//******************************************************************************
//	collsn.cpp - This file contains the Collision Detection System
//
//	MechCommander 2
//
//---------------------------------------------------------------------------//
// Copyright (C) Microsoft Corporation. All rights reserved.                 //
//===========================================================================//

// Include Files
#ifndef MCLIB_H
#include "mclib.h"
#endif

#ifndef COLLSN_H
#include "collsn.h"
#endif

#ifndef GAMEOBJ_H
#include "gameobj.h"
#endif

#ifndef OBJTYPE_H
#include "objtype.h"
#endif

#ifndef OBJMGR_H
#include "objmgr.h"
#endif

#ifndef MOVE_H
#include "move.h"
#endif

//------------------------------------------------------------------------------
// Static globals
//CollisionSystem *collisionSystem = NULL;
GlobalCollisionAlert *globalCollisionAlert = NULL;
UserHeapPtr CollisionSystem::collisionHeap = NULL;
unsigned long CollisionSystem::maxObjects = 0;
unsigned long CollisionSystem::gridRadius = 0;
unsigned long CollisionSystem::xGridSize = 0;
unsigned long CollisionSystem::yGridSize = 0;
unsigned long CollisionSystem::maxCollisions = 0;


//------------------------------------------------------------------------------
// class CollisionGrid 
//------------------------------------------------------------------------------
long GlobalCollisionAlert::init (unsigned long maxCollisionAlerts)
{
	maxAlerts = maxCollisionAlerts;
	
	collisionAlerts = (CollisionAlertRecordPtr)systemHeap->Malloc(sizeof(CollisionAlertRecord) * maxAlerts);
	gosASSERT(collisionAlerts != NULL);

	purgeRecords();
	
	return(NO_ERR);
}

//------------------------------------------------------------------------------
void GlobalCollisionAlert::destroy (void)
{
	systemHeap->Free(collisionAlerts);
	collisionAlerts = NULL;
	maxAlerts = nextRecord = 0;
}

//------------------------------------------------------------------------------
long GlobalCollisionAlert::addRecord (GameObjectPtr obj1, GameObjectPtr obj2, float distance, float time)
{
	if (nextRecord < maxAlerts)
	{
		collisionAlerts[nextRecord].object1 = obj1;
		collisionAlerts[nextRecord].object2 = obj2;

		collisionAlerts[nextRecord].currentDistance = distance;
		collisionAlerts[nextRecord].timeToImpact = time;
		nextRecord++;	
		
		return(NO_ERR);
	}
	
	return(-1);
}
		
//------------------------------------------------------------------------------
CollisionAlertRecordPtr GlobalCollisionAlert::findAlert (GameObjectPtr object, CollisionAlertRecordPtr startRecord)
{
	unsigned long startIndex = 0;
	if (startRecord)
	{
		for (long i=startIndex;i<(long)nextRecord;i++)
		{
			if (&(collisionAlerts[i]) == startRecord)
			{
				break;
			}
		}
		
		startIndex = i+1;
	}
	
	if (startIndex < nextRecord)
	{
		for (long i=startIndex;i<(long)nextRecord;i++)
		{
			if (( (collisionAlerts[i].object1) == object) ||
				( (collisionAlerts[i].object2) == object))
			{
				return(&(collisionAlerts[i]));
			}
		}
	}
		
	return(NULL);
}

//------------------------------------------------------------------------------
void GlobalCollisionAlert::purgeRecords (void)
{
	nextRecord = 0;
	
	for (long i=0;i<(long)maxAlerts;i++)
	{
		collisionAlerts[i].object1 = NULL;
		collisionAlerts[i].object2 = NULL;

		collisionAlerts[i].currentDistance = 0.0;
		collisionAlerts[i].timeToImpact = 0.0;
	}
}

//------------------------------------------------------------------------------
// class CollisionGrid 
void * CollisionGrid::operator new (size_t mySize)
{
	void *result = NULL;
	
	if (CollisionSystem::collisionHeap && CollisionSystem::collisionHeap->heapReady())
		result = CollisionSystem::collisionHeap->Malloc(mySize);
	
	return(result);
}

//------------------------------------------------------------------------------
void CollisionGrid::operator delete (void *us)
{
	if (CollisionSystem::collisionHeap && CollisionSystem::collisionHeap->heapReady())
		CollisionSystem::collisionHeap->Free(us);
}

//------------------------------------------------------------------------------
long CollisionGrid::init (Stuff::Vector3D &newOrigin)
{
	//--------------------------------------------------
	// Check if stuff is allocated.  Once this happens
	// it is silly to call destroy each time.  We can
	// simply reinit and check if allocs already go.
	if (!gridIsGo)
	{
		xGridWidth = CollisionSystem::xGridSize;
		yGridWidth = CollisionSystem::yGridSize;
		
		maxGridRadius = CollisionSystem::gridRadius;
		maxObjects = CollisionSystem::maxObjects;

		gridSize = sizeof(CollisionGridNodePtr) * xGridWidth * yGridWidth;
		nodeSize = sizeof(CollisionGridNode) * maxObjects;
		
		if (CollisionSystem::collisionHeap && CollisionSystem::collisionHeap->heapReady())
			grid = (CollisionGridNodePtr *)CollisionSystem::collisionHeap->Malloc(gridSize);
		
		gosASSERT(grid != NULL);
		
		if (CollisionSystem::collisionHeap && CollisionSystem::collisionHeap->heapReady())
			nodes = (CollisionGridNodePtr)CollisionSystem::collisionHeap->Malloc(nodeSize);
		
		gosASSERT(nodes != NULL);
		
		gridXOffset = ((xGridWidth + 1) * maxGridRadius) / 2;
		gridYOffset = ((yGridWidth + 1) * maxGridRadius) / 2;
		
		gridXCheck = xGridWidth * maxGridRadius;
		gridYCheck = yGridWidth * maxGridRadius;
			
		gridIsGo = TRUE;
	}

	//-----------------------------
	// Reset all of the grid data.	
	memset(grid,0,gridSize);
	memset(nodes,0,nodeSize);
		
	nextAvailableNode = 0;
	gridOrigin = newOrigin;
	
	giantObjects = NULL;

	return(NO_ERR);
}
		
//------------------------------------------------------------------------------
void CollisionGrid::destroy (void)
{
	if (gridIsGo)
	{
		if (CollisionSystem::collisionHeap && CollisionSystem::collisionHeap->heapReady())
		{
			CollisionSystem::collisionHeap->Free(nodes);
			nodes = NULL;
			
			CollisionSystem::collisionHeap->Free(grid);
			grid = NULL;			
		}
		
		gridIsGo = FALSE;
		init();
	}
}	
		
//------------------------------------------------------------------------------
long CollisionGrid::add (unsigned long gridIndex, GameObjectPtr object)
{
	gosASSERT(nextAvailableNode < maxObjects);
	gosASSERT((gridIndex >= 0) && (gridIndex < (xGridWidth * yGridWidth)));
	
	CollisionGridNodePtr prev = grid[gridIndex];
	CollisionGridNodePtr node = &nodes[nextAvailableNode++];
	grid[gridIndex] = node;
	node->object = object;
	node->next = prev;
	
	return(NO_ERR);
}

//------------------------------------------------------------------------------
long CollisionGrid::add (GameObjectPtr object)
{
	if (object->getTangible())		//Can anything even hit me?
	{
		gosASSERT(nextAvailableNode < maxObjects);
		float objectRadius = object->getExtentRadius();
		
		//---------------------------------------------
		// Check if we are a giant Object
		if (objectRadius > maxGridRadius)
		{
			CollisionGridNodePtr node = &nodes[nextAvailableNode++];
			node->object = object;
			node->next = giantObjects;
			giantObjects = node;
			return NO_ERR;
		}
		
		float gx,gy;
		
		gx = object->getPosition().x;	// - gridOrigin.x;
		gx += gridXOffset;
		if (gx < 0)
			gx = 0;
		
		if (gx >= gridXCheck)
			gx = gridXCheck - 1;
		
		gx /= maxGridRadius;
		
		gy = object->getPosition().y;	// - gridOrigin.y;
		gy += gridYOffset;
		if (gy < 0)
			gy = 0;
		
		if (gy >= gridYCheck)	
			gy = gridYCheck - 1;
		
		gy /= maxGridRadius;	

		unsigned long gridIndex = float2long(gx-0.5f) + float2long(gy-0.5f) * xGridWidth;
		
		long result = add(gridIndex,object);
		return result;
	}

	return NO_ERR;
}	

//------------------------------------------------------------------------------
void CollisionGrid::createGrid (void)
{
	//------------------------------------------------
	// This block of code is only necessary if
	// we collide a giantObject against a giantObject.
	CollisionGridNodePtr g = giantObjects;
	unsigned long totalGiantObjects = 0;
	while (g)
	{
		if (g->next)
		{
			checkGrid(g->object,g->next);
			totalGiantObjects++;
		}
		g = g->next;
	}
	
	for (long y=0;y<(long)yGridWidth;y++)
	{
		for (long x=0;x<(long)xGridWidth;x++)
		{
			unsigned long gridIndex = x + y*xGridWidth;
			CollisionGridNodePtr g = grid[gridIndex];
			
			while (g)
			{
				GameObjectPtr obj = g->object;
				
				//--------------------------------------
				// Check against the big things.
				if (giantObjects)
					checkGrid(obj,giantObjects);
				
				CollisionGridNodePtr area = g->next;
				
				//---------------------------
				// Check same grid as object
				if (area)	
					checkGrid(obj,area);
				
				if (x < long(xGridWidth-1))
				{
					//---------------------
					// Check grid at x+1,y
					area = grid[gridIndex+1];
					if (area)
						checkGrid(obj,area);
					
					if (y < long(yGridWidth-1))
					{
						//-----------------------
						// Check grid at x+1,y+1
						area = grid[gridIndex+1+xGridWidth];
						if (area)
							checkGrid(obj,area);
					}
				}
				
				if (y < long(yGridWidth-1))
				{
					//---------------------
					// Check grid at x,y+1
					area = grid[gridIndex+xGridWidth];
					if (area)
						checkGrid(obj,area);
				}
				
				g = g->next;
			}
		}
	}
}	

//------------------------------------------------------------------------------
void CollisionGrid::checkGrid (GameObjectPtr obj1, CollisionGridNodePtr area)
{
	while (area)
	{
		GameObjectPtr obj2 = area->object;
		area = area->next;

		if (obj1 && obj2)
		{
			//-------------------------------------------------------------
			// CULL collisions between things which can never collide here
			//------------------------------------------------------------
			if ((obj1->getObjectClass() == TURRET) && (obj2->getObjectClass() == TURRET) ||
				(obj1->getObjectClass() == GATE) && (obj2->getObjectClass() == GATE) ||
				(obj1->getObjectClass() == GATE) && (obj2->getObjectClass() == TURRET) ||
				(obj1->getObjectClass() == TURRET) && (obj2->getObjectClass() == GATE) ||
				(obj1->getObjectClass() == TURRET) && (obj2->getObjectClass() == TREE) ||
				(obj1->getObjectClass() == TREE) && (obj2->getObjectClass() == TURRET) ||
				(obj1->getObjectClass() == EXPLOSION) && (obj2->getObjectClass() == EXPLOSION))
			{
				
			}
			else
			{
				//--------------------------------------------------------
				// At this point, we have two objects in the same area
				// and they can collide.  We now run the bigBoy detection
				CollisionSystem::detectCollision(obj1,obj2);
			}
		}
	}
}	

//------------------------------------------------------------------------------
// class CollisionSystem
void * CollisionSystem::operator new (size_t mySize)
{
	void *result = NULL;
	
	result = systemHeap->Malloc(mySize);
	
	return(result);
}

//------------------------------------------------------------------------------
void CollisionSystem::operator delete (void *us)
{
	systemHeap->Free(us);
}

//------------------------------------------------------------------------------
long CollisionSystem::init (FitIniFile *scenarioFile)
{
	xGridSize =24;
	yGridSize =24;
	gridRadius = 200;
	maxObjects = 300;
	maxCollisions = 100;
	warningDist = 250.0;                       //This is in world Units!!!
	alertTime = 2.5;                                     //This is in seconds
		
	collisionHeap = new UserHeap;
	gosASSERT(collisionHeap != NULL);
		
	long result = collisionHeap->init(65535);
	gosASSERT(result == NO_ERR);
	
	collisionGrid = new CollisionGrid;
	gosASSERT(collisionGrid != NULL);

	globalCollisionAlert = new GlobalCollisionAlert;
	gosASSERT(globalCollisionAlert);
	
	result = globalCollisionAlert->init(20);
	gosASSERT(result == NO_ERR);
	
	return(NO_ERR);
}

#define MAX_LISTS_TO_CHECK		3
//------------------------------------------------------------------------------
void CollisionSystem::checkObjects (void)
{
	Stuff::Vector3D gridCenter(0L,0L,0L);
	
	collisionGrid->init(gridCenter);

	//-----------------------------------------------------------
	// Reset the Collision Alerts
	globalCollisionAlert->purgeRecords();
	
#if 1

	GameObjectPtr* objList = NULL;
	long numCollidables = ObjectManager->getCollidableList(objList);
	for (long i = 0; i < numCollidables; i++) 
	{
		if (objList[i] && objList[i]->getExists() && objList[i]->getTangible())
		{
#ifdef _DEBUG
		long result = 
#endif
			collisionGrid->add(objList[i]);
			gosASSERT(result == NO_ERR);
			objList[i]->handleStaticCollision();
		}
	}

#else	
	//---------------------------------------------------------
	// Convert to Glenn's Magical New Object System!
	ObjectQueueNodePtr objList = objectList->getHeadList(); 		//Start with the default list.
	ObjectNodePtr objNode = NULL;
	unsigned long objectsPerList[MAX_LISTS_TO_CHECK] = 
	{
		0,0,0
	};
	
	while (objList && (currentList < MAX_LISTS_TO_CHECK))
	{
		//----------------------------------------------------
		// if getObjectType returns NULL we are a baseObject.
		// Something like the sun or terrain.  DO NOT CHECK!!
		// We cast as a GameObject and that will seriously
		// mess up if we are just a baseObject!
		if (objNode && objNode->getObjectType() != NULL)
		{
			result = collisionGrid->add((GameObjectPtr)objNode);
			objectsPerList[currentList]++;
			
			//----------------------------------------------------------
			// This can only happen if we are out of nodes.
			// Just break out of loop and check what we have, cause
			// no more are getting added!  We should probably Inform
			// the debug crowd of this!!
			gosASSERT(result == NO_ERR);
				
			//-----------------------------------------------------
			//-- For right now, just explosions and artillery
			//-- Movers need a revised check for the code to work.
			//-- Code is in.  Away we go.
			objNode->handleStaticCollision();
			
			objNode = objNode->next;
		}
		else
		{
			objNode = objList->head;
		}
		
		if (objNode == NULL)
		{
			objList = objList->next;
			currentList++;
		}
	}
#endif
	
	collisionGrid->createGrid();
}

//------------------------------------------------------------------------------

void CollisionSystem::detectCollision (GameObjectPtr obj1, GameObjectPtr obj2)
{
	float timeOfClosest = 0.0;

	//---------------------------------------------------------
	// Convert to Glenn's Magical New Object System!
	// Need some way to know this is a MOVER/Collider!
	if ((obj1->getObjectClass() < EXPLOSION) && (obj2->getObjectClass() < EXPLOSION))
	{
		//---------------------------------------------------------------
		// Objects have to be in the same move plane in order to collide.
		// Thus, a copter can't collide with a tree...
		long obj1Pos[2] = {0, 0};
		long obj2Pos[2] = {0, 0};
		obj1->getCellPosition(obj1Pos[0], obj1Pos[1]);
		obj2->getCellPosition(obj2Pos[0], obj2Pos[1]);

		//-------------------------------------------
		// Do a cell based collision.  Ignore Radii.
		long obj1Block, obj2Block;
		long obj1Vertex, obj2Vertex;
		obj1->getBlockAndVertexNumber(obj1Block,obj1Vertex);
		obj2->getBlockAndVertexNumber(obj2Block,obj2Vertex);
		
		if ((obj1Block == obj2Block) && (obj1Vertex == obj2Vertex))
			if ((obj1Pos[0] == obj2Pos[0]) && (obj1Pos[1] == obj2Pos[1])) {
	   			//------------------------------------------------
	   			// OK, we now need to check extents to determine
		   		// If collision happened.  May not need to go any
		   		// further for Honor Bound.
		   		checkExtents(obj1,obj2,timeOfClosest);
			}
	}
	else
	{
		//--------------------------------------------------------
		// First we check and see if we are already colliding.
		// If so, dump us to checkExtents.
		Stuff::Vector3D obj1Pos = obj1->getPosition();
		Stuff::Vector3D obj2Pos = obj2->getPosition();
		Stuff::Vector3D pos;
		pos.Subtract(obj2Pos, obj1Pos);
		pos.z = 0.0;		//Ignore Elevation.  May cause explosion/artillery f-ups!
		float distMag = pos.x * pos.x + pos.y * pos.y;//pos.magnitude();

		float dist0 = obj1->getExtentRadius();
		float dist1 = obj2->getExtentRadius();
		float maxDist = dist1 + dist0;
		maxDist *= maxDist;

		if (distMag < maxDist)
	   	{
	   		//------------------------------------------------
	   		// OK, we now need to check extents to determine
	   		// If collision happened.  May not need to go any
	   		// further for Honor Bound.
			checkExtents(obj1,obj2,timeOfClosest);
	   	}
		
	}
}

//------------------------------------------------------------------------------
void CollisionSystem::detectStaticCollision (GameObjectPtr obj1, GameObjectPtr obj2)
{
	float timeOfClosest = 0.0;

	//--------------------------------------------------------
	// First we check and see if we are already colliding.
	// If so, dump us to checkExtents.
	Stuff::Vector3D obj1Pos = obj1->getPosition();
	Stuff::Vector3D obj2Pos = obj2->getPosition();
	Stuff::Vector3D pos;
	pos.Subtract(obj2Pos,obj1Pos);

	float distMag = pos.x * pos.x + pos.y * pos.y;

	float dist0 = obj1->getExtentRadius();
	float dist1 = obj2->getExtentRadius();
	float maxDist = dist1 + dist0;
	maxDist *= maxDist;

	if (distMag < maxDist)
   	{
		//-------------------------------------------------------------------------------------------------------
		// If we are inside the extent radius AND standing on impassable terrain, we hit the static object.
		// ONLY if we are a mover.  We hit them if we are not a mover and we are an artillery or turret or gate.
		if (obj1->isMover() && (obj2->getObjectClass() != TREE) && (obj2->getObjectClass() != TERRAINOBJECT))
		{
			if (!(obj2->isSpecialBuilding()) && (obj2->getObjectClass() != BRIDGE))
			{
				long obj1Pos[2] = {0, 0};
				obj1->getCellPosition(obj1Pos[0], obj1Pos[1]);
				if (GameMap->getPassable(obj1Pos[0], obj1Pos[1]))
					return;
			}
		}
		checkExtents(obj1,obj2,timeOfClosest);
   	}
}

//------------------------------------------------------------------------------

void CollisionSystem::checkExtents (GameObjectPtr obj1, GameObjectPtr obj2, float time)
{
	//---------------------------------------------------------
	// We may not need any more information for MechCommander2
	// At this point, simply build a CollisionRecord.
	// If we do need more info, add extent checks here.
	
	//------------------------------------------------------------
	// If we are an explosion, handle our collisions here and
	// DO NOT add our record.  Fuel Tank Farms will completely
	// swamp this here otherwise.
	//
	// In fact, I can think of NO reason why we wouldn't just
	// handle all of the collisions here anyway.  Saves us the
	// trouble of ever running out of collision records and since
	// we run process collisions afterwards anyway and nothing
	// in MechCommander can ever go away, why not?
	//
	// We handle all here.  NO more collision records.
	//

	//Wow, does this not work.
	// Helicopters still need to collide with turrets and explosions and artillery.
	// Make it so.
	// -fs
	if (!obj1->getExists() || !obj2->getExists())
		return;

	if ((obj1->getMoveLevel() == 2) || (obj2->getMoveLevel() == 2))
	{
		if ((obj1->getMoveLevel() != obj2->getMoveLevel()) &&
			(obj1->getObjectClass() != TURRET) &&
			(obj2->getObjectClass() != TURRET) &&
			(obj1->getObjectClass() != ARTILLERY) &&
			(obj2->getObjectClass() != ARTILLERY) &&
			(obj1->getObjectClass() != EXPLOSION) &&
			(obj2->getObjectClass() != EXPLOSION))
			return;
	}

	ObjectTypePtr	obj1Type = obj1->getObjectType();
	ObjectTypePtr	obj2Type = obj2->getObjectType();
				
	bool obj1Result = obj1Type->handleCollision(obj1,obj2);
	bool obj2Result = obj2Type->handleCollision(obj2,obj1);
	
	//-----------------------------------------
	// If we came back TRUE, whack the object.
	if (obj1Result)
	{
		bool removeObject1 = obj1Type->handleDestruction(obj1,obj2);
		//------------------------------------------------------------
		// Pull the object from the objList here if this flag is set.
		// Otherwise, the object will still be around for a little
		// while as it destroys itself over the next several frames.
		if (removeObject1)
		{
			obj1->setExists(false);
		}
	}
	
	//-----------------------------------------
	// If we came back TRUE, whack the object.
	if (obj2Result)
	{
		bool removeObject2 = obj2Type->handleDestruction(obj2,obj1);
		//------------------------------------------------------------
		// Pull the object from the objList here if this flag is set.
		// Otherwise, the object will still be around for a little
		// while as it destroys itself over the next several frames.
		if (removeObject2)
		{
			obj2->setExists(false);
		}
	}
}


//------------------------------------------------------------------------------
float CollisionSystem::timeToImpact (GameObjectPtr obj1, GameObjectPtr obj2)
{
	float timeOfClosest = -1.0;

	//--------------------------------------------------------
	// First we check and see if we are already colliding.
	// If so, dump us to checkExtents.
	Stuff::Vector3D obj1Pos = obj1->getPosition();
	Stuff::Vector3D obj2Pos = obj2->getPosition();
	Stuff::Vector3D pos;
	pos.Subtract(obj2Pos,obj1Pos);

	float distMag = pos.x * pos.x + pos.y * pos.y;		//pos.magnitude();
	float dist0 = obj1->getExtentRadius();
	float dist1 = obj2->getExtentRadius();
	float maxDist =  dist1 + dist0;
	maxDist *= maxDist;

	if (distMag < maxDist)
   	{
   		//------------------------------------------------
   		// OK, we now need to check extents to determine
   		// If collision happened.  May not need to go any
   		// further for Honor Bound.
		timeOfClosest = 0.0;
		return(timeOfClosest);
   	}

	//--------------------------------------------------------
	// Then we check the current positions against the final
	// positions for the this frame and determine if the
	// objects are moving toward or away from each other.
	// If away, we're done.  If not, next step.
	Stuff::Vector3D obj1Vel = obj1->getVelocity();
	Stuff::Vector3D obj2Vel = obj2->getVelocity();
	
	Stuff::Vector3D obj1FPos;
	obj1Vel *= frameLength;
	obj1FPos.Add(obj1Pos,obj1Vel);

	Stuff::Vector3D obj2FPos;
	obj2Vel *= frameLength;
	obj2FPos.Add(obj2Pos,obj2Vel);
	
	Stuff::Vector3D obj1RPos;
	obj1RPos.Subtract(obj1FPos,obj1Pos);
	Stuff::Vector3D obj2RPos;
	obj2RPos.Subtract(obj2FPos,obj2Pos);
	
	float headingResult = obj1RPos * obj2RPos;
	
	//--------------------------------------------------------------
	// If this is negative, objects are heading towards each other.
	if (headingResult < 0)
	{
		//--------------------------------------------------------------
		// Now find the time of closest approach.  This is given by the
		// formula (pos DOT vel) / (vel DOT vel) = -timeOfClosest.
		Stuff::Vector3D vel;
		vel.Subtract(obj2Vel,obj1Vel);
		
		float timeOfClosest = -((pos * vel) / (vel * vel));
		if (timeOfClosest <= frameLength)
		{
			//------------------------------------------------
			// They are closest during this frame.
			// Find out what distance this is.
			Stuff::Vector3D dist;
			vel *= timeOfClosest;
			dist.Add(pos, vel);
			
			float distMag = dist.x*dist.x + dist.y*dist.y;		//dist.magnitude();
			
			if (distMag < maxDist)
			{
				//------------------------------------------------
				// OK, we now need to check extents to determine
				// If collision happened.  May not need to go any
				// further for Honor Bound.
				return(timeOfClosest);
				
			}
		}
	}
	
	return(timeOfClosest);
}

//------------------------------------------------------------------------------
void CollisionSystem::destroy (void)
{
	delete collisionGrid;
    collisionGrid = NULL;

	delete collisionHeap;
    collisionHeap = NULL;
	
	delete globalCollisionAlert;
	globalCollisionAlert = NULL;
}

//------------------------------------------------------------------------------