d3f416b34ae3b622f487db6aaf5eccd7872b1acb
[blender.git] / source / blender / blenkernel / intern / particle_system.c
1 /*
2  * ***** BEGIN GPL LICENSE BLOCK *****
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; either version 2
7  * of the License, or (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software Foundation,
16  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
17  *
18  * The Original Code is Copyright (C) 2007 by Janne Karhu.
19  * All rights reserved.
20  *
21  * The Original Code is: all of this file.
22  *
23  * Contributor(s): Raul Fernandez Hernandez (Farsthary), Stephen Swhitehorn.
24  *
25  * Adaptive time step
26  * Copyright 2011 AutoCRC
27  *
28  * ***** END GPL LICENSE BLOCK *****
29  */
30
31 /** \file blender/blenkernel/intern/particle_system.c
32  *  \ingroup bke
33  */
34
35
36 #include <stddef.h>
37
38 #include <stdlib.h>
39 #include <math.h>
40 #include <string.h>
41
42 #ifdef _OPENMP
43 #include <omp.h>
44 #endif
45
46 #include "MEM_guardedalloc.h"
47
48 #include "DNA_anim_types.h"
49 #include "DNA_boid_types.h"
50 #include "DNA_particle_types.h"
51 #include "DNA_mesh_types.h"
52 #include "DNA_meshdata_types.h"
53 #include "DNA_modifier_types.h"
54 #include "DNA_object_force.h"
55 #include "DNA_object_types.h"
56 #include "DNA_material_types.h"
57 #include "DNA_curve_types.h"
58 #include "DNA_group_types.h"
59 #include "DNA_scene_types.h"
60 #include "DNA_texture_types.h"
61 #include "DNA_ipo_types.h" // XXX old animation system stuff... to be removed!
62 #include "DNA_listBase.h"
63
64 #include "BLI_edgehash.h"
65 #include "BLI_rand.h"
66 #include "BLI_jitter.h"
67 #include "BLI_math.h"
68 #include "BLI_blenlib.h"
69 #include "BLI_kdtree.h"
70 #include "BLI_kdopbvh.h"
71 #include "BLI_threads.h"
72 #include "BLI_utildefines.h"
73 #include "BLI_linklist.h"
74
75 #include "BKE_main.h"
76 #include "BKE_animsys.h"
77 #include "BKE_boids.h"
78 #include "BKE_cdderivedmesh.h"
79 #include "BKE_collision.h"
80 #include "BKE_displist.h"
81 #include "BKE_effect.h"
82 #include "BKE_particle.h"
83 #include "BKE_global.h"
84
85 #include "BKE_DerivedMesh.h"
86 #include "BKE_object.h"
87 #include "BKE_material.h"
88 #include "BKE_cloth.h"
89 #include "BKE_depsgraph.h"
90 #include "BKE_lattice.h"
91 #include "BKE_pointcache.h"
92 #include "BKE_mesh.h"
93 #include "BKE_modifier.h"
94 #include "BKE_scene.h"
95 #include "BKE_bvhutils.h"
96
97 #include "PIL_time.h"
98
99 #include "RE_shader_ext.h"
100
101 /* fluid sim particle import */
102 #ifdef WITH_MOD_FLUID
103 #include "DNA_object_fluidsim.h"
104 #include "LBM_fluidsim.h"
105 #include <zlib.h>
106 #include <string.h>
107
108 #endif // WITH_MOD_FLUID
109
110 /************************************************/
111 /*                      Reacting to system events                       */
112 /************************************************/
113
114 static int particles_are_dynamic(ParticleSystem *psys)
115 {
116         if (psys->pointcache->flag & PTCACHE_BAKED)
117                 return 0;
118
119         if (psys->part->type == PART_HAIR)
120                 return psys->flag & PSYS_HAIR_DYNAMICS;
121         else
122                 return ELEM3(psys->part->phystype, PART_PHYS_NEWTON, PART_PHYS_BOIDS, PART_PHYS_FLUID);
123 }
124
125 static int psys_get_current_display_percentage(ParticleSystem *psys)
126 {
127         ParticleSettings *part=psys->part;
128
129         if ((psys->renderdata && !particles_are_dynamic(psys)) ||  /* non-dynamic particles can be rendered fully */
130             (part->child_nbr && part->childtype)  ||    /* display percentage applies to children */
131             (psys->pointcache->flag & PTCACHE_BAKING))  /* baking is always done with full amount */
132         {
133                 return 100;
134         }
135
136         return psys->part->disp;
137 }
138
139 static int tot_particles(ParticleSystem *psys, PTCacheID *pid)
140 {
141         if (pid && psys->pointcache->flag & PTCACHE_EXTERNAL)
142                 return pid->cache->totpoint;
143         else if (psys->part->distr == PART_DISTR_GRID && psys->part->from != PART_FROM_VERT)
144                 return psys->part->grid_res * psys->part->grid_res * psys->part->grid_res - psys->totunexist;
145         else
146                 return psys->part->totpart - psys->totunexist;
147 }
148
149 void psys_reset(ParticleSystem *psys, int mode)
150 {
151         PARTICLE_P;
152
153         if (ELEM(mode, PSYS_RESET_ALL, PSYS_RESET_DEPSGRAPH)) {
154                 if (mode == PSYS_RESET_ALL || !(psys->flag & PSYS_EDITED)) {
155                         /* don't free if not absolutely necessary */
156                         if (psys->totpart != tot_particles(psys, NULL)) {
157                                 psys_free_particles(psys);
158                                 psys->totpart= 0;
159                         }
160
161                         psys->totkeyed= 0;
162                         psys->flag &= ~(PSYS_HAIR_DONE|PSYS_KEYED);
163
164                         if (psys->edit && psys->free_edit) {
165                                 psys->free_edit(psys->edit);
166                                 psys->edit = NULL;
167                                 psys->free_edit = NULL;
168                         }
169                 }
170         }
171         else if (mode == PSYS_RESET_CACHE_MISS) {
172                 /* set all particles to be skipped */
173                 LOOP_PARTICLES
174                         pa->flag |= PARS_NO_DISP;
175         }
176
177         /* reset children */
178         if (psys->child) {
179                 MEM_freeN(psys->child);
180                 psys->child= NULL;
181         }
182
183         psys->totchild= 0;
184
185         /* reset path cache */
186         psys_free_path_cache(psys, psys->edit);
187
188         /* reset point cache */
189         BKE_ptcache_invalidate(psys->pointcache);
190
191         if (psys->fluid_springs) {
192                 MEM_freeN(psys->fluid_springs);
193                 psys->fluid_springs = NULL;
194         }
195
196         psys->tot_fluidsprings = psys->alloc_fluidsprings = 0;
197 }
198
199 static void realloc_particles(ParticleSimulationData *sim, int new_totpart)
200 {
201         ParticleSystem *psys = sim->psys;
202         ParticleSettings *part = psys->part;
203         ParticleData *newpars = NULL;
204         BoidParticle *newboids = NULL;
205         PARTICLE_P;
206         int totpart, totsaved = 0;
207
208         if (new_totpart<0) {
209                 if ((part->distr == PART_DISTR_GRID) && (part->from != PART_FROM_VERT)) {
210                         totpart= part->grid_res;
211                         totpart*=totpart*totpart;
212                 }
213                 else
214                         totpart=part->totpart;
215         }
216         else
217                 totpart=new_totpart;
218
219         if (totpart != psys->totpart) {
220                 if (psys->edit && psys->free_edit) {
221                         psys->free_edit(psys->edit);
222                         psys->edit = NULL;
223                         psys->free_edit = NULL;
224                 }
225
226                 if (totpart) {
227                         newpars= MEM_callocN(totpart*sizeof(ParticleData), "particles");
228                         if (newpars == NULL)
229                                 return;
230
231                         if (psys->part->phystype == PART_PHYS_BOIDS) {
232                                 newboids= MEM_callocN(totpart*sizeof(BoidParticle), "boid particles");
233
234                                 if (newboids == NULL) {
235                                          /* allocation error! */
236                                         if (newpars)
237                                                 MEM_freeN(newpars);
238                                         return;
239                                 }
240                         }
241                 }
242         
243                 if (psys->particles) {
244                         totsaved=MIN2(psys->totpart,totpart);
245                         /*save old pars*/
246                         if (totsaved) {
247                                 memcpy(newpars,psys->particles,totsaved*sizeof(ParticleData));
248
249                                 if (psys->particles->boid)
250                                         memcpy(newboids, psys->particles->boid, totsaved*sizeof(BoidParticle));
251                         }
252
253                         if (psys->particles->keys)
254                                 MEM_freeN(psys->particles->keys);
255
256                         if (psys->particles->boid)
257                                 MEM_freeN(psys->particles->boid);
258
259                         for (p=0, pa=newpars; p<totsaved; p++, pa++) {
260                                 if (pa->keys) {
261                                         pa->keys= NULL;
262                                         pa->totkey= 0;
263                                 }
264                         }
265
266                         for (p=totsaved, pa=psys->particles+totsaved; p<psys->totpart; p++, pa++)
267                                 if (pa->hair) MEM_freeN(pa->hair);
268
269                         MEM_freeN(psys->particles);
270                         psys_free_pdd(psys);
271                 }
272                 
273                 psys->particles=newpars;
274                 psys->totpart=totpart;
275
276                 if (newboids) {
277                         LOOP_PARTICLES
278                                 pa->boid = newboids++;
279                 }
280         }
281
282         if (psys->child) {
283                 MEM_freeN(psys->child);
284                 psys->child=NULL;
285                 psys->totchild=0;
286         }
287 }
288
289 static int get_psys_child_number(struct Scene *scene, ParticleSystem *psys)
290 {
291         int nbr;
292
293         if (!psys->part->childtype)
294                 return 0;
295
296         if (psys->renderdata)
297                 nbr= psys->part->ren_child_nbr;
298         else
299                 nbr= psys->part->child_nbr;
300
301         return get_render_child_particle_number(&scene->r, nbr);
302 }
303
304 static int get_psys_tot_child(struct Scene *scene, ParticleSystem *psys)
305 {
306         return psys->totpart*get_psys_child_number(scene, psys);
307 }
308
309 static void alloc_child_particles(ParticleSystem *psys, int tot)
310 {
311         if (psys->child) {
312                 /* only re-allocate if we have to */
313                 if (psys->part->childtype && psys->totchild == tot) {
314                         memset(psys->child, 0, tot*sizeof(ChildParticle));
315                         return;
316                 }
317
318                 MEM_freeN(psys->child);
319                 psys->child=NULL;
320                 psys->totchild=0;
321         }
322
323         if (psys->part->childtype) {
324                 psys->totchild= tot;
325                 if (psys->totchild)
326                         psys->child= MEM_callocN(psys->totchild*sizeof(ChildParticle), "child_particles");
327         }
328 }
329
330 /************************************************/
331 /*                      Distribution                                            */
332 /************************************************/
333
334 void psys_calc_dmcache(Object *ob, DerivedMesh *dm, ParticleSystem *psys)
335 {
336         /* use for building derived mesh mapping info:
337          *
338          * node: the allocated links - total derived mesh element count 
339          * nodearray: the array of nodes aligned with the base mesh's elements, so
340          *            each original elements can reference its derived elements
341          */
342         Mesh *me= (Mesh*)ob->data;
343         PARTICLE_P;
344         
345         /* CACHE LOCATIONS */
346         if (!dm->deformedOnly) {
347                 /* Will use later to speed up subsurf/derivedmesh */
348                 LinkNode *node, *nodedmelem, **nodearray;
349                 int totdmelem, totelem, i, *origindex;
350
351                 if (psys->part->from == PART_FROM_VERT) {
352                         totdmelem= dm->getNumVerts(dm);
353                         totelem= me->totvert;
354                         origindex= dm->getVertDataArray(dm, CD_ORIGINDEX);
355                 }
356                 else { /* FROM_FACE/FROM_VOLUME */
357                         totdmelem= dm->getNumTessFaces(dm);
358                         totelem= me->totpoly;
359                         origindex= dm->getTessFaceDataArray(dm, CD_ORIGINDEX);
360                 }
361         
362                 nodedmelem= MEM_callocN(sizeof(LinkNode)*totdmelem, "psys node elems");
363                 nodearray= MEM_callocN(sizeof(LinkNode *)*totelem, "psys node array");
364                 
365                 for (i=0, node=nodedmelem; i<totdmelem; i++, origindex++, node++) {
366                         node->link= SET_INT_IN_POINTER(i);
367
368                         if (*origindex != -1) {
369                                 if (nodearray[*origindex]) {
370                                         /* prepend */
371                                         node->next = nodearray[*origindex];
372                                         nodearray[*origindex] = node;
373                                 }
374                                 else
375                                         nodearray[*origindex] = node;
376                         }
377                 }
378                 
379                 /* cache the verts/faces! */
380                 LOOP_PARTICLES {
381                         if (pa->num < 0) {
382                                 pa->num_dmcache = -1;
383                                 continue;
384                         }
385
386                         if (psys->part->from == PART_FROM_VERT) {
387                                 if (nodearray[pa->num])
388                                         pa->num_dmcache= GET_INT_FROM_POINTER(nodearray[pa->num]->link);
389                         }
390                         else { /* FROM_FACE/FROM_VOLUME */
391                                 /* Note that sometimes the pa->num is over the nodearray size, this is bad, maybe there is a better place to fix this,
392                                  * but for now passing NULL is OK. every face will be searched for the particle so its slower - Campbell */
393                                 pa->num_dmcache= psys_particle_dm_face_lookup(ob, dm, pa->num, pa->fuv, pa->num < totelem ? nodearray[pa->num] : NULL);
394                         }
395                 }
396
397                 MEM_freeN(nodearray);
398                 MEM_freeN(nodedmelem);
399         }
400         else {
401                 /* TODO PARTICLE, make the following line unnecessary, each function
402                  * should know to use the num or num_dmcache, set the num_dmcache to
403                  * an invalid value, just in case */
404                 
405                 LOOP_PARTICLES
406                         pa->num_dmcache = -1;
407         }
408 }
409
410 static void distribute_simple_children(Scene *scene, Object *ob, DerivedMesh *finaldm, ParticleSystem *psys)
411 {
412         ChildParticle *cpa = NULL;
413         int i, p;
414         int child_nbr= get_psys_child_number(scene, psys);
415         int totpart= get_psys_tot_child(scene, psys);
416
417         alloc_child_particles(psys, totpart);
418
419         cpa = psys->child;
420         for (i=0; i<child_nbr; i++) {
421                 for (p=0; p<psys->totpart; p++,cpa++) {
422                         float length=2.0;
423                         cpa->parent=p;
424                                         
425                         /* create even spherical distribution inside unit sphere */
426                         while (length>=1.0f) {
427                                 cpa->fuv[0]=2.0f*BLI_frand()-1.0f;
428                                 cpa->fuv[1]=2.0f*BLI_frand()-1.0f;
429                                 cpa->fuv[2]=2.0f*BLI_frand()-1.0f;
430                                 length=len_v3(cpa->fuv);
431                         }
432
433                         cpa->num=-1;
434                 }
435         }
436         /* dmcache must be updated for parent particles if children from faces is used */
437         psys_calc_dmcache(ob, finaldm, psys);
438 }
439 static void distribute_grid(DerivedMesh *dm, ParticleSystem *psys)
440 {
441         ParticleData *pa=NULL;
442         float min[3], max[3], delta[3], d;
443         MVert *mv, *mvert = dm->getVertDataArray(dm,0);
444         int totvert=dm->getNumVerts(dm), from=psys->part->from;
445         int i, j, k, p, res=psys->part->grid_res, size[3], axis;
446
447         mv=mvert;
448
449         /* find bounding box of dm */
450         copy_v3_v3(min, mv->co);
451         copy_v3_v3(max, mv->co);
452         mv++;
453
454         for (i=1; i<totvert; i++, mv++) {
455                 min[0]=MIN2(min[0],mv->co[0]);
456                 min[1]=MIN2(min[1],mv->co[1]);
457                 min[2]=MIN2(min[2],mv->co[2]);
458
459                 max[0]=MAX2(max[0],mv->co[0]);
460                 max[1]=MAX2(max[1],mv->co[1]);
461                 max[2]=MAX2(max[2],mv->co[2]);
462         }
463
464         sub_v3_v3v3(delta, max, min);
465
466         /* determine major axis */
467         axis = (delta[0]>=delta[1]) ? 0 : ((delta[1]>=delta[2]) ? 1 : 2);
468          
469         d = delta[axis]/(float)res;
470
471         size[axis] = res;
472         size[(axis+1)%3] = (int)ceil(delta[(axis+1)%3]/d);
473         size[(axis+2)%3] = (int)ceil(delta[(axis+2)%3]/d);
474
475         /* float errors grrr.. */
476         size[(axis+1)%3] = MIN2(size[(axis+1)%3],res);
477         size[(axis+2)%3] = MIN2(size[(axis+2)%3],res);
478
479         size[0] = MAX2(size[0], 1);
480         size[1] = MAX2(size[1], 1);
481         size[2] = MAX2(size[2], 1);
482
483         /* no full offset for flat/thin objects */
484         min[0]+= d < delta[0] ? d/2.f : delta[0]/2.f;
485         min[1]+= d < delta[1] ? d/2.f : delta[1]/2.f;
486         min[2]+= d < delta[2] ? d/2.f : delta[2]/2.f;
487
488         for (i=0,p=0,pa=psys->particles; i<res; i++) {
489                 for (j=0; j<res; j++) {
490                         for (k=0; k<res; k++,p++,pa++) {
491                                 pa->fuv[0] = min[0] + (float)i*d;
492                                 pa->fuv[1] = min[1] + (float)j*d;
493                                 pa->fuv[2] = min[2] + (float)k*d;
494                                 pa->flag |= PARS_UNEXIST;
495                                 pa->hair_index = 0; /* abused in volume calculation */
496                         }
497                 }
498         }
499
500         /* enable particles near verts/edges/faces/inside surface */
501         if (from==PART_FROM_VERT) {
502                 float vec[3];
503
504                 pa=psys->particles;
505
506                 min[0] -= d/2.0f;
507                 min[1] -= d/2.0f;
508                 min[2] -= d/2.0f;
509
510                 for (i=0,mv=mvert; i<totvert; i++,mv++) {
511                         sub_v3_v3v3(vec,mv->co,min);
512                         vec[0]/=delta[0];
513                         vec[1]/=delta[1];
514                         vec[2]/=delta[2];
515                         (pa     + ((int)(vec[0] * (size[0] - 1)) * res +
516                                (int)(vec[1] * (size[1] - 1))) * res +
517                                 (int)(vec[2] * (size[2] - 1)))->flag &= ~PARS_UNEXIST;
518                 }
519         }
520         else if (ELEM(from,PART_FROM_FACE,PART_FROM_VOLUME)) {
521                 float co1[3], co2[3];
522
523                 MFace *mface= NULL, *mface_array;
524                 float v1[3], v2[3], v3[3], v4[4], lambda;
525                 int a, a1, a2, a0mul, a1mul, a2mul, totface;
526                 int amax= from==PART_FROM_FACE ? 3 : 1;
527
528                 totface=dm->getNumTessFaces(dm);
529                 mface=mface_array=dm->getTessFaceDataArray(dm,CD_MFACE);
530                 
531                 for (a=0; a<amax; a++) {
532                         if (a==0) { a0mul=res*res; a1mul=res; a2mul=1; }
533                         else if (a==1) { a0mul=res; a1mul=1; a2mul=res*res; }
534                         else { a0mul=1; a1mul=res*res; a2mul=res; }
535
536                         for (a1=0; a1<size[(a+1)%3]; a1++) {
537                                 for (a2=0; a2<size[(a+2)%3]; a2++) {
538                                         mface= mface_array;
539
540                                         pa = psys->particles + a1*a1mul + a2*a2mul;
541                                         copy_v3_v3(co1, pa->fuv);
542                                         co1[a] -= d < delta[a] ? d/2.f : delta[a]/2.f;
543                                         copy_v3_v3(co2, co1);
544                                         co2[a] += delta[a] + 0.001f*d;
545                                         co1[a] -= 0.001f*d;
546                                         
547                                         /* lets intersect the faces */
548                                         for (i=0; i<totface; i++,mface++) {
549                                                 copy_v3_v3(v1, mvert[mface->v1].co);
550                                                 copy_v3_v3(v2, mvert[mface->v2].co);
551                                                 copy_v3_v3(v3, mvert[mface->v3].co);
552
553                                                 if (isect_axial_line_tri_v3(a, co1, co2, v2, v3, v1, &lambda)) {
554                                                         if (from==PART_FROM_FACE)
555                                                                 (pa+(int)(lambda*size[a])*a0mul)->flag &= ~PARS_UNEXIST;
556                                                         else /* store number of intersections */
557                                                                 (pa+(int)(lambda*size[a])*a0mul)->hair_index++;
558                                                 }
559                                                 
560                                                 if (mface->v4) {
561                                                         copy_v3_v3(v4, mvert[mface->v4].co);
562
563                                                         if (isect_axial_line_tri_v3(a, co1, co2, v4, v1, v3, &lambda)) {
564                                                                 if (from==PART_FROM_FACE)
565                                                                         (pa+(int)(lambda*size[a])*a0mul)->flag &= ~PARS_UNEXIST;
566                                                                 else
567                                                                         (pa+(int)(lambda*size[a])*a0mul)->hair_index++;
568                                                         }
569                                                 }
570                                         }
571
572                                         if (from==PART_FROM_VOLUME) {
573                                                 int in=pa->hair_index%2;
574                                                 if (in) pa->hair_index++;
575                                                 for (i=0; i<size[0]; i++) {
576                                                         if (in || (pa+i*a0mul)->hair_index%2)
577                                                                 (pa+i*a0mul)->flag &= ~PARS_UNEXIST;
578                                                         /* odd intersections == in->out / out->in */
579                                                         /* even intersections -> in stays same */
580                                                         in=(in + (pa+i*a0mul)->hair_index) % 2;
581                                                 }
582                                         }
583                                 }
584                         }
585                 }
586         }
587
588         if (psys->part->flag & PART_GRID_HEXAGONAL) {
589                 for (i=0,p=0,pa=psys->particles; i<res; i++) {
590                         for (j=0; j<res; j++) {
591                                 for (k=0; k<res; k++,p++,pa++) {
592                                         if (j%2)
593                                                 pa->fuv[0] += d/2.f;
594
595                                         if (k%2) {
596                                                 pa->fuv[0] += d/2.f;
597                                                 pa->fuv[1] += d/2.f;
598                                         }
599                                 }
600                         }
601                 }
602         }
603
604         if (psys->part->flag & PART_GRID_INVERT) {
605                 for (i=0; i<size[0]; i++) {
606                         for (j=0; j<size[1]; j++) {
607                                 pa=psys->particles + res*(i*res + j);
608                                 for (k=0; k<size[2]; k++, pa++) {
609                                         pa->flag ^= PARS_UNEXIST;
610                                 }
611                         }
612                 }
613         }
614
615         if (psys->part->grid_rand > 0.f) {
616                 float rfac = d * psys->part->grid_rand;
617                 for (p=0,pa=psys->particles; p<psys->totpart; p++,pa++) {
618                         if (pa->flag & PARS_UNEXIST)
619                                 continue;
620
621                         pa->fuv[0] += rfac * (PSYS_FRAND(p + 31) - 0.5f);
622                         pa->fuv[1] += rfac * (PSYS_FRAND(p + 32) - 0.5f);
623                         pa->fuv[2] += rfac * (PSYS_FRAND(p + 33) - 0.5f);
624                 }
625         }
626 }
627
628 /* modified copy from rayshade.c */
629 static void hammersley_create(float *out, int n, int seed, float amount)
630 {
631         RNG *rng;
632         double p, t, offs[2];
633         int k, kk;
634
635         rng = rng_new(31415926 + n + seed);
636         offs[0] = rng_getDouble(rng) + (double)amount;
637         offs[1] = rng_getDouble(rng) + (double)amount;
638         rng_free(rng);
639
640         for (k = 0; k < n; k++) {
641                 t = 0;
642                 for (p = 0.5, kk = k; kk; p *= 0.5, kk >>= 1)
643                         if (kk & 1) /* kk mod 2 = 1 */
644                                 t += p;
645
646                 out[2*k + 0] = fmod((double)k/(double)n + offs[0], 1.0);
647                 out[2*k + 1] = fmod(t + offs[1], 1.0);
648         }
649 }
650
651 /* modified copy from effect.c */
652 static void init_mv_jit(float *jit, int num, int seed2, float amount)
653 {
654         RNG *rng;
655         float *jit2, x, rad1, rad2, rad3;
656         int i, num2;
657
658         if (num==0) return;
659
660         rad1= (float)(1.0f/sqrtf((float)num));
661         rad2= (float)(1.0f/((float)num));
662         rad3= (float)sqrt((float)num)/((float)num);
663
664         rng = rng_new(31415926 + num + seed2);
665         x= 0;
666                 num2 = 2 * num;
667         for (i=0; i<num2; i+=2) {
668         
669                 jit[i] = x + amount*rad1*(0.5f - rng_getFloat(rng));
670                 jit[i+1] = i/(2.0f*num) + amount*rad1*(0.5f - rng_getFloat(rng));
671                 
672                 jit[i]-= (float)floor(jit[i]);
673                 jit[i+1]-= (float)floor(jit[i+1]);
674                 
675                 x+= rad3;
676                 x -= (float)floor(x);
677         }
678
679         jit2= MEM_mallocN(12 + 2*sizeof(float)*num, "initjit");
680
681         for (i=0 ; i<4 ; i++) {
682                 BLI_jitterate1(jit, jit2, num, rad1);
683                 BLI_jitterate1(jit, jit2, num, rad1);
684                 BLI_jitterate2(jit, jit2, num, rad2);
685         }
686         MEM_freeN(jit2);
687         rng_free(rng);
688 }
689
690 static void psys_uv_to_w(float u, float v, int quad, float *w)
691 {
692         float vert[4][3], co[3];
693
694         if (!quad) {
695                 if (u+v > 1.0f)
696                         v= 1.0f-v;
697                 else
698                         u= 1.0f-u;
699         }
700
701         vert[0][0] = 0.0f; vert[0][1] = 0.0f; vert[0][2] = 0.0f;
702         vert[1][0] = 1.0f; vert[1][1] = 0.0f; vert[1][2] = 0.0f;
703         vert[2][0] = 1.0f; vert[2][1] = 1.0f; vert[2][2] = 0.0f;
704
705         co[0] = u;
706         co[1] = v;
707         co[2] = 0.0f;
708
709         if (quad) {
710                 vert[3][0] = 0.0f; vert[3][1] = 1.0f; vert[3][2] = 0.0f;
711                 interp_weights_poly_v3( w,vert, 4, co);
712         }
713         else {
714                 interp_weights_poly_v3( w,vert, 3, co);
715                 w[3] = 0.0f;
716         }
717 }
718
719 /* Find the index in "sum" array before "value" is crossed. */
720 static int distribute_binary_search(float *sum, int n, float value)
721 {
722         int mid, low=0, high=n;
723
724         if (value == 0.f)
725                 return 0;
726
727         while (low <= high) {
728                 mid= (low + high)/2;
729                 
730                 if (sum[mid] < value && value <= sum[mid+1])
731                         return mid;
732                 
733                 if (sum[mid] >= value)
734                         high= mid - 1;
735                 else if (sum[mid] < value)
736                         low= mid + 1;
737                 else
738                         return mid;
739         }
740
741         return low;
742 }
743
744 /* the max number if calls to rng_* funcs within psys_thread_distribute_particle
745  * be sure to keep up to date if this changes */
746 #define PSYS_RND_DIST_SKIP 2
747
748 /* note: this function must be thread safe, for from == PART_FROM_CHILD */
749 #define ONLY_WORKING_WITH_PA_VERTS 0
750 static void distribute_threads_exec(ParticleThread *thread, ParticleData *pa, ChildParticle *cpa, int p)
751 {
752         ParticleThreadContext *ctx= thread->ctx;
753         Object *ob= ctx->sim.ob;
754         DerivedMesh *dm= ctx->dm;
755         float *v1, *v2, *v3, *v4, nor[3], orco1[3], co1[3], co2[3], nor1[3];
756         float cur_d, min_d, randu, randv;
757         int from= ctx->from;
758         int cfrom= ctx->cfrom;
759         int distr= ctx->distr;
760         int i, intersect, tot;
761         int rng_skip_tot= PSYS_RND_DIST_SKIP; /* count how many rng_* calls wont need skipping */
762
763         if (from == PART_FROM_VERT) {
764                 /* TODO_PARTICLE - use original index */
765                 pa->num= ctx->index[p];
766                 pa->fuv[0] = 1.0f;
767                 pa->fuv[1] = pa->fuv[2] = pa->fuv[3] = 0.0;
768
769 #if ONLY_WORKING_WITH_PA_VERTS
770                 if (ctx->tree) {
771                         KDTreeNearest ptn[3];
772                         int w, maxw;
773
774                         psys_particle_on_dm(ctx->dm,from,pa->num,pa->num_dmcache,pa->fuv,pa->foffset,co1,0,0,0,orco1,0);
775                         BKE_mesh_orco_verts_transform((Mesh*)ob->data, &orco1, 1, 1);
776                         maxw = BLI_kdtree_find_n_nearest(ctx->tree,3,orco1,NULL,ptn);
777
778                         for (w=0; w<maxw; w++) {
779                                 pa->verts[w]=ptn->num;
780                         }
781                 }
782 #endif
783         }
784         else if (from == PART_FROM_FACE || from == PART_FROM_VOLUME) {
785                 MFace *mface;
786
787                 pa->num = i = ctx->index[p];
788                 mface = dm->getTessFaceData(dm,i,CD_MFACE);
789                 
790                 switch (distr) {
791                 case PART_DISTR_JIT:
792                         if (ctx->jitlevel == 1) {
793                                 if (mface->v4)
794                                         psys_uv_to_w(0.5f, 0.5f, mface->v4, pa->fuv);
795                                 else
796                                         psys_uv_to_w(0.33333f, 0.33333f, mface->v4, pa->fuv);
797                         }
798                         else {
799                                 ctx->jitoff[i] = fmod(ctx->jitoff[i],(float)ctx->jitlevel);
800                                 if (!isnan(ctx->jitoff[i])) {
801                                         psys_uv_to_w(ctx->jit[2*(int)ctx->jitoff[i]], ctx->jit[2*(int)ctx->jitoff[i]+1], mface->v4, pa->fuv);
802                                         ctx->jitoff[i]++;
803                                 }
804                         }
805                         break;
806                 case PART_DISTR_RAND:
807                         randu= rng_getFloat(thread->rng);
808                         randv= rng_getFloat(thread->rng);
809                         rng_skip_tot -= 2;
810
811                         psys_uv_to_w(randu, randv, mface->v4, pa->fuv);
812                         break;
813                 }
814                 pa->foffset= 0.0f;
815                 
816                 /* experimental */
817                 if (from==PART_FROM_VOLUME) {
818                         MVert *mvert=dm->getVertDataArray(dm,CD_MVERT);
819
820                         tot=dm->getNumTessFaces(dm);
821
822                         psys_interpolate_face(mvert,mface,0,0,pa->fuv,co1,nor,0,0,0,0);
823
824                         normalize_v3(nor);
825                         mul_v3_fl(nor,-100.0);
826
827                         add_v3_v3v3(co2,co1,nor);
828
829                         min_d=2.0;
830                         intersect=0;
831
832                         for (i=0,mface=dm->getTessFaceDataArray(dm,CD_MFACE); i<tot; i++,mface++) {
833                                 if (i==pa->num) continue;
834
835                                 v1=mvert[mface->v1].co;
836                                 v2=mvert[mface->v2].co;
837                                 v3=mvert[mface->v3].co;
838
839                                 if (isect_line_tri_v3(co1, co2, v2, v3, v1, &cur_d, 0)) {
840                                         if (cur_d<min_d) {
841                                                 min_d=cur_d;
842                                                 pa->foffset=cur_d*50.0f; /* to the middle of volume */
843                                                 intersect=1;
844                                         }
845                                 }
846                                 if (mface->v4) {
847                                         v4=mvert[mface->v4].co;
848
849                                         if (isect_line_tri_v3(co1, co2, v4, v1, v3, &cur_d, 0)) {
850                                                 if (cur_d<min_d) {
851                                                         min_d=cur_d;
852                                                         pa->foffset=cur_d*50.0f; /* to the middle of volume */
853                                                         intersect=1;
854                                                 }
855                                         }
856                                 }
857                         }
858                         if (intersect==0)
859                                 pa->foffset=0.0;
860                         else {
861                                 switch (distr) {
862                                         case PART_DISTR_JIT:
863                                                 pa->foffset *= ctx->jit[p % (2 * ctx->jitlevel)];
864                                                 break;
865                                         case PART_DISTR_RAND:
866                                                 pa->foffset *= BLI_frand();
867                                                 break;
868                                 }
869                         }
870                 }
871         }
872         else if (from == PART_FROM_CHILD) {
873                 MFace *mf;
874
875                 if (ctx->index[p] < 0) {
876                         cpa->num=0;
877                         cpa->fuv[0]=cpa->fuv[1]=cpa->fuv[2]=cpa->fuv[3]=0.0f;
878                         cpa->pa[0]=cpa->pa[1]=cpa->pa[2]=cpa->pa[3]=0;
879                         return;
880                 }
881
882                 mf= dm->getTessFaceData(dm, ctx->index[p], CD_MFACE);
883
884                 randu= rng_getFloat(thread->rng);
885                 randv= rng_getFloat(thread->rng);
886                 rng_skip_tot -= 2;
887
888                 psys_uv_to_w(randu, randv, mf->v4, cpa->fuv);
889
890                 cpa->num = ctx->index[p];
891
892                 if (ctx->tree) {
893                         KDTreeNearest ptn[10];
894                         int w,maxw;//, do_seams;
895                         float maxd /*, mind,dd */, totw= 0.0f;
896                         int parent[10];
897                         float pweight[10];
898
899                         psys_particle_on_dm(dm,cfrom,cpa->num,DMCACHE_ISCHILD,cpa->fuv,cpa->foffset,co1,nor1,NULL,NULL,orco1,NULL);
900                         BKE_mesh_orco_verts_transform((Mesh*)ob->data, &orco1, 1, 1);
901                         maxw = BLI_kdtree_find_n_nearest(ctx->tree,4,orco1,NULL,ptn);
902
903                         maxd=ptn[maxw-1].dist;
904                         /* mind=ptn[0].dist; */ /* UNUSED */
905                         
906                         /* the weights here could be done better */
907                         for (w=0; w<maxw; w++) {
908                                 parent[w]=ptn[w].index;
909                                 pweight[w]=(float)pow(2.0,(double)(-6.0f*ptn[w].dist/maxd));
910                         }
911                         for (;w<10; w++) {
912                                 parent[w]=-1;
913                                 pweight[w]=0.0f;
914                         }
915
916                         for (w=0,i=0; w<maxw && i<4; w++) {
917                                 if (parent[w]>=0) {
918                                         cpa->pa[i]=parent[w];
919                                         cpa->w[i]=pweight[w];
920                                         totw+=pweight[w];
921                                         i++;
922                                 }
923                         }
924                         for (;i<4; i++) {
925                                 cpa->pa[i]=-1;
926                                 cpa->w[i]=0.0f;
927                         }
928
929                         if (totw>0.0f) for (w=0; w<4; w++)
930                                 cpa->w[w]/=totw;
931
932                         cpa->parent=cpa->pa[0];
933                 }
934         }
935
936         if (rng_skip_tot > 0) /* should never be below zero */
937                 rng_skip(thread->rng, rng_skip_tot);
938 }
939
940 static void *distribute_threads_exec_cb(void *data)
941 {
942         ParticleThread *thread= (ParticleThread*)data;
943         ParticleSystem *psys= thread->ctx->sim.psys;
944         ParticleData *pa;
945         ChildParticle *cpa;
946         int p, totpart;
947
948         if (thread->ctx->from == PART_FROM_CHILD) {
949                 totpart= psys->totchild;
950                 cpa= psys->child;
951
952                 for (p=0; p<totpart; p++, cpa++) {
953                         if (thread->ctx->skip) /* simplification skip */
954                                 rng_skip(thread->rng, PSYS_RND_DIST_SKIP * thread->ctx->skip[p]);
955
956                         if ((p+thread->num) % thread->tot == 0)
957                                 distribute_threads_exec(thread, NULL, cpa, p);
958                         else /* thread skip */
959                                 rng_skip(thread->rng, PSYS_RND_DIST_SKIP);
960                 }
961         }
962         else {
963                 totpart= psys->totpart;
964                 pa= psys->particles + thread->num;
965                 for (p=thread->num; p<totpart; p+=thread->tot, pa+=thread->tot)
966                         distribute_threads_exec(thread, pa, NULL, p);
967         }
968
969         return 0;
970 }
971
972 /* not thread safe, but qsort doesn't take userdata argument */
973 static int *COMPARE_ORIG_INDEX = NULL;
974 static int distribute_compare_orig_index(const void *p1, const void *p2)
975 {
976         int index1 = COMPARE_ORIG_INDEX[*(const int *)p1];
977         int index2 = COMPARE_ORIG_INDEX[*(const int *)p2];
978
979         if (index1 < index2)
980                 return -1;
981         else if (index1 == index2) {
982                 /* this pointer comparison appears to make qsort stable for glibc,
983                  * and apparently on solaris too, makes the renders reproducible */
984                 if (p1 < p2)
985                         return -1;
986                 else if (p1 == p2)
987                         return 0;
988                 else
989                         return 1;
990         }
991         else
992                 return 1;
993 }
994
995 static void distribute_invalid(Scene *scene, ParticleSystem *psys, int from)
996 {
997         if (from == PART_FROM_CHILD) {
998                 ChildParticle *cpa;
999                 int p, totchild = get_psys_tot_child(scene, psys);
1000
1001                 if (psys->child && totchild) {
1002                         for (p=0,cpa=psys->child; p<totchild; p++,cpa++) {
1003                                 cpa->fuv[0]=cpa->fuv[1]=cpa->fuv[2]=cpa->fuv[3] = 0.0;
1004                                 cpa->foffset= 0.0f;
1005                                 cpa->parent=0;
1006                                 cpa->pa[0]=cpa->pa[1]=cpa->pa[2]=cpa->pa[3]=0;
1007                                 cpa->num= -1;
1008                         }
1009                 }
1010         }
1011         else {
1012                 PARTICLE_P;
1013                 LOOP_PARTICLES {
1014                         pa->fuv[0] = pa->fuv[1] = pa->fuv[2] = pa->fuv[3] = 0.0;
1015                         pa->foffset= 0.0f;
1016                         pa->num= -1;
1017                 }
1018         }
1019 }
1020
1021 /* Creates a distribution of coordinates on a DerivedMesh       */
1022 /* This is to denote functionality that does not yet work with mesh - only derived mesh */
1023 static int distribute_threads_init_data(ParticleThread *threads, Scene *scene, DerivedMesh *finaldm, int from)
1024 {
1025         ParticleThreadContext *ctx= threads[0].ctx;
1026         Object *ob= ctx->sim.ob;
1027         ParticleSystem *psys= ctx->sim.psys;
1028         ParticleData *pa=0, *tpars= 0;
1029         ParticleSettings *part;
1030         ParticleSeam *seams= 0;
1031         KDTree *tree=0;
1032         DerivedMesh *dm= NULL;
1033         float *jit= NULL;
1034         int i, seed, p=0, totthread= threads[0].tot;
1035         int cfrom=0;
1036         int totelem=0, totpart, *particle_element=0, children=0, totseam=0;
1037         int jitlevel= 1, distr;
1038         float *element_weight=NULL,*element_sum=NULL,*jitter_offset=NULL, *vweight=NULL;
1039         float cur, maxweight=0.0, tweight, totweight, inv_totweight, co[3], nor[3], orco[3], ornor[3];
1040         
1041         if (ELEM3(NULL, ob, psys, psys->part))
1042                 return 0;
1043
1044         part=psys->part;
1045         totpart=psys->totpart;
1046         if (totpart==0)
1047                 return 0;
1048
1049         if (!finaldm->deformedOnly && !finaldm->getTessFaceDataArray(finaldm, CD_ORIGINDEX)) {
1050                 printf("Can't create particles with the current modifier stack, disable destructive modifiers\n");
1051 // XXX          error("Can't paint with the current modifier stack, disable destructive modifiers");
1052                 return 0;
1053         }
1054
1055         /* First handle special cases */
1056         if (from == PART_FROM_CHILD) {
1057                 /* Simple children */
1058                 if (part->childtype != PART_CHILD_FACES) {
1059                         BLI_srandom(31415926 + psys->seed + psys->child_seed);
1060                         distribute_simple_children(scene, ob, finaldm, psys);
1061                         return 0;
1062                 }
1063         }
1064         else {
1065                 /* Grid distribution */
1066                 if (part->distr==PART_DISTR_GRID && from != PART_FROM_VERT) {
1067                         BLI_srandom(31415926 + psys->seed);
1068                         dm= CDDM_from_mesh((Mesh*)ob->data, ob);
1069                         DM_ensure_tessface(dm);
1070                         distribute_grid(dm,psys);
1071                         dm->release(dm);
1072                         return 0;
1073                 }
1074         }
1075         
1076         /* Create trees and original coordinates if needed */
1077         if (from == PART_FROM_CHILD) {
1078                 distr=PART_DISTR_RAND;
1079                 BLI_srandom(31415926 + psys->seed + psys->child_seed);
1080                 dm= finaldm;
1081
1082                 /* BMESH ONLY */
1083                 DM_ensure_tessface(dm);
1084
1085                 children=1;
1086
1087                 tree=BLI_kdtree_new(totpart);
1088
1089                 for (p=0,pa=psys->particles; p<totpart; p++,pa++) {
1090                         psys_particle_on_dm(dm,part->from,pa->num,pa->num_dmcache,pa->fuv,pa->foffset,co,nor,0,0,orco,ornor);
1091                         BKE_mesh_orco_verts_transform((Mesh*)ob->data, &orco, 1, 1);
1092                         BLI_kdtree_insert(tree, p, orco, ornor);
1093                 }
1094
1095                 BLI_kdtree_balance(tree);
1096
1097                 totpart = get_psys_tot_child(scene, psys);
1098                 cfrom = from = PART_FROM_FACE;
1099         }
1100         else {
1101                 distr = part->distr;
1102                 BLI_srandom(31415926 + psys->seed);
1103                 
1104                 dm= CDDM_from_mesh((Mesh*)ob->data, ob);
1105
1106                 /* BMESH ONLY, for verts we don't care about tessfaces */
1107                 if (from != PART_FROM_VERT) {
1108                         DM_ensure_tessface(dm);
1109                 }
1110
1111                 /* we need orco for consistent distributions */
1112                 DM_add_vert_layer(dm, CD_ORCO, CD_ASSIGN, BKE_mesh_orco_verts_get(ob));
1113
1114                 if (from == PART_FROM_VERT) {
1115                         MVert *mv= dm->getVertDataArray(dm, CD_MVERT);
1116                         float (*orcodata)[3] = dm->getVertDataArray(dm, CD_ORCO);
1117                         int totvert = dm->getNumVerts(dm);
1118
1119                         tree=BLI_kdtree_new(totvert);
1120
1121                         for (p=0; p<totvert; p++) {
1122                                 if (orcodata) {
1123                                         copy_v3_v3(co,orcodata[p]);
1124                                         BKE_mesh_orco_verts_transform((Mesh*)ob->data, &co, 1, 1);
1125                                 }
1126                                 else
1127                                         copy_v3_v3(co,mv[p].co);
1128                                 BLI_kdtree_insert(tree,p,co,NULL);
1129                         }
1130
1131                         BLI_kdtree_balance(tree);
1132                 }
1133         }
1134
1135         /* Get total number of emission elements and allocate needed arrays */
1136         totelem = (from == PART_FROM_VERT) ? dm->getNumVerts(dm) : dm->getNumTessFaces(dm);
1137
1138         if (totelem == 0) {
1139                 distribute_invalid(scene, psys, children ? PART_FROM_CHILD : 0);
1140
1141                 if (G.debug & G_DEBUG)
1142                         fprintf(stderr,"Particle distribution error: Nothing to emit from!\n");
1143
1144                 if (dm != finaldm) dm->release(dm);
1145
1146                 BLI_kdtree_free(tree);
1147
1148                 return 0;
1149         }
1150
1151         element_weight  = MEM_callocN(sizeof(float)*totelem, "particle_distribution_weights");
1152         particle_element= MEM_callocN(sizeof(int)*totpart, "particle_distribution_indexes");
1153         element_sum             = MEM_callocN(sizeof(float)*(totelem+1), "particle_distribution_sum");
1154         jitter_offset   = MEM_callocN(sizeof(float)*totelem, "particle_distribution_jitoff");
1155
1156         /* Calculate weights from face areas */
1157         if ((part->flag&PART_EDISTR || children) && from != PART_FROM_VERT) {
1158                 MVert *v1, *v2, *v3, *v4;
1159                 float totarea=0.f, co1[3], co2[3], co3[3], co4[3];
1160                 float (*orcodata)[3];
1161                 
1162                 orcodata= dm->getVertDataArray(dm, CD_ORCO);
1163
1164                 for (i=0; i<totelem; i++) {
1165                         MFace *mf=dm->getTessFaceData(dm,i,CD_MFACE);
1166
1167                         if (orcodata) {
1168                                 copy_v3_v3(co1, orcodata[mf->v1]);
1169                                 copy_v3_v3(co2, orcodata[mf->v2]);
1170                                 copy_v3_v3(co3, orcodata[mf->v3]);
1171                                 BKE_mesh_orco_verts_transform((Mesh*)ob->data, &co1, 1, 1);
1172                                 BKE_mesh_orco_verts_transform((Mesh*)ob->data, &co2, 1, 1);
1173                                 BKE_mesh_orco_verts_transform((Mesh*)ob->data, &co3, 1, 1);
1174                                 if (mf->v4) {
1175                                         copy_v3_v3(co4, orcodata[mf->v4]);
1176                                         BKE_mesh_orco_verts_transform((Mesh*)ob->data, &co4, 1, 1);
1177                                 }
1178                         }
1179                         else {
1180                                 v1= (MVert*)dm->getVertData(dm,mf->v1,CD_MVERT);
1181                                 v2= (MVert*)dm->getVertData(dm,mf->v2,CD_MVERT);
1182                                 v3= (MVert*)dm->getVertData(dm,mf->v3,CD_MVERT);
1183                                 copy_v3_v3(co1, v1->co);
1184                                 copy_v3_v3(co2, v2->co);
1185                                 copy_v3_v3(co3, v3->co);
1186                                 if (mf->v4) {
1187                                         v4= (MVert*)dm->getVertData(dm,mf->v4,CD_MVERT);
1188                                         copy_v3_v3(co4, v4->co);
1189                                 }
1190                         }
1191
1192                         cur = mf->v4 ? area_quad_v3(co1, co2, co3, co4) : area_tri_v3(co1, co2, co3);
1193                         
1194                         if (cur > maxweight)
1195                                 maxweight = cur;
1196
1197                         element_weight[i] = cur;
1198                         totarea += cur;
1199                 }
1200
1201                 for (i=0; i<totelem; i++)
1202                         element_weight[i] /= totarea;
1203
1204                 maxweight /= totarea;
1205         }
1206         else {
1207                 float min=1.0f/(float)(MIN2(totelem,totpart));
1208                 for (i=0; i<totelem; i++)
1209                         element_weight[i]=min;
1210                 maxweight=min;
1211         }
1212
1213         /* Calculate weights from vgroup */
1214         vweight = psys_cache_vgroup(dm,psys,PSYS_VG_DENSITY);
1215
1216         if (vweight) {
1217                 if (from==PART_FROM_VERT) {
1218                         for (i=0;i<totelem; i++)
1219                                 element_weight[i]*=vweight[i];
1220                 }
1221                 else { /* PART_FROM_FACE / PART_FROM_VOLUME */
1222                         for (i=0;i<totelem; i++) {
1223                                 MFace *mf=dm->getTessFaceData(dm,i,CD_MFACE);
1224                                 tweight = vweight[mf->v1] + vweight[mf->v2] + vweight[mf->v3];
1225                                 
1226                                 if (mf->v4) {
1227                                         tweight += vweight[mf->v4];
1228                                         tweight /= 4.0f;
1229                                 }
1230                                 else {
1231                                         tweight /= 3.0f;
1232                                 }
1233
1234                                 element_weight[i]*=tweight;
1235                         }
1236                 }
1237                 MEM_freeN(vweight);
1238         }
1239
1240         /* Calculate total weight of all elements */
1241         totweight= 0.0f;
1242         for (i=0;i<totelem; i++)
1243                 totweight += element_weight[i];
1244
1245         inv_totweight = (totweight > 0.f ? 1.f/totweight : 0.f);
1246
1247         /* Calculate cumulative weights */
1248         element_sum[0] = 0.0f;
1249         for (i=0; i<totelem; i++)
1250                 element_sum[i+1] = element_sum[i] + element_weight[i] * inv_totweight;
1251         
1252         /* Finally assign elements to particles */
1253         if ((part->flag&PART_TRAND) || (part->simplify_flag&PART_SIMPLIFY_ENABLE)) {
1254                 float pos;
1255
1256                 for (p=0; p<totpart; p++) {
1257                         /* In theory element_sum[totelem] should be 1.0, but due to float errors this is not necessarily always true, so scale pos accordingly. */
1258                         pos= BLI_frand() * element_sum[totelem];
1259                         particle_element[p] = distribute_binary_search(element_sum, totelem, pos);
1260                         particle_element[p] = MIN2(totelem-1, particle_element[p]);
1261                         jitter_offset[particle_element[p]] = pos;
1262                 }
1263         }
1264         else {
1265                 double step, pos;
1266                 
1267                 step= (totpart < 2) ? 0.5 : 1.0/(double)totpart;
1268                 pos= 1e-6; /* tiny offset to avoid zero weight face */
1269                 i= 0;
1270
1271                 for (p=0; p<totpart; p++, pos+=step) {
1272                         while ((i < totelem) && (pos > element_sum[i+1]))
1273                                 i++;
1274
1275                         particle_element[p] = MIN2(totelem-1, i);
1276
1277                         /* avoid zero weight face */
1278                         if (p == totpart-1 && element_weight[particle_element[p]] == 0.0f)
1279                                 particle_element[p] = particle_element[p-1];
1280
1281                         jitter_offset[particle_element[p]] = pos;
1282                 }
1283         }
1284
1285         MEM_freeN(element_sum);
1286
1287         /* For hair, sort by origindex (allows optimization's in rendering), */
1288         /* however with virtual parents the children need to be in random order. */
1289         if (part->type == PART_HAIR && !(part->childtype==PART_CHILD_FACES && part->parents!=0.0f)) {
1290                 COMPARE_ORIG_INDEX = NULL;
1291
1292                 if (from == PART_FROM_VERT) {
1293                         if (dm->numVertData)
1294                                 COMPARE_ORIG_INDEX= dm->getVertDataArray(dm, CD_ORIGINDEX);
1295                 }
1296                 else {
1297                         if (dm->numTessFaceData)
1298                                 COMPARE_ORIG_INDEX= dm->getTessFaceDataArray(dm, CD_ORIGINDEX);
1299                 }
1300
1301                 if (COMPARE_ORIG_INDEX) {
1302                         qsort(particle_element, totpart, sizeof(int), distribute_compare_orig_index);
1303                         COMPARE_ORIG_INDEX = NULL;
1304                 }
1305         }
1306
1307         /* Create jittering if needed */
1308         if (distr==PART_DISTR_JIT && ELEM(from,PART_FROM_FACE,PART_FROM_VOLUME)) {
1309                 jitlevel= part->userjit;
1310                 
1311                 if (jitlevel == 0) {
1312                         jitlevel= totpart/totelem;
1313                         if (part->flag & PART_EDISTR) jitlevel*= 2;     /* looks better in general, not very scietific */
1314                         if (jitlevel<3) jitlevel= 3;
1315                 }
1316                 
1317                 jit= MEM_callocN((2+ jitlevel*2)*sizeof(float), "jit");
1318
1319                 /* for small amounts of particles we use regular jitter since it looks
1320                  * a bit better, for larger amounts we switch to hammersley sequence 
1321                  * because it is much faster */
1322                 if (jitlevel < 25)
1323                         init_mv_jit(jit, jitlevel, psys->seed, part->jitfac);
1324                 else
1325                         hammersley_create(jit, jitlevel+1, psys->seed, part->jitfac);
1326                 BLI_array_randomize(jit, 2*sizeof(float), jitlevel, psys->seed); /* for custom jit or even distribution */
1327         }
1328
1329         /* Setup things for threaded distribution */
1330         ctx->tree= tree;
1331         ctx->seams= seams;
1332         ctx->totseam= totseam;
1333         ctx->sim.psys= psys;
1334         ctx->index= particle_element;
1335         ctx->jit= jit;
1336         ctx->jitlevel= jitlevel;
1337         ctx->jitoff= jitter_offset;
1338         ctx->weight= element_weight;
1339         ctx->maxweight= maxweight;
1340         ctx->from= (children)? PART_FROM_CHILD: from;
1341         ctx->cfrom= cfrom;
1342         ctx->distr= distr;
1343         ctx->dm= dm;
1344         ctx->tpars= tpars;
1345
1346         if (children) {
1347                 totpart= psys_render_simplify_distribution(ctx, totpart);
1348                 alloc_child_particles(psys, totpart);
1349         }
1350
1351         if (!children || psys->totchild < 10000)
1352                 totthread= 1;
1353         
1354         seed= 31415926 + ctx->sim.psys->seed;
1355         for (i=0; i<totthread; i++) {
1356                 threads[i].rng= rng_new(seed);
1357                 threads[i].tot= totthread;
1358         }
1359
1360         return 1;
1361 }
1362
1363 static void distribute_particles_on_dm(ParticleSimulationData *sim, int from)
1364 {
1365         DerivedMesh *finaldm = sim->psmd->dm;
1366         ListBase threads;
1367         ParticleThread *pthreads;
1368         ParticleThreadContext *ctx;
1369         int i, totthread;
1370
1371         pthreads= psys_threads_create(sim);
1372
1373         if (!distribute_threads_init_data(pthreads, sim->scene, finaldm, from)) {
1374                 psys_threads_free(pthreads);
1375                 return;
1376         }
1377
1378         totthread= pthreads[0].tot;
1379         if (totthread > 1) {
1380                 BLI_init_threads(&threads, distribute_threads_exec_cb, totthread);
1381
1382                 for (i=0; i<totthread; i++)
1383                         BLI_insert_thread(&threads, &pthreads[i]);
1384
1385                 BLI_end_threads(&threads);
1386         }
1387         else
1388                 distribute_threads_exec_cb(&pthreads[0]);
1389
1390         psys_calc_dmcache(sim->ob, finaldm, sim->psys);
1391
1392         ctx= pthreads[0].ctx;
1393         if (ctx->dm != finaldm)
1394                 ctx->dm->release(ctx->dm);
1395
1396         psys_threads_free(pthreads);
1397 }
1398
1399 /* ready for future use, to emit particles without geometry */
1400 static void distribute_particles_on_shape(ParticleSimulationData *sim, int UNUSED(from))
1401 {
1402         distribute_invalid(sim->scene, sim->psys, 0);
1403
1404         fprintf(stderr,"Shape emission not yet possible!\n");
1405 }
1406
1407 static void distribute_particles(ParticleSimulationData *sim, int from)
1408 {
1409         PARTICLE_PSMD;
1410         int distr_error=0;
1411
1412         if (psmd) {
1413                 if (psmd->dm)
1414                         distribute_particles_on_dm(sim, from);
1415                 else
1416                         distr_error=1;
1417         }
1418         else
1419                 distribute_particles_on_shape(sim, from);
1420
1421         if (distr_error) {
1422                 distribute_invalid(sim->scene, sim->psys, from);
1423
1424                 fprintf(stderr,"Particle distribution error!\n");
1425         }
1426 }
1427
1428 /* threaded child particle distribution and path caching */
1429 ParticleThread *psys_threads_create(ParticleSimulationData *sim)
1430 {
1431         ParticleThread *threads;
1432         ParticleThreadContext *ctx;
1433         int i, totthread;
1434
1435         if (sim->scene->r.mode & R_FIXED_THREADS)
1436                 totthread= sim->scene->r.threads;
1437         else
1438                 totthread= BLI_system_thread_count();
1439         
1440         threads= MEM_callocN(sizeof(ParticleThread)*totthread, "ParticleThread");
1441         ctx= MEM_callocN(sizeof(ParticleThreadContext), "ParticleThreadContext");
1442
1443         ctx->sim = *sim;
1444         ctx->dm= ctx->sim.psmd->dm;
1445         ctx->ma= give_current_material(sim->ob, sim->psys->part->omat);
1446
1447         memset(threads, 0, sizeof(ParticleThread)*totthread);
1448
1449         for (i=0; i<totthread; i++) {
1450                 threads[i].ctx= ctx;
1451                 threads[i].num= i;
1452                 threads[i].tot= totthread;
1453         }
1454
1455         return threads;
1456 }
1457
1458 void psys_threads_free(ParticleThread *threads)
1459 {
1460         ParticleThreadContext *ctx= threads[0].ctx;
1461         int i, totthread= threads[0].tot;
1462
1463         /* path caching */
1464         if (ctx->vg_length)
1465                 MEM_freeN(ctx->vg_length);
1466         if (ctx->vg_clump)
1467                 MEM_freeN(ctx->vg_clump);
1468         if (ctx->vg_kink)
1469                 MEM_freeN(ctx->vg_kink);
1470         if (ctx->vg_rough1)
1471                 MEM_freeN(ctx->vg_rough1);
1472         if (ctx->vg_rough2)
1473                 MEM_freeN(ctx->vg_rough2);
1474         if (ctx->vg_roughe)
1475                 MEM_freeN(ctx->vg_roughe);
1476
1477         if (ctx->sim.psys->lattice) {
1478                 end_latt_deform(ctx->sim.psys->lattice);
1479                 ctx->sim.psys->lattice= NULL;
1480         }
1481
1482         /* distribution */
1483         if (ctx->jit) MEM_freeN(ctx->jit);
1484         if (ctx->jitoff) MEM_freeN(ctx->jitoff);
1485         if (ctx->weight) MEM_freeN(ctx->weight);
1486         if (ctx->index) MEM_freeN(ctx->index);
1487         if (ctx->skip) MEM_freeN(ctx->skip);
1488         if (ctx->seams) MEM_freeN(ctx->seams);
1489         //if (ctx->vertpart) MEM_freeN(ctx->vertpart);
1490         BLI_kdtree_free(ctx->tree);
1491
1492         /* threads */
1493         for (i=0; i<totthread; i++) {
1494                 if (threads[i].rng)
1495                         rng_free(threads[i].rng);
1496                 if (threads[i].rng_path)
1497                         rng_free(threads[i].rng_path);
1498         }
1499
1500         MEM_freeN(ctx);
1501         MEM_freeN(threads);
1502 }
1503
1504 /* set particle parameters that don't change during particle's life */
1505 void initialize_particle(ParticleSimulationData *sim, ParticleData *pa, int p)
1506 {
1507         ParticleSystem *psys = sim->psys;
1508         ParticleSettings *part = psys->part;
1509         ParticleTexture ptex;
1510
1511         pa->flag &= ~PARS_UNEXIST;
1512
1513         if (part->type != PART_FLUID) {
1514                 psys_get_texture(sim, pa, &ptex, PAMAP_INIT, 0.f);
1515                 
1516                 if (ptex.exist < PSYS_FRAND(p+125))
1517                         pa->flag |= PARS_UNEXIST;
1518
1519                 pa->time = (part->type == PART_HAIR) ? 0.f : part->sta + (part->end - part->sta)*ptex.time;
1520         }
1521
1522         pa->hair_index = 0;
1523         /* we can't reset to -1 anymore since we've figured out correct index in distribute_particles */
1524         /* usage other than straight after distribute has to handle this index by itself - jahka*/
1525         //pa->num_dmcache = DMCACHE_NOTFOUND; /* assume we don't have a derived mesh face */
1526 }
1527 static void initialize_all_particles(ParticleSimulationData *sim)
1528 {
1529         ParticleSystem *psys = sim->psys;
1530         PARTICLE_P;
1531
1532         psys->totunexist = 0;
1533
1534         LOOP_PARTICLES {
1535                 if ((pa->flag & PARS_UNEXIST)==0)
1536                         initialize_particle(sim, pa, p);
1537
1538                 if (pa->flag & PARS_UNEXIST)
1539                         psys->totunexist++;
1540         }
1541
1542         /* Free unexisting particles. */
1543         if (psys->totpart && psys->totunexist == psys->totpart) {
1544                 if (psys->particles->boid)
1545                         MEM_freeN(psys->particles->boid);
1546
1547                 MEM_freeN(psys->particles);
1548                 psys->particles = NULL;
1549                 psys->totpart = psys->totunexist = 0;
1550         }
1551
1552         if (psys->totunexist) {
1553                 int newtotpart = psys->totpart - psys->totunexist;
1554                 ParticleData *npa, *newpars;
1555                 
1556                 npa = newpars = MEM_callocN(newtotpart * sizeof(ParticleData), "particles");
1557
1558                 for (p=0, pa=psys->particles; p<newtotpart; p++, pa++, npa++) {
1559                         while (pa->flag & PARS_UNEXIST)
1560                                 pa++;
1561
1562                         memcpy(npa, pa, sizeof(ParticleData));
1563                 }
1564
1565                 if (psys->particles->boid)
1566                         MEM_freeN(psys->particles->boid);
1567                 MEM_freeN(psys->particles);
1568                 psys->particles = newpars;
1569                 psys->totpart -= psys->totunexist;
1570
1571                 if (psys->particles->boid) {
1572                         BoidParticle *newboids = MEM_callocN(psys->totpart * sizeof(BoidParticle), "boid particles");
1573
1574                         LOOP_PARTICLES
1575                                 pa->boid = newboids++;
1576
1577                 }
1578         }
1579 }
1580
1581 static void get_angular_velocity_vector(short avemode, ParticleKey *state, float vec[3])
1582 {
1583         switch (avemode) {
1584                 case PART_AVE_VELOCITY:
1585                         copy_v3_v3(vec, state->vel);
1586                         break;
1587                 case PART_AVE_HORIZONTAL:
1588                 {
1589                         float zvec[3];
1590                         zvec[0] = zvec[1] = 0;
1591                         zvec[2] = 1.f;
1592                         cross_v3_v3v3(vec, state->vel, zvec);
1593                         break;
1594                 }
1595                 case PART_AVE_VERTICAL:
1596                 {
1597                         float zvec[3], temp[3];
1598                         zvec[0] = zvec[1] = 0;
1599                         zvec[2] = 1.f;
1600                         cross_v3_v3v3(temp, state->vel, zvec);
1601                         cross_v3_v3v3(vec, temp, state->vel);
1602                         break;
1603                 }
1604                 case PART_AVE_GLOBAL_X:
1605                         vec[0] = 1.f;
1606                         vec[1] = vec[2] = 0;
1607                         break;
1608                 case PART_AVE_GLOBAL_Y:
1609                         vec[1] = 1.f;
1610                         vec[0] = vec[2] = 0;
1611                         break;
1612                 case PART_AVE_GLOBAL_Z:
1613                         vec[2] = 1.f;
1614                         vec[0] = vec[1] = 0;
1615                         break;
1616         }
1617 }
1618
1619 void psys_get_birth_coordinates(ParticleSimulationData *sim, ParticleData *pa, ParticleKey *state, float dtime, float cfra)
1620 {
1621         Object *ob = sim->ob;
1622         ParticleSystem *psys = sim->psys;
1623         ParticleSettings *part;
1624         ParticleTexture ptex;
1625         float fac, phasefac, nor[3] = {0,0,0},loc[3],vel[3] = {0.0,0.0,0.0},rot[4],q2[4];
1626         float r_vel[3],r_ave[3],r_rot[4],vec[3],p_vel[3] = {0.0,0.0,0.0};
1627         float x_vec[3] = {1.0,0.0,0.0}, utan[3] = {0.0,1.0,0.0}, vtan[3] = {0.0,0.0,1.0}, rot_vec[3] = {0.0,0.0,0.0};
1628         float q_phase[4];
1629         int p = pa - psys->particles;
1630         part=psys->part;
1631
1632         /* get birth location from object               */
1633         if (part->tanfac != 0.f)
1634                 psys_particle_on_emitter(sim->psmd, part->from,pa->num, pa->num_dmcache, pa->fuv,pa->foffset,loc,nor,utan,vtan,0,0);
1635         else
1636                 psys_particle_on_emitter(sim->psmd, part->from,pa->num, pa->num_dmcache, pa->fuv,pa->foffset,loc,nor,0,0,0,0);
1637                 
1638         /* get possible textural influence */
1639         psys_get_texture(sim, pa, &ptex, PAMAP_IVEL, cfra);
1640
1641         /* particles live in global space so    */
1642         /* let's convert:                                               */
1643         /* -location                                                    */
1644         mul_m4_v3(ob->obmat, loc);
1645                 
1646         /* -normal                                                              */
1647         mul_mat3_m4_v3(ob->obmat, nor);
1648         normalize_v3(nor);
1649
1650         /* -tangent                                                             */
1651         if (part->tanfac!=0.0f) {
1652                 //float phase=vg_rot?2.0f*(psys_particle_value_from_verts(sim->psmd->dm,part->from,pa,vg_rot)-0.5f):0.0f;
1653                 float phase=0.0f;
1654                 mul_v3_fl(vtan,-cosf((float)M_PI*(part->tanphase+phase)));
1655                 fac= -sinf((float)M_PI*(part->tanphase+phase));
1656                 madd_v3_v3fl(vtan, utan, fac);
1657
1658                 mul_mat3_m4_v3(ob->obmat,vtan);
1659
1660                 copy_v3_v3(utan, nor);
1661                 mul_v3_fl(utan,dot_v3v3(vtan,nor));
1662                 sub_v3_v3(vtan, utan);
1663                         
1664                 normalize_v3(vtan);
1665         }
1666                 
1667
1668         /* -velocity (boids need this even if there's no random velocity) */
1669         if (part->randfac != 0.0f || (part->phystype==PART_PHYS_BOIDS && pa->boid)) {
1670                 r_vel[0] = 2.0f * (PSYS_FRAND(p + 10) - 0.5f);
1671                 r_vel[1] = 2.0f * (PSYS_FRAND(p + 11) - 0.5f);
1672                 r_vel[2] = 2.0f * (PSYS_FRAND(p + 12) - 0.5f);
1673
1674                 mul_mat3_m4_v3(ob->obmat, r_vel);
1675                 normalize_v3(r_vel);
1676         }
1677
1678         /* -angular velocity                                    */
1679         if (part->avemode==PART_AVE_RAND) {
1680                 r_ave[0] = 2.0f * (PSYS_FRAND(p + 13) - 0.5f);
1681                 r_ave[1] = 2.0f * (PSYS_FRAND(p + 14) - 0.5f);
1682                 r_ave[2] = 2.0f * (PSYS_FRAND(p + 15) - 0.5f);
1683
1684                 mul_mat3_m4_v3(ob->obmat,r_ave);
1685                 normalize_v3(r_ave);
1686         }
1687                 
1688         /* -rotation                                                    */
1689         if (part->randrotfac != 0.0f) {
1690                 r_rot[0] = 2.0f * (PSYS_FRAND(p + 16) - 0.5f);
1691                 r_rot[1] = 2.0f * (PSYS_FRAND(p + 17) - 0.5f);
1692                 r_rot[2] = 2.0f * (PSYS_FRAND(p + 18) - 0.5f);
1693                 r_rot[3] = 2.0f * (PSYS_FRAND(p + 19) - 0.5f);
1694                 normalize_qt(r_rot);
1695
1696                 mat4_to_quat(rot,ob->obmat);
1697                 mul_qt_qtqt(r_rot,r_rot,rot);
1698         }
1699
1700         if (part->phystype==PART_PHYS_BOIDS && pa->boid) {
1701                 float dvec[3], q[4], mat[3][3];
1702
1703                 copy_v3_v3(state->co,loc);
1704
1705                 /* boids don't get any initial velocity  */
1706                 zero_v3(state->vel);
1707
1708                 /* boids store direction in ave */
1709                 if (fabsf(nor[2])==1.0f) {
1710                         sub_v3_v3v3(state->ave, loc, ob->obmat[3]);
1711                         normalize_v3(state->ave);
1712                 }
1713                 else {
1714                         copy_v3_v3(state->ave, nor);
1715                 }
1716
1717                 /* calculate rotation matrix */
1718                 project_v3_v3v3(dvec, r_vel, state->ave);
1719                 sub_v3_v3v3(mat[0], state->ave, dvec);
1720                 normalize_v3(mat[0]);
1721                 negate_v3_v3(mat[2], r_vel);
1722                 normalize_v3(mat[2]);
1723                 cross_v3_v3v3(mat[1], mat[2], mat[0]);
1724                 
1725                 /* apply rotation */
1726                 mat3_to_quat_is_ok( q,mat);
1727                 copy_qt_qt(state->rot, q);
1728         }
1729         else {
1730                 /* conversion done so now we apply new: */
1731                 /* -velocity from:                                              */
1732
1733                 /*              *reactions                                              */
1734                 if (dtime > 0.f) {
1735                         sub_v3_v3v3(vel, pa->state.vel, pa->prev_state.vel);
1736                 }
1737
1738                 /*              *emitter velocity                               */
1739                 if (dtime != 0.f && part->obfac != 0.f) {
1740                         sub_v3_v3v3(vel, loc, state->co);
1741                         mul_v3_fl(vel, part->obfac/dtime);
1742                 }
1743                 
1744                 /*              *emitter normal                                 */
1745                 if (part->normfac != 0.f)
1746                         madd_v3_v3fl(vel, nor, part->normfac);
1747                 
1748                 /*              *emitter tangent                                */
1749                 if (sim->psmd && part->tanfac != 0.f)
1750                         madd_v3_v3fl(vel, vtan, part->tanfac);
1751
1752                 /*              *emitter object orientation             */
1753                 if (part->ob_vel[0] != 0.f) {
1754                         normalize_v3_v3(vec, ob->obmat[0]);
1755                         madd_v3_v3fl(vel, vec, part->ob_vel[0]);
1756                 }
1757                 if (part->ob_vel[1] != 0.f) {
1758                         normalize_v3_v3(vec, ob->obmat[1]);
1759                         madd_v3_v3fl(vel, vec, part->ob_vel[1]);
1760                 }
1761                 if (part->ob_vel[2] != 0.f) {
1762                         normalize_v3_v3(vec, ob->obmat[2]);
1763                         madd_v3_v3fl(vel, vec, part->ob_vel[2]);
1764                 }
1765
1766                 /*              *texture                                                */
1767                 /* TODO */
1768
1769                 /*              *random                                                 */
1770                 if (part->randfac != 0.f)
1771                         madd_v3_v3fl(vel, r_vel, part->randfac);
1772
1773                 /*              *particle                                               */
1774                 if (part->partfac != 0.f)
1775                         madd_v3_v3fl(vel, p_vel, part->partfac);
1776                 
1777                 mul_v3_v3fl(state->vel, vel, ptex.ivel);
1778
1779                 /* -location from emitter                               */
1780                 copy_v3_v3(state->co,loc);
1781
1782                 /* -rotation                                                    */
1783                 unit_qt(state->rot);
1784
1785                 if (part->rotmode) {
1786                         /* create vector into which rotation is aligned */
1787                         switch (part->rotmode) {
1788                                 case PART_ROT_NOR:
1789                                         copy_v3_v3(rot_vec, nor);
1790                                         break;
1791                                 case PART_ROT_VEL:
1792                                         copy_v3_v3(rot_vec, vel);
1793                                         break;
1794                                 case PART_ROT_GLOB_X:
1795                                 case PART_ROT_GLOB_Y:
1796                                 case PART_ROT_GLOB_Z:
1797                                         rot_vec[part->rotmode - PART_ROT_GLOB_X] = 1.0f;
1798                                         break;
1799                                 case PART_ROT_OB_X:
1800                                 case PART_ROT_OB_Y:
1801                                 case PART_ROT_OB_Z:
1802                                         copy_v3_v3(rot_vec, ob->obmat[part->rotmode - PART_ROT_OB_X]);
1803                                         break;
1804                         }
1805                         
1806                         /* create rotation quat */
1807                         negate_v3(rot_vec);
1808                         vec_to_quat( q2,rot_vec, OB_POSX, OB_POSZ);
1809
1810                         /* randomize rotation quat */
1811                         if (part->randrotfac!=0.0f)
1812                                 interp_qt_qtqt(rot, q2, r_rot, part->randrotfac);
1813                         else
1814                                 copy_qt_qt(rot,q2);
1815
1816                         /* rotation phase */
1817                         phasefac = part->phasefac;
1818                         if (part->randphasefac != 0.0f)
1819                                 phasefac += part->randphasefac * PSYS_FRAND(p + 20);
1820                         axis_angle_to_quat( q_phase,x_vec, phasefac*(float)M_PI);
1821
1822                         /* combine base rotation & phase */
1823                         mul_qt_qtqt(state->rot, rot, q_phase);
1824                 }
1825
1826                 /* -angular velocity                                    */
1827
1828                 zero_v3(state->ave);
1829
1830                 if (part->avemode) {
1831                         if (part->avemode == PART_AVE_RAND)
1832                                 copy_v3_v3(state->ave, r_ave);
1833                         else
1834                                 get_angular_velocity_vector(part->avemode, state, state->ave);
1835
1836                         normalize_v3(state->ave);
1837                         mul_v3_fl(state->ave, part->avefac);
1838                 }
1839         }
1840 }
1841 /* sets particle to the emitter surface with initial velocity & rotation */
1842 void reset_particle(ParticleSimulationData *sim, ParticleData *pa, float dtime, float cfra)
1843 {
1844         Object *ob = sim->ob;
1845         ParticleSystem *psys = sim->psys;
1846         ParticleSettings *part;
1847         ParticleTexture ptex;
1848         int p = pa - psys->particles;
1849         part=psys->part;
1850         
1851         /* get precise emitter matrix if particle is born */
1852         if (part->type!=PART_HAIR && dtime > 0.f && pa->time < cfra && pa->time >= sim->psys->cfra) {
1853                 /* we have to force RECALC_ANIM here since where_is_objec_time only does drivers */
1854                 while (ob) {
1855                         BKE_animsys_evaluate_animdata(sim->scene, &ob->id, ob->adt, pa->time, ADT_RECALC_ANIM);
1856                         ob = ob->parent;
1857                 }
1858                 ob = sim->ob;
1859                 BKE_object_where_is_calc_time(sim->scene, ob, pa->time);
1860
1861                 psys->flag |= PSYS_OB_ANIM_RESTORE;
1862         }
1863
1864         psys_get_birth_coordinates(sim, pa, &pa->state, dtime, cfra);
1865
1866         if (part->phystype==PART_PHYS_BOIDS && pa->boid) {
1867                 BoidParticle *bpa = pa->boid;
1868
1869                 /* and gravity in r_ve */
1870                 bpa->gravity[0] = bpa->gravity[1] = 0.0f;
1871                 bpa->gravity[2] = -1.0f;
1872                 if ((sim->scene->physics_settings.flag & PHYS_GLOBAL_GRAVITY) &&
1873                     (sim->scene->physics_settings.gravity[2] != 0.0f))
1874                 {
1875                         bpa->gravity[2] = sim->scene->physics_settings.gravity[2];
1876                 }
1877
1878                 bpa->data.health = part->boids->health;
1879                 bpa->data.mode = eBoidMode_InAir;
1880                 bpa->data.state_id = ((BoidState*)part->boids->states.first)->id;
1881                 bpa->data.acc[0]=bpa->data.acc[1]=bpa->data.acc[2]=0.0f;
1882         }
1883
1884
1885         if (part->type == PART_HAIR) {
1886                 pa->lifetime = 100.0f;
1887         }
1888         else {
1889                 /* get possible textural influence */
1890                 psys_get_texture(sim, pa, &ptex, PAMAP_LIFE, cfra);
1891
1892                 pa->lifetime = part->lifetime * ptex.life;
1893
1894                 if (part->randlife != 0.0f)
1895                         pa->lifetime *= 1.0f - part->randlife * PSYS_FRAND(p + 21);
1896         }
1897
1898         pa->dietime = pa->time + pa->lifetime;
1899
1900         if (sim->psys->pointcache && sim->psys->pointcache->flag & PTCACHE_BAKED &&
1901                 sim->psys->pointcache->mem_cache.first) {
1902                 float dietime = psys_get_dietime_from_cache(sim->psys->pointcache, p);
1903                 pa->dietime = MIN2(pa->dietime, dietime);
1904         }
1905
1906         if (pa->time > cfra)
1907                 pa->alive = PARS_UNBORN;
1908         else if (pa->dietime <= cfra)
1909                 pa->alive = PARS_DEAD;
1910         else
1911                 pa->alive = PARS_ALIVE;
1912
1913         pa->state.time = cfra;
1914 }
1915 static void reset_all_particles(ParticleSimulationData *sim, float dtime, float cfra, int from)
1916 {
1917         ParticleData *pa;
1918         int p, totpart=sim->psys->totpart;
1919         
1920         for (p=from, pa=sim->psys->particles+from; p<totpart; p++, pa++)
1921                 reset_particle(sim, pa, dtime, cfra);
1922 }
1923 /************************************************/
1924 /*                      Particle targets                                        */
1925 /************************************************/
1926 ParticleSystem *psys_get_target_system(Object *ob, ParticleTarget *pt)
1927 {
1928         ParticleSystem *psys = NULL;
1929
1930         if (pt->ob == NULL || pt->ob == ob)
1931                 psys = BLI_findlink(&ob->particlesystem, pt->psys-1);
1932         else
1933                 psys = BLI_findlink(&pt->ob->particlesystem, pt->psys-1);
1934
1935         if (psys)
1936                 pt->flag |= PTARGET_VALID;
1937         else
1938                 pt->flag &= ~PTARGET_VALID;
1939
1940         return psys;
1941 }
1942 /************************************************/
1943 /*                      Keyed particles                                         */
1944 /************************************************/
1945 /* Counts valid keyed targets */
1946 void psys_count_keyed_targets(ParticleSimulationData *sim)
1947 {
1948         ParticleSystem *psys = sim->psys, *kpsys;
1949         ParticleTarget *pt = psys->targets.first;
1950         int keys_valid = 1;
1951         psys->totkeyed = 0;
1952
1953         for (; pt; pt=pt->next) {
1954                 kpsys = psys_get_target_system(sim->ob, pt);
1955
1956                 if (kpsys && kpsys->totpart) {
1957                         psys->totkeyed += keys_valid;
1958                         if (psys->flag & PSYS_KEYED_TIMING && pt->duration != 0.0f)
1959                                 psys->totkeyed += 1;
1960                 }
1961                 else {
1962                         keys_valid = 0;
1963                 }
1964         }
1965
1966         psys->totkeyed *= psys->flag & PSYS_KEYED_TIMING ? 1 : psys->part->keyed_loops;
1967 }
1968
1969 static void set_keyed_keys(ParticleSimulationData *sim)
1970 {
1971         ParticleSystem *psys = sim->psys;
1972         ParticleSimulationData ksim= {0};
1973         ParticleTarget *pt;
1974         PARTICLE_P;
1975         ParticleKey *key;
1976         int totpart = psys->totpart, k, totkeys = psys->totkeyed;
1977         int keyed_flag = 0;
1978
1979         ksim.scene= sim->scene;
1980         
1981         /* no proper targets so let's clear and bail out */
1982         if (psys->totkeyed==0) {
1983                 free_keyed_keys(psys);
1984                 psys->flag &= ~PSYS_KEYED;
1985                 return;
1986         }
1987
1988         if (totpart && psys->particles->totkey != totkeys) {
1989                 free_keyed_keys(psys);
1990                 
1991                 key = MEM_callocN(totpart*totkeys*sizeof(ParticleKey), "Keyed keys");
1992                 
1993                 LOOP_PARTICLES {
1994                         pa->keys = key;
1995                         pa->totkey = totkeys;
1996                         key += totkeys;
1997                 }
1998         }
1999         
2000         psys->flag &= ~PSYS_KEYED;
2001
2002
2003         pt = psys->targets.first;
2004         for (k=0; k<totkeys; k++) {
2005                 ksim.ob = pt->ob ? pt->ob : sim->ob;
2006                 ksim.psys = BLI_findlink(&ksim.ob->particlesystem, pt->psys - 1);
2007                 keyed_flag = (ksim.psys->flag & PSYS_KEYED);
2008                 ksim.psys->flag &= ~PSYS_KEYED;
2009
2010                 LOOP_PARTICLES {
2011                         key = pa->keys + k;
2012                         key->time = -1.0; /* use current time */
2013
2014                         psys_get_particle_state(&ksim, p%ksim.psys->totpart, key, 1);
2015
2016                         if (psys->flag & PSYS_KEYED_TIMING) {
2017                                 key->time = pa->time + pt->time;
2018                                 if (pt->duration != 0.0f && k+1 < totkeys) {
2019                                         copy_particle_key(key+1, key, 1);
2020                                         (key+1)->time = pa->time + pt->time + pt->duration;
2021                                 }
2022                         }
2023                         else if (totkeys > 1)
2024                                 key->time = pa->time + (float)k / (float)(totkeys - 1) * pa->lifetime;
2025                         else
2026                                 key->time = pa->time;
2027                 }
2028
2029                 if (psys->flag & PSYS_KEYED_TIMING && pt->duration!=0.0f)
2030                         k++;
2031
2032                 ksim.psys->flag |= keyed_flag;
2033
2034                 pt = (pt->next && pt->next->flag & PTARGET_VALID)? pt->next : psys->targets.first;
2035         }
2036
2037         psys->flag |= PSYS_KEYED;
2038 }
2039
2040 /************************************************/
2041 /*                      Point Cache                                                     */
2042 /************************************************/
2043 void psys_make_temp_pointcache(Object *ob, ParticleSystem *psys)
2044 {
2045         PointCache *cache = psys->pointcache;
2046
2047         if (cache->flag & PTCACHE_DISK_CACHE && cache->mem_cache.first == NULL) {
2048                 PTCacheID pid;
2049                 BKE_ptcache_id_from_particles(&pid, ob, psys);
2050                 cache->flag &= ~PTCACHE_DISK_CACHE;
2051                 BKE_ptcache_disk_to_mem(&pid);
2052                 cache->flag |= PTCACHE_DISK_CACHE;
2053         }
2054 }
2055 static void psys_clear_temp_pointcache(ParticleSystem *psys)
2056 {
2057         if (psys->pointcache->flag & PTCACHE_DISK_CACHE)
2058                 BKE_ptcache_free_mem(&psys->pointcache->mem_cache);
2059 }
2060 void psys_get_pointcache_start_end(Scene *scene, ParticleSystem *psys, int *sfra, int *efra)
2061 {
2062         ParticleSettings *part = psys->part;
2063
2064         *sfra = MAX2(1, (int)part->sta);
2065         *efra = MIN2((int)(part->end + part->lifetime + 1.0f), scene->r.efra);
2066 }
2067
2068 /************************************************/
2069 /*                      Effectors                                                       */
2070 /************************************************/
2071 static void psys_update_particle_bvhtree(ParticleSystem *psys, float cfra)
2072 {
2073         if (psys) {
2074                 PARTICLE_P;
2075                 int totpart = 0;
2076
2077                 if (!psys->bvhtree || psys->bvhtree_frame != cfra) {
2078                         LOOP_SHOWN_PARTICLES {
2079                                 totpart++;
2080                         }
2081                         
2082                         BLI_bvhtree_free(psys->bvhtree);
2083                         psys->bvhtree = BLI_bvhtree_new(totpart, 0.0, 4, 6);
2084
2085                         LOOP_SHOWN_PARTICLES {
2086                                 if (pa->alive == PARS_ALIVE) {
2087                                         if (pa->state.time == cfra)
2088                                                 BLI_bvhtree_insert(psys->bvhtree, p, pa->prev_state.co, 1);
2089                                         else
2090                                                 BLI_bvhtree_insert(psys->bvhtree, p, pa->state.co, 1);
2091                                 }
2092                         }
2093                         BLI_bvhtree_balance(psys->bvhtree);
2094
2095                         psys->bvhtree_frame = cfra;
2096                 }
2097         }
2098 }
2099 void psys_update_particle_tree(ParticleSystem *psys, float cfra)
2100 {
2101         if (psys) {
2102                 PARTICLE_P;
2103                 int totpart = 0;
2104
2105                 if (!psys->tree || psys->tree_frame != cfra) {
2106                         LOOP_SHOWN_PARTICLES {
2107                                 totpart++;
2108                         }
2109
2110                         BLI_kdtree_free(psys->tree);
2111                         psys->tree = BLI_kdtree_new(psys->totpart);
2112
2113                         LOOP_SHOWN_PARTICLES {
2114                                 if (pa->alive == PARS_ALIVE) {
2115                                         if (pa->state.time == cfra)
2116                                                 BLI_kdtree_insert(psys->tree, p, pa->prev_state.co, NULL);
2117                                         else
2118                                                 BLI_kdtree_insert(psys->tree, p, pa->state.co, NULL);
2119                                 }
2120                         }
2121                         BLI_kdtree_balance(psys->tree);
2122
2123                         psys->tree_frame = cfra;
2124                 }
2125         }
2126 }
2127
2128 static void psys_update_effectors(ParticleSimulationData *sim)
2129 {
2130         pdEndEffectors(&sim->psys->effectors);
2131         sim->psys->effectors = pdInitEffectors(sim->scene, sim->ob, sim->psys, sim->psys->part->effector_weights);
2132         precalc_guides(sim, sim->psys->effectors);
2133 }
2134
2135 static void integrate_particle(ParticleSettings *part, ParticleData *pa, float dtime, float *external_acceleration, void (*force_func)(void *forcedata, ParticleKey *state, float *force, float *impulse), void *forcedata)
2136 {
2137         ParticleKey states[5];
2138         float force[3],acceleration[3],impulse[3],dx[4][3],dv[4][3],oldpos[3];
2139         float pa_mass= (part->flag & PART_SIZEMASS ? part->mass * pa->size : part->mass);
2140         int i, steps=1;
2141         int integrator = part->integrator;
2142
2143         copy_v3_v3(oldpos, pa->state.co);
2144         
2145         /* Verlet integration behaves strangely with moving emitters, so do first step with euler. */
2146         if (pa->prev_state.time < 0.f && integrator == PART_INT_VERLET)
2147                 integrator = PART_INT_EULER;
2148
2149         switch (integrator) {
2150                 case PART_INT_EULER:
2151                         steps=1;
2152                         break;
2153                 case PART_INT_MIDPOINT:
2154                         steps=2;
2155                         break;
2156                 case PART_INT_RK4:
2157                         steps=4;
2158                         break;
2159                 case PART_INT_VERLET:
2160                         steps=1;
2161                         break;
2162         }
2163
2164         for (i=0; i<steps; i++) {
2165                 copy_particle_key(states + i, &pa->state, 1);
2166         }
2167
2168         states->time = 0.f;
2169
2170         for (i=0; i<steps; i++) {
2171                 zero_v3(force);
2172                 zero_v3(impulse);
2173
2174                 force_func(forcedata, states+i, force, impulse);
2175
2176                 /* force to acceleration*/
2177                 mul_v3_v3fl(acceleration, force, 1.0f/pa_mass);
2178
2179                 if (external_acceleration)
2180                         add_v3_v3(acceleration, external_acceleration);
2181                 
2182                 /* calculate next state */
2183                 add_v3_v3(states[i].vel, impulse);
2184
2185                 switch (integrator) {
2186                         case PART_INT_EULER:
2187                                 madd_v3_v3v3fl(pa->state.co, states->co, states->vel, dtime);
2188                                 madd_v3_v3v3fl(pa->state.vel, states->vel, acceleration, dtime);
2189                                 break;
2190                         case PART_INT_MIDPOINT:
2191                                 if (i==0) {
2192                                         madd_v3_v3v3fl(states[1].co, states->co, states->vel, dtime*0.5f);
2193                                         madd_v3_v3v3fl(states[1].vel, states->vel, acceleration, dtime*0.5f);
2194                                         states[1].time = dtime*0.5f;
2195                                         /*fra=sim->psys->cfra+0.5f*dfra;*/
2196                                 }
2197                                 else {
2198                                         madd_v3_v3v3fl(pa->state.co, states->co, states[1].vel, dtime);
2199                                         madd_v3_v3v3fl(pa->state.vel, states->vel, acceleration, dtime);
2200                                 }
2201                                 break;
2202                         case PART_INT_RK4:
2203                                 switch (i) {
2204                                         case 0:
2205                                                 copy_v3_v3(dx[0], states->vel);
2206                                                 mul_v3_fl(dx[0], dtime);
2207                                                 copy_v3_v3(dv[0], acceleration);
2208                                                 mul_v3_fl(dv[0], dtime);
2209
2210                                                 madd_v3_v3v3fl(states[1].co, states->co, dx[0], 0.5f);
2211                                                 madd_v3_v3v3fl(states[1].vel, states->vel, dv[0], 0.5f);
2212                                                 states[1].time = dtime*0.5f;
2213                                                 /*fra=sim->psys->cfra+0.5f*dfra;*/
2214                                                 break;
2215                                         case 1:
2216                                                 madd_v3_v3v3fl(dx[1], states->vel, dv[0], 0.5f);
2217                                                 mul_v3_fl(dx[1], dtime);
2218                                                 copy_v3_v3(dv[1], acceleration);
2219                                                 mul_v3_fl(dv[1], dtime);
2220
2221                                                 madd_v3_v3v3fl(states[2].co, states->co, dx[1], 0.5f);
2222                                                 madd_v3_v3v3fl(states[2].vel, states->vel, dv[1], 0.5f);
2223                                                 states[2].time = dtime*0.5f;
2224                                                 break;
2225                                         case 2:
2226                                                 madd_v3_v3v3fl(dx[2], states->vel, dv[1], 0.5f);
2227                                                 mul_v3_fl(dx[2], dtime);
2228                                                 copy_v3_v3(dv[2], acceleration);
2229                                                 mul_v3_fl(dv[2], dtime);
2230
2231                                                 add_v3_v3v3(states[3].co, states->co, dx[2]);
2232                                                 add_v3_v3v3(states[3].vel, states->vel, dv[2]);
2233                                                 states[3].time = dtime;
2234                                                 /*fra=cfra;*/
2235                                                 break;
2236                                         case 3:
2237                                                 add_v3_v3v3(dx[3], states->vel, dv[2]);
2238                                                 mul_v3_fl(dx[3], dtime);
2239                                                 copy_v3_v3(dv[3], acceleration);
2240                                                 mul_v3_fl(dv[3], dtime);
2241
2242                                                 madd_v3_v3v3fl(pa->state.co, states->co, dx[0], 1.0f/6.0f);
2243                                                 madd_v3_v3fl(pa->state.co, dx[1], 1.0f/3.0f);
2244                                                 madd_v3_v3fl(pa->state.co, dx[2], 1.0f/3.0f);
2245                                                 madd_v3_v3fl(pa->state.co, dx[3], 1.0f/6.0f);
2246
2247                                                 madd_v3_v3v3fl(pa->state.vel, states->vel, dv[0], 1.0f/6.0f);
2248                                                 madd_v3_v3fl(pa->state.vel, dv[1], 1.0f/3.0f);
2249                                                 madd_v3_v3fl(pa->state.vel, dv[2], 1.0f/3.0f);
2250                                                 madd_v3_v3fl(pa->state.vel, dv[3], 1.0f/6.0f);
2251                                 }
2252                                 break;
2253                         case PART_INT_VERLET:   /* Verlet integration */
2254                                 madd_v3_v3v3fl(pa->state.vel, pa->prev_state.vel, acceleration, dtime);
2255                                 madd_v3_v3v3fl(pa->state.co, pa->prev_state.co, pa->state.vel, dtime);
2256
2257                                 sub_v3_v3v3(pa->state.vel, pa->state.co, oldpos);
2258                                 mul_v3_fl(pa->state.vel, 1.0f/dtime);
2259                                 break;
2260                 }
2261         }
2262 }
2263
2264 /*********************************************************************************************************
2265  *                    SPH fluid physics 
2266  *
2267  * In theory, there could be unlimited implementation of SPH simulators
2268  *
2269  * This code uses in some parts adapted algorithms from the pseudo code as outlined in the Research paper:
2270  *
2271  * Titled: Particle-based Viscoelastic Fluid Simulation.
2272  * Authors: Simon Clavet, Philippe Beaudoin and Pierre Poulin
2273  * Website: http://www.iro.umontreal.ca/labs/infographie/papers/Clavet-2005-PVFS/
2274  *
2275  * Presented at Siggraph, (2005)
2276  *
2277  * ********************************************************************************************************/
2278 #define PSYS_FLUID_SPRINGS_INITIAL_SIZE 256
2279 static ParticleSpring *sph_spring_add(ParticleSystem *psys, ParticleSpring *spring)
2280 {
2281         /* Are more refs required? */
2282         if (psys->alloc_fluidsprings == 0 || psys->fluid_springs == NULL) {
2283                 psys->alloc_fluidsprings = PSYS_FLUID_SPRINGS_INITIAL_SIZE;
2284                 psys->fluid_springs = (ParticleSpring*)MEM_callocN(psys->alloc_fluidsprings * sizeof(ParticleSpring), "Particle Fluid Springs");
2285         }
2286         else if (psys->tot_fluidsprings == psys->alloc_fluidsprings) {
2287                 /* Double the number of refs allocated */
2288                 psys->alloc_fluidsprings *= 2;
2289                 psys->fluid_springs = (ParticleSpring*)MEM_reallocN(psys->fluid_springs, psys->alloc_fluidsprings * sizeof(ParticleSpring));
2290         }
2291
2292         memcpy(psys->fluid_springs + psys->tot_fluidsprings, spring, sizeof(ParticleSpring));
2293         psys->tot_fluidsprings++;
2294
2295         return psys->fluid_springs + psys->tot_fluidsprings - 1;
2296 }
2297 static void sph_spring_delete(ParticleSystem *psys, int j)
2298 {
2299         if (j != psys->tot_fluidsprings - 1)
2300                 psys->fluid_springs[j] = psys->fluid_springs[psys->tot_fluidsprings - 1];
2301
2302         psys->tot_fluidsprings--;
2303
2304         if (psys->tot_fluidsprings < psys->alloc_fluidsprings/2 && psys->alloc_fluidsprings > PSYS_FLUID_SPRINGS_INITIAL_SIZE) {
2305                 psys->alloc_fluidsprings /= 2;
2306                 psys->fluid_springs = (ParticleSpring*)MEM_reallocN(psys->fluid_springs,  psys->alloc_fluidsprings * sizeof(ParticleSpring));
2307         }
2308 }
2309 static void sph_springs_modify(ParticleSystem *psys, float dtime)
2310 {
2311         SPHFluidSettings *fluid = psys->part->fluid;
2312         ParticleData *pa1, *pa2;
2313         ParticleSpring *spring = psys->fluid_springs;
2314         
2315         float h, d, Rij[3], rij, Lij;
2316         int i;
2317
2318         float yield_ratio = fluid->yield_ratio;
2319         float plasticity = fluid->plasticity_constant;
2320         /* scale things according to dtime */
2321         float timefix = 25.f * dtime;
2322
2323         if ((fluid->flag & SPH_VISCOELASTIC_SPRINGS)==0 || fluid->spring_k == 0.f)
2324                 return;
2325
2326         /* Loop through the springs */
2327         for (i=0; i<psys->tot_fluidsprings; i++, spring++) {
2328                 pa1 = psys->particles + spring->particle_index[0];
2329                 pa2 = psys->particles + spring->particle_index[1];
2330
2331                 sub_v3_v3v3(Rij, pa2->prev_state.co, pa1->prev_state.co);
2332                 rij = normalize_v3(Rij);
2333
2334                 /* adjust rest length */
2335                 Lij = spring->rest_length;
2336                 d = yield_ratio * timefix * Lij;
2337
2338                 if (rij > Lij + d) // Stretch
2339                         spring->rest_length += plasticity * (rij - Lij - d) * timefix;
2340                 else if (rij < Lij - d) // Compress
2341                         spring->rest_length -= plasticity * (Lij - d - rij) * timefix;
2342
2343                 h = 4.f*pa1->size;
2344
2345                 if (spring->rest_length > h)
2346                         spring->delete_flag = 1;
2347         }
2348
2349         /* Loop through springs backwaqrds - for efficient delete function */
2350         for (i=psys->tot_fluidsprings-1; i >= 0; i--) {
2351                 if (psys->fluid_springs[i].delete_flag)
2352                         sph_spring_delete(psys, i);
2353         }
2354 }
2355 static EdgeHash *sph_springhash_build(ParticleSystem *psys)
2356 {
2357         EdgeHash *springhash = NULL;
2358         ParticleSpring *spring;
2359         int i = 0;
2360
2361         springhash = BLI_edgehash_new();
2362
2363         for (i=0, spring=psys->fluid_springs; i<psys->tot_fluidsprings; i++, spring++)
2364                 BLI_edgehash_insert(springhash, spring->particle_index[0], spring->particle_index[1], SET_INT_IN_POINTER(i+1));
2365
2366         return springhash;
2367 }
2368
2369 #define SPH_NEIGHBORS 512
2370 typedef struct SPHNeighbor {
2371         ParticleSystem *psys;
2372         int index;
2373 } SPHNeighbor;
2374
2375 typedef struct SPHRangeData {
2376         SPHNeighbor neighbors[SPH_NEIGHBORS];
2377         int tot_neighbors;
2378
2379         float density, near_density;
2380         float h;
2381
2382         ParticleSystem *npsys;
2383         ParticleData *pa;
2384
2385         float massfac;
2386         int use_size;
2387 } SPHRangeData;
2388
2389 typedef struct SPHData {
2390         ParticleSystem *psys[10];
2391         ParticleData *pa;
2392         float mass;
2393         EdgeHash *eh;
2394         float *gravity;
2395         /* Average distance to neighbors (other particles in the support domain),
2396          * for calculating the Courant number (adaptive time step). */
2397         int pass;
2398         float element_size;
2399         float flow[3];
2400
2401         /* Integrator callbacks. This allows different SPH implementations. */
2402         void (*force_cb) (void *sphdata_v, ParticleKey *state, float *force, float *impulse);
2403         void (*density_cb) (void *rangedata_v, int index, float squared_dist);
2404 } SPHData;
2405
2406 static void sph_density_accum_cb(void *userdata, int index, float squared_dist)
2407 {
2408         SPHRangeData *pfr = (SPHRangeData *)userdata;
2409         ParticleData *npa = pfr->npsys->particles + index;
2410         float q;
2411         float dist;
2412
2413         if (npa == pfr->pa || squared_dist < FLT_EPSILON)
2414                 return;
2415
2416         /* Ugh! One particle has too many neighbors! If some aren't taken into
2417          * account, the forces will be biased by the tree search order. This
2418          * effectively adds enery to the system, and results in a churning motion.
2419          * But, we have to stop somewhere, and it's not the end of the world.
2420          *  - jahka and z0r
2421          */
2422         if (pfr->tot_neighbors >= SPH_NEIGHBORS)
2423                 return;
2424
2425         pfr->neighbors[pfr->tot_neighbors].index = index;
2426         pfr->neighbors[pfr->tot_neighbors].psys = pfr->npsys;
2427         pfr->tot_neighbors++;
2428
2429         dist = sqrtf(squared_dist);
2430         q = (1.f - dist/pfr->h) * pfr->massfac;
2431
2432         if (pfr->use_size)
2433                 q *= npa->size;
2434
2435         pfr->density += q*q;
2436         pfr->near_density += q*q*q;
2437 }
2438
2439 /*
2440  * Find the Courant number for an SPH particle (used for adaptive time step).
2441  */
2442 static void sph_particle_courant(SPHData *sphdata, SPHRangeData *pfr)
2443 {
2444         ParticleData *pa, *npa;
2445         int i;
2446         float flow[3], offset[3], dist;
2447
2448         zero_v3(flow);
2449
2450         dist = 0.0f;
2451         if (pfr->tot_neighbors > 0) {
2452                 pa = pfr->pa;
2453                 for (i=0; i < pfr->tot_neighbors; i++) {
2454                         npa = pfr->neighbors[i].psys->particles + pfr->neighbors[i].index;
2455                         sub_v3_v3v3(offset, pa->prev_state.co, npa->prev_state.co);
2456                         dist += len_v3(offset);
2457                         add_v3_v3(flow, npa->prev_state.vel);
2458                 }
2459                 dist += sphdata->psys[0]->part->fluid->radius; // TODO: remove this? - z0r
2460                 sphdata->element_size = dist / pfr->tot_neighbors;
2461                 mul_v3_v3fl(sphdata->flow, flow, 1.0f / pfr->tot_neighbors);
2462         }
2463         else {
2464                 sphdata->element_size = MAXFLOAT;
2465                 copy_v3_v3(sphdata->flow, flow);
2466         }
2467 }
2468 static void sph_force_cb(void *sphdata_v, ParticleKey *state, float *force, float *UNUSED(impulse))
2469 {
2470         SPHData *sphdata = (SPHData *)sphdata_v;
2471         ParticleSystem **psys = sphdata->psys;
2472         ParticleData *pa = sphdata->pa;
2473         SPHFluidSettings *fluid = psys[0]->part->fluid;
2474         ParticleSpring *spring = NULL;
2475         SPHRangeData pfr;
2476         SPHNeighbor *pfn;
2477         float mass = sphdata->mass;
2478         float *gravity = sphdata->gravity;
2479         EdgeHash *springhash = sphdata->eh;
2480
2481         float q, u, rij, dv[3];
2482         float pressure, near_pressure;
2483
2484         float visc = fluid->viscosity_omega;
2485         float stiff_visc = fluid->viscosity_beta * (fluid->flag & SPH_FAC_VISCOSITY ? fluid->viscosity_omega : 1.f);
2486
2487         float inv_mass = 1.0f/mass;
2488         float spring_constant = fluid->spring_k;
2489         
2490         float h = fluid->radius * (fluid->flag & SPH_FAC_RADIUS ? 4.f*pa->size : 1.f); /* 4.0 seems to be a pretty good value */
2491         float rest_density = fluid->rest_density * (fluid->flag & SPH_FAC_DENSITY ? 4.77f : 1.f); /* 4.77 is an experimentally determined density factor */
2492         float rest_length = fluid->rest_length * (fluid->flag & SPH_FAC_REST_LENGTH ? 2.588f * pa->size : 1.f);
2493
2494         float stiffness = fluid->stiffness_k;
2495         float stiffness_near_fac = fluid->stiffness_knear * (fluid->flag & SPH_FAC_REPULSION ? fluid->stiffness_k : 1.f);
2496
2497         ParticleData *npa;
2498         float vec[3];
2499         float vel[3];
2500         float co[3];
2501
2502         int i, spring_index, index = pa - psys[0]->particles;
2503
2504         pfr.tot_neighbors = 0;
2505         pfr.density = pfr.near_density = 0.f;
2506         pfr.h = h;
2507         pfr.pa = pa;
2508
2509         for (i=0; i<10 && psys[i]; i++) {
2510                 pfr.npsys = psys[i];
2511                 pfr.massfac = psys[i]->part->mass*inv_mass;
2512                 pfr.use_size = psys[i]->part->flag & PART_SIZEMASS;
2513
2514                 BLI_bvhtree_range_query(psys[i]->bvhtree, state->co, h, sphdata->density_cb, &pfr);
2515         }
2516
2517         pressure =  stiffness * (pfr.density - rest_density);
2518         near_pressure = stiffness_near_fac * pfr.near_density;
2519
2520         pfn = pfr.neighbors;
2521         for (i=0; i<pfr.tot_neighbors; i++, pfn++) {
2522                 npa = pfn->psys->particles + pfn->index;
2523
2524                 madd_v3_v3v3fl(co, npa->prev_state.co, npa->prev_state.vel, state->time);
2525
2526                 sub_v3_v3v3(vec, co, state->co);
2527                 rij = normalize_v3(vec);
2528
2529                 q = (1.f - rij/h) * pfn->psys->part->mass * inv_mass;
2530
2531                 if (pfn->psys->part->flag & PART_SIZEMASS)
2532                         q *= npa->size;
2533
2534                 copy_v3_v3(vel, npa->prev_state.vel);
2535
2536                 /* Double Density Relaxation */
2537                 madd_v3_v3fl(force, vec, -(pressure + near_pressure*q)*q);
2538
2539                 /* Viscosity */
2540                 if (visc > 0.f  || stiff_visc > 0.f) {
2541                         sub_v3_v3v3(dv, vel, state->vel);
2542                         u = dot_v3v3(vec, dv);
2543
2544                         if (u < 0.f && visc > 0.f)
2545                                 madd_v3_v3fl(force, vec, 0.5f * q * visc * u );
2546
2547                         if (u > 0.f && stiff_visc > 0.f)
2548                                 madd_v3_v3fl(force, vec, 0.5f * q * stiff_visc * u );
2549                 }
2550
2551                 if (spring_constant > 0.f) {
2552                         /* Viscoelastic spring force */
2553                         if (pfn->psys == psys[0] && fluid->flag & SPH_VISCOELASTIC_SPRINGS && springhash) {
2554                                 /* BLI_edgehash_lookup appears to be thread-safe. - z0r */
2555                                 spring_index = GET_INT_FROM_POINTER(BLI_edgehash_lookup(springhash, index, pfn->index));
2556
2557                                 if (spring_index) {
2558                                         spring = psys[0]->fluid_springs + spring_index - 1;
2559
2560                                         madd_v3_v3fl(force, vec, -10.f * spring_constant * (1.f - rij/h) * (spring->rest_length - rij));
2561                                 }
2562                                 else if (fluid->spring_frames == 0 || (pa->prev_state.time-pa->time) <= fluid->spring_frames) {
2563                                         ParticleSpring temp_spring;
2564                                         temp_spring.particle_index[0] = index;
2565                                         temp_spring.particle_index[1] = pfn->index;
2566                                         temp_spring.rest_length = (fluid->flag & SPH_CURRENT_REST_LENGTH) ? rij : rest_length;
2567                                         temp_spring.delete_flag = 0;
2568
2569                                         /* sph_spring_add is not thread-safe. - z0r */
2570                                         #pragma omp critical
2571                                         sph_spring_add(psys[0], &temp_spring);
2572                                 }
2573                         }
2574                         else {/* PART_SPRING_HOOKES - Hooke's spring force */
2575                                 madd_v3_v3fl(force, vec, -10.f * spring_constant * (1.f - rij/h) * (rest_length - rij));
2576                         }
2577                 }
2578         }
2579         
2580         /* Artificial buoyancy force in negative gravity direction  */
2581         if (fluid->buoyancy > 0.f && gravity)
2582                 madd_v3_v3fl(force, gravity, fluid->buoyancy * (pfr.density-rest_density));
2583
2584         if (sphdata->pass == 0 && psys[0]->part->time_flag & PART_TIME_AUTOSF)
2585                 sph_particle_courant(sphdata, &pfr);
2586         sphdata->pass++;
2587 }
2588
2589 static void sph_solver_init(ParticleSimulationData *sim, SPHData *sphdata)
2590 {
2591         ParticleTarget *pt;
2592         int i;
2593
2594         // Add other coupled particle systems.
2595         sphdata->psys[0] = sim->psys;
2596         for (i=1, pt=sim->psys->targets.first; i<10; i++, pt=(pt?pt->next:NULL))
2597                 sphdata->psys[i] = pt ? psys_get_target_system(sim->ob, pt) : NULL;
2598
2599         if (psys_uses_gravity(sim))
2600                 sphdata->gravity = sim->scene->physics_settings.gravity;
2601         else
2602                 sphdata->gravity = NULL;
2603         sphdata->eh = sph_springhash_build(sim->psys);
2604
2605         // These per-particle values should be overridden later, but just for
2606         // completeness we give them default values now.
2607         sphdata->pa = NULL;
2608         sphdata->mass = 1.0f;
2609
2610         sphdata->force_cb = sph_force_cb;
2611         sphdata->density_cb = sph_density_accum_cb;
2612 }
2613
2614 static void sph_solver_finalise(SPHData *sphdata)
2615 {
2616         if (sphdata->eh) {
2617                 BLI_edgehash_free(sphdata->eh, NULL);
2618                 sphdata->eh = NULL;
2619         }
2620 }
2621
2622 static void sph_integrate(ParticleSimulationData *sim, ParticleData *pa, float dfra, SPHData *sphdata)
2623 {
2624         ParticleSettings *part = sim->psys->part;
2625         // float timestep = psys_get_timestep(sim); // UNUSED
2626         float pa_mass = part->mass * (part->flag & PART_SIZEMASS ? pa->size : 1.f);
2627         float dtime = dfra*psys_get_timestep(sim);
2628         // int steps = 1; // UNUSED
2629         float effector_acceleration[3];
2630
2631         sphdata->pa = pa;
2632         sphdata->mass = pa_mass;
2633         sphdata->pass = 0;
2634         //sphdata.element_size and sphdata.flow are set in the callback.
2635
2636         /* restore previous state and treat gravity & effectors as external acceleration*/
2637         sub_v3_v3v3(effector_acceleration, pa->state.vel, pa->prev_state.vel);
2638         mul_v3_fl(effector_acceleration, 1.f/dtime);
2639
2640         copy_particle_key(&pa->state, &pa->prev_state, 0);
2641
2642         integrate_particle(part, pa, dtime, effector_acceleration, sphdata->force_cb, sphdata);
2643 }
2644
2645 /************************************************/
2646 /*                      Basic physics                                           */
2647 /************************************************/
2648 typedef struct EfData {
2649         ParticleTexture ptex;
2650         ParticleSimulationData *sim;
2651         ParticleData *pa;
2652 } EfData;
2653 static void basic_force_cb(void *efdata_v, ParticleKey *state, float *force, float *impulse)
2654 {
2655         EfData *efdata = (EfData *)efdata_v;
2656         ParticleSimulationData *sim = efdata->sim;
2657         ParticleSettings *part = sim->psys->part;
2658         ParticleData *pa = efdata->pa;
2659         EffectedPoint epoint;
2660
2661         /* add effectors */
2662         pd_point_from_particle(efdata->sim, efdata->pa, state, &epoint);
2663         if (part->type != PART_HAIR || part->effector_weights->flag & EFF_WEIGHT_DO_HAIR)
2664                 pdDoEffectors(sim->psys->effectors, sim->colliders, part->effector_weights, &epoint, force, impulse);
2665
2666         mul_v3_fl(force, efdata->ptex.field);
2667         mul_v3_fl(impulse, efdata->ptex.field);
2668
2669         /* calculate air-particle interaction */
2670         if (part->dragfac != 0.0f)
2671                 madd_v3_v3fl(force, state->vel, -part->dragfac * pa->size * pa->size * len_v3(state->vel));
2672
2673         /* brownian force */
2674         if (part->brownfac != 0.0f) {
2675                 force[0] += (BLI_frand()-0.5f) * part->brownfac;
2676                 force[1] += (BLI_frand()-0.5f) * part->brownfac;
2677                 force[2] += (BLI_frand()-0.5f) * part->brownfac;
2678         }
2679
2680         if (part->flag & PART_ROT_DYN && epoint.ave)
2681                 copy_v3_v3(pa->state.ave, epoint.ave);
2682 }
2683 /* gathers all forces that effect particles and calculates a new state for the particle */
2684 static void basic_integrate(ParticleSimulationData *sim, int p, float dfra, float cfra)
2685 {
2686         ParticleSettings *part = sim->psys->part;
2687         ParticleData *pa = sim->psys->particles + p;
2688         ParticleKey tkey;
2689         float dtime=dfra*psys_get_timestep(sim), time;
2690         float *gravity = NULL, gr[3];
2691         EfData efdata;
2692
2693         psys_get_texture(sim, pa, &efdata.ptex, PAMAP_PHYSICS, cfra);
2694
2695         efdata.pa = pa;
2696         efdata.sim = sim;
2697
2698         /* add global acceleration (gravitation) */
2699         if (psys_uses_gravity(sim) &&
2700                 /* normal gravity is too strong for hair so it's disabled by default */
2701                 (part->type != PART_HAIR || part->effector_weights->flag & EFF_WEIGHT_DO_HAIR))
2702         {
2703                 zero_v3(gr);
2704                 madd_v3_v3fl(gr, sim->scene->physics_settings.gravity, part->effector_weights->global_gravity * efdata.ptex.gravity);
2705                 gravity = gr;
2706         }
2707
2708         /* maintain angular velocity */
2709         copy_v3_v3(pa->state.ave, pa->prev_state.ave);
2710
2711         integrate_particle(part, pa, dtime, gravity, basic_force_cb, &efdata);
2712
2713         /* damp affects final velocity */
2714         if (part->dampfac != 0.f)
2715                 mul_v3_fl(pa->state.vel, 1.f - part->dampfac * efdata.ptex.damp * 25.f * dtime);
2716
2717         //copy_v3_v3(pa->state.ave, states->ave);
2718
2719         /* finally we do guides */
2720         time=(cfra-pa->time)/pa->lifetime;
2721         CLAMP(time, 0.0f, 1.0f);
2722
2723         copy_v3_v3(tkey.co,pa->state.co);
2724         copy_v3_v3(tkey.vel,pa->state.vel);
2725         tkey.time=pa->state.time;
2726
2727         if (part->type != PART_HAIR) {
2728                 if (do_guides(sim->psys->effectors, &tkey, p, time)) {
2729                         copy_v3_v3(pa->state.co,tkey.co);
2730                         /* guides don't produce valid velocity */
2731                         sub_v3_v3v3(pa->state.vel, tkey.co, pa->prev_state.co);
2732                         mul_v3_fl(pa->state.vel,1.0f/dtime);
2733                         pa->state.time=tkey.time;
2734                 }
2735         }
2736 }
2737 static void basic_rotate(ParticleSettings *part, ParticleData *pa, float dfra, float timestep)
2738 {
2739         float rotfac, rot1[4], rot2[4] = {1.0,0.0,0.0,0.0}, dtime=dfra*timestep, extrotfac;
2740
2741         if ((part->flag & PART_ROTATIONS) == 0) {
2742                 unit_qt(pa->state.rot);
2743                 return;
2744         }
2745
2746         if (part->flag & PART_ROT_DYN) {
2747                 extrotfac = len_v3(pa->state.ave);
2748         }
2749         else {
2750                 extrotfac = 0.0f;
2751         }
2752
2753         if ((part->flag & PART_ROT_DYN) && ELEM3(part->avemode, PART_AVE_VELOCITY, PART_AVE_HORIZONTAL, PART_AVE_VERTICAL)) {
2754                 float angle;
2755                 float len1 = len_v3(pa->prev_state.vel);
2756                 float len2 = len_v3(pa->state.vel);
2757                 float vec[3];
2758
2759                 if (len1 == 0.0f || len2 == 0.0f) {
2760                         zero_v3(pa->state.ave);
2761                 }
2762                 else {
2763                         cross_v3_v3v3(pa->state.ave, pa->prev_state.vel, pa->state.vel);
2764                         normalize_v3(pa->state.ave);
2765                         angle = dot_v3v3(pa->prev_state.vel, pa->state.vel) / (len1 * len2);
2766                         mul_v3_fl(pa->state.ave, saacos(angle) / dtime);
2767                 }
2768
2769                 get_angular_velocity_vector(part->avemode, &pa->state, vec);
2770                 axis_angle_to_quat(rot2, vec, dtime*part->avefac);
2771         }
2772
2773         rotfac = len_v3(pa->state.ave);
2774         if (rotfac == 0.0f || (part->flag & PART_ROT_DYN)==0 || extrotfac == 0.0f) {
2775                 unit_qt(rot1);
2776         }
2777         else {
2778                 axis_angle_to_quat(rot1,pa->state.ave,rotfac*dtime);
2779         }
2780         mul_qt_qtqt(pa->state.rot,rot1,pa->prev_state.rot);
2781         mul_qt_qtqt(pa->state.rot,rot2,pa->state.rot);
2782
2783         /* keep rotation quat in good health */
2784         normalize_qt(pa->state.rot);
2785 }
2786
2787 /************************************************/
2788 /*                      Collisions                                                      */
2789 /************************************************/
2790 #define COLLISION_MAX_COLLISIONS        10
2791 #define COLLISION_MIN_RADIUS 0.001f
2792 #define COLLISION_MIN_DISTANCE 0.0001f
2793 #define COLLISION_ZERO 0.00001f
2794 typedef float (*NRDistanceFunc)(float *p, float radius, ParticleCollisionElement *pce, float *nor);
2795 static float nr_signed_distance_to_plane(float *p, float radius, ParticleCollisionElement *pce, float *nor)
2796 {
2797         float p0[3], e1[3], e2[3], d;
2798
2799         sub_v3_v3v3(e1, pce->x1, pce->x0);
2800         sub_v3_v3v3(e2, pce->x2, pce->x0);
2801         sub_v3_v3v3(p0, p, pce->x0);
2802
2803         cross_v3_v3v3(nor, e1, e2);
2804         normalize_v3(nor);
2805
2806         d = dot_v3v3(p0, nor);
2807
2808         if (pce->inv_nor == -1) {
2809                 if (d < 0.f)
2810                         pce->inv_nor = 1;
2811                 else
2812                         pce->inv_nor = 0;
2813         }
2814
2815         if (pce->inv_nor == 1) {
2816                 negate_v3(nor);
2817                 d = -d;
2818         }
2819
2820         return d - radius;
2821 }
2822 static float nr_distance_to_edge(float *p, float radius, ParticleCollisionElement *pce, float *UNUSED(nor))
2823 {
2824         float v0[3], v1[3], v2[3], c[3];
2825
2826         sub_v3_v3v3(v0, pce->x1, pce->x0);
2827         sub_v3_v3v3(v1, p, pce->x0);
2828         sub_v3_v3v3(v2, p, pce->x1);
2829
2830         cross_v3_v3v3(c, v1, v2);
2831
2832         return fabsf(len_v3(c)/len_v3(v0)) - radius;
2833 }
2834 static float nr_distance_to_vert(float *p, float radius, ParticleCollisionElement *pce, float *UNUSED(nor))
2835 {
2836         return len_v3v3(p, pce->x0) - radius;
2837 }
2838 static void collision_interpolate_element(ParticleCollisionElement *pce, float t, float fac, ParticleCollision *col)
2839 {
2840         /* t is the current time for newton rhapson */
2841         /* fac is the starting factor for current collision iteration */
2842         /* the col->fac's are factors for the particle subframe step start and end during collision modifier step */
2843         float f = fac + t*(1.f-fac);
2844         float mul = col->fac1 + f * (col->fac2-col->fac1);
2845         if (pce->tot > 0) {
2846                 madd_v3_v3v3fl(pce->x0, pce->x[0], pce->v[0], mul);
2847
2848                 if (pce->tot > 1) {
2849                         madd_v3_v3v3fl(pce->x1, pce->x[1], pce->v[1], mul);
2850
2851                         if (pce->tot > 2)
2852                                 madd_v3_v3v3fl(pce->x2, pce->x[2], pce->v[2], mul);
2853                 }
2854         }
2855 }
2856 static void collision_point_velocity(ParticleCollisionElement *pce)
2857 {
2858         float v[3];
2859
2860         copy_v3_v3(pce->vel, pce->v[0]);
2861
2862         if (pce->tot > 1) {
2863                 sub_v3_v3v3(v, pce->v[1], pce->v[0]);
2864                 madd_v3_v3fl(pce->vel, v, pce->uv[0]);
2865
2866                 if (pce->tot > 2) {
2867                         sub_v3_v3v3(v, pce->v[2], pce->v[0]);
2868                         madd_v3_v3fl(pce->vel, v, pce->uv[1]);
2869                 }
2870         }
2871 }
2872 static float collision_point_distance_with_normal(float p[3], ParticleCollisionElement *pce, float fac, ParticleCollision *col, float *nor)
2873 {
2874         if (fac >= 0.f)
2875                 collision_interpolate_element(pce, 0.f, fac, col);
2876
2877         switch (pce->tot) {
2878                 case 1:
2879                 {
2880                         sub_v3_v3v3(nor, p, pce->x0);
2881                         return normalize_v3(nor);
2882                 }
2883                 case 2:
2884                 {
2885                         float u, e[3], vec[3];
2886                         sub_v3_v3v3(e, pce->x1, pce->x0);
2887                         sub_v3_v3v3(vec, p, pce->x0);
2888                         u = dot_v3v3(vec, e) / dot_v3v3(e, e);
2889
2890                         madd_v3_v3v3fl(nor, vec, e, -u);
2891                         return normalize_v3(nor);
2892                 }
2893                 case 3:
2894                         return nr_signed_distance_to_plane(p, 0.f, pce, nor);
2895         }
2896         return 0;
2897 }
2898 static void collision_point_on_surface(float p[3], ParticleCollisionElement *pce, float fac, ParticleCollision *col, float *co)
2899 {
2900         collision_interpolate_element(pce, 0.f, fac, col);
2901
2902         switch (pce->tot) {
2903                 case 1:
2904                 {
2905                         sub_v3_v3v3(co, p, pce->x0);
2906                         normalize_v3(co);
2907                         madd_v3_v3v3fl(co, pce->x0, co, col->radius);
2908                         break;
2909                 }
2910                 case 2:
2911                 {
2912                         float u, e[3], vec[3], nor[3];
2913                         sub_v3_v3v3(e, pce->x1, pce->x0);
2914                         sub_v3_v3v3(vec, p, pce->x0);
2915                         u = dot_v3v3(vec, e) / dot_v3v3(e, e);
2916
2917                         madd_v3_v3v3fl(nor, vec, e, -u);
2918                         normalize_v3(nor);
2919
2920                         madd_v3_v3v3fl(co, pce->x0, e, pce->uv[0]);
2921                         madd_v3_v3fl(co, nor, col->radius);
2922                         break;
2923                 }
2924                 case 3:
2925                 {
2926                                 float p0[3], e1[3], e2[3], nor[3];
2927
2928                                 sub_v3_v3v3(e1, pce->x1, pce->x0);
2929                                 sub_v3_v3v3(e2, pce->x2, pce->x0);
2930                                 sub_v3_v3v3(p0, p, pce->x0);
2931
2932                                 cross_v3_v3v3(nor, e1, e2);
2933                                 normalize_v3(nor);
2934
2935                                 if (pce->inv_nor == 1)
2936                                         negate_v3(nor);
2937
2938                                 madd_v3_v3v3fl(co, pce->x0, nor, col->radius);
2939                                 madd_v3_v3fl(co, e1, pce->uv[0]);
2940                                 madd_v3_v3fl(co, e2, pce->uv[1]);
2941                         break;
2942                 }
2943         }
2944 }
2945 /* find first root in range [0-1] starting from 0 */
2946 static float collision_newton_rhapson(ParticleCollision *col, float radius, ParticleCollisionElement *pce, NRDistanceFunc distance_func)
2947 {
2948         float t0, t1, d0, d1, dd, n[3];
2949         int iter;
2950
2951         pce->inv_nor = -1;
2952
2953         /* start from the beginning */
2954         t0 = 0.f;
2955         collision_interpolate_element(pce, t0, col->f, col);
2956         d0 = distance_func(col->co1, radius, pce, n);
2957         t1 = 0.001f;
2958         d1 = 0.f;
2959
2960         for (iter=0; iter<10; iter++) {//, itersum++) {
2961                 /* get current location */
2962                 collision_interpolate_element(pce, t1, col->f, col);
2963                 interp_v3_v3v3(pce->p, col->co1, col->co2, t1);
2964
2965                 d1 = distance_func(pce->p, radius, pce, n);
2966
2967                 /* no movement, so no collision */
2968                 if (d1 == d0) {
2969                         return -1.f;
2970                 }
2971
2972                 /* particle already inside face, so report collision */
2973                 if (iter == 0 && d0 < 0.f && d0 > -radius) {
2974                         copy_v3_v3(pce->p, col->co1);
2975                         copy_v3_v3(pce->nor, n);
2976                         pce->inside = 1;
2977                         return 0.f;
2978                 }
2979                 
2980                 dd = (t1-t0)/(d1-d0);
2981
2982                 t0 = t1;
2983                 d0 = d1;
2984
2985                 t1 -= d1*dd;
2986
2987                 /* particle movin away from plane could also mean a strangely rotating face, so check from end */
2988                 if (iter == 0 && t1 < 0.f) {
2989                         t0 = 1.f;
2990                         collision_interpolate_element(pce, t0, col->f, col);
2991                         d0 = distance_func(col->co2, radius, pce, n);
2992                         t1 = 0.999f;
2993                         d1 = 0.f;
2994
2995                         continue;
2996                 }
2997                 else if (iter == 1 && (t1 < -COLLISION_ZERO || t1 > 1.f))
2998                         return -1.f;
2999
3000                 if (d1 <= COLLISION_ZERO && d1 >= -COLLISION_ZERO) {
3001                         if (t1 >= -COLLISION_ZERO && t1 <= 1.f) {
3002                                 if (distance_func == nr_signed_distance_to_plane)
3003                                         copy_v3_v3(pce->nor, n);
3004
3005                                 CLAMP(t1, 0.f, 1.f);
3006
3007                                 return t1;
3008                         }
3009                         else
3010                                 return -1.f;
3011                 }
3012         }