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
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
|
/*
* Adapted from code Copyright 2009-2010 NVIDIA Corporation
* Modifications Copyright 2011, 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
/*
* "Persistent while-while kernel" used in:
*
* "Understanding the Efficiency of Ray Traversal on GPUs",
* Timo Aila and Samuli Laine,
* Proc. High-Performance Graphics 2009
*/
/* bottom-most stack entry, indicating the end of traversal */
#define ENTRYPOINT_SENTINEL 0x76543210
/* 64 object BVH + 64 mesh BVH + 64 object node splitting */
#define BVH_STACK_SIZE 192
#define BVH_NODE_SIZE 4
#define TRI_NODE_SIZE 3
/* silly workaround for float extended precision that happens when compiling
* without sse support on x86, it results in different results for float ops
* that you would otherwise expect to compare correctly */
#if !defined(__i386__) || defined(__SSE__)
#define NO_EXTENDED_PRECISION
#else
#define NO_EXTENDED_PRECISION volatile
#endif
__device_inline float3 bvh_inverse_direction(float3 dir)
{
/* avoid divide by zero (ooeps = exp2f(-80.0f)) */
float ooeps = 0.00000000000000000000000082718061255302767487140869206996285356581211090087890625f;
float3 idir;
idir.x = 1.0f/((fabsf(dir.x) > ooeps)? dir.x: copysignf(ooeps, dir.x));
idir.y = 1.0f/((fabsf(dir.y) > ooeps)? dir.y: copysignf(ooeps, dir.y));
idir.z = 1.0f/((fabsf(dir.z) > ooeps)? dir.z: copysignf(ooeps, dir.z));
return idir;
}
__device_inline void bvh_instance_push(KernelGlobals *kg, int object, const Ray *ray, float3 *P, float3 *idir, float *t, const float tmax)
{
Transform tfm = object_fetch_transform(kg, object, OBJECT_INVERSE_TRANSFORM);
*P = transform_point(&tfm, ray->P);
float3 dir = transform_direction(&tfm, ray->D);
float len;
dir = normalize_len(dir, &len);
*idir = bvh_inverse_direction(dir);
if(*t != FLT_MAX)
*t *= len;
}
__device_inline void bvh_instance_pop(KernelGlobals *kg, int object, const Ray *ray, float3 *P, float3 *idir, float *t, const float tmax)
{
if(*t != FLT_MAX) {
Transform tfm = object_fetch_transform(kg, object, OBJECT_TRANSFORM);
*t *= len(transform_direction(&tfm, 1.0f/(*idir)));
}
*P = ray->P;
*idir = bvh_inverse_direction(ray->D);
}
#ifdef __OBJECT_MOTION__
__device_inline void bvh_instance_motion_push(KernelGlobals *kg, int object, const Ray *ray, float3 *P, float3 *idir, float *t, Transform *tfm, const float tmax)
{
Transform itfm;
*tfm = object_fetch_transform_motion_test(kg, object, ray->time, &itfm);
*P = transform_point(&itfm, ray->P);
float3 dir = transform_direction(&itfm, ray->D);
float len;
dir = normalize_len(dir, &len);
*idir = bvh_inverse_direction(dir);
if(*t != FLT_MAX)
*t *= len;
}
__device_inline void bvh_instance_motion_pop(KernelGlobals *kg, int object, const Ray *ray, float3 *P, float3 *idir, float *t, Transform *tfm, const float tmax)
{
if(*t != FLT_MAX)
*t *= len(transform_direction(tfm, 1.0f/(*idir)));
*P = ray->P;
*idir = bvh_inverse_direction(ray->D);
}
#endif
/* intersect two bounding boxes */
__device_inline void bvh_node_intersect(KernelGlobals *kg,
bool *traverseChild0, bool *traverseChild1,
bool *closestChild1, int *nodeAddr0, int *nodeAddr1,
float3 P, float3 idir, float t, uint visibility, int nodeAddr)
{
/* fetch node data */
float4 n0xy = kernel_tex_fetch(__bvh_nodes, nodeAddr*BVH_NODE_SIZE+0);
float4 n1xy = kernel_tex_fetch(__bvh_nodes, nodeAddr*BVH_NODE_SIZE+1);
float4 nz = kernel_tex_fetch(__bvh_nodes, nodeAddr*BVH_NODE_SIZE+2);
float4 cnodes = kernel_tex_fetch(__bvh_nodes, nodeAddr*BVH_NODE_SIZE+3);
/* intersect ray against child nodes */
float3 ood = P * idir;
float c0lox = n0xy.x * idir.x - ood.x;
float c0hix = n0xy.y * idir.x - ood.x;
float c0loy = n0xy.z * idir.y - ood.y;
float c0hiy = n0xy.w * idir.y - ood.y;
float c0loz = nz.x * idir.z - ood.z;
float c0hiz = nz.y * idir.z - ood.z;
NO_EXTENDED_PRECISION float c0min = max4(min(c0lox, c0hix), min(c0loy, c0hiy), min(c0loz, c0hiz), 0.0f);
NO_EXTENDED_PRECISION float c0max = min4(max(c0lox, c0hix), max(c0loy, c0hiy), max(c0loz, c0hiz), t);
float c1loz = nz.z * idir.z - ood.z;
float c1hiz = nz.w * idir.z - ood.z;
float c1lox = n1xy.x * idir.x - ood.x;
float c1hix = n1xy.y * idir.x - ood.x;
float c1loy = n1xy.z * idir.y - ood.y;
float c1hiy = n1xy.w * idir.y - ood.y;
NO_EXTENDED_PRECISION float c1min = max4(min(c1lox, c1hix), min(c1loy, c1hiy), min(c1loz, c1hiz), 0.0f);
NO_EXTENDED_PRECISION float c1max = min4(max(c1lox, c1hix), max(c1loy, c1hiy), max(c1loz, c1hiz), t);
/* decide which nodes to traverse next */
#ifdef __VISIBILITY_FLAG__
/* this visibility test gives a 5% performance hit, how to solve? */
*traverseChild0 = (c0max >= c0min) && (__float_as_int(cnodes.z) & visibility);
*traverseChild1 = (c1max >= c1min) && (__float_as_int(cnodes.w) & visibility);
#else
*traverseChild0 = (c0max >= c0min);
*traverseChild1 = (c1max >= c1min);
#endif
*nodeAddr0 = __float_as_int(cnodes.x);
*nodeAddr1 = __float_as_int(cnodes.y);
*closestChild1 = (c1min < c0min);
}
/* Sven Woop's algorithm */
__device_inline void bvh_triangle_intersect(KernelGlobals *kg, Intersection *isect,
float3 P, float3 idir, uint visibility, int object, int triAddr)
{
/* compute and check intersection t-value */
float4 v00 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+0);
float4 v11 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+1);
float3 dir = 1.0f/idir;
float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z;
float invDz = 1.0f/(dir.x*v00.x + dir.y*v00.y + dir.z*v00.z);
float t = Oz * invDz;
if(t > 0.0f && t < isect->t) {
/* compute and check barycentric u */
float Ox = v11.w + P.x*v11.x + P.y*v11.y + P.z*v11.z;
float Dx = dir.x*v11.x + dir.y*v11.y + dir.z*v11.z;
float u = Ox + t*Dx;
if(u >= 0.0f) {
/* compute and check barycentric v */
float4 v22 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+2);
float Oy = v22.w + P.x*v22.x + P.y*v22.y + P.z*v22.z;
float Dy = dir.x*v22.x + dir.y*v22.y + dir.z*v22.z;
float v = Oy + t*Dy;
if(v >= 0.0f && u + v <= 1.0f) {
#ifdef __VISIBILITY_FLAG__
/* visibility flag test. we do it here under the assumption
* that most triangles are culled by node flags */
if(kernel_tex_fetch(__prim_visibility, triAddr) & visibility)
#endif
{
/* record intersection */
isect->prim = triAddr;
isect->object = object;
isect->u = u;
isect->v = v;
isect->t = t;
}
}
}
}
}
#ifdef __HAIR__
__device_inline void bvh_curve_intersect(KernelGlobals *kg, Intersection *isect,
float3 P, float3 idir, uint visibility, int object, int curveAddr, int segment)
{
/* curve Intersection check */
int flags = kernel_data.curve_kernel_data.curveflags;
int prim = kernel_tex_fetch(__prim_index, curveAddr);
float4 v00 = kernel_tex_fetch(__curves, prim);
int k0 = __float_as_int(v00.x) + segment;
int k1 = k0 + 1;
float4 P1 = kernel_tex_fetch(__curve_keys, k0);
float4 P2 = kernel_tex_fetch(__curve_keys, k1);
float l = len(P2 - P1); // XXX slower
float r1 = P1.w;
float r2 = P2.w;
float mr = max(r1,r2);
float3 p1 = float4_to_float3(P1);
float3 p2 = float4_to_float3(P2);
float3 dif = P - p1;
float3 dir = 1.0f/idir;
/* test bounding sphere intersection (introduce circular artifacts)*/
/*float3 bvector = 0.5f * (p1 + p2) - P;
float bvectorl_sq = len_squared(bvector);
float dot_bv_dir = dot(bvector,dir);
float maxdist = l * 0.5f + mr;
if(bvectorl_sq - dot_bv_dir * dot_bv_dir > maxdist * maxdist)
return;*/
/* obtain parameters and test midpoint distance for suitable modes*/
float3 tg = (p2 - p1) / l;
float gd = (r2 - r1) / l;
float dirz = dot(dir,tg);
float difz = dot(dif,tg);
float a = 1.0f - (dirz*dirz*(1 + gd*gd));
float halfb = (dot(dir,dif) - dirz*(difz + gd*(difz*gd + r1)));
float tcentre = -halfb/a;
float zcentre = difz + (dirz * tcentre);
if((tcentre > isect->t) && !(flags & CURVE_KN_ACCURATE))
return;
if((zcentre < 0 || zcentre > l) && !(flags & CURVE_KN_ACCURATE) && !(flags & CURVE_KN_INTERSECTCORRECTION))
return;
/* test minimum separation*/
float3 cprod = cross(tg, dir);
float3 cprod2 = cross(tg, dif);
float cprodsq = len_squared(cprod);
float cprod2sq = len_squared(cprod2);
float distscaled = dot(cprod,dif);
if(cprodsq == 0)
distscaled = cprod2sq;
else
distscaled = (distscaled*distscaled)/cprodsq;
if(distscaled > mr*mr)
return;
/* calculate true intersection*/
float3 tdif = P - p1 + tcentre * dir;
float tdifz = dot(tdif,tg);
float tb = 2*(dot(dir,tdif) - dirz*(tdifz + gd*(tdifz*gd + r1)));
float tc = dot(tdif,tdif) - tdifz * tdifz * (1 + gd*gd) - r1*r1 - 2*r1*tdifz*gd;
float td = tb*tb - 4*a*tc;
if (td<0)
return;
float rootd = 0.0f;
float correction = 0.0f;
if(flags & CURVE_KN_ACCURATE) {
rootd = sqrtf(td);
correction = ((-tb - rootd)/(2*a));
}
float t = tcentre + correction;
if(t < isect->t) {
if(flags & CURVE_KN_INTERSECTCORRECTION) {
rootd = sqrtf(td);
correction = ((-tb - rootd)/(2*a));
t = tcentre + correction;
}
float z = zcentre + (dirz * correction);
bool backface = false;
if(flags & CURVE_KN_BACKFACING && (t < 0.0f || z < 0 || z > l)) {
backface = true;
correction = ((-tb + rootd)/(2*a));
t = tcentre + correction;
z = zcentre + (dirz * correction);
}
if(t > 0.0f && t < isect->t && z >= 0 && z <= l) {
if (flags & CURVE_KN_ENCLOSEFILTER) {
float enc_ratio = kernel_data.curve_kernel_data.encasing_ratio;
if((dot(P - p1, tg) > -r1 * enc_ratio) && (dot(P - p2, tg) < r2 * enc_ratio)) {
float a2 = 1.0f - (dirz*dirz*(1 + gd*gd*enc_ratio*enc_ratio));
float c2 = dot(dif,dif) - difz * difz * (1 + gd*gd*enc_ratio*enc_ratio) - r1*r1*enc_ratio*enc_ratio - 2*r1*difz*gd*enc_ratio;
if(a2*c2 < 0.0f)
return;
}
}
/*remove overlap - not functional yet*/
/*if (flags & CURVE_KN_CURVEDATA) {
float3 tg1 = float4_to_float3(kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+0));
float3 tg2 = float4_to_float3(kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+1));
if((dot(P + t * dir - p1, tg1) < 0.0f) || (dot(P + t * dir - p2, tg2) > 0.0f))
return;
}*/
#ifdef __VISIBILITY_FLAG__
/* visibility flag test. we do it here under the assumption
* that most triangles are culled by node flags */
if(kernel_tex_fetch(__prim_visibility, curveAddr) & visibility)
#endif
{
/* record intersection */
isect->prim = curveAddr;
isect->segment = segment;
isect->object = object;
isect->u = z/l;
isect->v = td/(4*a*a);
isect->t = t;
if(backface)
isect->u = -isect->u;
}
}
}
}
#endif
__device_inline bool bvh_intersect(KernelGlobals *kg, const Ray *ray, const uint visibility, Intersection *isect)
{
/* traversal stack in CUDA thread-local memory */
int traversalStack[BVH_STACK_SIZE];
traversalStack[0] = ENTRYPOINT_SENTINEL;
/* traversal variables in registers */
int stackPtr = 0;
int nodeAddr = kernel_data.bvh.root;
/* ray parameters in registers */
const float tmax = ray->t;
float3 P = ray->P;
float3 idir = bvh_inverse_direction(ray->D);
int object = ~0;
isect->t = tmax;
isect->object = ~0;
isect->prim = ~0;
isect->u = 0.0f;
isect->v = 0.0f;
/* traversal loop */
do {
do
{
/* traverse internal nodes */
while(nodeAddr >= 0 && nodeAddr != ENTRYPOINT_SENTINEL)
{
bool traverseChild0, traverseChild1, closestChild1;
int nodeAddrChild1;
bvh_node_intersect(kg, &traverseChild0, &traverseChild1,
&closestChild1, &nodeAddr, &nodeAddrChild1,
P, idir, isect->t, visibility, nodeAddr);
if(traverseChild0 != traverseChild1) {
/* one child was intersected */
if(traverseChild1) {
nodeAddr = nodeAddrChild1;
}
}
else {
if(!traverseChild0) {
/* neither child was intersected */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
else {
/* both children were intersected, push the farther one */
if(closestChild1) {
int tmp = nodeAddr;
nodeAddr = nodeAddrChild1;
nodeAddrChild1 = tmp;
}
++stackPtr;
traversalStack[stackPtr] = nodeAddrChild1;
}
}
}
/* if node is leaf, fetch triangle list */
if(nodeAddr < 0) {
float4 leaf = kernel_tex_fetch(__bvh_nodes, (-nodeAddr-1)*BVH_NODE_SIZE+(BVH_NODE_SIZE-1));
int primAddr = __float_as_int(leaf.x);
#ifdef __INSTANCING__
if(primAddr >= 0) {
#endif
int primAddr2 = __float_as_int(leaf.y);
/* pop */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
/* primitive intersection */
while(primAddr < primAddr2) {
/* intersect ray against primitive */
#ifdef __HAIR__
uint segment = kernel_tex_fetch(__prim_segment, primAddr);
if(segment != ~0)
bvh_curve_intersect(kg, isect, P, idir, visibility, object, primAddr, segment);
else
#endif
bvh_triangle_intersect(kg, isect, P, idir, visibility, object, primAddr);
/* shadow ray early termination */
if(visibility == PATH_RAY_SHADOW_OPAQUE && isect->prim != ~0)
return true;
primAddr++;
}
#ifdef __INSTANCING__
}
else {
/* instance push */
object = kernel_tex_fetch(__prim_object, -primAddr-1);
bvh_instance_push(kg, object, ray, &P, &idir, &isect->t, tmax);
++stackPtr;
traversalStack[stackPtr] = ENTRYPOINT_SENTINEL;
nodeAddr = kernel_tex_fetch(__object_node, object);
}
#endif
}
} while(nodeAddr != ENTRYPOINT_SENTINEL);
#ifdef __INSTANCING__
if(stackPtr >= 0) {
kernel_assert(object != ~0);
/* instance pop */
bvh_instance_pop(kg, object, ray, &P, &idir, &isect->t, tmax);
object = ~0;
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
#endif
} while(nodeAddr != ENTRYPOINT_SENTINEL);
return (isect->prim != ~0);
}
#ifdef __OBJECT_MOTION__
__device_inline bool bvh_intersect_motion(KernelGlobals *kg, const Ray *ray, const uint visibility, Intersection *isect)
{
/* traversal stack in CUDA thread-local memory */
int traversalStack[BVH_STACK_SIZE];
traversalStack[0] = ENTRYPOINT_SENTINEL;
/* traversal variables in registers */
int stackPtr = 0;
int nodeAddr = kernel_data.bvh.root;
/* ray parameters in registers */
const float tmax = ray->t;
float3 P = ray->P;
float3 idir = bvh_inverse_direction(ray->D);
int object = ~0;
Transform ob_tfm;
isect->t = tmax;
isect->object = ~0;
isect->prim = ~0;
isect->u = 0.0f;
isect->v = 0.0f;
/* traversal loop */
do {
do
{
/* traverse internal nodes */
while(nodeAddr >= 0 && nodeAddr != ENTRYPOINT_SENTINEL)
{
bool traverseChild0, traverseChild1, closestChild1;
int nodeAddrChild1;
bvh_node_intersect(kg, &traverseChild0, &traverseChild1,
&closestChild1, &nodeAddr, &nodeAddrChild1,
P, idir, isect->t, visibility, nodeAddr);
if(traverseChild0 != traverseChild1) {
/* one child was intersected */
if(traverseChild1) {
nodeAddr = nodeAddrChild1;
}
}
else {
if(!traverseChild0) {
/* neither child was intersected */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
else {
/* both children were intersected, push the farther one */
if(closestChild1) {
int tmp = nodeAddr;
nodeAddr = nodeAddrChild1;
nodeAddrChild1 = tmp;
}
++stackPtr;
traversalStack[stackPtr] = nodeAddrChild1;
}
}
}
/* if node is leaf, fetch triangle list */
if(nodeAddr < 0) {
float4 leaf = kernel_tex_fetch(__bvh_nodes, (-nodeAddr-1)*BVH_NODE_SIZE+(BVH_NODE_SIZE-1));
int primAddr = __float_as_int(leaf.x);
if(primAddr >= 0) {
int primAddr2 = __float_as_int(leaf.y);
/* pop */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
/* primitive intersection */
while(primAddr < primAddr2) {
/* intersect ray against primitive */
#ifdef __HAIR__
uint segment = kernel_tex_fetch(__prim_segment, primAddr);
if(segment != ~0)
bvh_curve_intersect(kg, isect, P, idir, visibility, object, primAddr, segment);
else
#endif
bvh_triangle_intersect(kg, isect, P, idir, visibility, object, primAddr);
/* shadow ray early termination */
if(visibility == PATH_RAY_SHADOW_OPAQUE && isect->prim != ~0)
return true;
primAddr++;
}
}
else {
/* instance push */
object = kernel_tex_fetch(__prim_object, -primAddr-1);
bvh_instance_motion_push(kg, object, ray, &P, &idir, &isect->t, &ob_tfm, tmax);
++stackPtr;
traversalStack[stackPtr] = ENTRYPOINT_SENTINEL;
nodeAddr = kernel_tex_fetch(__object_node, object);
}
}
} while(nodeAddr != ENTRYPOINT_SENTINEL);
if(stackPtr >= 0) {
kernel_assert(object != ~0);
/* instance pop */
bvh_instance_motion_pop(kg, object, ray, &P, &idir, &isect->t, &ob_tfm, tmax);
object = ~0;
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
} while(nodeAddr != ENTRYPOINT_SENTINEL);
return (isect->prim != ~0);
}
#endif
__device_inline bool scene_intersect(KernelGlobals *kg, const Ray *ray, const uint visibility, Intersection *isect)
{
#ifdef __OBJECT_MOTION__
if(kernel_data.bvh.have_motion)
return bvh_intersect_motion(kg, ray, visibility, isect);
else
return bvh_intersect(kg, ray, visibility, isect);
#else
return bvh_intersect(kg, ray, visibility, isect);
#endif
}
__device_inline float3 ray_offset(float3 P, float3 Ng)
{
#ifdef __INTERSECTION_REFINE__
const float epsilon_f = 1e-5f;
/* ideally this should match epsilon_f, but instancing/mblur
* precision makes it problematic */
const float epsilon_test = 1e-1f;
const int epsilon_i = 32;
float3 res;
/* x component */
if(fabsf(P.x) < epsilon_test) {
res.x = P.x + Ng.x*epsilon_f;
}
else {
uint ix = __float_as_uint(P.x);
ix += ((ix ^ __float_as_uint(Ng.x)) >> 31)? -epsilon_i: epsilon_i;
res.x = __uint_as_float(ix);
}
/* y component */
if(fabsf(P.y) < epsilon_test) {
res.y = P.y + Ng.y*epsilon_f;
}
else {
uint iy = __float_as_uint(P.y);
iy += ((iy ^ __float_as_uint(Ng.y)) >> 31)? -epsilon_i: epsilon_i;
res.y = __uint_as_float(iy);
}
/* z component */
if(fabsf(P.z) < epsilon_test) {
res.z = P.z + Ng.z*epsilon_f;
}
else {
uint iz = __float_as_uint(P.z);
iz += ((iz ^ __float_as_uint(Ng.z)) >> 31)? -epsilon_i: epsilon_i;
res.z = __uint_as_float(iz);
}
return res;
#else
const float epsilon_f = 1e-4f;
return P + epsilon_f*Ng;
#endif
}
__device_inline float3 bvh_triangle_refine(KernelGlobals *kg, ShaderData *sd, const Intersection *isect, const Ray *ray)
{
float3 P = ray->P;
float3 D = ray->D;
float t = isect->t;
#ifdef __INTERSECTION_REFINE__
if(isect->object != ~0) {
#ifdef __OBJECT_MOTION__
Transform tfm = sd->ob_itfm;
#else
Transform tfm = object_fetch_transform(kg, isect->object, OBJECT_INVERSE_TRANSFORM);
#endif
P = transform_point(&tfm, P);
D = transform_direction(&tfm, D*t);
D = normalize_len(D, &t);
}
P = P + D*t;
float4 v00 = kernel_tex_fetch(__tri_woop, isect->prim*TRI_NODE_SIZE+0);
float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z;
float invDz = 1.0f/(D.x*v00.x + D.y*v00.y + D.z*v00.z);
float rt = Oz * invDz;
P = P + D*rt;
if(isect->object != ~0) {
#ifdef __OBJECT_MOTION__
Transform tfm = sd->ob_tfm;
#else
Transform tfm = object_fetch_transform(kg, isect->object, OBJECT_TRANSFORM);
#endif
P = transform_point(&tfm, P);
}
return P;
#else
return P + D*t;
#endif
}
#ifdef __HAIR__
__device_inline float3 bvh_curve_refine(KernelGlobals *kg, ShaderData *sd, const Intersection *isect, const Ray *ray, float t)
{
int flag = kernel_data.curve_kernel_data.curveflags;
float3 P = ray->P;
float3 D = ray->D;
if(isect->object != ~0) {
#ifdef __OBJECT_MOTION__
Transform tfm = sd->ob_itfm;
#else
Transform tfm = object_fetch_transform(kg, isect->object, OBJECT_INVERSE_TRANSFORM);
#endif
P = transform_point(&tfm, P);
D = transform_direction(&tfm, D*t);
D = normalize_len(D, &t);
}
int prim = kernel_tex_fetch(__prim_index, isect->prim);
float4 v00 = kernel_tex_fetch(__curves, prim);
int k0 = __float_as_int(v00.x) + isect->segment;
int k1 = k0 + 1;
float4 P1 = kernel_tex_fetch(__curve_keys, k0);
float4 P2 = kernel_tex_fetch(__curve_keys, k1);
float l = len(P2 - P1); // XXX slower
float r1 = P1.w;
float r2 = P2.w;
float3 tg = float4_to_float3(P2 - P1) / l;
float3 dif = P - float4_to_float3(P1) + t * D;
float gd = ((r2 - r1)/l);
P = P + D*t;
dif = P - float4_to_float3(P1);
#ifdef __UV__
sd->u = dot(dif,tg)/l;
sd->v = 0.0f;
#endif
if (flag & CURVE_KN_TRUETANGENTGNORMAL) {
sd->Ng = -(D - tg * (dot(tg,D) * kernel_data.curve_kernel_data.normalmix));
sd->Ng = normalize(sd->Ng);
if (flag & CURVE_KN_NORMALCORRECTION)
{
//sd->Ng = normalize(sd->Ng);
sd->Ng = sd->Ng - gd * tg;
sd->Ng = normalize(sd->Ng);
}
}
else {
sd->Ng = (dif - tg * sd->u * l) / (P1.w + sd->u * l * gd);
if (gd != 0.0f) {
sd->Ng = sd->Ng - gd * tg ;
sd->Ng = normalize(sd->Ng);
}
}
sd->N = sd->Ng;
if (flag & CURVE_KN_TANGENTGNORMAL && !(flag & CURVE_KN_TRUETANGENTGNORMAL)) {
sd->N = -(D - tg * (dot(tg,D) * kernel_data.curve_kernel_data.normalmix));
sd->N = normalize(sd->N);
if (flag & CURVE_KN_NORMALCORRECTION) {
//sd->N = normalize(sd->N);
sd->N = sd->N - gd * tg;
sd->N = normalize(sd->N);
}
}
if (!(flag & CURVE_KN_TANGENTGNORMAL) && flag & CURVE_KN_TRUETANGENTGNORMAL) {
sd->N = (dif - tg * sd->u * l) / (P1.w + sd->u * l * gd);
if (gd != 0.0f) {
sd->N = sd->N - gd * tg ;
sd->N = normalize(sd->N);
}
}
#ifdef __DPDU__
/* dPdu/dPdv */
sd->dPdu = tg;
sd->dPdv = cross(tg,sd->Ng);
#endif
if(isect->object != ~0) {
#ifdef __OBJECT_MOTION__
Transform tfm = sd->ob_tfm;
#else
Transform tfm = object_fetch_transform(kg, isect->object, OBJECT_TRANSFORM);
#endif
P = transform_point(&tfm, P);
}
return P;
}
#endif
CCL_NAMESPACE_END
|