/** 
 * @file llvieweroctree.cpp
 * @brief LLViewerOctreeGroup class implementation and supporting functions
 *
 * $LicenseInfo:firstyear=2003&license=viewerlgpl$
 * 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 "llvieweroctree.h"
#include "llviewerregion.h"
#include "pipeline.h"
#include "llviewercontrol.h"
#include "llappviewer.h"
#include "llglslshader.h"
#include "llviewershadermgr.h"
#include "lldrawpoolwater.h"

//-----------------------------------------------------------------------------------
//static variables definitions
//-----------------------------------------------------------------------------------
U32 LLViewerOctreeEntryData::sCurVisible = 10; //reserve the low numbers for special use.
bool LLViewerOctreeDebug::sInDebug = false;

static LLTrace::CountStatHandle<S32> sOcclusionQueries("occlusion_queries", "Number of occlusion queries executed"),
									 sNumObjectsOccluded("occluded_objects", "Count of objects being occluded by a query"),
									 sNumObjectsUnoccluded("unoccluded_objects", "Count of objects being unoccluded by a query");

//-----------------------------------------------------------------------------------
//some global functions definitions
//-----------------------------------------------------------------------------------
typedef enum
{
	b000 = 0x00,
	b001 = 0x01,
	b010 = 0x02,
	b011 = 0x03,
	b100 = 0x04,
	b101 = 0x05,
	b110 = 0x06,
	b111 = 0x07,
} eLoveTheBits;

//contact Runitai Linden for a copy of the SL object used to write this table
//basically, you give the table a bitmask of the look-at vector to a node and it
//gives you a triangle fan index array
static U16 sOcclusionIndices[] =
{
	 //000
		b111, b110, b010, b011, b001, b101, b100, b110,
	 //001 
		b011, b010, b000, b001, b101, b111, b110, b010,
	 //010
		b101, b100, b110, b111, b011, b001, b000, b100,
	 //011 
		b001, b000, b100, b101, b111, b011, b010, b000,
	 //100 
		b110, b000, b010, b011, b111, b101, b100, b000,
	 //101 
		b010, b100, b000, b001, b011, b111, b110, b100,
	 //110
		b100, b010, b110, b111, b101, b001, b000, b010,
	 //111
		b000, b110, b100, b101, b001, b011, b010, b110,
};

U32 get_box_fan_indices(LLCamera* camera, const LLVector4a& center)
{
	LLVector4a origin;
	origin.load3(camera->getOrigin().mV);

	S32 cypher = center.greaterThan(origin).getGatheredBits() & 0x7;
	
	return cypher*8;
}

U8* get_box_fan_indices_ptr(LLCamera* camera, const LLVector4a& center)
{
	LLVector4a origin;
	origin.load3(camera->getOrigin().mV);

	S32 cypher = center.greaterThan(origin).getGatheredBits() & 0x7;
	
	return (U8*) (sOcclusionIndices+cypher*8);
}

//create a vertex buffer for efficiently rendering cubes
LLVertexBuffer* ll_create_cube_vb(U32 type_mask)
{
	LLVertexBuffer* ret = new LLVertexBuffer(type_mask);

	ret->allocateBuffer(8, 64);

	LLStrider<LLVector3> pos;
	LLStrider<U16> idx;

	ret->getVertexStrider(pos);
	ret->getIndexStrider(idx);

	pos[0] = LLVector3(-1,-1,-1);
	pos[1] = LLVector3(-1,-1, 1);
	pos[2] = LLVector3(-1, 1,-1);
	pos[3] = LLVector3(-1, 1, 1);
	pos[4] = LLVector3( 1,-1,-1);
	pos[5] = LLVector3( 1,-1, 1);
	pos[6] = LLVector3( 1, 1,-1);
	pos[7] = LLVector3( 1, 1, 1);

	for (U32 i = 0; i < 64; i++)
	{
		idx[i] = sOcclusionIndices[i];
	}

	ret->unmapBuffer();

	return ret;
}


#define LL_TRACK_PENDING_OCCLUSION_QUERIES 0

const F32 SG_OCCLUSION_FUDGE = 0.25f;
#define SG_DISCARD_TOLERANCE 0.01f


S32 AABBSphereIntersect(const LLVector3& min, const LLVector3& max, const LLVector3 &origin, const F32 &rad)
{
	return AABBSphereIntersectR2(min, max, origin, rad*rad);
}

S32 AABBSphereIntersectR2(const LLVector3& min, const LLVector3& max, const LLVector3 &origin, const F32 &r)
{
	F32 d = 0.f;
	F32 t;
	
	if ((min-origin).magVecSquared() < r &&
		(max-origin).magVecSquared() < r)
	{
		return 2;
	}

	for (U32 i = 0; i < 3; i++)
	{
		if (origin.mV[i] < min.mV[i])
		{
			t = min.mV[i] - origin.mV[i];
			d += t*t;
		}
		else if (origin.mV[i] > max.mV[i])
		{
			t = origin.mV[i] - max.mV[i];
			d += t*t;
		}

		if (d > r)
		{
			return 0;
		}
	}

	return 1;
}


S32 AABBSphereIntersect(const LLVector4a& min, const LLVector4a& max, const LLVector3 &origin, const F32 &rad)
{
	return AABBSphereIntersectR2(min, max, origin, rad*rad);
}

S32 AABBSphereIntersectR2(const LLVector4a& min, const LLVector4a& max, const LLVector3 &origin, const F32 &r)
{
	F32 d = 0.f;
	F32 t;
	
	LLVector4a origina;
	origina.load3(origin.mV);

	LLVector4a v;
	v.setSub(min, origina);
	
	if (v.dot3(v) < r)
	{
		v.setSub(max, origina);
		if (v.dot3(v) < r)
		{
			return 2;
		}
	}


	for (U32 i = 0; i < 3; i++)
	{
		if (origin.mV[i] < min[i])
		{
			t = min[i] - origin.mV[i];
			d += t*t;
		}
		else if (origin.mV[i] > max[i])
		{
			t = origin.mV[i] - max[i];
			d += t*t;
		}

		if (d > r)
		{
			return 0;
		}
	}

	return 1;
}

//-----------------------------------------------------------------------------------
//class LLViewerOctreeEntry definitions
//-----------------------------------------------------------------------------------
LLViewerOctreeEntry::LLViewerOctreeEntry() 
:	mGroup(NULL),
	mBinRadius(0.f),
	mBinIndex(-1),
	mVisible(0)
{
	mPositionGroup.clear();
	mExtents[0].clear();
	mExtents[1].clear();	

	for(S32 i = 0; i < NUM_DATA_TYPE; i++)
	{
		mData[i] = NULL;
	}
}

LLViewerOctreeEntry::~LLViewerOctreeEntry()
{
	llassert(!mGroup);
}

void LLViewerOctreeEntry::addData(LLViewerOctreeEntryData* data)
{
	//llassert(mData[data->getDataType()] == NULL);	
	llassert(data != NULL);

	mData[data->getDataType()] = data;
}

void LLViewerOctreeEntry::removeData(LLViewerOctreeEntryData* data)
{
	//llassert(data->getDataType() != LLVOCACHEENTRY); //can not remove VOCache entry

	if(!mData[data->getDataType()])
	{
		return;
	}
	if(mData[data->getDataType()] != data)
	{
		return;
	}

	mData[data->getDataType()] = NULL;
	
	if(mGroup != NULL && !mData[LLDRAWABLE])
	{
		LLViewerOctreeGroup* group = mGroup;
		mGroup = NULL;
		group->removeFromGroup(data);

		llassert(mBinIndex == -1);				
	}
}

//called by group handleDestruction() ONLY when group is destroyed by octree.
void LLViewerOctreeEntry::nullGroup()
{
	mGroup = NULL;
}

void LLViewerOctreeEntry::setGroup(LLViewerOctreeGroup* group)
{
	if(mGroup == group)
	{
		return;
	}

	if(mGroup)
	{
		LLViewerOctreeGroup* old_group = mGroup;
		mGroup = NULL;
		old_group->removeFromGroup(this);

		llassert(mBinIndex == -1);
	}

	mGroup = group;
}

//-----------------------------------------------------------------------------------
//class LLViewerOctreeEntryData definitions
//-----------------------------------------------------------------------------------
LLViewerOctreeEntryData::~LLViewerOctreeEntryData()
{
	if(mEntry)
	{
		mEntry->removeData(this);
	}
}

LLViewerOctreeEntryData::LLViewerOctreeEntryData(LLViewerOctreeEntry::eEntryDataType_t data_type)
	: mDataType(data_type),
	  mEntry(NULL)
{
}

//virtual
void LLViewerOctreeEntryData::setOctreeEntry(LLViewerOctreeEntry* entry)
{
	llassert_always(mEntry.isNull());

	if(mEntry.notNull())
	{
		return; 
	}

	if(!entry)
	{
		mEntry = new LLViewerOctreeEntry();
	}
	else
	{
		mEntry = entry;
	}
	mEntry->addData(this);
}

void LLViewerOctreeEntryData::removeOctreeEntry()
{
	if(mEntry)
	{
		mEntry->removeData(this);
		mEntry = NULL;
	}
}

void LLViewerOctreeEntryData::setSpatialExtents(const LLVector3& min, const LLVector3& max)
{ 
	mEntry->mExtents[0].load3(min.mV); 
	mEntry->mExtents[1].load3(max.mV);
}

void LLViewerOctreeEntryData::setSpatialExtents(const LLVector4a& min, const LLVector4a& max)
{ 
	mEntry->mExtents[0] = min; 
	mEntry->mExtents[1] = max;
}

void LLViewerOctreeEntryData::setPositionGroup(const LLVector4a& pos)
{
	mEntry->mPositionGroup = pos;
}

const LLVector4a* LLViewerOctreeEntryData::getSpatialExtents() const 
{
	return mEntry->getSpatialExtents();
}

//virtual
void LLViewerOctreeEntryData::setGroup(LLViewerOctreeGroup* group)
{
	mEntry->setGroup(group);
}

void LLViewerOctreeEntryData::shift(const LLVector4a &shift_vector)
{
	mEntry->mExtents[0].add(shift_vector);
	mEntry->mExtents[1].add(shift_vector);
	mEntry->mPositionGroup.add(shift_vector);
}

LLViewerOctreeGroup* LLViewerOctreeEntryData::getGroup()const        
{
	return mEntry.notNull() ? mEntry->mGroup : NULL;
}

const LLVector4a& LLViewerOctreeEntryData::getPositionGroup() const  
{
	return mEntry->getPositionGroup();
}	

//virtual
bool LLViewerOctreeEntryData::isVisible() const
{
	if(mEntry)
	{
		return mEntry->mVisible == sCurVisible;
	}
	return false;
}

//virtual
bool LLViewerOctreeEntryData::isRecentlyVisible() const
{
	if(!mEntry)
	{
		return false;
	}

	if(isVisible())
	{
		return true;
	}
	if(getGroup() && getGroup()->isRecentlyVisible())
	{
		setVisible();
		return true;
	}

	return false;
}

void LLViewerOctreeEntryData::setVisible() const
{
	if(mEntry)
	{
		mEntry->mVisible = sCurVisible;
	}
}

void LLViewerOctreeEntryData::resetVisible() const
{
	if(mEntry)
	{
		mEntry->mVisible = 0;
	}
}
//-----------------------------------------------------------------------------------
//class LLViewerOctreeGroup definitions
//-----------------------------------------------------------------------------------

LLViewerOctreeGroup::~LLViewerOctreeGroup()
{
	//empty here
}

LLViewerOctreeGroup::LLViewerOctreeGroup(OctreeNode* node)
:	mOctreeNode(node),
	mAnyVisible(0),
	mState(CLEAN)
{
	LLVector4a tmp;
	tmp.splat(0.f);
	mExtents[0] = mExtents[1] = mObjectBounds[0] = mObjectBounds[1] =
		mObjectExtents[0] = mObjectExtents[1] = tmp;
	
	mBounds[0] = node->getCenter();
	mBounds[1] = node->getSize();

	mOctreeNode->addListener(this);
}

bool LLViewerOctreeGroup::hasElement(LLViewerOctreeEntryData* data) 
{ 
	if(!data->getEntry())
	{
		return false;
	}
	return std::find(getDataBegin(), getDataEnd(), data->getEntry()) != getDataEnd(); 
}

bool LLViewerOctreeGroup::removeFromGroup(LLViewerOctreeEntryData* data)
{
	return removeFromGroup(data->getEntry());
}

bool LLViewerOctreeGroup::removeFromGroup(LLViewerOctreeEntry* entry)
{
	llassert(entry != NULL);
	llassert(!entry->getGroup());
	
	if(isDead()) //group is about to be destroyed, not need to double delete the entry.
	{
		entry->setBinIndex(-1);
		return true;
	}

	unbound();
	setState(OBJECT_DIRTY);

	if (mOctreeNode)
	{
		if (!mOctreeNode->remove(entry)) //this could cause *this* pointer to be destroyed, so no more function calls after this.
		{
			OCT_ERRS << "Could not remove LLVOCacheEntry from LLVOCacheOctreeGroup" << LL_ENDL;
			return false;
		}
	}	

	return true;
}

//virtual 
void LLViewerOctreeGroup::unbound()
{
    LL_PROFILE_ZONE_SCOPED;
	if (isDirty())
	{
		return;
	}

	setState(DIRTY);
	
	//all the parent nodes need to rebound this child
	if (mOctreeNode)
	{
		OctreeNode* parent = (OctreeNode*) mOctreeNode->getParent();
		while (parent != NULL)
		{
			LLViewerOctreeGroup* group = (LLViewerOctreeGroup*) parent->getListener(0);
			if (!group || group->isDirty())
			{
				return;
			}
			
			group->setState(DIRTY);
			parent = (OctreeNode*) parent->getParent();
		}
	}
}
	
//virtual 
void LLViewerOctreeGroup::rebound()
{
    LL_PROFILE_ZONE_SCOPED_CATEGORY_OCTREE;
	if (!isDirty())
	{	
		return;
	}
	
	if (mOctreeNode->getChildCount() == 1 && mOctreeNode->getElementCount() == 0)
	{
		LLViewerOctreeGroup* group = (LLViewerOctreeGroup*) mOctreeNode->getChild(0)->getListener(0);
		group->rebound();
		
		//copy single child's bounding box
		mBounds[0] = group->mBounds[0];
		mBounds[1] = group->mBounds[1];
		mExtents[0] = group->mExtents[0];
		mExtents[1] = group->mExtents[1];
		
		group->setState(SKIP_FRUSTUM_CHECK);
	}
	else if (mOctreeNode->getChildCount() == 0)
	{ //copy object bounding box if this is a leaf
		boundObjects(true, mExtents[0], mExtents[1]);
		mBounds[0] = mObjectBounds[0];
		mBounds[1] = mObjectBounds[1];
	}
	else
	{
		LLVector4a& newMin = mExtents[0];
		LLVector4a& newMax = mExtents[1];
		LLViewerOctreeGroup* group = (LLViewerOctreeGroup*) mOctreeNode->getChild(0)->getListener(0);
		group->clearState(SKIP_FRUSTUM_CHECK);
		group->rebound();
		//initialize to first child
		newMin = group->mExtents[0];
		newMax = group->mExtents[1];

		//first, rebound children
		for (U32 i = 1; i < mOctreeNode->getChildCount(); i++)
		{
			group = (LLViewerOctreeGroup*) mOctreeNode->getChild(i)->getListener(0);
			group->clearState(SKIP_FRUSTUM_CHECK);
			group->rebound();
			const LLVector4a& max = group->mExtents[1];
			const LLVector4a& min = group->mExtents[0];

			newMax.setMax(newMax, max);
			newMin.setMin(newMin, min);
		}

		boundObjects(false, newMin, newMax);
		
		mBounds[0].setAdd(newMin, newMax);
		mBounds[0].mul(0.5f);
		mBounds[1].setSub(newMax, newMin);
		mBounds[1].mul(0.5f);
	}
	
	clearState(DIRTY);

	return;
}

//virtual 
void LLViewerOctreeGroup::handleInsertion(const TreeNode* node, LLViewerOctreeEntry* obj)
{
	obj->setGroup(this);	
	unbound();
	setState(OBJECT_DIRTY);
}
	
//virtual 
void LLViewerOctreeGroup::handleRemoval(const TreeNode* node, LLViewerOctreeEntry* obj)
{
	unbound();
	setState(OBJECT_DIRTY);

	obj->setGroup(NULL); //this could cause *this* pointer to be destroyed. So no more function calls after this.	
}
	
//virtual 
void LLViewerOctreeGroup::handleDestruction(const TreeNode* node)
{
    if (isDead())
    {
        return;
    }
    setState(DEAD);
	for (OctreeNode::element_iter i = mOctreeNode->getDataBegin(); i != mOctreeNode->getDataEnd(); ++i)
	{
		LLViewerOctreeEntry* obj = *i;
		if (obj && obj->getGroup() == this)
		{
			obj->nullGroup();
		}
	}
	mOctreeNode = NULL;
}
	
//virtual 
void LLViewerOctreeGroup::handleStateChange(const TreeNode* node)
{
	//drop bounding box upon state change
	if (mOctreeNode != node)
	{
		mOctreeNode = (OctreeNode*) node;
	}
	unbound();
}
	
//virtual 
void LLViewerOctreeGroup::handleChildAddition(const OctreeNode* parent, OctreeNode* child)
{
	if (child->getListenerCount() == 0)
	{
		new LLViewerOctreeGroup(child);
	}
	else
	{
		OCT_ERRS << "LLViewerOctreeGroup redundancy detected." << LL_ENDL;
	}

	unbound();
	
	((LLViewerOctreeGroup*)child->getListener(0))->unbound();
}
	
//virtual 
void LLViewerOctreeGroup::handleChildRemoval(const OctreeNode* parent, const OctreeNode* child)
{
	unbound();
}

LLViewerOctreeGroup* LLViewerOctreeGroup::getParent()
{
	if (isDead())
	{
		return NULL;
	}

	if(!mOctreeNode)
	{
		return NULL;
	}
	
	OctreeNode* parent = mOctreeNode->getOctParent();

	if (parent)
	{
		return (LLViewerOctreeGroup*) parent->getListener(0);
	}

	return NULL;
}

//virtual 
bool LLViewerOctreeGroup::boundObjects(bool empty, LLVector4a& minOut, LLVector4a& maxOut)
{
	const OctreeNode* node = mOctreeNode;

	if (node->isEmpty())
	{	//don't do anything if there are no objects
		if (empty && mOctreeNode->getParent())
		{	//only root is allowed to be empty
			OCT_ERRS << "Empty leaf found in octree." << LL_ENDL;
		}
		return false;
	}

	LLVector4a& newMin = mObjectExtents[0];
	LLVector4a& newMax = mObjectExtents[1];
	
	if (hasState(OBJECT_DIRTY))
	{ //calculate new bounding box
		clearState(OBJECT_DIRTY);

		//initialize bounding box to first element
		OctreeNode::const_element_iter i = node->getDataBegin();
		LLViewerOctreeEntry* entry = *i;
		const LLVector4a* minMax = entry->getSpatialExtents();

		newMin = minMax[0];
		newMax = minMax[1];

		for (++i; i != node->getDataEnd(); ++i)
		{
			entry = *i;
			minMax = entry->getSpatialExtents();
			
			update_min_max(newMin, newMax, minMax[0]);
			update_min_max(newMin, newMax, minMax[1]);
		}

		mObjectBounds[0].setAdd(newMin, newMax);
		mObjectBounds[0].mul(0.5f);
		mObjectBounds[1].setSub(newMax, newMin);
		mObjectBounds[1].mul(0.5f);
	}
	
	if (empty)
	{
		minOut = newMin;
		maxOut = newMax;
	}
	else
	{
		minOut.setMin(minOut, newMin);
		maxOut.setMax(maxOut, newMax);
	}
		
	return true;
}

//virtual 
bool LLViewerOctreeGroup::isVisible() const
{
	return mVisible[LLViewerCamera::sCurCameraID] >= LLViewerOctreeEntryData::getCurrentFrame() ? true : false;
}

//virtual 
bool LLViewerOctreeGroup::isRecentlyVisible() const 
{
	return false;
}

void LLViewerOctreeGroup::setVisible()
{
	mVisible[LLViewerCamera::sCurCameraID] = LLViewerOctreeEntryData::getCurrentFrame();
	
	if(LLViewerCamera::sCurCameraID < LLViewerCamera::CAMERA_WATER0)
	{
		mAnyVisible = LLViewerOctreeEntryData::getCurrentFrame();
	}
}

void LLViewerOctreeGroup::checkStates()
{
#if LL_OCTREE_PARANOIA_CHECK
	//LLOctreeStateCheck checker;
	//checker.traverse(mOctreeNode);
#endif
}

//-------------------------------------------------------------------------------------------
//occulsion culling functions and classes
//-------------------------------------------------------------------------------------------
std::set<U32> LLOcclusionCullingGroup::sPendingQueries;

static std::queue<GLuint> sFreeQueries;

#define QUERY_POOL_SIZE 1024

U32 LLOcclusionCullingGroup::getNewOcclusionQueryObjectName()
{
    LL_PROFILE_ZONE_SCOPED;
    
    if (sFreeQueries.empty())
    {
        //seed 1024 query names into the free query pool
        GLuint queries[1024];
        glGenQueries(1024, queries);
        for (int i = 0; i < 1024; ++i)
        {
            sFreeQueries.push(queries[i]);
        }
    }

    // pull from pool
    GLuint ret = sFreeQueries.front();
    sFreeQueries.pop();
    return ret;
}

void LLOcclusionCullingGroup::releaseOcclusionQueryObjectName(GLuint name)
{
    if (name != 0)
    {
        LL_PROFILE_ZONE_SCOPED;
        sFreeQueries.push(name);
    }
}

//=====================================
//		Occlusion State Set/Clear
//=====================================
class LLSpatialSetOcclusionState : public OctreeTraveler
{
public:
	U32 mState;
	LLSpatialSetOcclusionState(U32 state) : mState(state) { }
	virtual void visit(const OctreeNode* branch) 
	{ 
		LLOcclusionCullingGroup* group = (LLOcclusionCullingGroup*)branch->getListener(0);
		if(group)
		{
			group->setOcclusionState(mState); 
		}
	}
};

class LLSpatialSetOcclusionStateDiff : public LLSpatialSetOcclusionState
{
public:
	LLSpatialSetOcclusionStateDiff(U32 state) : LLSpatialSetOcclusionState(state) { }

	virtual void traverse(const OctreeNode* n)
	{
		LLOcclusionCullingGroup* group = (LLOcclusionCullingGroup*) n->getListener(0);
		
		if (group && !group->isOcclusionState(mState))
		{
			OctreeTraveler::traverse(n);
		}
	}
};


LLOcclusionCullingGroup::LLOcclusionCullingGroup(OctreeNode* node, LLViewerOctreePartition* part) : 
	LLViewerOctreeGroup(node),
	mSpatialPartition(part)
{
	part->mLODSeed = (part->mLODSeed+1)%part->mLODPeriod;
	mLODHash = part->mLODSeed;

	OctreeNode* oct_parent = node->getOctParent();
	LLOcclusionCullingGroup* parent = oct_parent ? (LLOcclusionCullingGroup*) oct_parent->getListener(0) : NULL;

	for (U32 i = 0; i < LLViewerCamera::NUM_CAMERAS; i++)
	{
		mOcclusionQuery[i] = 0;
        mOcclusionCheckCount[i] = 0;
		mOcclusionIssued[i] = 0;
		mOcclusionState[i] = parent ? SG_STATE_INHERIT_MASK & parent->mOcclusionState[i] : 0;
		mVisible[i] = 0;
	}
}

LLOcclusionCullingGroup::~LLOcclusionCullingGroup()
{
	releaseOcclusionQueryObjectNames();
}

bool LLOcclusionCullingGroup::needsUpdate()
{
	return (LLDrawable::getCurrentFrame() % mSpatialPartition->mLODPeriod == mLODHash) ? true : false;
}

bool LLOcclusionCullingGroup::isRecentlyVisible() const
{
	const S32 MIN_VIS_FRAME_RANGE = 2;
	return (LLDrawable::getCurrentFrame() - mVisible[LLViewerCamera::sCurCameraID]) < MIN_VIS_FRAME_RANGE ;
}

bool LLOcclusionCullingGroup::isAnyRecentlyVisible() const
{
	const S32 MIN_VIS_FRAME_RANGE = 2;
	return (LLDrawable::getCurrentFrame() - mAnyVisible) < MIN_VIS_FRAME_RANGE ;
}

//virtual 
void LLOcclusionCullingGroup::handleChildAddition(const OctreeNode* parent, OctreeNode* child)
{
	if (child->getListenerCount() == 0)
	{
		new LLOcclusionCullingGroup(child, mSpatialPartition);
	}
	else
	{
		OCT_ERRS << "LLOcclusionCullingGroup redundancy detected." << LL_ENDL;
	}

	unbound();
	
	((LLViewerOctreeGroup*)child->getListener(0))->unbound();
}

void LLOcclusionCullingGroup::releaseOcclusionQueryObjectNames()
{
	for (U32 i = 0; i < LLViewerCamera::NUM_CAMERAS; ++i)
	{
		if (mOcclusionQuery[i])
		{
			releaseOcclusionQueryObjectName(mOcclusionQuery[i]);
			mOcclusionQuery[i] = 0;
		}
	}
}

void LLOcclusionCullingGroup::setOcclusionState(U32 state, S32 mode /* = STATE_MODE_SINGLE */ ) 
{
    switch (mode)
    {
    case STATE_MODE_SINGLE:
        if (state & OCCLUDED)
        {
            add(sNumObjectsOccluded, 1);
        }
        mOcclusionState[LLViewerCamera::sCurCameraID] |= state;
        if ((state & DISCARD_QUERY) && mOcclusionQuery[LLViewerCamera::sCurCameraID])
        {
            releaseOcclusionQueryObjectName(mOcclusionQuery[LLViewerCamera::sCurCameraID]);
            mOcclusionQuery[LLViewerCamera::sCurCameraID] = 0;
        }
        break;

    case STATE_MODE_DIFF:
        if (mOctreeNode)
        {
            LLSpatialSetOcclusionStateDiff setter(state);
            setter.traverse(mOctreeNode);
        }
        break;

    case STATE_MODE_BRANCH:
        if (mOctreeNode)
        {
            LLSpatialSetOcclusionState setter(state);
            setter.traverse(mOctreeNode);
        }
        break;

    case STATE_MODE_ALL_CAMERAS:
        for (U32 i = 0; i < LLViewerCamera::NUM_CAMERAS; i++)
        {
            mOcclusionState[i] |= state;

            if ((state & DISCARD_QUERY) && mOcclusionQuery[i])
            {
                releaseOcclusionQueryObjectName(mOcclusionQuery[i]);
                mOcclusionQuery[i] = 0;
            }
        }
        break;

    default:
        break;
    }
}

class LLSpatialClearOcclusionState : public OctreeTraveler
{
public:
	U32 mState;
	
	LLSpatialClearOcclusionState(U32 state) : mState(state) { }
	virtual void visit(const OctreeNode* branch) 
	{ 
		LLOcclusionCullingGroup* group = (LLOcclusionCullingGroup*)branch->getListener(0);
		if(group)
		{
			group->clearOcclusionState(mState); 
		}
	}
};

class LLSpatialClearOcclusionStateDiff : public LLSpatialClearOcclusionState
{
public:
	LLSpatialClearOcclusionStateDiff(U32 state) : LLSpatialClearOcclusionState(state) { }

	virtual void traverse(const OctreeNode* n)
	{
		LLOcclusionCullingGroup* group = (LLOcclusionCullingGroup*) n->getListener(0);
		
		if (group && group->isOcclusionState(mState))
		{
			OctreeTraveler::traverse(n);
		}
	}
};

void LLOcclusionCullingGroup::clearOcclusionState(U32 state, S32 mode /* = STATE_MODE_SINGLE */)
{
    switch (mode)
    {
        case STATE_MODE_SINGLE:
            if (state & OCCLUDED)
            {
                add(sNumObjectsUnoccluded, 1);
            }
            mOcclusionState[LLViewerCamera::sCurCameraID] &= ~state;
            break;

        case STATE_MODE_DIFF:
            if (mOctreeNode)
            {
                LLSpatialClearOcclusionStateDiff clearer(state);
                clearer.traverse(mOctreeNode);
            }
            break;

        case STATE_MODE_BRANCH:
            if (mOctreeNode)
            {
                LLSpatialClearOcclusionState clearer(state);
                clearer.traverse(mOctreeNode);
            }
            break;

        case STATE_MODE_ALL_CAMERAS:
            for (U32 i = 0; i < LLViewerCamera::NUM_CAMERAS; i++)
            {
                mOcclusionState[i] &= ~state;
            }
            break;

        default:
            break;
    }
}

bool LLOcclusionCullingGroup::earlyFail(LLCamera* camera, const LLVector4a* bounds)
{
    LL_PROFILE_ZONE_SCOPED_CATEGORY_OCTREE;
	if (camera->getOrigin().isExactlyZero())
	{
		return false;
	}

	const F32 vel = SG_OCCLUSION_FUDGE*2.f;
	LLVector4a fudge;
	fudge.splat(vel);

	const LLVector4a& c = bounds[0];
	LLVector4a r;
	r.setAdd(bounds[1], fudge);

	/*if (r.magVecSquared() > 1024.0*1024.0)
	{
		return true;
	}*/

	LLVector4a e;
	e.load3(camera->getOrigin().mV);
	
	LLVector4a min;
	min.setSub(c,r);
	LLVector4a max;
	max.setAdd(c,r);
	
	S32 lt = e.lessThan(min).getGatheredBits() & 0x7;
	if (lt)
	{
		return false;
	}

	S32 gt = e.greaterThan(max).getGatheredBits() & 0x7;
	if (gt)
	{
		return false;
	}

	return true;
}

U32 LLOcclusionCullingGroup::getLastOcclusionIssuedTime()
{
	return mOcclusionIssued[LLViewerCamera::sCurCameraID];
}

void LLOcclusionCullingGroup::checkOcclusion()
{
    if (LLPipeline::sUseOcclusion < 2) return;  // 0 - NoOcclusion, 1 = ReadOnly, 2 = ModifyOcclusionState  TODO: DJH 11-2021 ENUM this

    LL_PROFILE_ZONE_SCOPED_CATEGORY_OCTREE;
    LLOcclusionCullingGroup* parent = (LLOcclusionCullingGroup*)getParent();
    if (parent && parent->isOcclusionState(LLOcclusionCullingGroup::OCCLUDED))
    {	//if the parent has been marked as occluded, the child is implicitly occluded
        clearOcclusionState(QUERY_PENDING | DISCARD_QUERY);
        return;
    }

    if (mOcclusionQuery[LLViewerCamera::sCurCameraID] && isOcclusionState(QUERY_PENDING))
    {	
        if (isOcclusionState(DISCARD_QUERY))
        {   // delete the query to avoid holding onto hundreds of pending queries
            releaseOcclusionQueryObjectName(mOcclusionQuery[LLViewerCamera::sCurCameraID]);
            mOcclusionQuery[LLViewerCamera::sCurCameraID] = 0;
            // mark non-occluded
            clearOcclusionState(LLOcclusionCullingGroup::OCCLUDED, LLOcclusionCullingGroup::STATE_MODE_DIFF);
            clearOcclusionState(QUERY_PENDING | DISCARD_QUERY);
        }
        else
        {
            GLuint available;
            {
                LL_PROFILE_ZONE_NAMED_CATEGORY_OCTREE("co - query available");
                glGetQueryObjectuiv(mOcclusionQuery[LLViewerCamera::sCurCameraID], GL_QUERY_RESULT_AVAILABLE, &available);
                mOcclusionCheckCount[LLViewerCamera::sCurCameraID]++;
            }

            static LLCachedControl<S32> occlusion_timeout(gSavedSettings, "RenderOcclusionTimeout", 4);

            if (available || mOcclusionCheckCount[LLViewerCamera::sCurCameraID] > occlusion_timeout)
            {   
                mOcclusionCheckCount[LLViewerCamera::sCurCameraID] = 0;
                GLuint query_result;    // Will be # samples drawn, or a boolean depending on mHasOcclusionQuery2 (both are type GLuint)
                {
                    LL_PROFILE_ZONE_NAMED_CATEGORY_OCTREE("co - query result");
                    glGetQueryObjectuiv(mOcclusionQuery[LLViewerCamera::sCurCameraID], GL_QUERY_RESULT, &query_result);
                }
#if LL_TRACK_PENDING_OCCLUSION_QUERIES
                sPendingQueries.erase(mOcclusionQuery[LLViewerCamera::sCurCameraID]);
#endif

                if (query_result > 0)
                {
                    clearOcclusionState(LLOcclusionCullingGroup::OCCLUDED, LLOcclusionCullingGroup::STATE_MODE_DIFF);
                }
                else
                {
                    setOcclusionState(LLOcclusionCullingGroup::OCCLUDED, LLOcclusionCullingGroup::STATE_MODE_DIFF);
                }
                clearOcclusionState(QUERY_PENDING);
            }
        }
    }
    else if (mSpatialPartition->isOcclusionEnabled() && isOcclusionState(LLOcclusionCullingGroup::OCCLUDED))
    {	//check occlusion has been issued for occluded node that has not had a query issued
        assert_states_valid(this);
        //clearOcclusionState(LLOcclusionCullingGroup::OCCLUDED, LLOcclusionCullingGroup::STATE_MODE_DIFF);
        assert_states_valid(this);
    }
}

void LLOcclusionCullingGroup::doOcclusion(LLCamera* camera, const LLVector4a* shift)
{
    LL_PROFILE_ZONE_SCOPED_CATEGORY_OCTREE;
	if (mSpatialPartition->isOcclusionEnabled() && LLPipeline::sUseOcclusion > 1)
	{
		//move mBounds to the agent space if necessary
		LLVector4a bounds[2];
		bounds[0] = mBounds[0];
		bounds[1] = mBounds[1];
		if(shift != NULL)
		{
			bounds[0].add(*shift);
		}

		F32 OCCLUSION_FUDGE_Z = SG_OCCLUSION_FUDGE; //<-- #Solution #2
		if (LLPipeline::RENDER_TYPE_VOIDWATER == mSpatialPartition->mDrawableType)
		{
			OCCLUSION_FUDGE_Z = 1.;
		}

		if (earlyFail(camera, bounds))
		{
            LL_PROFILE_ZONE_NAMED_CATEGORY_OCTREE("doOcclusion - early fail");
			setOcclusionState(LLOcclusionCullingGroup::DISCARD_QUERY);
			assert_states_valid(this);
			clearOcclusionState(LLOcclusionCullingGroup::OCCLUDED, LLOcclusionCullingGroup::STATE_MODE_DIFF);
			assert_states_valid(this);
		}
		else
		{
			if (!isOcclusionState(QUERY_PENDING) || isOcclusionState(DISCARD_QUERY))
			{
				{ //no query pending, or previous query to be discarded
                    LL_PROFILE_ZONE_NAMED_CATEGORY_OCTREE("doOcclusion - render");

					if (!mOcclusionQuery[LLViewerCamera::sCurCameraID])
					{
						mOcclusionQuery[LLViewerCamera::sCurCameraID] = getNewOcclusionQueryObjectName();
					}

					// Depth clamp all water to avoid it being culled as a result of being
					// behind the far clip plane, and in the case of edge water to avoid
					// it being culled while still visible.
					bool const use_depth_clamp = (mSpatialPartition->mDrawableType == LLPipeline::RENDER_TYPE_WATER ||
												mSpatialPartition->mDrawableType == LLPipeline::RENDER_TYPE_VOIDWATER);

					LLGLEnable clamp(use_depth_clamp ? GL_DEPTH_CLAMP : 0);
						
					U32 mode = gGLManager.mGLVersion >= 3.3f ? GL_ANY_SAMPLES_PASSED : GL_SAMPLES_PASSED;
					
#if LL_TRACK_PENDING_OCCLUSION_QUERIES
					sPendingQueries.insert(mOcclusionQuery[LLViewerCamera::sCurCameraID]);
#endif
					add(sOcclusionQueries, 1);

					{
                        LL_PROFILE_ZONE_NAMED_CATEGORY_OCTREE("doOcclusion - push");
						
						//store which frame this query was issued on
						mOcclusionIssued[LLViewerCamera::sCurCameraID] = gFrameCount;

                        {
                            LL_PROFILE_ZONE_NAMED("glBeginQuery");

                            //get an occlusion query that hasn't been used in awhile
                            releaseOcclusionQueryObjectName(mOcclusionQuery[LLViewerCamera::sCurCameraID]);
                            mOcclusionQuery[LLViewerCamera::sCurCameraID] = getNewOcclusionQueryObjectName();
                            glBeginQuery(mode, mOcclusionQuery[LLViewerCamera::sCurCameraID]);
                        }
					
						LLGLSLShader* shader = LLGLSLShader::sCurBoundShaderPtr;
						llassert(shader);

						shader->uniform3fv(LLShaderMgr::BOX_CENTER, 1, bounds[0].getF32ptr());
						shader->uniform3f(LLShaderMgr::BOX_SIZE, bounds[1][0]+SG_OCCLUSION_FUDGE, 
																 bounds[1][1]+SG_OCCLUSION_FUDGE, 
																 bounds[1][2]+OCCLUSION_FUDGE_Z);

						if (!use_depth_clamp && mSpatialPartition->mDrawableType == LLPipeline::RENDER_TYPE_VOIDWATER)
						{
                            LL_PROFILE_ZONE_NAMED_CATEGORY_OCTREE("doOcclusion - draw water");

							LLGLSquashToFarClip squash;
							if (camera->getOrigin().isExactlyZero())
							{ //origin is invalid, draw entire box
								gPipeline.mCubeVB->drawRange(LLRender::TRIANGLE_FAN, 0, 7, 8, 0);
								gPipeline.mCubeVB->drawRange(LLRender::TRIANGLE_FAN, 0, 7, 8, b111*8);
							}
							else
							{
								gPipeline.mCubeVB->drawRange(LLRender::TRIANGLE_FAN, 0, 7, 8, get_box_fan_indices(camera, bounds[0]));
							}
						}
						else
						{
                            LL_PROFILE_ZONE_NAMED_CATEGORY_OCTREE("doOcclusion - draw");
							if (camera->getOrigin().isExactlyZero())
							{ //origin is invalid, draw entire box
								gPipeline.mCubeVB->drawRange(LLRender::TRIANGLE_FAN, 0, 7, 8, 0);
								gPipeline.mCubeVB->drawRange(LLRender::TRIANGLE_FAN, 0, 7, 8, b111*8);
							}
							else
							{
								gPipeline.mCubeVB->drawRange(LLRender::TRIANGLE_FAN, 0, 7, 8, get_box_fan_indices(camera, bounds[0]));
							}
						}
	
                        {
                            LL_PROFILE_ZONE_NAMED("glEndQuery");
                            glEndQuery(mode);
                        }
					}
				}

				{
                    LL_PROFILE_ZONE_NAMED_CATEGORY_OCTREE("doOcclusion - set state");
					setOcclusionState(LLOcclusionCullingGroup::QUERY_PENDING);
					clearOcclusionState(LLOcclusionCullingGroup::DISCARD_QUERY);
				}
			}
		}
	}
}
//-------------------------------------------------------------------------------------------
//end of occulsion culling functions and classes
//-------------------------------------------------------------------------------------------

//-----------------------------------------------------------------------------------
//class LLViewerOctreePartition definitions
//-----------------------------------------------------------------------------------
LLViewerOctreePartition::LLViewerOctreePartition() : 
	mRegionp(NULL), 
	mOcclusionEnabled(true), 
	mDrawableType(0),
	mLODSeed(0),
	mLODPeriod(1)
{
	LLVector4a center, size;
	center.splat(0.f);
	size.splat(1.f);

	mOctree = new OctreeRoot(center,size, NULL);
}
	
LLViewerOctreePartition::~LLViewerOctreePartition()
{
    cleanup();
}

void LLViewerOctreePartition::cleanup()
{
    delete mOctree;
    mOctree = nullptr;
}

bool LLViewerOctreePartition::isOcclusionEnabled()
{
	return mOcclusionEnabled || LLPipeline::sUseOcclusion > 2;
}


//-----------------------------------------------------------------------------------
//class LLViewerOctreeCull definitions
//-----------------------------------------------------------------------------------

//virtual 
bool LLViewerOctreeCull::earlyFail(LLViewerOctreeGroup* group)
{	
	return false;
}
	
//virtual 
void LLViewerOctreeCull::traverse(const OctreeNode* n)
{
	LLViewerOctreeGroup* group = (LLViewerOctreeGroup*) n->getListener(0);

	if (earlyFail(group))
	{
		return;
	}
		
	if (mRes == 2 || 
		(mRes && group->hasState(LLViewerOctreeGroup::SKIP_FRUSTUM_CHECK)))
	{	//fully in, just add everything
		OctreeTraveler::traverse(n);
	}
	else
	{
		mRes = frustumCheck(group);
				
		if (mRes)
		{ //at least partially in, run on down
			OctreeTraveler::traverse(n);
		}

		mRes = 0;
	}
}
	
//------------------------------------------
//agent space group culling
S32 LLViewerOctreeCull::AABBInFrustumNoFarClipGroupBounds(const LLViewerOctreeGroup* group)
{
	return mCamera->AABBInFrustumNoFarClip(group->mBounds[0], group->mBounds[1]);
}

S32 LLViewerOctreeCull::AABBSphereIntersectGroupExtents(const LLViewerOctreeGroup* group)
{
	return AABBSphereIntersect(group->mExtents[0], group->mExtents[1], mCamera->getOrigin(), mCamera->mFrustumCornerDist);
}

S32 LLViewerOctreeCull::AABBInFrustumGroupBounds(const LLViewerOctreeGroup* group)
{
	return mCamera->AABBInFrustum(group->mBounds[0], group->mBounds[1]);
}
//------------------------------------------

//------------------------------------------
//agent space object set culling
S32 LLViewerOctreeCull::AABBInFrustumNoFarClipObjectBounds(const LLViewerOctreeGroup* group)
{
	return mCamera->AABBInFrustumNoFarClip(group->mObjectBounds[0], group->mObjectBounds[1]);
}

S32 LLViewerOctreeCull::AABBSphereIntersectObjectExtents(const LLViewerOctreeGroup* group)
{
	return AABBSphereIntersect(group->mObjectExtents[0], group->mObjectExtents[1], mCamera->getOrigin(), mCamera->mFrustumCornerDist);
}

S32 LLViewerOctreeCull::AABBInFrustumObjectBounds(const LLViewerOctreeGroup* group)
{
	return mCamera->AABBInFrustum(group->mObjectBounds[0], group->mObjectBounds[1]);
}
//------------------------------------------

//------------------------------------------
//local regional space group culling
S32 LLViewerOctreeCull::AABBInRegionFrustumNoFarClipGroupBounds(const LLViewerOctreeGroup* group)
{
	return mCamera->AABBInRegionFrustumNoFarClip(group->mBounds[0], group->mBounds[1]);
}

S32 LLViewerOctreeCull::AABBInRegionFrustumGroupBounds(const LLViewerOctreeGroup* group)
{
	return mCamera->AABBInRegionFrustum(group->mBounds[0], group->mBounds[1]);
}

S32 LLViewerOctreeCull::AABBRegionSphereIntersectGroupExtents(const LLViewerOctreeGroup* group, const LLVector3& shift)
{
	return AABBSphereIntersect(group->mExtents[0], group->mExtents[1], mCamera->getOrigin() - shift, mCamera->mFrustumCornerDist);
}
//------------------------------------------

//------------------------------------------
//local regional space object culling
S32 LLViewerOctreeCull::AABBInRegionFrustumObjectBounds(const LLViewerOctreeGroup* group)
{
	return mCamera->AABBInRegionFrustum(group->mObjectBounds[0], group->mObjectBounds[1]);
}

S32 LLViewerOctreeCull::AABBInRegionFrustumNoFarClipObjectBounds(const LLViewerOctreeGroup* group)
{
	return mCamera->AABBInRegionFrustumNoFarClip(group->mObjectBounds[0], group->mObjectBounds[1]);
}

S32 LLViewerOctreeCull::AABBRegionSphereIntersectObjectExtents(const LLViewerOctreeGroup* group, const LLVector3& shift)
{
	return AABBSphereIntersect(group->mObjectExtents[0], group->mObjectExtents[1], mCamera->getOrigin() - shift, mCamera->mFrustumCornerDist);
}
//------------------------------------------
//check if the objects projection large enough

bool LLViewerOctreeCull::checkProjectionArea(const LLVector4a& center, const LLVector4a& size, const LLVector3& shift, F32 pixel_threshold, F32 near_radius)
{	
	LLVector3 local_orig = mCamera->getOrigin() - shift;
	LLVector4a origin;
	origin.load3(local_orig.mV);

	LLVector4a lookAt;
	lookAt.setSub(center, origin);
	F32 distance = lookAt.getLength3().getF32();
	if(distance <= near_radius)
	{
		return true; //always load close-by objects
	}

	// treat object as if it were near_radius meters closer than it actually was.
	// this allows us to get some temporal coherence on visibility...objects that can be reached quickly will tend to be visible
	distance -= near_radius;

	F32 squared_rad = size.dot3(size).getF32();
	return squared_rad / distance > pixel_threshold;
}

//virtual 
bool LLViewerOctreeCull::checkObjects(const OctreeNode* branch, const LLViewerOctreeGroup* group)
{
	if (branch->getElementCount() == 0) //no elements
	{
		return false;
	}
	else if (branch->getChildCount() == 0) //leaf state, already checked tightest bounding box
	{
		return true;
	}
	else if (mRes == 1 && !frustumCheckObjects(group)) //no objects in frustum
	{
		return false;
	}
		
	return true;
}

//virtual 
void LLViewerOctreeCull::preprocess(LLViewerOctreeGroup* group)
{		
}
	
//virtual 
void LLViewerOctreeCull::processGroup(LLViewerOctreeGroup* group)
{
}
	
//virtual 
void LLViewerOctreeCull::visit(const OctreeNode* branch) 
{	
	LLViewerOctreeGroup* group = (LLViewerOctreeGroup*) branch->getListener(0);

	preprocess(group);
		
	if (checkObjects(branch, group))
	{
		processGroup(group);
	}
}

//--------------------------------------------------------------
//class LLViewerOctreeDebug
//virtual 
void LLViewerOctreeDebug::visit(const OctreeNode* branch)
{
#if 0
	LL_INFOS() << "Node: " << (U32)branch << " # Elements: " << branch->getElementCount() << " # Children: " << branch->getChildCount() << LL_ENDL;
	for (U32 i = 0; i < branch->getChildCount(); i++)
	{
		LL_INFOS() << "Child " << i << " : " << (U32)branch->getChild(i) << LL_ENDL;
	}
#endif
	LLViewerOctreeGroup* group = (LLViewerOctreeGroup*) branch->getListener(0);
	processGroup(group);	
}

//virtual 
void LLViewerOctreeDebug::processGroup(LLViewerOctreeGroup* group)
{
#if 0
	const LLVector4a* vec4 = group->getBounds();
	LLVector3 vec[2];
	vec[0].set(vec4[0].getF32ptr());
	vec[1].set(vec4[1].getF32ptr());
	LL_INFOS() << "Bounds: " << vec[0] << " : " << vec[1] << LL_ENDL;

	vec4 = group->getExtents();
	vec[0].set(vec4[0].getF32ptr());
	vec[1].set(vec4[1].getF32ptr());
	LL_INFOS() << "Extents: " << vec[0] << " : " << vec[1] << LL_ENDL;

	vec4 = group->getObjectBounds();
	vec[0].set(vec4[0].getF32ptr());
	vec[1].set(vec4[1].getF32ptr());
	LL_INFOS() << "ObjectBounds: " << vec[0] << " : " << vec[1] << LL_ENDL;

	vec4 = group->getObjectExtents();
	vec[0].set(vec4[0].getF32ptr());
	vec[1].set(vec4[1].getF32ptr());
	LL_INFOS() << "ObjectExtents: " << vec[0] << " : " << vec[1] << LL_ENDL;
#endif
}
//--------------------------------------------------------------