccl_device bool kernel_branched_path_surface_bounce(KernelGlobals *kg, RNG *rng,
ShaderData *sd, const ShaderClosure *sc, int sample, int num_samples,
float3 *throughput, PathState *state, PathRadiance *L, Ray *ray)
{
/* sample BSDF */
float bsdf_pdf;
BsdfEval bsdf_eval;
float3 bsdf_omega_in;
differential3 bsdf_domega_in;
float bsdf_u, bsdf_v;
path_branched_rng_2D(kg, rng, state, sample, num_samples, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
int label;
label = shader_bsdf_sample_closure(kg, sd, sc, bsdf_u, bsdf_v, &bsdf_eval,
&bsdf_omega_in, &bsdf_domega_in, &bsdf_pdf);
if(bsdf_pdf == 0.0f || bsdf_eval_is_zero(&bsdf_eval))
return false;
/* modify throughput */
path_radiance_bsdf_bounce(L, throughput, &bsdf_eval, bsdf_pdf, state->bounce, label);
/* modify path state */
path_state_next(kg, state, label);
/* setup ray */
ray->P = ray_offset(sd->P, (label & LABEL_TRANSMIT)? -sd->Ng: sd->Ng);
ray->D = bsdf_omega_in;
ray->t = FLT_MAX;
#ifdef __RAY_DIFFERENTIALS__
ray->dP = sd->dP;
ray->dD = bsdf_domega_in;
#endif
#ifdef __OBJECT_MOTION__
ray->time = sd->time;
#endif
#ifdef __VOLUME__
/* enter/exit volume */
if(label & LABEL_TRANSMIT)
kernel_volume_stack_enter_exit(kg, sd, state->volume_stack);
#endif
/* branch RNG state */
path_state_branch(state, sample, num_samples);
/* set MIS state */
state->min_ray_pdf = fminf(bsdf_pdf, FLT_MAX);
state->ray_pdf = bsdf_pdf;
#ifdef __LAMP_MIS__
state->ray_t = 0.0f;
#endif
return true;
}
#endif
/* path tracing: connect path directly to position on a light and add it to L */
ccl_device_inline void kernel_path_surface_connect_light(KernelGlobals *kg, RNG *rng,
ShaderData *sd, float3 throughput, PathState *state, PathRadiance *L)
{
#ifdef __EMISSION__
if(!(kernel_data.integrator.use_direct_light && (sd->flag & SD_BSDF_HAS_EVAL)))
return;
/* sample illumination from lights to find path contribution */
float light_t = path_state_rng_1D(kg, rng, state, PRNG_LIGHT);
float light_u, light_v;
path_state_rng_2D(kg, rng, state, PRNG_LIGHT_U, &light_u, &light_v);
Ray light_ray;
BsdfEval L_light;
bool is_lamp;
#ifdef __OBJECT_MOTION__
light_ray.time = sd->time;
#endif
LightSample ls;
light_sample(kg, light_t, light_u, light_v, sd->time, sd->P, &ls, false);
if(direct_emission(kg, sd, &ls, &light_ray, &L_light, &is_lamp, state->bounce, state->transparent_bounce)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, throughput, &L_light, shadow, 1.0f, state->bounce, is_lamp);
}
}
#endif
}
/* path tracing: bounce off or through surface to with new direction stored in ray */
ccl_device_inline bool kernel_path_surface_bounce(KernelGlobals *kg, RNG *rng,
ShaderData *sd, float3 *throughput, PathState *state, PathRadiance *L, Ray *ray)
{
/* no BSDF? we can stop here */
if(sd->flag & SD_BSDF) {
/* sample BSDF */
float bsdf_pdf;
BsdfEval bsdf_eval;
float3 bsdf_omega_in;
differential3 bsdf_domega_in;
float bsdf_u, bsdf_v;
path_state_rng_2D(kg, rng, state, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
int label;
label = shader_bsdf_sample(kg, sd, bsdf_u, bsdf_v, &bsdf_eval,
&bsdf_omega_in, &bsdf_domega_in, &bsdf_pdf);
if(bsdf_pdf == 0.0f || bsdf_eval_is_zero(&bsdf_eval))
return false;
/* modify throughput */
path_radiance_bsdf_bounce(L, throughput, &bsdf_eval, bsdf_pdf, state->bounce, label);
/* set labels */
if(!(label & LABEL_TRANSPARENT)) {
state->ray_pdf = bsdf_pdf;
#ifdef __LAMP_MIS__
state->ray_t = 0.0f;
#endif
state->min_ray_pdf = fminf(bsdf_pdf, state->min_ray_pdf);
}
/* update path state */
path_state_next(kg, state, label);
/* setup ray */
ray->P = ray_offset(sd->P, (label & LABEL_TRANSMIT)? -sd->Ng: sd->Ng);
ray->D = bsdf_omega_in;
if(state->bounce == 0)
ray->t -= sd->ray_length; /* clipping works through transparent */
else
ray->t = FLT_MAX;
#ifdef __RAY_DIFFERENTIALS__
ray->dP = sd->dP;
ray->dD = bsdf_domega_in;
#endif
#ifdef __VOLUME__
/* enter/exit volume */
if(label & LABEL_TRANSMIT)
kernel_volume_stack_enter_exit(kg, sd, state->volume_stack);
#endif
return true;
}
#ifdef __VOLUME__
else if(sd->flag & SD_HAS_ONLY_VOLUME) {
/* no surface shader but have a volume shader? act transparent */
/* update path state, count as transparent */
path_state_next(kg, state, LABEL_TRANSPARENT);
/* setup ray position, direction stays unchanged */
ray->P = ray_offset(sd->P, -sd->Ng);
#ifdef __RAY_DIFFERENTIALS__
ray->dP = sd->dP;
#endif
/* enter/exit volume */
kernel_volume_stack_enter_exit(kg, sd, state->volume_stack);
return true;
}
#endif
else {
/* no bsdf or volume? */
return false;
}
}
CCL_NAMESPACE_END
|