summaryrefslogtreecommitdiff
path: root/indra/newview/llviewerpartsim.cpp
blob: 8acdc08b0025d258648de851fcb0ce16866fff2a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
/** 
 * @file llviewerpartsim.cpp
 * @brief LLViewerPart class implementation
 *
 * $LicenseInfo:firstyear=2003&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "llviewerprecompiledheaders.h"

#include "llviewerpartsim.h"

#include "llviewercontrol.h"

#include "llagent.h"
#include "llviewercamera.h"
#include "llviewerobjectlist.h"
#include "llviewerpartsource.h"
#include "llviewerregion.h"
#include "llvopartgroup.h"
#include "llworld.h"
#include "pipeline.h"
#include "llspatialpartition.h"
#include "llvovolume.h"

const F32 PART_SIM_BOX_SIDE = 16.f;
const F32 PART_SIM_BOX_OFFSET = 0.5f*PART_SIM_BOX_SIDE;
const F32 PART_SIM_BOX_RAD = 0.5f*F_SQRT3*PART_SIM_BOX_SIDE;

//static
S32 LLViewerPartSim::sMaxParticleCount = 0;
S32 LLViewerPartSim::sParticleCount = 0;
S32 LLViewerPartSim::sParticleCount2 = 0;
// This controls how greedy individual particle burst sources are allowed to be, and adapts according to how near the particle-count limit we are.
F32 LLViewerPartSim::sParticleAdaptiveRate = 0.0625f;
F32 LLViewerPartSim::sParticleBurstRate = 0.5f;

//static
const S32 LLViewerPartSim::MAX_PART_COUNT = 8192;
const F32 LLViewerPartSim::PART_THROTTLE_THRESHOLD = 0.9f;
const F32 LLViewerPartSim::PART_ADAPT_RATE_MULT = 2.0f;

//static
const F32 LLViewerPartSim::PART_THROTTLE_RESCALE = PART_THROTTLE_THRESHOLD / (1.0f-PART_THROTTLE_THRESHOLD);
const F32 LLViewerPartSim::PART_ADAPT_RATE_MULT_RECIP = 1.0f/PART_ADAPT_RATE_MULT;


U32 LLViewerPart::sNextPartID = 1;

F32 calc_desired_size(LLViewerCamera* camera, LLVector3 pos, LLVector2 scale)
{
	F32 desired_size = (pos - camera->getOrigin()).magVec();
	desired_size /= 4;
	return llclamp(desired_size, scale.magVec()*0.5f, PART_SIM_BOX_SIDE*2);
}

LLViewerPart::LLViewerPart() :
	mPartID(0),
	mLastUpdateTime(0.f),
	mSkipOffset(0.f),
	mVPCallback(NULL),
	mImagep(NULL)
{
	mPartSourcep = NULL;

	++LLViewerPartSim::sParticleCount2 ;
}

LLViewerPart::~LLViewerPart()
{
	mPartSourcep = NULL;

	--LLViewerPartSim::sParticleCount2 ;
}

void LLViewerPart::init(LLPointer<LLViewerPartSource> sourcep, LLViewerTexture *imagep, LLVPCallback cb)
{
	mPartID = LLViewerPart::sNextPartID;
	LLViewerPart::sNextPartID++;
	mFlags = 0x00f;
	mLastUpdateTime = 0.f;
	mMaxAge = 10.f;
	mSkipOffset = 0.0f;

	mVPCallback = cb;
	mPartSourcep = sourcep;

	mImagep = imagep;
}


/////////////////////////////
//
// LLViewerPartGroup implementation
//
//


LLViewerPartGroup::LLViewerPartGroup(const LLVector3 &center_agent, const F32 box_side, bool hud)
 : mHud(hud)
{
	mVOPartGroupp = NULL;
	mUniformParticles = TRUE;

	mRegionp = LLWorld::getInstance()->getRegionFromPosAgent(center_agent);
	llassert_always(center_agent.isFinite());
	
	if (!mRegionp)
	{
		//llwarns << "No region at position, using agent region!" << llendl;
		mRegionp = gAgent.getRegion();
	}
	mCenterAgent = center_agent;
	mBoxRadius = F_SQRT3*box_side*0.5f;

	if (mHud)
	{
		mVOPartGroupp = (LLVOPartGroup *)gObjectList.createObjectViewer(LLViewerObject::LL_VO_HUD_PART_GROUP, getRegion());
	}
	else
	{
	mVOPartGroupp = (LLVOPartGroup *)gObjectList.createObjectViewer(LLViewerObject::LL_VO_PART_GROUP, getRegion());
	}
	mVOPartGroupp->setViewerPartGroup(this);
	mVOPartGroupp->setPositionAgent(getCenterAgent());
	F32 scale = box_side * 0.5f;
	mVOPartGroupp->setScale(LLVector3(scale,scale,scale));
	
	//gPipeline.addObject(mVOPartGroupp);
	gPipeline.createObject(mVOPartGroupp);

	LLSpatialGroup* group = mVOPartGroupp->mDrawable->getSpatialGroup();

	if (group != NULL)
	{
		LLVector3 center(group->getOctreeNode()->getCenter().getF32ptr());
		LLVector3 size(group->getOctreeNode()->getSize().getF32ptr());
		size += LLVector3(0.01f, 0.01f, 0.01f);
		mMinObjPos = center - size;
		mMaxObjPos = center + size;
	}
	else 
	{
		// Not sure what else to set the obj bounds to when the drawable has no spatial group.
		LLVector3 extents(mBoxRadius, mBoxRadius, mBoxRadius);
		mMinObjPos = center_agent - extents;
		mMaxObjPos = center_agent + extents;
	}

	mSkippedTime = 0.f;

	static U32 id_seed = 0;
	mID = ++id_seed;
}

LLViewerPartGroup::~LLViewerPartGroup()
{
	cleanup();
	
	S32 count = (S32) mParticles.size();
	for(S32 i = 0 ; i < count ; i++)
	{
		delete mParticles[i] ;
	}
	mParticles.clear();
	
	LLViewerPartSim::decPartCount(count);
}

void LLViewerPartGroup::cleanup()
{
	if (mVOPartGroupp)
	{
		if (!mVOPartGroupp->isDead())
		{
			gObjectList.killObject(mVOPartGroupp);
		}
		mVOPartGroupp = NULL;
	}
}

BOOL LLViewerPartGroup::posInGroup(const LLVector3 &pos, const F32 desired_size)
{
	if ((pos.mV[VX] < mMinObjPos.mV[VX])
		|| (pos.mV[VY] < mMinObjPos.mV[VY])
		|| (pos.mV[VZ] < mMinObjPos.mV[VZ]))
	{
		return FALSE;
	}

	if ((pos.mV[VX] > mMaxObjPos.mV[VX])
		|| (pos.mV[VY] > mMaxObjPos.mV[VY])
		|| (pos.mV[VZ] > mMaxObjPos.mV[VZ]))
	{
		return FALSE;
	}

	if (desired_size > 0 && 
		(desired_size < mBoxRadius*0.5f ||
		desired_size > mBoxRadius*2.f))
	{
		return FALSE;
	}

	return TRUE;
}


BOOL LLViewerPartGroup::addPart(LLViewerPart* part, F32 desired_size)
{
	if (part->mFlags & LLPartData::LL_PART_HUD && !mHud)
	{
		return FALSE;
	}

	BOOL uniform_part = part->mScale.mV[0] == part->mScale.mV[1] && 
					!(part->mFlags & LLPartData::LL_PART_FOLLOW_VELOCITY_MASK);

	if (!posInGroup(part->mPosAgent, desired_size) ||
		(mUniformParticles && !uniform_part) ||
		(!mUniformParticles && uniform_part))
	{
		return FALSE;
	}

	gPipeline.markRebuild(mVOPartGroupp->mDrawable, LLDrawable::REBUILD_ALL, TRUE);
	
	mParticles.push_back(part);
	part->mSkipOffset=mSkippedTime;
	LLViewerPartSim::incPartCount(1);
	return TRUE;
}


void LLViewerPartGroup::updateParticles(const F32 lastdt)
{
	F32 dt;
	
	LLVector3 gravity(0.f, 0.f, GRAVITY);

	LLViewerPartSim::checkParticleCount(mParticles.size());

	LLViewerCamera* camera = LLViewerCamera::getInstance();
	LLViewerRegion *regionp = getRegion();
	S32 end = (S32) mParticles.size();
	for (S32 i = 0 ; i < (S32)mParticles.size();)
	{
		LLVector3 a(0.f, 0.f, 0.f);
		LLViewerPart* part = mParticles[i] ;

		dt = lastdt + mSkippedTime - part->mSkipOffset;
		part->mSkipOffset = 0.f;

		// Update current time
		const F32 cur_time = part->mLastUpdateTime + dt;
		const F32 frac = cur_time / part->mMaxAge;

		// "Drift" the object based on the source object
		if (part->mFlags & LLPartData::LL_PART_FOLLOW_SRC_MASK)
		{
			part->mPosAgent = part->mPartSourcep->mPosAgent;
			part->mPosAgent += part->mPosOffset;
		}

		// Do a custom callback if we have one...
		if (part->mVPCallback)
		{
			(*part->mVPCallback)(*part, dt);
		}

		if (part->mFlags & LLPartData::LL_PART_WIND_MASK)
		{
			LLVector3 tempVel(part->mVelocity);
			part->mVelocity *= 1.f - 0.1f*dt;
			part->mVelocity += 0.1f*dt*regionp->mWind.getVelocity(regionp->getPosRegionFromAgent(part->mPosAgent));
		}

		// Now do interpolation towards a target
		if (part->mFlags & LLPartData::LL_PART_TARGET_POS_MASK)
		{
			F32 remaining = part->mMaxAge - part->mLastUpdateTime;
			F32 step = dt / remaining;

			step = llclamp(step, 0.f, 0.1f);
			step *= 5.f;
			// we want a velocity that will result in reaching the target in the 
			// Interpolate towards the target.
			LLVector3 delta_pos = part->mPartSourcep->mTargetPosAgent - part->mPosAgent;

			delta_pos /= remaining;

			part->mVelocity *= (1.f - step);
			part->mVelocity += step*delta_pos;
		}


		if (part->mFlags & LLPartData::LL_PART_TARGET_LINEAR_MASK)
		{
			LLVector3 delta_pos = part->mPartSourcep->mTargetPosAgent - part->mPartSourcep->mPosAgent;			
			part->mPosAgent = part->mPartSourcep->mPosAgent;
			part->mPosAgent += frac*delta_pos;
			part->mVelocity = delta_pos;
		}
		else
		{
			// Do velocity interpolation
			part->mPosAgent += dt*part->mVelocity;
			part->mPosAgent += 0.5f*dt*dt*part->mAccel;
			part->mVelocity += part->mAccel*dt;
		}

		// Do a bounce test
		if (part->mFlags & LLPartData::LL_PART_BOUNCE_MASK)
		{
			// Need to do point vs. plane check...
			// For now, just check relative to object height...
			F32 dz = part->mPosAgent.mV[VZ] - part->mPartSourcep->mPosAgent.mV[VZ];
			if (dz < 0)
			{
				part->mPosAgent.mV[VZ] += -2.f*dz;
				part->mVelocity.mV[VZ] *= -0.75f;
			}
		}


		// Reset the offset from the source position
		if (part->mFlags & LLPartData::LL_PART_FOLLOW_SRC_MASK)
		{
			part->mPosOffset = part->mPosAgent;
			part->mPosOffset -= part->mPartSourcep->mPosAgent;
		}

		// Do color interpolation
		if (part->mFlags & LLPartData::LL_PART_INTERP_COLOR_MASK)
		{
			part->mColor.setVec(part->mStartColor);
			// note: LLColor4's v%k means multiply-alpha-only,
			//       LLColor4's v*k means multiply-rgb-only
			part->mColor *= 1.f - frac; // rgb*k
			part->mColor %= 1.f - frac; // alpha*k
			part->mColor += frac%(frac*part->mEndColor); // rgb,alpha
		}

		// Do scale interpolation
		if (part->mFlags & LLPartData::LL_PART_INTERP_SCALE_MASK)
		{
			part->mScale.setVec(part->mStartScale);
			part->mScale *= 1.f - frac;
			part->mScale += frac*part->mEndScale;
		}

		// Set the last update time to now.
		part->mLastUpdateTime = cur_time;


		// Kill dead particles (either flagged dead, or too old)
		if ((part->mLastUpdateTime > part->mMaxAge) || (LLViewerPart::LL_PART_DEAD_MASK == part->mFlags))
		{
			mParticles[i] = mParticles.back() ;
			mParticles.pop_back() ;
			delete part ;
		}
		else 
		{
			F32 desired_size = calc_desired_size(camera, part->mPosAgent, part->mScale);
			if (!posInGroup(part->mPosAgent, desired_size))
			{
				// Transfer particles between groups
				LLViewerPartSim::getInstance()->put(part) ;
				mParticles[i] = mParticles.back() ;
				mParticles.pop_back() ;
			}
			else
			{
				i++ ;
			}
		}
	}

	S32 removed = end - (S32)mParticles.size();
	if (removed > 0)
	{
		// we removed one or more particles, so flag this group for update
		if (mVOPartGroupp.notNull())
		{
			gPipeline.markRebuild(mVOPartGroupp->mDrawable, LLDrawable::REBUILD_ALL, TRUE);
		}
		LLViewerPartSim::decPartCount(removed);
	}
	
	// Kill the viewer object if this particle group is empty
	if (mParticles.empty())
	{
		gObjectList.killObject(mVOPartGroupp);
		mVOPartGroupp = NULL;
	}

	LLViewerPartSim::checkParticleCount() ;
}


void LLViewerPartGroup::shift(const LLVector3 &offset)
{
	mCenterAgent += offset;
	mMinObjPos += offset;
	mMaxObjPos += offset;

	for (S32 i = 0 ; i < (S32)mParticles.size(); i++)
	{
		mParticles[i]->mPosAgent += offset;
	}
}

void LLViewerPartGroup::removeParticlesByID(const U32 source_id)
{
	for (S32 i = 0; i < (S32)mParticles.size(); i++)
	{
		if(mParticles[i]->mPartSourcep->getID() == source_id)
		{
			mParticles[i]->mFlags = LLViewerPart::LL_PART_DEAD_MASK;
		}		
	}
}

//////////////////////////////////
//
// LLViewerPartSim implementation
//
//

//static
void LLViewerPartSim::checkParticleCount(U32 size)
{
	if(LLViewerPartSim::sParticleCount2 != LLViewerPartSim::sParticleCount)
	{
		llerrs << "sParticleCount: " << LLViewerPartSim::sParticleCount << " ; sParticleCount2: " << LLViewerPartSim::sParticleCount2 << llendl ;
	}

	if(size > (U32)LLViewerPartSim::sParticleCount2)
	{
		llerrs << "curren particle size: " << LLViewerPartSim::sParticleCount2 << " array size: " << size << llendl ;
	}
}

LLViewerPartSim::LLViewerPartSim()
{
	sMaxParticleCount = llmin(gSavedSettings.getS32("RenderMaxPartCount"), LL_MAX_PARTICLE_COUNT);
	static U32 id_seed = 0;
	mID = ++id_seed;
}


void LLViewerPartSim::destroyClass()
{
	S32 i;
	S32 count;

	// Kill all of the groups (and particles)
	count = (S32) mViewerPartGroups.size();
	for (i = 0; i < count; i++)
	{
		delete mViewerPartGroups[i];
	}
	mViewerPartGroups.clear();

	// Kill all of the sources 
	mViewerPartSources.clear();
}

//static
BOOL LLViewerPartSim::shouldAddPart()
{
	if (sParticleCount > PART_THROTTLE_THRESHOLD*sMaxParticleCount)
	{

		F32 frac = (F32)sParticleCount/(F32)sMaxParticleCount;
		frac -= PART_THROTTLE_THRESHOLD;
		frac *= PART_THROTTLE_RESCALE;
		if (ll_frand() < frac)
		{
			// Skip...
			return FALSE;
		}
	}
	if (sParticleCount >= MAX_PART_COUNT)
	{
		return FALSE;
	}

	return TRUE;
}

void LLViewerPartSim::addPart(LLViewerPart* part)
{
	if (sParticleCount < MAX_PART_COUNT)
	{
		put(part);
	}
	else
	{
		//delete the particle if can not add it in
		delete part ;
		part = NULL ;
	}
}


LLViewerPartGroup *LLViewerPartSim::put(LLViewerPart* part)
{
	const F32 MAX_MAG = 1000000.f*1000000.f; // 1 million
	LLViewerPartGroup *return_group = NULL ;
	if (part->mPosAgent.magVecSquared() > MAX_MAG || !part->mPosAgent.isFinite())
	{
#if 0 && !LL_RELEASE_FOR_DOWNLOAD
		llwarns << "LLViewerPartSim::put Part out of range!" << llendl;
		llwarns << part->mPosAgent << llendl;
#endif
	}
	else
	{	
		LLViewerCamera* camera = LLViewerCamera::getInstance();
		F32 desired_size = calc_desired_size(camera, part->mPosAgent, part->mScale);

		S32 count = (S32) mViewerPartGroups.size();
		for (S32 i = 0; i < count; i++)
		{
			if (mViewerPartGroups[i]->addPart(part, desired_size))
			{
				// We found a spatial group that we fit into, add us and exit
				return_group = mViewerPartGroups[i];
				break ;
			}
		}

		// Hmm, we didn't fit in any of the existing spatial groups
		// Create a new one...
		if(!return_group)
		{
			llassert_always(part->mPosAgent.isFinite());
			LLViewerPartGroup *groupp = createViewerPartGroup(part->mPosAgent, desired_size, part->mFlags & LLPartData::LL_PART_HUD);
			groupp->mUniformParticles = (part->mScale.mV[0] == part->mScale.mV[1] && 
									!(part->mFlags & LLPartData::LL_PART_FOLLOW_VELOCITY_MASK));
			if (!groupp->addPart(part))
			{
				llwarns << "LLViewerPartSim::put - Particle didn't go into its box!" << llendl;
				llinfos << groupp->getCenterAgent() << llendl;
				llinfos << part->mPosAgent << llendl;
				mViewerPartGroups.pop_back() ;
				delete groupp;
				groupp = NULL ;
			}
			return_group = groupp;
		}
	}

	if(!return_group) //failed to insert the particle
	{
		delete part ;
		part = NULL ;
	}

	return return_group ;
}

LLViewerPartGroup *LLViewerPartSim::createViewerPartGroup(const LLVector3 &pos_agent, const F32 desired_size, bool hud)
{
	//find a box that has a center position divisible by PART_SIM_BOX_SIDE that encompasses
	//pos_agent
	LLViewerPartGroup *groupp = new LLViewerPartGroup(pos_agent, desired_size, hud);
	mViewerPartGroups.push_back(groupp);
	return groupp;
}


void LLViewerPartSim::shift(const LLVector3 &offset)
{
	S32 i;
	S32 count;

	count = (S32) mViewerPartSources.size();
	for (i = 0; i < count; i++)
	{
		mViewerPartSources[i]->mPosAgent += offset;
		mViewerPartSources[i]->mTargetPosAgent += offset;
		mViewerPartSources[i]->mLastUpdatePosAgent += offset;
	}

	count = (S32) mViewerPartGroups.size();
	for (i = 0; i < count; i++)
	{
		mViewerPartGroups[i]->shift(offset);
	}
}

static LLFastTimer::DeclareTimer FTM_SIMULATE_PARTICLES("Simulate Particles");

void LLViewerPartSim::updateSimulation()
{
	static LLFrameTimer update_timer;

	const F32 dt = llmin(update_timer.getElapsedTimeAndResetF32(), 0.1f);

 	if (!(gPipeline.hasRenderType(LLPipeline::RENDER_TYPE_PARTICLES)))
	{
		return;
	}

	LLFastTimer ftm(FTM_SIMULATE_PARTICLES);

	// Start at a random particle system so the same
	// particle system doesn't always get first pick at the
	// particles.  Theoretically we'd want to do this in distance
	// order or something, but sorting particle sources will be a big
	// pain.
	S32 i;
	S32 count = (S32) mViewerPartSources.size();
	S32 start = (S32)ll_frand((F32)count);
	S32 dir = 1;
	S32 deldir = 0;
	if (ll_frand() > 0.5f)
	{
		dir = -1;
		deldir = -1;
	}

	S32 num_updates = 0;
	for (i = start; num_updates < count;)
	{
		if (i >= count)
		{
			i = 0;
		}
		if (i < 0)
		{
			i = count - 1;
		}

		if (!mViewerPartSources[i]->isDead())
		{
			BOOL upd = TRUE;
			if (!LLPipeline::sRenderAttachedParticles)
			{
				LLViewerObject* vobj = mViewerPartSources[i]->mSourceObjectp;
				if (vobj && (vobj->getPCode() == LL_PCODE_VOLUME))
				{
					LLVOVolume* vvo = (LLVOVolume *)vobj;
					if (vvo && vvo->isAttachment())
					{
						upd = FALSE;
					}
				}
			}

			if (upd) 
			{
				mViewerPartSources[i]->update(dt);
			}
		}

		if (mViewerPartSources[i]->isDead())
		{
			mViewerPartSources.erase(mViewerPartSources.begin() + i);
			count--;
			i+=deldir;
		}
		else
        {
			 i += dir;
        }
		num_updates++;
	}

	count = (S32) mViewerPartGroups.size();
	for (i = 0; i < count; i++)
	{
		LLViewerObject* vobj = mViewerPartGroups[i]->mVOPartGroupp;

		S32 visirate = 1;
		if (vobj)
		{
			LLSpatialGroup* group = vobj->mDrawable->getSpatialGroup();
			if (group && !group->isVisible()) // && !group->isState(LLSpatialGroup::OBJECT_DIRTY))
			{
				visirate = 8;
			}
		}

		if ((LLDrawable::getCurrentFrame()+mViewerPartGroups[i]->mID)%visirate == 0)
		{
			if (vobj)
			{
				gPipeline.markRebuild(vobj->mDrawable, LLDrawable::REBUILD_ALL, TRUE);
			}
			mViewerPartGroups[i]->updateParticles(dt * visirate);
			mViewerPartGroups[i]->mSkippedTime=0.0f;
			if (!mViewerPartGroups[i]->getCount())
			{
				delete mViewerPartGroups[i];
				mViewerPartGroups.erase(mViewerPartGroups.begin() + i);
				i--;
				count--;
			}
		}
		else
		{	
			mViewerPartGroups[i]->mSkippedTime+=dt;
		}

	}
	if (LLDrawable::getCurrentFrame()%16==0)
	{
		if (sParticleCount > sMaxParticleCount * 0.875f
		    && sParticleAdaptiveRate < 2.0f)
		{
			sParticleAdaptiveRate *= PART_ADAPT_RATE_MULT;
		}
		else
		{
			if (sParticleCount < sMaxParticleCount * 0.5f
			    && sParticleAdaptiveRate > 0.03125f)
			{
				sParticleAdaptiveRate *= PART_ADAPT_RATE_MULT_RECIP;
			}
		}
	}

	updatePartBurstRate() ;

	//llinfos << "Particles: " << sParticleCount << " Adaptive Rate: " << sParticleAdaptiveRate << llendl;
}

void LLViewerPartSim::updatePartBurstRate()
{
	if (!(LLDrawable::getCurrentFrame() & 0xf))
	{
		if (sParticleCount >= MAX_PART_COUNT) //set rate to zero
		{
			sParticleBurstRate = 0.0f ;
		}
		else if(sParticleCount > 0)
		{
			if(sParticleBurstRate > 0.0000001f)
			{				
				F32 total_particles = sParticleCount / sParticleBurstRate ; //estimated
				F32 new_rate = llclamp(0.9f * sMaxParticleCount / total_particles, 0.0f, 1.0f) ;
				F32 delta_rate_threshold = llmin(0.1f * llmax(new_rate, sParticleBurstRate), 0.1f) ;
				F32 delta_rate = llclamp(new_rate - sParticleBurstRate, -1.0f * delta_rate_threshold, delta_rate_threshold) ;

				sParticleBurstRate = llclamp(sParticleBurstRate + 0.5f * delta_rate, 0.0f, 1.0f) ;
			}
			else
			{
				sParticleBurstRate += 0.0000001f ;
			}
		}
		else
		{
			sParticleBurstRate += 0.00125f ;
		}
	}
}

void LLViewerPartSim::addPartSource(LLPointer<LLViewerPartSource> sourcep)
{
	if (!sourcep)
	{
		llwarns << "Null part source!" << llendl;
		return;
	}
	sourcep->setStart() ;
	mViewerPartSources.push_back(sourcep);
}

void LLViewerPartSim::removeLastCreatedSource()
{
	mViewerPartSources.pop_back();
}

void LLViewerPartSim::cleanupRegion(LLViewerRegion *regionp)
{
	for (group_list_t::iterator i = mViewerPartGroups.begin(); i != mViewerPartGroups.end(); )
	{
		group_list_t::iterator iter = i++;

		if ((*iter)->getRegion() == regionp)
		{
			delete *iter;
			i = mViewerPartGroups.erase(iter);			
		}
	}
}

void LLViewerPartSim::clearParticlesByID(const U32 system_id)
{
	for (group_list_t::iterator g = mViewerPartGroups.begin(); g != mViewerPartGroups.end(); ++g)
	{
		(*g)->removeParticlesByID(system_id);
	}
	for (source_list_t::iterator i = mViewerPartSources.begin(); i != mViewerPartSources.end(); ++i)
	{
		if ((*i)->getID() == system_id)
		{
			(*i)->setDead();	
			break;
		}
	}
	
}

void LLViewerPartSim::clearParticlesByOwnerID(const LLUUID& task_id)
{
	for (source_list_t::iterator iter = mViewerPartSources.begin(); iter != mViewerPartSources.end(); ++iter)
	{
		if ((*iter)->getOwnerUUID() == task_id)
		{
			clearParticlesByID((*iter)->getID());
		}
	}
}