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
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
|
/*
* 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__) || defined(__SHADOW_TRICKS__) || \
defined(__BAKING__)
/* branched path tracing: connect path directly to position on one or more lights and add it to L
*/
ccl_device_noinline_cpu void kernel_branched_path_surface_connect_light(
KernelGlobals *kg,
ShaderData *sd,
ShaderData *emission_sd,
ccl_addr_space PathState *state,
float3 throughput,
float num_samples_adjust,
PathRadiance *L,
int sample_all_lights)
{
# ifdef __EMISSION__
/* sample illumination from lights to find path contribution */
BsdfEval L_light;
int num_lights = 0;
if (kernel_data.integrator.use_direct_light) {
if (sample_all_lights) {
num_lights = kernel_data.integrator.num_all_lights;
if (kernel_data.integrator.pdf_triangles != 0.0f) {
num_lights += 1;
}
}
else {
num_lights = 1;
}
}
for (int i = 0; i < num_lights; i++) {
/* sample one light at random */
int num_samples = 1;
int num_all_lights = 1;
uint lamp_rng_hash = state->rng_hash;
bool double_pdf = false;
bool is_mesh_light = false;
bool is_lamp = false;
if (sample_all_lights) {
/* lamp sampling */
is_lamp = i < kernel_data.integrator.num_all_lights;
if (is_lamp) {
if (UNLIKELY(light_select_reached_max_bounces(kg, i, state->bounce))) {
continue;
}
num_samples = ceil_to_int(num_samples_adjust * light_select_num_samples(kg, i));
num_all_lights = kernel_data.integrator.num_all_lights;
lamp_rng_hash = cmj_hash(state->rng_hash, i);
double_pdf = kernel_data.integrator.pdf_triangles != 0.0f;
}
/* mesh light sampling */
else {
num_samples = ceil_to_int(num_samples_adjust * kernel_data.integrator.mesh_light_samples);
double_pdf = kernel_data.integrator.num_all_lights != 0;
is_mesh_light = true;
}
}
float num_samples_inv = num_samples_adjust / (num_samples * num_all_lights);
for (int j = 0; j < num_samples; j++) {
Ray light_ray;
light_ray.t = 0.0f; /* reset ray */
# ifdef __OBJECT_MOTION__
light_ray.time = sd->time;
# endif
bool has_emission = false;
if (kernel_data.integrator.use_direct_light && (sd->flag & SD_BSDF_HAS_EVAL)) {
float light_u, light_v;
path_branched_rng_2D(
kg, lamp_rng_hash, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
float terminate = path_branched_rng_light_termination(
kg, lamp_rng_hash, state, j, num_samples);
/* only sample triangle lights */
if (is_mesh_light && double_pdf) {
light_u = 0.5f * light_u;
}
LightSample ls;
const int lamp = is_lamp ? i : -1;
if (light_sample(kg, lamp, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) {
/* The sampling probability returned by lamp_light_sample assumes that all lights were
* sampled. However, this code only samples lamps, so if the scene also had mesh lights,
* the real probability is twice as high. */
if (double_pdf) {
ls.pdf *= 2.0f;
}
has_emission = direct_emission(
kg, sd, emission_sd, &ls, state, &light_ray, &L_light, &is_lamp, terminate);
}
}
/* trace shadow ray */
float3 shadow;
const bool blocked = shadow_blocked(kg, sd, emission_sd, state, &light_ray, &shadow);
if (has_emission) {
if (!blocked) {
/* accumulate */
path_radiance_accum_light(
L, state, throughput * num_samples_inv, &L_light, shadow, num_samples_inv, is_lamp);
}
else {
path_radiance_accum_total_light(L, state, throughput * num_samples_inv, &L_light);
}
}
}
}
# 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,
ShaderData *sd,
const ShaderClosure *sc,
int sample,
int num_samples,
ccl_addr_space float3 *throughput,
ccl_addr_space PathState *state,
PathRadianceState *L_state,
ccl_addr_space Ray *ray,
float sum_sample_weight)
{
/* 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, state->rng_hash, 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(kg, L_state, throughput, &bsdf_eval, bsdf_pdf, state->bounce, label);
# ifdef __DENOISING_FEATURES__
state->denoising_feature_weight *= sc->sample_weight / (sum_sample_weight * num_samples);
# endif
/* 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 = normalize(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,
ShaderData *sd,
ShaderData *emission_sd,
float3 throughput,
ccl_addr_space PathState *state,
PathRadiance *L)
{
PROFILING_INIT(kg, PROFILING_CONNECT_LIGHT);
#ifdef __EMISSION__
# ifdef __SHADOW_TRICKS__
int all = (state->flag & PATH_RAY_SHADOW_CATCHER);
kernel_branched_path_surface_connect_light(kg, sd, emission_sd, state, throughput, 1.0f, L, all);
# else
/* sample illumination from lights to find path contribution */
Ray light_ray;
BsdfEval L_light;
bool is_lamp = false;
bool has_emission = false;
light_ray.t = 0.0f;
# ifdef __OBJECT_MOTION__
light_ray.time = sd->time;
# endif
if (kernel_data.integrator.use_direct_light && (sd->flag & SD_BSDF_HAS_EVAL)) {
float light_u, light_v;
path_state_rng_2D(kg, state, PRNG_LIGHT_U, &light_u, &light_v);
LightSample ls;
if (light_sample(kg, -1, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) {
float terminate = path_state_rng_light_termination(kg, state);
has_emission = direct_emission(
kg, sd, emission_sd, &ls, state, &light_ray, &L_light, &is_lamp, terminate);
}
}
/* trace shadow ray */
float3 shadow;
const bool blocked = shadow_blocked(kg, sd, emission_sd, state, &light_ray, &shadow);
if (has_emission) {
if (!blocked) {
/* accumulate */
path_radiance_accum_light(L, state, throughput, &L_light, shadow, 1.0f, is_lamp);
}
else {
path_radiance_accum_total_light(L, state, throughput, &L_light);
}
}
# endif
#endif
}
/* path tracing: bounce off or through surface to with new direction stored in ray */
ccl_device bool kernel_path_surface_bounce(KernelGlobals *kg,
ShaderData *sd,
ccl_addr_space float3 *throughput,
ccl_addr_space PathState *state,
PathRadianceState *L_state,
ccl_addr_space Ray *ray)
{
PROFILING_INIT(kg, PROFILING_SURFACE_BOUNCE);
/* 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, 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(kg, L_state, 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 = normalize(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) {
if (!path_state_volume_next(kg, state)) {
return false;
}
if (state->bounce == 0)
ray->t -= sd->ray_length; /* clipping works through transparent */
else
ray->t = FLT_MAX;
/* 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
|