/** 
 * @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)
	{
		//LL_WARNS() << "No region at position, using agent region!" << LL_ENDL;
		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)
	{
		LL_ERRS() << "sParticleCount: " << LLViewerPartSim::sParticleCount << " ; sParticleCount2: " << LLViewerPartSim::sParticleCount2 << LL_ENDL ;
	}

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

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

//enable/disable particle system
void LLViewerPartSim::enable(bool enabled)
{
	if(!enabled && sMaxParticleCount > 0)
	{
		sMaxParticleCount = 0; //disable
	}
	else if(enabled && sMaxParticleCount < 1)
	{
		sMaxParticleCount = llmin(gSavedSettings.getS32("RenderMaxPartCount"), LL_MAX_PARTICLE_COUNT);
	}

	return;
}

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 >= MAX_PART_COUNT)
	{
		return FALSE;
	}

	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;
		}
	}

	// Check frame rate, and don't add more if the viewer is really slow
	const F32 MIN_FRAME_RATE_FOR_NEW_PARTICLES = 4.f;
	if (gFPSClamped < MIN_FRAME_RATE_FOR_NEW_PARTICLES)
	{
		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
		LL_WARNS() << "LLViewerPartSim::put Part out of range!" << LL_ENDL;
		LL_WARNS() << part->mPosAgent << LL_ENDL;
#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))
			{
				LL_WARNS() << "LLViewerPartSim::put - Particle didn't go into its box!" << LL_ENDL;
				LL_INFOS() << groupp->getCenterAgent() << LL_ENDL;
				LL_INFOS() << part->mPosAgent << LL_ENDL;
				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() ;

	//LL_INFOS() << "Particles: " << sParticleCount << " Adaptive Rate: " << sParticleAdaptiveRate << LL_ENDL;
}

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)
	{
		LL_WARNS() << "Null part source!" << LL_ENDL;
		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());
		}
	}
}