hlsdk-portable/dlls/nodes.cpp

/***
*
*	Copyright (c) 1996-2002, Valve LLC. All rights reserved.
*	
*	This product contains software technology licensed from Id 
*	Software, Inc. ("Id Technology").  Id Technology (c) 1996 Id Software, Inc. 
*	All Rights Reserved.
*
*   This source code contains proprietary and confidential information of
*   Valve LLC and its suppliers.  Access to this code is restricted to
*   persons who have executed a written SDK license with Valve.  Any access,
*   use or distribution of this code by or to any unlicensed person is illegal.
*
****/
//=========================================================
// nodes.cpp - AI node tree stuff.
//=========================================================

#include	"extdll.h"
#include	"util.h"
#include	"cbase.h"
#include	"monsters.h"
#include	"nodes.h"
#include	"nodes_compat.h"
#include	"animation.h"
#include	"doors.h"

#define	HULL_STEP_SIZE 16// how far the test hull moves on each step
#define	NODE_HEIGHT	8	// how high to lift nodes off the ground after we drop them all (make stair/ramp mapping easier)

// to help eliminate node clutter by level designers, this is used to cap how many other nodes
// any given node is allowed to 'see' in the first stage of graph creation "LinkVisibleNodes()".
#define	MAX_NODE_INITIAL_LINKS	128
#define	MAX_NODES               1024

extern DLL_GLOBAL edict_t *g_pBodyQueueHead;

Vector VecBModelOrigin( entvars_t *pevBModel );

CGraph WorldGraph;

LINK_ENTITY_TO_CLASS( info_node, CNodeEnt )
LINK_ENTITY_TO_CLASS( info_node_air, CNodeEnt )

#if !defined _WIN32
#include <unistd.h>
#include <sys/stat.h>
#define CreateDirectoryA(p, n) mkdir(p, 0777)
#endif

//=========================================================
// CGraph - InitGraph - prepares the graph for use. Frees any
// memory currently in use by the world graph, NULLs 
// all pointers, and zeros the node count.
//=========================================================
void CGraph::InitGraph( void )
{
	// Make the graph unavailable
	//
	m_fGraphPresent = FALSE;
	m_fGraphPointersSet = FALSE;
	m_fRoutingComplete = FALSE;

	// Free the link pool
	//
	if( m_pLinkPool )
	{
		free( m_pLinkPool );
		m_pLinkPool = NULL;
	}

	// Free the node info
	//
	if( m_pNodes )
	{
		free( m_pNodes );
		m_pNodes = NULL;
	}

	if( m_di )
	{
		free( m_di );
		m_di = NULL;
	}

	// Free the routing info.
	//
	if( m_pRouteInfo )
	{
		free( m_pRouteInfo );
		m_pRouteInfo = NULL;
	}

	if( m_pHashLinks )
	{
		free( m_pHashLinks );
		m_pHashLinks = NULL;
	}

	// Zero node and link counts
	//
	m_cNodes = 0;
	m_cLinks = 0;
	m_nRouteInfo = 0;

	m_iLastActiveIdleSearch = 0;
	m_iLastCoverSearch = 0;
}
	
//=========================================================
// CGraph - AllocNodes - temporary function that mallocs a
// reasonable number of nodes so we can build the path which
// will be saved to disk.
//=========================================================
int CGraph::AllocNodes( void )
{
	//  malloc all of the nodes
	WorldGraph.m_pNodes = (CNode *)calloc( sizeof(CNode), MAX_NODES );

	// could not malloc space for all the nodes!
	if( !WorldGraph.m_pNodes )
	{
		ALERT( at_aiconsole, "**ERROR**\nCouldn't malloc %d nodes!\n", WorldGraph.m_cNodes );
		return FALSE;
	}

	return TRUE;
}

//=========================================================
// CGraph - LinkEntForLink - sometimes the ent that blocks
// a path is a usable door, in which case the monster just
// needs to face the door and fire it. In other cases, the
// monster needs to operate a button or lever to get the 
// door to open. This function will return a pointer to the
// button if the monster needs to hit a button to open the 
// door, or returns a pointer to the door if the monster 
// need only use the door.
//
// pNode is the node the monster will be standing on when it
// will need to stop and trigger the ent.
//=========================================================
entvars_t *CGraph::LinkEntForLink( CLink *pLink, CNode *pNode )
{
	edict_t	*pentSearch;
	edict_t	*pentTrigger;
	entvars_t *pevTrigger;
	entvars_t *pevLinkEnt;
	TraceResult tr;

	pevLinkEnt = pLink->m_pLinkEnt;
	if( !pevLinkEnt )
		return NULL;

	pentSearch = NULL;// start search at the top of the ent list.

	if( FClassnameIs( pevLinkEnt, "func_door" ) || FClassnameIs( pevLinkEnt, "func_door_rotating" ) )
	{
		///!!!UNDONE - check for TOGGLE or STAY open doors here. If a door is in the way, and is 
		// TOGGLE or STAY OPEN, even monsters that can't open doors can go that way.

		if( ( pevLinkEnt->spawnflags & SF_DOOR_USE_ONLY ) )
		{
			// door is use only, so the door is all the monster has to worry about
			return pevLinkEnt;
		}

		while( 1 )
		{
			pentTrigger = FIND_ENTITY_BY_TARGET( pentSearch, STRING( pevLinkEnt->targetname ) );// find the button or trigger

			if( FNullEnt( pentTrigger ) )
			{
				// no trigger found

				// right now this is a problem among auto-open doors, or any door that opens through the use 
				// of a trigger brush. Trigger brushes have no models, and don't show up in searches. Just allow
				// monsters to open these sorts of doors for now. 
				return pevLinkEnt;
			}

			pentSearch = pentTrigger;
			pevTrigger = VARS( pentTrigger );

			if( FClassnameIs( pevTrigger, "func_button" ) || FClassnameIs( pevTrigger, "func_rot_button" ) )
			{
				// only buttons are handled right now.

				// trace from the node to the trigger, make sure it's one we can see from the node.
				// !!!HACKHACK Use bodyqueue here cause there are no ents we really wish to ignore!
				UTIL_TraceLine( pNode->m_vecOrigin, VecBModelOrigin( pevTrigger ), ignore_monsters, g_pBodyQueueHead, &tr );

				if( VARS(tr.pHit) == pevTrigger )
				{
					// good to go!
					return VARS( tr.pHit );
				}
			}
		}
	}
	else
	{
		ALERT( at_aiconsole, "Unsupported PathEnt:\n'%s'\n", STRING( pevLinkEnt->classname ) );
		return NULL;
	}
}

//=========================================================
// CGraph - HandleLinkEnt - a brush ent is between two
// nodes that would otherwise be able to see each other. 
// Given the monster's capability, determine whether
// or not the monster can go this way. 
//=========================================================
int CGraph::HandleLinkEnt( int iNode, entvars_t *pevLinkEnt, int afCapMask, NODEQUERY queryType )
{
	//edict_t *pentWorld;
	CBaseEntity *pDoor;
	TraceResult tr;

	if( !m_fGraphPresent || !m_fGraphPointersSet )
	{
		// protect us in the case that the node graph isn't available
		ALERT( at_aiconsole, "Graph not ready!\n" );
		return FALSE;
	}

	if( FNullEnt( pevLinkEnt ) )
	{
		ALERT( at_aiconsole, "dead path ent!\n" );
		return TRUE;
	}
	//pentWorld = NULL;

	// func_door
	if( FClassnameIs( pevLinkEnt, "func_door" ) || FClassnameIs( pevLinkEnt, "func_door_rotating" ) )
	{
		// ent is a door.
		pDoor = ( CBaseEntity::Instance( pevLinkEnt ) );

		if( ( pevLinkEnt->spawnflags & SF_DOOR_USE_ONLY ) ) 
		{
			// door is use only.
			if( ( afCapMask & bits_CAP_OPEN_DOORS ) )
			{
				// let monster right through if he can open doors
				return TRUE;
			}
			else 
			{
				// monster should try for it if the door is open and looks as if it will stay that way
				if( pDoor->GetToggleState()== TS_AT_TOP && ( pevLinkEnt->spawnflags & SF_DOOR_NO_AUTO_RETURN ) )
				{
					return TRUE;
				}

				return FALSE;
			}
		}
		else 
		{
			// door must be opened with a button or trigger field.

			// monster should try for it if the door is open and looks as if it will stay that way
			if( pDoor->GetToggleState() == TS_AT_TOP && ( pevLinkEnt->spawnflags & SF_DOOR_NO_AUTO_RETURN ) )
			{
				return TRUE;
			}
			if( ( afCapMask & bits_CAP_OPEN_DOORS ) )
			{
				if( !( pevLinkEnt->spawnflags & SF_DOOR_NOMONSTERS ) || queryType == NODEGRAPH_STATIC )
					return TRUE;
			}

			return FALSE;
		}
	}
	// func_breakable
	else if( FClassnameIs( pevLinkEnt, "func_breakable" ) && queryType == NODEGRAPH_STATIC )
	{
		return TRUE;
	}
	else
	{
		ALERT( at_aiconsole, "Unhandled Ent in Path %s\n", STRING( pevLinkEnt->classname ) );
		return FALSE;
	}

	return FALSE;
}

#if 0
//=========================================================
// FindNearestLink - finds the connection (line) nearest
// the given point. Returns FALSE if fails, or TRUE if it
// has stuffed the index into the nearest link pool connection
// into the passed int pointer, and a BOOL telling whether or 
// not the point is along the line into the passed BOOL pointer.
//=========================================================
int CGraph::FindNearestLink( const Vector &vecTestPoint, int *piNearestLink, BOOL *pfAlongLine )
{
	int i, j;// loops

	int iNearestLink;// index into the link pool, this is the nearest node at any time. 
	float flMinDist;// the distance of of the nearest case so far
	float flDistToLine;// the distance of the current test case

	BOOL fCurrentAlongLine;
	BOOL fSuccess;

	//float flConstant;// line constant
	Vector vecSpot1, vecSpot2;
	Vector2D vec2Spot1, vec2Spot2, vec2TestPoint;
	Vector2D vec2Normal;// line normal
	Vector2D vec2Line;

	TraceResult tr;

	iNearestLink = -1;// prepare for failure
	fSuccess = FALSE;

	flMinDist = 9999;// anything will be closer than this

	// go through all of the nodes, and each node's connections	
	int cSkip = 0;// how many links proper pairing allowed us to skip
	int cChecked = 0;// how many links were checked

	for( i = 0; i < m_cNodes; i++ )
	{
		vecSpot1 = m_pNodes[i].m_vecOrigin;

		if( m_pNodes[i].m_cNumLinks <= 0 )
		{
			// this shouldn't happen!
			ALERT( at_aiconsole, "**Node %d has no links\n", i );
			continue;
		}

		for( j = 0; j < m_pNodes[i].m_cNumLinks; j++ )
		{
			/*
			!!!This optimization only works when the node graph consists of properly linked pairs. 
			if( INodeLink( i, j ) <= i )
			{
				// since we're going through the nodes in order, don't check
				// any connections whose second node is lower in the list
				// than the node we're currently working with. This eliminates
				// redundant checks.
				cSkip++;
				continue;
			}
			*/

			vecSpot2 = PNodeLink( i, j )->m_vecOrigin;

			// these values need a little attention now and then, or sometimes ramps cause trouble.
			if( fabs( vecSpot1.z - vecTestPoint.z ) > 48 && fabs( vecSpot2.z - vecTestPoint.z ) > 48 )
			{
				// if both endpoints of the line are 32 units or more above or below the monster, 
				// the monster won't be able to get to them, so we do a bit of trivial rejection here.
				// this may change if monsters are allowed to jump down. 
				// 
				// !!!LATER: some kind of clever X/Y hashing should be used here, too
				continue;
			}

			// now we have two endpoints for a line segment that we've not already checked. 
			// since all lines that make it this far are within -/+ 32 units of the test point's
			// Z Plane, we can get away with doing the point->line check in 2d.

			cChecked++;

			vec2Spot1 = vecSpot1.Make2D();
			vec2Spot2 = vecSpot2.Make2D();
			vec2TestPoint = vecTestPoint.Make2D();

			// get the line normal.
			vec2Line = ( vec2Spot1 - vec2Spot2 ).Normalize();
			vec2Normal.x = -vec2Line.y;
			vec2Normal.y = vec2Line.x;

			if( DotProduct( vec2Line, ( vec2TestPoint - vec2Spot1 ) ) > 0 )
			{
				// point outside of line
				flDistToLine = ( vec2TestPoint - vec2Spot1 ).Length();
				fCurrentAlongLine = FALSE;
			}
			else if( DotProduct( vec2Line, ( vec2TestPoint - vec2Spot2 ) ) < 0 )
			{
				// point outside of line
				flDistToLine = ( vec2TestPoint - vec2Spot2 ).Length();
				fCurrentAlongLine = FALSE;
			}
			else
			{
				// point inside line
				flDistToLine = fabs( DotProduct( vec2TestPoint - vec2Spot2, vec2Normal ) );
				fCurrentAlongLine = TRUE;
			}

			if( flDistToLine < flMinDist )
			{
				// just found a line nearer than any other so far
				UTIL_TraceLine( vecTestPoint, SourceNode( i, j ).m_vecOrigin, ignore_monsters, g_pBodyQueueHead, &tr );

				if( tr.flFraction != 1.0 )
				{
					// crap. can't see the first node of this link, try to see the other
					UTIL_TraceLine ( vecTestPoint, DestNode( i, j ).m_vecOrigin, ignore_monsters, g_pBodyQueueHead, &tr );
					if( tr.flFraction != 1.0 )
					{
						// can't use this link, cause can't see either node!
						continue;
					}
				}

				fSuccess = TRUE;// we know there will be something to return.
				flMinDist = flDistToLine;
				iNearestLink = m_pNodes[i].m_iFirstLink + j;
				*piNearestLink = m_pNodes[i].m_iFirstLink + j;
				*pfAlongLine = fCurrentAlongLine;
			}
		}
	}
/*
	if( fSuccess )
	{
		WRITE_BYTE( MSG_BROADCAST, SVC_TEMPENTITY );
		WRITE_BYTE( MSG_BROADCAST, TE_SHOWLINE );

		WRITE_COORD( MSG_BROADCAST, m_pNodes[m_pLinkPool[iNearestLink].m_iSrcNode].m_vecOrigin.x );
		WRITE_COORD( MSG_BROADCAST, m_pNodes[m_pLinkPool[iNearestLink].m_iSrcNode].m_vecOrigin.y );
		WRITE_COORD( MSG_BROADCAST, m_pNodes[m_pLinkPool[iNearestLink].m_iSrcNode].m_vecOrigin.z + NODE_HEIGHT );

		WRITE_COORD( MSG_BROADCAST, m_pNodes[m_pLinkPool[iNearestLink].m_iDestNode].m_vecOrigin.x );
		WRITE_COORD( MSG_BROADCAST, m_pNodes[m_pLinkPool[iNearestLink].m_iDestNode].m_vecOrigin.y );
		WRITE_COORD( MSG_BROADCAST, m_pNodes[m_pLinkPool[iNearestLink].m_iDestNode].m_vecOrigin.z + NODE_HEIGHT );
	}
*/
	ALERT( at_aiconsole, "%d Checked\n", cChecked );
	return fSuccess;
}
#endif

int CGraph::HullIndex( const CBaseEntity *pEntity )
{
	if( pEntity->pev->movetype == MOVETYPE_FLY )
		return NODE_FLY_HULL;

	if( pEntity->pev->mins == Vector( -12, -12, 0 ) )
		return NODE_SMALL_HULL;
	else if( pEntity->pev->mins == VEC_HUMAN_HULL_MIN )
		return NODE_HUMAN_HULL;
	else if( pEntity->pev->mins == Vector( -32, -32, 0 ) )
		return NODE_LARGE_HULL;

	//ALERT( at_aiconsole, "Unknown Hull Mins!\n" );
	return NODE_HUMAN_HULL;
}

int CGraph::NodeType( const CBaseEntity *pEntity )
{
	if( pEntity->pev->movetype == MOVETYPE_FLY )
	{
		if( pEntity->pev->waterlevel != 0 )
		{
			return bits_NODE_WATER;
		}
		else
		{
			return bits_NODE_AIR;
		}
	}
	return bits_NODE_LAND;
}

// Sum up graph weights on the path from iStart to iDest to determine path length
float CGraph::PathLength( int iStart, int iDest, int iHull, int afCapMask )
{
	float distance = 0;
	int iNext;

	int iMaxLoop = m_cNodes;

	int iCurrentNode = iStart;
	int iCap = CapIndex( afCapMask );

	while( iCurrentNode != iDest )
	{
		if( iMaxLoop-- <= 0 )
		{
			ALERT( at_console, "Route Failure\n" );
			return 0;
		}

		iNext = NextNodeInRoute( iCurrentNode, iDest, iHull, iCap );
		if( iCurrentNode == iNext )
		{
			//ALERT( at_aiconsole, "SVD: Can't get there from here..\n" );
			return 0;
		}

		int iLink;
		HashSearch( iCurrentNode, iNext, iLink );
		if( iLink < 0 )
		{
			ALERT( at_console, "HashLinks is broken from %d to %d.\n", iCurrentNode, iDest );
			return 0;
		}
		CLink &link = Link( iLink );
		distance += link.m_flWeight;

		iCurrentNode = iNext;
	}

	return distance;
}

// Parse the routing table at iCurrentNode for the next node on the shortest path to iDest
int CGraph::NextNodeInRoute( int iCurrentNode, int iDest, int iHull, int iCap )
{
	int iNext = iCurrentNode;
	int nCount = iDest + 1;
	signed char *pRoute = m_pRouteInfo + m_pNodes[iCurrentNode].m_pNextBestNode[iHull][iCap];

	// Until we decode the next best node
	//
	while( nCount > 0 )
	{
		signed char ch = *pRoute++;
		//ALERT( at_aiconsole, "C(%d)", ch );
		if( ch < 0 )
		{
			// Sequence phrase
			//
			ch = -ch;
			if( nCount <= ch )
			{
				iNext = iDest;
				nCount = 0;
				//ALERT( at_aiconsole, "SEQ: iNext/iDest=%d\n", iNext );
			}
			else
			{
				//ALERT( at_aiconsole, "SEQ: nCount + ch (%d + %d)\n", nCount, ch );
				nCount = nCount - ch;
			}
		}
		else
		{
			//ALERT( at_aiconsole, "C(%d)", *pRoute );

			// Repeat phrase
			//
			if( nCount <= ch + 1 )
			{
				iNext = iCurrentNode + *pRoute;
				if( iNext >= m_cNodes )
					iNext -= m_cNodes;
				else if( iNext < 0 )
					iNext += m_cNodes;
				nCount = 0;
				//ALERT( at_aiconsole, "REP: iNext=%d\n", iNext );
			}
			else
			{
				//ALERT( at_aiconsole, "REP: nCount - ch+1 (%d - %d+1)\n", nCount, ch );
				nCount = nCount - ch - 1;
			}
			pRoute++;
		}
	}

	return iNext;
}

//=========================================================
// CGraph - FindShortestPath 
//
// accepts a capability mask (afCapMask), and will only 
// find a path usable by a monster with those capabilities
// returns the number of nodes copied into supplied array
//=========================================================
int CGraph::FindShortestPath( int *piPath, int iStart, int iDest, int iHull, int afCapMask )
{
	int iVisitNode;
	int iCurrentNode;
	int iNumPathNodes;
	int iHullMask = 0;

	if( !m_fGraphPresent || !m_fGraphPointersSet )
	{
		// protect us in the case that the node graph isn't available or built
		ALERT( at_aiconsole, "Graph not ready!\n" );
		return FALSE;
	}

	if( iStart < 0 || iStart > m_cNodes )
	{
		// The start node is bad?
		ALERT( at_aiconsole, "Can't build a path, iStart is %d!\n", iStart );
		return FALSE;
	}

	if( iStart == iDest )
	{
		piPath[0] = iStart;
		piPath[1] = iDest;
		return 2;
	}

	// Is routing information present.
	//
	if( m_fRoutingComplete )
	{
		int iCap = CapIndex( afCapMask );

		iNumPathNodes = 0;
		piPath[iNumPathNodes++] = iStart;
		iCurrentNode = iStart;
		int iNext;

		//ALERT( at_aiconsole, "GOAL: %d to %d\n", iStart, iDest );

		// Until we arrive at the destination
		//
		while( iCurrentNode != iDest )
		{
			iNext = NextNodeInRoute( iCurrentNode, iDest, iHull, iCap );
			if( iCurrentNode == iNext )
			{
				//ALERT( at_aiconsole, "SVD: Can't get there from here..\n" );
				return 0;
				break;
			}
			if( iNumPathNodes >= MAX_PATH_SIZE )
			{
				//ALERT( at_aiconsole, "SVD: Don't return the entire path.\n" );
				break;
			}
			piPath[iNumPathNodes++] = iNext;
			iCurrentNode = iNext;
		}
		//ALERT( at_aiconsole, "SVD: Path with %d nodes.\n", iNumPathNodes );
	}
	else
	{
		int i;
		CQueuePriority queue;

		switch( iHull )
		{
		case NODE_SMALL_HULL:
			iHullMask = bits_LINK_SMALL_HULL;
			break;
		case NODE_HUMAN_HULL:
			iHullMask = bits_LINK_HUMAN_HULL;
			break;
		case NODE_LARGE_HULL:
			iHullMask = bits_LINK_LARGE_HULL;
			break;
		case NODE_FLY_HULL:
			iHullMask = bits_LINK_FLY_HULL;
			break;
		}

		// Mark all the nodes as unvisited.
		//
		for ( i = 0; i < m_cNodes; i++)
		{
			m_pNodes[i].m_flClosestSoFar = -1.0f;
		}

		m_pNodes[iStart].m_flClosestSoFar = 0.0;
		m_pNodes[iStart].m_iPreviousNode = iStart;// tag this as the origin node
		queue.Insert( iStart, 0.0 );// insert start node 

		while( !queue.Empty() )
		{
			// now pull a node out of the queue
			float flCurrentDistance;
			iCurrentNode = queue.Remove( flCurrentDistance );

			// For straight-line weights, the following Shortcut works. For arbitrary weights,
			// it doesn't.
			//
			if( iCurrentNode == iDest )
				break;

			CNode *pCurrentNode = &m_pNodes[iCurrentNode];

			for( i = 0; i < pCurrentNode->m_cNumLinks; i++ )
			{
				// run through all of this node's neighbors
				iVisitNode = INodeLink( iCurrentNode, i );
				if( ( m_pLinkPool[m_pNodes[iCurrentNode].m_iFirstLink + i].m_afLinkInfo & iHullMask ) != iHullMask )
				{
					// monster is too large to walk this connection
					//ALERT( at_aiconsole, "fat ass %d/%d\n",m_pLinkPool[m_pNodes[iCurrentNode].m_iFirstLink + i].m_afLinkInfo, iMonsterHull );
					continue;
				}
				// check the connection from the current node to the node we're about to mark visited and push into the queue				
				if( m_pLinkPool[m_pNodes[iCurrentNode].m_iFirstLink + i].m_pLinkEnt != NULL )
				{
					// there's a brush ent in the way! Don't mark this node or put it into the queue unless the monster can negotiate it
					if( !HandleLinkEnt( iCurrentNode, m_pLinkPool[m_pNodes[iCurrentNode].m_iFirstLink + i].m_pLinkEnt, afCapMask, NODEGRAPH_STATIC ) )
					{
						// monster should not try to go this way.
						continue;
					}
				}
				float flOurDistance = flCurrentDistance + m_pLinkPool[m_pNodes[iCurrentNode].m_iFirstLink + i].m_flWeight;
				if(  m_pNodes[iVisitNode].m_flClosestSoFar < -0.5f
				   || flOurDistance < m_pNodes[iVisitNode].m_flClosestSoFar - 0.001f )
				{
					m_pNodes[iVisitNode].m_flClosestSoFar = flOurDistance;
					m_pNodes[iVisitNode].m_iPreviousNode = iCurrentNode;

					queue.Insert( iVisitNode, flOurDistance );
				}
			}
		}
		if( m_pNodes[iDest].m_flClosestSoFar < -0.5f )
		{
			// Destination is unreachable, no path found.
			return 0;
		}

		// the queue is not empty
		// now we must walk backwards through the m_iPreviousNode field, and count how many connections there are in the path
		iCurrentNode = iDest;
		iNumPathNodes = 1;// count the dest

		while( iCurrentNode != iStart )
		{
			iNumPathNodes++;
			iCurrentNode = m_pNodes[iCurrentNode].m_iPreviousNode;
		}

		iCurrentNode = iDest;
		for( i = iNumPathNodes - 1; i >= 0; i-- )
		{
			piPath[i] = iCurrentNode;
			iCurrentNode = m_pNodes[iCurrentNode].m_iPreviousNode;
		}
	}
#if 0
	if( m_fRoutingComplete )
	{
		// This will draw the entire path that was generated for the monster.
		for( int i = 0; i < iNumPathNodes - 1; i++ )
		{
			MESSAGE_BEGIN( MSG_BROADCAST, SVC_TEMPENTITY );
				WRITE_BYTE( TE_SHOWLINE );

				WRITE_COORD( m_pNodes[piPath[i]].m_vecOrigin.x );
				WRITE_COORD( m_pNodes[piPath[i]].m_vecOrigin.y );
				WRITE_COORD( m_pNodes[piPath[i]].m_vecOrigin.z + NODE_HEIGHT );

				WRITE_COORD( m_pNodes[piPath[i + 1]].m_vecOrigin.x );
				WRITE_COORD( m_pNodes[piPath[i + 1]].m_vecOrigin.y );
				WRITE_COORD( m_pNodes[piPath[i + 1]].m_vecOrigin.z + NODE_HEIGHT );
			MESSAGE_END();
		}
	}
#endif
#if 0 // MAZE map
	MESSAGE_BEGIN( MSG_BROADCAST, SVC_TEMPENTITY );
		WRITE_BYTE( TE_SHOWLINE );

		WRITE_COORD( m_pNodes[4].m_vecOrigin.x );
		WRITE_COORD( m_pNodes[4].m_vecOrigin.y );
		WRITE_COORD( m_pNodes[4].m_vecOrigin.z + NODE_HEIGHT );

		WRITE_COORD( m_pNodes[9].m_vecOrigin.x );
		WRITE_COORD( m_pNodes[9].m_vecOrigin.y );
		WRITE_COORD( m_pNodes[9].m_vecOrigin.z + NODE_HEIGHT );
	MESSAGE_END();
#endif
	return iNumPathNodes;
}

inline ULONG Hash( void *p, int len )
{
	CRC32_t ulCrc;
	CRC32_INIT( &ulCrc );
	CRC32_PROCESS_BUFFER( &ulCrc, p, len );
	return CRC32_FINAL( ulCrc );
}

void inline CalcBounds( int &Lower, int &Upper, int Goal, int Best )
{
	int Temp = 2 * Goal - Best;
	if( Best > Goal )
	{
		Lower = Q_max( 0, Temp );
		Upper = Best;
	}
	else
	{
		Upper = Q_min( 255, Temp );
		Lower = Best;
	}
}

// Convert from [-8192,8192] to [0, 255]
//
inline int CALC_RANGE( int x, int lower, int upper )
{
	return NUM_RANGES * ( x - lower ) / ( ( upper - lower + 1 ) );
}

void inline UpdateRange( int &minValue, int &maxValue, int Goal, int Best )
{
	int Lower, Upper;
	CalcBounds( Lower, Upper, Goal, Best );
	if( Upper < maxValue )
		maxValue = Upper;
	if( minValue < Lower )
		minValue = Lower;
}

void CGraph::CheckNode( Vector vecOrigin, int iNode )
{
	// Have we already seen this point before?.
	//
	if( m_di[iNode].m_CheckedEvent == m_CheckedCounter )
		return;

	m_di[iNode].m_CheckedEvent = m_CheckedCounter;

	float flDist = ( vecOrigin - m_pNodes[iNode].m_vecOriginPeek ).Length();

	if( flDist < m_flShortest )
	{
		TraceResult tr;

		// make sure that vecOrigin can trace to this node!
		UTIL_TraceLine( vecOrigin, m_pNodes[iNode].m_vecOriginPeek, ignore_monsters, 0, &tr );

		if( tr.flFraction == 1.0f )
		{
			m_iNearest = iNode;
			m_flShortest = flDist;

			UpdateRange( m_minX, m_maxX, CALC_RANGE( vecOrigin.x, m_RegionMin[0], m_RegionMax[0] ), m_pNodes[iNode].m_Region[0] );
			UpdateRange( m_minY, m_maxY, CALC_RANGE( vecOrigin.y, m_RegionMin[1], m_RegionMax[1] ), m_pNodes[iNode].m_Region[1] );
			UpdateRange( m_minZ, m_maxZ, CALC_RANGE( vecOrigin.z, m_RegionMin[2], m_RegionMax[2] ), m_pNodes[iNode].m_Region[2] );

			// From maxCircle, calculate maximum bounds box. All points must be
			// simultaneously inside all bounds of the box.
			//
			m_minBoxX = CALC_RANGE( vecOrigin.x - flDist, m_RegionMin[0], m_RegionMax[0] );
			m_maxBoxX = CALC_RANGE( vecOrigin.x + flDist, m_RegionMin[0], m_RegionMax[0] );
			m_minBoxY = CALC_RANGE( vecOrigin.y - flDist, m_RegionMin[1], m_RegionMax[1] );
			m_maxBoxY = CALC_RANGE( vecOrigin.y + flDist, m_RegionMin[1], m_RegionMax[1] );
			m_minBoxZ = CALC_RANGE( vecOrigin.z - flDist, m_RegionMin[2], m_RegionMax[2] );
			m_maxBoxZ = CALC_RANGE( vecOrigin.z + flDist, m_RegionMin[2], m_RegionMax[2] );
		}
	}
}

//=========================================================
// CGraph - FindNearestNode - returns the index of the node nearest
// the given vector -1 is failure (couldn't find a valid
// near node )
//=========================================================
int CGraph::FindNearestNode( const Vector &vecOrigin,  CBaseEntity *pEntity )
{
	return FindNearestNode( vecOrigin, NodeType( pEntity ) );
}

int CGraph::FindNearestNode( const Vector &vecOrigin, int afNodeTypes )
{
	int i;
	TraceResult tr;

	if( !m_fGraphPresent || !m_fGraphPointersSet )
	{
		// protect us in the case that the node graph isn't available
		ALERT( at_aiconsole, "Graph not ready!\n" );
		return -1;
	}

	// Check with the cache
	//
	ULONG iHash = ( CACHE_SIZE - 1 ) & Hash( (void *)(const float *)vecOrigin, sizeof(vecOrigin) );
	if( m_Cache[iHash].v == vecOrigin )
	{
		//ALERT( at_aiconsole, "Cache Hit.\n" );
		return m_Cache[iHash].n;
	}
/*	else
	{
		//ALERT( at_aiconsole, "Cache Miss.\n" );
	}
*/
	// Mark all points as unchecked.
	//
	m_CheckedCounter++;
	if( m_CheckedCounter == 0 )
	{
		for( i = 0; i < m_cNodes; i++ )
		{
			m_di[i].m_CheckedEvent = 0;
		}
		m_CheckedCounter++;
	}

	m_iNearest = -1;
	m_flShortest = 999999.0f; // just a big number.

	// If we can find a visible point, then let CalcBounds set the limits, but if
	// we have no visible point at all to start with, then don't restrict the limits.
	//
#if 1
	m_minX = 0; m_maxX = 255;
	m_minY = 0; m_maxY = 255;
	m_minZ = 0; m_maxZ = 255;
	m_minBoxX = 0; m_maxBoxX = 255;
	m_minBoxY = 0; m_maxBoxY = 255;
	m_minBoxZ = 0; m_maxBoxZ = 255;
#else
	m_minBoxX = CALC_RANGE( vecOrigin.x - flDist, m_RegionMin[0], m_RegionMax[0] );
	m_maxBoxX = CALC_RANGE( vecOrigin.x + flDist, m_RegionMin[0], m_RegionMax[0] );
	m_minBoxY = CALC_RANGE( vecOrigin.y - flDist, m_RegionMin[1], m_RegionMax[1] );
	m_maxBoxY = CALC_RANGE( vecOrigin.y + flDist, m_RegionMin[1], m_RegionMax[1] );
	m_minBoxZ = CALC_RANGE( vecOrigin.z - flDist, m_RegionMin[2], m_RegionMax[2] );
	m_maxBoxZ = CALC_RANGE( vecOrigin.z + flDist, m_RegionMin[2], m_RegionMax[2] );
	CalcBounds( m_minX, m_maxX, CALC_RANGE( vecOrigin.x, m_RegionMin[0], m_RegionMax[0] ), m_pNodes[m_iNearest].m_Region[0] );
	CalcBounds( m_minY, m_maxY, CALC_RANGE( vecOrigin.y, m_RegionMin[1], m_RegionMax[1] ), m_pNodes[m_iNearest].m_Region[1] );
	CalcBounds( m_minZ, m_maxZ, CALC_RANGE( vecOrigin.z, m_RegionMin[2], m_RegionMax[2] ), m_pNodes[m_iNearest].m_Region[2] );
#endif
	int halfX = ( m_minX + m_maxX ) / 2;
	int halfY = ( m_minY + m_maxY ) / 2;
	int halfZ = ( m_minZ + m_maxZ ) / 2;

	int j;

	for( i = halfX; i >= m_minX; i-- )
	{
		for( j = m_RangeStart[0][i]; j <= m_RangeEnd[0][i]; j++ )
		{
			if( !( m_pNodes[m_di[j].m_SortedBy[0]].m_afNodeInfo & afNodeTypes ) )
				continue;

			int rgY = m_pNodes[m_di[j].m_SortedBy[0]].m_Region[1];
			if( rgY > m_maxBoxY )
				break;

			if( rgY < m_minBoxY )
				continue;

			int rgZ = m_pNodes[m_di[j].m_SortedBy[0]].m_Region[2];
			if( rgZ < m_minBoxZ )
				continue;

			if( rgZ > m_maxBoxZ )
				continue;

			CheckNode( vecOrigin, m_di[j].m_SortedBy[0] );
		}
	}

	for( i = Q_max( m_minY, halfY + 1 ); i <= m_maxY; i++ )
	{
		for( j = m_RangeStart[1][i]; j <= m_RangeEnd[1][i]; j++ )
		{
			if( !( m_pNodes[m_di[j].m_SortedBy[1]].m_afNodeInfo & afNodeTypes ) )
				continue;

			int rgZ = m_pNodes[m_di[j].m_SortedBy[1]].m_Region[2];
			if( rgZ > m_maxBoxZ )
				break;

			if( rgZ < m_minBoxZ )
				continue;

			int rgX = m_pNodes[m_di[j].m_SortedBy[1]].m_Region[0];
			if( rgX < m_minBoxX )
				continue;

			if( rgX > m_maxBoxX )
				continue;

			CheckNode( vecOrigin, m_di[j].m_SortedBy[1] );
		}
	}

	for( i = Q_min( m_maxZ, halfZ ); i >= m_minZ; i-- )
	{
		for( j = m_RangeStart[2][i]; j <= m_RangeEnd[2][i]; j++ )
		{
			if( !( m_pNodes[m_di[j].m_SortedBy[2]].m_afNodeInfo & afNodeTypes ) )
				continue;

			int rgX = m_pNodes[m_di[j].m_SortedBy[2]].m_Region[0];
			if( rgX > m_maxBoxX )
				break;

			if( rgX < m_minBoxX )
				continue;

			int rgY = m_pNodes[m_di[j].m_SortedBy[2]].m_Region[1];
			if( rgY < m_minBoxY )
				continue;

			if( rgY > m_maxBoxY )
				continue;

			CheckNode( vecOrigin, m_di[j].m_SortedBy[2] );
		}
	}

	for( i = Q_max( m_minX, halfX + 1 ); i <= m_maxX; i++ )
	{
		for( j = m_RangeStart[0][i]; j <= m_RangeEnd[0][i]; j++ )
		{
			if( !( m_pNodes[m_di[j].m_SortedBy[0]].m_afNodeInfo & afNodeTypes ) )
				continue;

			int rgY = m_pNodes[m_di[j].m_SortedBy[0]].m_Region[1];
			if( rgY > m_maxBoxY )
				break;
			if( rgY < m_minBoxY )
				continue;

			int rgZ = m_pNodes[m_di[j].m_SortedBy[0]].m_Region[2];
			if( rgZ < m_minBoxZ )
				continue;
			if( rgZ > m_maxBoxZ )
				continue;
			CheckNode( vecOrigin, m_di[j].m_SortedBy[0] );
		}
	}

	for( i = Q_min( m_maxY, halfY ); i >= m_minY; i-- )
	{
		for( j = m_RangeStart[1][i]; j <= m_RangeEnd[1][i]; j++ )
		{
			if( !( m_pNodes[m_di[j].m_SortedBy[1]].m_afNodeInfo & afNodeTypes ) )
				continue;

			int rgZ = m_pNodes[m_di[j].m_SortedBy[1]].m_Region[2];
			if( rgZ > m_maxBoxZ )
				break;
			if( rgZ < m_minBoxZ )
				continue;
			int rgX = m_pNodes[m_di[j].m_SortedBy[1]].m_Region[0];
			if( rgX < m_minBoxX )
				continue;
			if( rgX > m_maxBoxX )
				continue;
			CheckNode( vecOrigin, m_di[j].m_SortedBy[1] );
		}
	}

	for( i = Q_max( m_minZ, halfZ + 1 ); i <= m_maxZ; i++ )
	{
		for( j = m_RangeStart[2][i]; j <= m_RangeEnd[2][i]; j++ )
		{
			if( !( m_pNodes[m_di[j].m_SortedBy[2]].m_afNodeInfo & afNodeTypes ) )
				continue;

			int rgX = m_pNodes[m_di[j].m_SortedBy[2]].m_Region[0];
			if( rgX > m_maxBoxX )
				break;
			if( rgX < m_minBoxX )
				continue;
			int rgY = m_pNodes[m_di[j].m_SortedBy[2]].m_Region[1];
			if( rgY < m_minBoxY )
				continue;
			if( rgY > m_maxBoxY )
				continue;
			CheckNode(vecOrigin, m_di[j].m_SortedBy[2]);
		}
	}

#if 0
	// Verify our answers.
	//
	int iNearestCheck = -1;
	m_flShortest = 8192;// find nodes within this radius

	for( i = 0; i < m_cNodes; i++ )
	{
		float flDist = ( vecOrigin - m_pNodes[i].m_vecOriginPeek ).Length();

		if( flDist < m_flShortest )
		{
			// make sure that vecOrigin can trace to this node!
			UTIL_TraceLine( vecOrigin, m_pNodes[i].m_vecOriginPeek, ignore_monsters, 0, &tr );

			if( tr.flFraction == 1.0 )
			{
				iNearestCheck = i;
				m_flShortest = flDist;
			}
		}
	}

	if( iNearestCheck != m_iNearest )
	{
		ALERT( at_aiconsole, "NOT closest %d(%f,%f,%f) %d(%f,%f,%f).\n",
			iNearestCheck,
			m_pNodes[iNearestCheck].m_vecOriginPeek.x,
			m_pNodes[iNearestCheck].m_vecOriginPeek.y,
			m_pNodes[iNearestCheck].m_vecOriginPeek.z,
			m_iNearest,
			( m_iNearest == -1?0.0:m_pNodes[m_iNearest].m_vecOriginPeek.x ),
			( m_iNearest == -1?0.0:m_pNodes[m_iNearest].m_vecOriginPeek.y ),
			( m_iNearest == -1?0.0:m_pNodes[m_iNearest].m_vecOriginPeek.z ) );
	}
	if( m_iNearest == -1 )
	{
		ALERT( at_aiconsole, "All that work for nothing.\n" );
	}
#endif
	m_Cache[iHash].v = vecOrigin;
	m_Cache[iHash].n = m_iNearest;
	return m_iNearest;
}

//=========================================================
// CGraph - ShowNodeConnections - draws a line from the given node
// to all connected nodes
//=========================================================
void CGraph::ShowNodeConnections( int iNode )
{
	Vector vecSpot;
	CNode *pNode;
	CNode *pLinkNode;
	int i;

	if( !m_fGraphPresent || !m_fGraphPointersSet )
	{
		// protect us in the case that the node graph isn't available or built
		ALERT( at_aiconsole, "Graph not ready!\n" );
		return;
	}

	if( iNode < 0 )
	{
		ALERT( at_aiconsole, "Can't show connections for node %d\n", iNode );
		return;
	}

	pNode = &m_pNodes[iNode];

	UTIL_ParticleEffect( pNode->m_vecOrigin, g_vecZero, 255, 20 );// show node position

	if( pNode->m_cNumLinks <= 0 )
	{
		// no connections!
		ALERT ( at_aiconsole, "**No Connections!\n" );
	}

	for( i = 0; i < pNode->m_cNumLinks; i++ )
	{
		pLinkNode = &Node( NodeLink( iNode, i ).m_iDestNode );
		vecSpot = pLinkNode->m_vecOrigin;

		MESSAGE_BEGIN( MSG_BROADCAST, SVC_TEMPENTITY );
			WRITE_BYTE( TE_SHOWLINE );

			WRITE_COORD( m_pNodes[iNode].m_vecOrigin.x );
			WRITE_COORD( m_pNodes[iNode].m_vecOrigin.y );
			WRITE_COORD( m_pNodes[iNode].m_vecOrigin.z + NODE_HEIGHT );

			WRITE_COORD( vecSpot.x );
			WRITE_COORD( vecSpot.y );
			WRITE_COORD( vecSpot.z + NODE_HEIGHT );
		MESSAGE_END();

	}
}

//=========================================================
// CGraph - LinkVisibleNodes - the first, most basic
// function of node graph creation, this connects every
// node to every other node that it can see. Expects a 
// pointer to an empty connection pool and a file pointer 
// to write progress to. Returns the total number of initial
// links.
//
// If there's a problem with this process, the index
// of the offending node will be written to piBadNode
//=========================================================
int CGraph::LinkVisibleNodes( CLink *pLinkPool, FILE *file, int *piBadNode )
{
	int i, j, z;
	edict_t *pTraceEnt;
	int cTotalLinks, cLinksThisNode, cMaxInitialLinks;
	TraceResult tr;

	// !!!BUGBUG - this function returns 0 if there is a problem in the middle of connecting the graph
	// it also returns 0 if none of the nodes in a level can see each other. piBadNode is ALWAYS read
	// by BuildNodeGraph() if this function returns a 0, so make sure that it doesn't get some random
	// number back.
	*piBadNode = 0;

	if( m_cNodes <= 0 )
	{
		ALERT( at_aiconsole, "No Nodes!\n" );
		return FALSE;
	}

	// if the file pointer is bad, don't blow up, just don't write the
	// file.
	if( !file )
	{
		ALERT( at_aiconsole, "**LinkVisibleNodes:\ncan't write to file." );
	}
	else
	{
		fprintf( file, "----------------------------------------------------------------------------\n" );
		fprintf( file, "LinkVisibleNodes - Initial Connections\n" );
		fprintf( file, "----------------------------------------------------------------------------\n" );
	}

	cTotalLinks = 0;// start with no connections

	// to keep track of the maximum number of initial links any node had so far.
	// this lets us keep an eye on MAX_NODE_INITIAL_LINKS to ensure that we are
	// being generous enough.
	cMaxInitialLinks = 0;

	for( i = 0; i < m_cNodes; i++ )
	{
		cLinksThisNode = 0;// reset this count for each node.

		if( file )
		{
			fprintf( file, "Node #%4d:\n\n", i );
		}

		for( z = 0; z < MAX_NODE_INITIAL_LINKS; z++ )
		{
			// clear out the important fields in the link pool for this node
			pLinkPool[cTotalLinks + z].m_iSrcNode = i;// so each link knows which node it originates from
			pLinkPool[cTotalLinks + z].m_iDestNode = 0;
			pLinkPool[cTotalLinks + z].m_pLinkEnt = NULL;
		}

		m_pNodes[i].m_iFirstLink = cTotalLinks;

		// now build a list of every other node that this node can see
		for( j = 0; j < m_cNodes; j++ )
  		{
			if( j == i )
			{
				// don't connect to self!
				continue;
			}
#if 0
			if( ( m_pNodes[i].m_afNodeInfo & bits_NODE_WATER ) != ( m_pNodes[j].m_afNodeInfo & bits_NODE_WATER ) )
			{
				// don't connect water nodes to air nodes or land nodes. It just wouldn't be prudent at this juncture.
				continue;
			}
#else
			if( ( m_pNodes[i].m_afNodeInfo & bits_NODE_GROUP_REALM ) != ( m_pNodes[j].m_afNodeInfo & bits_NODE_GROUP_REALM ) )
			{
				// don't connect air nodes to water nodes to land nodes. It just wouldn't be prudent at this juncture.
				continue;
			}
#endif
			tr.pHit = NULL;// clear every time so we don't get stuck with last trace's hit ent
			pTraceEnt = 0;

			UTIL_TraceLine( m_pNodes[i].m_vecOrigin,
							m_pNodes[j].m_vecOrigin,
							ignore_monsters,
							g_pBodyQueueHead,//!!!HACKHACK no real ent to supply here, using a global we don't care about
							&tr );

			if( tr.fStartSolid )
				continue;

			if( tr.flFraction != 1.0f )
			{
				// trace hit a brush ent, trace backwards to make sure that this ent is the only thing in the way.
				pTraceEnt = tr.pHit;// store the ent that the trace hit, for comparison

				UTIL_TraceLine( m_pNodes[j].m_vecOrigin,
								m_pNodes[i].m_vecOrigin,
								ignore_monsters,
								g_pBodyQueueHead,//!!!HACKHACK no real ent to supply here, using a global we don't care about
								&tr );

// there is a solid_bsp ent in the way of these two nodes, so we must record several things about in order to keep
// track of it in the pathfinding code, as well as through save and restore of the node graph. ANY data that is manipulated 
// as part of the process of adding a LINKENT to a connection here must also be done in CGraph::SetGraphPointers, where reloaded
// graphs are prepared for use.
				if( tr.pHit == pTraceEnt && !FClassnameIs( tr.pHit, "worldspawn" ) )
				{
					// get a pointer
					pLinkPool[cTotalLinks].m_pLinkEnt = VARS( tr.pHit );

					// record the modelname, so that we can save/load node trees
					memcpy( pLinkPool[cTotalLinks].m_szLinkEntModelname, STRING( VARS( tr.pHit )->model ), 4 );

					// set the flag for this ent that indicates that it is attached to the world graph
					// if this ent is removed from the world, it must also be removed from the connections
					// that it formerly blocked.
					if( !FBitSet( VARS( tr.pHit )->flags, FL_GRAPHED ) )
					{
						VARS( tr.pHit )->flags += FL_GRAPHED;
					}
				}
				else
				{
					// even if the ent wasn't there, these nodes couldn't be connected. Skip.
					continue;
				}
			}

			if( file )
			{
				fprintf( file, "%4d", j );

				if( !FNullEnt( pLinkPool[cTotalLinks].m_pLinkEnt ) )
				{
					// record info about the ent in the way, if any.
					fprintf( file, "  Entity on connection: %s, name: %s  Model: %s", STRING( VARS( pTraceEnt )->classname ), STRING( VARS( pTraceEnt )->targetname ), STRING( VARS( tr.pHit )->model ) );
				}

				//fprintf( file, "\n", j );
				fprintf( file, "\n" );
			}

			pLinkPool[cTotalLinks].m_iDestNode = j;
			cLinksThisNode++;
			cTotalLinks++;

			// If we hit this, either a level designer is placing too many nodes in the same area, or 
			// we need to allow for a larger initial link pool.
			if( cLinksThisNode == MAX_NODE_INITIAL_LINKS )
			{
				ALERT( at_aiconsole, "**LinkVisibleNodes:\nNode %d has NodeLinks > MAX_NODE_INITIAL_LINKS", i );
				fprintf( file, "** NODE %d HAS NodeLinks > MAX_NODE_INITIAL_LINKS **\n", i );
				*piBadNode = i;
				return FALSE;
			}
			else if( cTotalLinks > MAX_NODE_INITIAL_LINKS * m_cNodes )
			{
				// this is paranoia
				ALERT( at_aiconsole, "**LinkVisibleNodes:\nTotalLinks > MAX_NODE_INITIAL_LINKS * NUMNODES" );
				*piBadNode = i;
				return FALSE;
			}

			if( cLinksThisNode == 0 )
			{
				fprintf( file, "**NO INITIAL LINKS**\n" );
			}

			// record the connection info in the link pool
			WorldGraph.m_pNodes[i].m_cNumLinks = cLinksThisNode;

			// keep track of the most initial links ANY node had, so we can figure out
			// if we have a large enough default link pool
			if( cLinksThisNode > cMaxInitialLinks )
			{
				cMaxInitialLinks = cLinksThisNode;
			}
		}

		if( file )
		{
			fprintf( file, "----------------------------------------------------------------------------\n" );
		}
	}

	fprintf( file, "\n%4d Total Initial Connections - %4d Maximum connections for a single node.\n", cTotalLinks, cMaxInitialLinks );
	fprintf( file, "----------------------------------------------------------------------------\n\n\n" );

	return cTotalLinks;
}

//=========================================================
// CGraph - RejectInlineLinks - expects a pointer to a link
// pool, and a pointer to and already-open file ( if you
// want status reports written to disk ). RETURNS the number
// of connections that were rejected
//=========================================================
int CGraph::RejectInlineLinks( CLink *pLinkPool, FILE *file )
{
	int i, j, k;
	int cRejectedLinks;

	BOOL fRestartLoop;// have to restart the J loop if we eliminate a link.

	CNode *pSrcNode;
	CNode *pCheckNode;// the node we are testing for (one of pSrcNode's connections)
	CNode *pTestNode;// the node we are checking against ( also one of pSrcNode's connections)

	float flDistToTestNode, flDistToCheckNode;

	Vector2D vec2DirToTestNode, vec2DirToCheckNode;

	if( file )
	{
		fprintf( file, "----------------------------------------------------------------------------\n" );
		fprintf( file, "InLine Rejection:\n" );
		fprintf( file, "----------------------------------------------------------------------------\n" );
	}

	cRejectedLinks = 0;

	for( i = 0; i < m_cNodes; i++ )
	{
		pSrcNode = &m_pNodes[i];

		if( file )
		{
			fprintf( file, "Node %3d:\n", i );
		}

		for( j = 0; j < pSrcNode->m_cNumLinks; j++ )
		{
			pCheckNode = &m_pNodes[pLinkPool[pSrcNode->m_iFirstLink + j].m_iDestNode];

			vec2DirToCheckNode = ( pCheckNode->m_vecOrigin - pSrcNode->m_vecOrigin ).Make2D(); 
			flDistToCheckNode = vec2DirToCheckNode.Length();
			vec2DirToCheckNode = vec2DirToCheckNode.Normalize();

			pLinkPool[pSrcNode->m_iFirstLink + j].m_flWeight = flDistToCheckNode;

			fRestartLoop = FALSE;
			for( k = 0; k < pSrcNode->m_cNumLinks && !fRestartLoop; k++ )
			{
				if( k == j )
				{
					// don't check against same node
					continue;
				}

				pTestNode = &m_pNodes[pLinkPool[pSrcNode->m_iFirstLink + k].m_iDestNode];

				vec2DirToTestNode = ( pTestNode->m_vecOrigin - pSrcNode->m_vecOrigin ).Make2D(); 

				flDistToTestNode = vec2DirToTestNode.Length();
				vec2DirToTestNode = vec2DirToTestNode.Normalize();

				if( DotProduct( vec2DirToCheckNode, vec2DirToTestNode ) >= 0.998f )
				{
					// there's a chance that TestNode intersects the line to CheckNode. If so, we should disconnect the link to CheckNode. 
					if( flDistToTestNode < flDistToCheckNode )
					{
						if( file )
						{
							fprintf( file, "REJECTED NODE %3d through Node %3d, Dot = %8f\n", pLinkPool[pSrcNode->m_iFirstLink + j].m_iDestNode, pLinkPool[pSrcNode->m_iFirstLink + k].m_iDestNode, (double)DotProduct( vec2DirToCheckNode, vec2DirToTestNode ) );
						}

						pLinkPool[pSrcNode->m_iFirstLink + j] = pLinkPool[pSrcNode->m_iFirstLink + ( pSrcNode->m_cNumLinks - 1 )];
						pSrcNode->m_cNumLinks--;
						j--;

						cRejectedLinks++;// keeping track of how many links are cut, so that we can return that value.

						fRestartLoop = TRUE;
					}
				}
			}
		}

		if( file )
		{
			fprintf( file, "----------------------------------------------------------------------------\n\n" );
		}
	}

	return cRejectedLinks;
}

//=========================================================
// TestHull is a modelless clip hull that verifies reachable
// nodes by walking from every node to each of it's connections
//=========================================================
class CTestHull : public CBaseMonster
{
public:
	void Spawn( entvars_t *pevMasterNode );
	virtual int ObjectCaps( void ) { return CBaseMonster :: ObjectCaps() & ~FCAP_ACROSS_TRANSITION; }
	void EXPORT CallBuildNodeGraph ( void );
	void BuildNodeGraph( void );
	void EXPORT ShowBadNode( void );
	void EXPORT DropDelay( void );
	void EXPORT PathFind( void );

	Vector vecBadNodeOrigin;
};

LINK_ENTITY_TO_CLASS( testhull, CTestHull )

//=========================================================
// CTestHull::Spawn
//=========================================================
void CTestHull::Spawn( entvars_t *pevMasterNode )
{
	SET_MODEL( ENT( pev ), "models/player.mdl" );
	UTIL_SetSize( pev, VEC_HUMAN_HULL_MIN, VEC_HUMAN_HULL_MAX );

	pev->solid = SOLID_SLIDEBOX;
	pev->movetype = MOVETYPE_STEP;
	pev->effects = 0;
	pev->health = 50;
	pev->yaw_speed = 8;

	if( WorldGraph.m_fGraphPresent )
	{
		// graph loaded from disk, so we don't need the test hull
		SetThink( &CBaseEntity::SUB_Remove );
		pev->nextthink = gpGlobals->time;
	}
	else
	{
		SetThink( &CTestHull::DropDelay );
		pev->nextthink = gpGlobals->time + 1.0f;
	}

	// Make this invisible
	// UNDONE: Shouldn't we just use EF_NODRAW?  This doesn't need to go to the client.
	pev->rendermode = kRenderTransTexture;
	pev->renderamt = 0;
}

//=========================================================
// TestHull::DropDelay - spawns TestHull on top of 
// the 0th node and drops it to the ground.
//=========================================================
void CTestHull::DropDelay( void )
{
	UTIL_CenterPrintAll( "Node Graph out of Date. Rebuilding..." );

	UTIL_SetOrigin( VARS( pev ), WorldGraph.m_pNodes[0].m_vecOrigin );

	SetThink( &CTestHull::CallBuildNodeGraph );

	pev->nextthink = gpGlobals->time + 1.0f;
}

//=========================================================
// nodes start out as ents in the world. As they are spawned,
// the node info is recorded then the ents are discarded.
//=========================================================
void CNodeEnt::KeyValue( KeyValueData *pkvd )
{
	if( FStrEq( pkvd->szKeyName, "hinttype" ) )
	{
		m_sHintType = (short)atoi( pkvd->szValue );
		pkvd->fHandled = TRUE;
	}

	if( FStrEq( pkvd->szKeyName, "activity" ) )
	{
		m_sHintActivity = (short)atoi( pkvd->szValue );
		pkvd->fHandled = TRUE;
	}
	else
		CBaseEntity::KeyValue( pkvd );
}

//=========================================================
//=========================================================
void CNodeEnt::Spawn( void )
{
	pev->movetype = MOVETYPE_NONE;
	pev->solid = SOLID_NOT;// always solid_not 

	if( WorldGraph.m_fGraphPresent )
	{
		// graph loaded from disk, so discard all these node ents as soon as they spawn
		REMOVE_ENTITY( edict() );
		return;
	}

	if( WorldGraph.m_cNodes == 0 )
	{
		// this is the first node to spawn, spawn the test hull entity that builds and walks the node tree
		CTestHull *pHull = GetClassPtr( (CTestHull *)NULL );
		pHull->Spawn( pev );
	}

	if( WorldGraph.m_cNodes >= MAX_NODES )
	{
		ALERT( at_aiconsole, "cNodes > MAX_NODES\n" );
		return;
	}

	WorldGraph.m_pNodes[WorldGraph.m_cNodes].m_vecOriginPeek =
	WorldGraph.m_pNodes[WorldGraph.m_cNodes].m_vecOrigin = pev->origin;
	WorldGraph.m_pNodes[WorldGraph.m_cNodes].m_flHintYaw = pev->angles.y;
	WorldGraph.m_pNodes[WorldGraph.m_cNodes].m_sHintType = m_sHintType;
	WorldGraph.m_pNodes[WorldGraph.m_cNodes].m_sHintActivity = m_sHintActivity;

	if( FClassnameIs( pev, "info_node_air" ) )
		WorldGraph.m_pNodes[WorldGraph.m_cNodes].m_afNodeInfo = bits_NODE_AIR;
	else
		WorldGraph.m_pNodes[WorldGraph.m_cNodes].m_afNodeInfo = 0;

	WorldGraph.m_cNodes++;

	REMOVE_ENTITY( edict() );
}

//=========================================================
// CTestHull - ShowBadNode - makes a bad node fizzle. When
// there's a problem with node graph generation, the test 
// hull will be placed up the bad node's location and will generate
// particles
//=========================================================
void CTestHull::ShowBadNode( void )
{
	pev->movetype = MOVETYPE_FLY;
	pev->angles.y = pev->angles.y + 4;

	UTIL_MakeVectors( pev->angles );

	UTIL_ParticleEffect( pev->origin, g_vecZero, 255, 25 );
	UTIL_ParticleEffect( pev->origin + gpGlobals->v_forward * 64, g_vecZero, 255, 25 );
	UTIL_ParticleEffect( pev->origin - gpGlobals->v_forward * 64, g_vecZero, 255, 25 );
	UTIL_ParticleEffect( pev->origin + gpGlobals->v_right * 64, g_vecZero, 255, 25 );
	UTIL_ParticleEffect( pev->origin - gpGlobals->v_right * 64, g_vecZero, 255, 25 );

	pev->nextthink = gpGlobals->time + 0.1f;
}

extern BOOL gTouchDisabled;

void CTestHull::CallBuildNodeGraph( void )
{
	// TOUCH HACK -- Don't allow this entity to call anyone's "touch" function
	gTouchDisabled = TRUE;
	BuildNodeGraph();
	gTouchDisabled = FALSE;
	// Undo TOUCH HACK
}

//=========================================================
// BuildNodeGraph - think function called by the empty walk
// hull that is spawned by the first node to spawn. This
// function links all nodes that can see each other, then
// eliminates all inline links, then uses a monster-sized 
// hull that walks between each node and each of its links
// to ensure that a monster can actually fit through the space
//=========================================================
void CTestHull::BuildNodeGraph( void )
{
	//TraceResult tr;
	FILE *file;

	char szNrpFilename [MAX_PATH];// text node report filename

	CLink *pTempPool; // temporary link pool 

	CNode *pSrcNode;// node we're currently working with
	CNode *pDestNode;// the other node in comparison operations

	BOOL fSkipRemainingHulls;//if smallest hull can't fit, don't check any others
	BOOL fPairsValid;// are all links in the graph evenly paired?

	int i, j, hull;

	int iBadNode;// this is the node that caused graph generation to fail

	//int cMaxInitialLinks = 0;
	//int cMaxValidLinks = 0;

	//int iPoolIndex = 0;
	int cPoolLinks;// number of links in the pool.

	Vector vecDirToCheckNode;
	Vector vecDirToTestNode;
	Vector vecStepCheckDir;
	Vector vecTraceSpot;
	Vector vecSpot;

	Vector2D vec2DirToCheckNode;
	Vector2D vec2DirToTestNode;
	Vector2D vec2StepCheckDir;
	Vector2D vec2TraceSpot;
	Vector2D vec2Spot;

	float flYaw;// use this stuff to walk the hull between nodes
	float flDist;
	int step;

	SetThink( &CBaseEntity::SUB_Remove );// no matter what happens, the hull gets rid of itself.
	pev->nextthink = gpGlobals->time;

	//malloc a swollen temporary connection pool that we trim down after we know exactly how many connections there are.
	pTempPool = (CLink *)calloc( sizeof(CLink), ( WorldGraph.m_cNodes * MAX_NODE_INITIAL_LINKS ) );
	if( !pTempPool )
	{
		ALERT( at_aiconsole, "**Could not malloc TempPool!\n" );
		return;
	}

	// make sure directories have been made
	GET_GAME_DIR( szNrpFilename );
	strcat( szNrpFilename, "/maps" );
	CreateDirectoryA( szNrpFilename, NULL );
	strcat( szNrpFilename, "/graphs" );
	CreateDirectoryA( szNrpFilename, NULL );

	strcat( szNrpFilename, "/" );
	strcat( szNrpFilename, STRING( gpGlobals->mapname ) );
	strcat( szNrpFilename, ".nrp" );

	file = fopen( szNrpFilename, "w+" );

	if( !file )
	{
		// file error
		ALERT( at_aiconsole, "Couldn't create %s!\n", szNrpFilename );

		if( pTempPool )
		{
			free( pTempPool );
		}

		return;
	}

	fprintf( file, "Node Graph Report for map:  %s.bsp\n", STRING( gpGlobals->mapname ) );
	fprintf( file, "%d Total Nodes\n\n", WorldGraph.m_cNodes );

	for( i = 0; i < WorldGraph.m_cNodes; i++ )
	{
		// print all node numbers and their locations to the file.
		WorldGraph.m_pNodes[i].m_cNumLinks = 0;
		WorldGraph.m_pNodes[i].m_iFirstLink = 0;
		memset( WorldGraph.m_pNodes[i].m_pNextBestNode, 0, sizeof(WorldGraph.m_pNodes[i].m_pNextBestNode) );

		fprintf( file, "Node#         %4d\n", i );
		fprintf( file, "Location      %4d,%4d,%4d\n",(int)WorldGraph.m_pNodes[i].m_vecOrigin.x, (int)WorldGraph.m_pNodes[i].m_vecOrigin.y, (int)WorldGraph.m_pNodes[i].m_vecOrigin.z );
		fprintf( file, "HintType:     %4d\n", WorldGraph.m_pNodes[i].m_sHintType );
		fprintf( file, "HintActivity: %4d\n", WorldGraph.m_pNodes[i].m_sHintActivity );
		fprintf( file, "HintYaw:      %4f\n", (double)WorldGraph.m_pNodes[i].m_flHintYaw );
		fprintf( file, "-------------------------------------------------------------------------------\n" );
	}
	fprintf( file, "\n\n" );

	// Automatically recognize WATER nodes and drop the LAND nodes to the floor.
	//
	for( i = 0; i < WorldGraph.m_cNodes; i++)
	{
		if( WorldGraph.m_pNodes[i].m_afNodeInfo & bits_NODE_AIR )
		{
			// do nothing
		}
		else if( UTIL_PointContents( WorldGraph.m_pNodes[i].m_vecOrigin ) == CONTENTS_WATER )
		{
			WorldGraph.m_pNodes[i].m_afNodeInfo |= bits_NODE_WATER;
		}
		else
		{
			WorldGraph.m_pNodes[i].m_afNodeInfo |= bits_NODE_LAND;

			// trace to the ground, then pop up 8 units and place node there to make it
			// easier for them to connect (think stairs, chairs, and bumps in the floor).
			// After the routing is done, push them back down.
			//
			TraceResult tr;

			UTIL_TraceLine( WorldGraph.m_pNodes[i].m_vecOrigin,
							WorldGraph.m_pNodes[i].m_vecOrigin - Vector( 0, 0, 384 ),
							ignore_monsters,
							g_pBodyQueueHead,//!!!HACKHACK no real ent to supply here, using a global we don't care about
							&tr );

			// This trace is ONLY used if we hit an entity flagged with FL_WORLDBRUSH
			TraceResult trEnt;
			UTIL_TraceLine( WorldGraph.m_pNodes[i].m_vecOrigin,
							WorldGraph.m_pNodes[i].m_vecOrigin - Vector( 0, 0, 384 ),
							dont_ignore_monsters,
							g_pBodyQueueHead,//!!!HACKHACK no real ent to supply here, using a global we don't care about
							&trEnt );

			
			// Did we hit something closer than the floor?
			if( trEnt.flFraction < tr.flFraction )
			{
				// If it was a world brush entity, copy the node location
				if( trEnt.pHit && ( trEnt.pHit->v.flags & FL_WORLDBRUSH ) )
					tr.vecEndPos = trEnt.vecEndPos;
			}

			WorldGraph.m_pNodes[i].m_vecOriginPeek.z = 
				WorldGraph.m_pNodes[i].m_vecOrigin.z = tr.vecEndPos.z + NODE_HEIGHT;
		}
	}

	cPoolLinks = WorldGraph.LinkVisibleNodes( pTempPool, file, &iBadNode );

	if( !cPoolLinks )
	{
		ALERT( at_aiconsole, "**ConnectVisibleNodes FAILED!\n" );

		SetThink( &CTestHull::ShowBadNode );// send the hull off to show the offending node.
		//pev->solid = SOLID_NOT;
		pev->origin = WorldGraph.m_pNodes[iBadNode].m_vecOrigin;

		if( pTempPool )
		{
			free( pTempPool );
		}

		if( file )
		{
			// close the file
			fclose( file );
		}

		return;
	}

	// send the walkhull to all of this node's connections now. We'll do this here since
	// so much of it relies on being able to control the test hull.
	fprintf( file, "----------------------------------------------------------------------------\n" );
	fprintf( file, "Walk Rejection:\n");	

	for( i = 0; i < WorldGraph.m_cNodes; i++ )
	{
		pSrcNode = &WorldGraph.m_pNodes[i];

		fprintf( file, "-------------------------------------------------------------------------------\n" );
		fprintf( file, "Node %4d:\n\n", i );

		for( j = 0; j < pSrcNode->m_cNumLinks; j++ )
		{
			// assume that all hulls can walk this link, then eliminate the ones that can't.
			pTempPool[pSrcNode->m_iFirstLink + j].m_afLinkInfo = bits_LINK_SMALL_HULL | bits_LINK_HUMAN_HULL | bits_LINK_LARGE_HULL | bits_LINK_FLY_HULL;

			// do a check for each hull size.

			// if we can't fit a tiny hull through a connection, no other hulls with fit either, so we 
			// should just fall out of the loop. Do so by setting the SkipRemainingHulls flag.
			fSkipRemainingHulls = FALSE;
			for( hull = 0; hull < MAX_NODE_HULLS; hull++ )
			{
				if( fSkipRemainingHulls && ( hull == NODE_HUMAN_HULL || hull == NODE_LARGE_HULL ) ) // skip the remaining walk hulls
					continue;

				switch( hull )
				{
				case NODE_SMALL_HULL:
					UTIL_SetSize( pev, Vector( -12, -12, 0 ), Vector( 12, 12, 24 ) );
					break;
				case NODE_HUMAN_HULL:
					UTIL_SetSize( pev, VEC_HUMAN_HULL_MIN, VEC_HUMAN_HULL_MAX );
					break;
				case NODE_LARGE_HULL:
					UTIL_SetSize( pev, Vector( -32, -32, 0 ), Vector( 32, 32, 64 ) );
					break;
				case NODE_FLY_HULL:
					UTIL_SetSize( pev, Vector( -32, -32, 0 ), Vector( 32, 32, 64 ) );
					// UTIL_SetSize( pev, Vector( 0, 0, 0 ), Vector( 0, 0, 0 ) );
					break;
				}

				UTIL_SetOrigin( pev, pSrcNode->m_vecOrigin );// place the hull on the node

				if( !FBitSet( pev->flags, FL_ONGROUND ) )
				{
					ALERT( at_aiconsole, "OFFGROUND!\n" );
				}

				// now build a yaw that points to the dest node, and get the distance.
				if( j < 0 )
				{
					ALERT( at_aiconsole, "**** j = %d ****\n", j );
					if( pTempPool )
					{
						free( pTempPool );
					}

					if( file )
					{
						// close the file
						fclose( file );
					}
					return;
				}
				
				pDestNode = &WorldGraph.m_pNodes[pTempPool[pSrcNode->m_iFirstLink + j].m_iDestNode];

				vecSpot = pDestNode->m_vecOrigin;
				//vecSpot.z = pev->origin.z;

				if( hull < NODE_FLY_HULL )
				{
					int SaveFlags = pev->flags;
					int MoveMode = WALKMOVE_WORLDONLY;
					if( pSrcNode->m_afNodeInfo & bits_NODE_WATER )
					{
						pev->flags |= FL_SWIM;
						MoveMode = WALKMOVE_NORMAL;
					}

					flYaw = UTIL_VecToYaw( pDestNode->m_vecOrigin - pev->origin );

					flDist = ( vecSpot - pev->origin ).Length2D();

					int fWalkFailed = FALSE;

					// in this loop we take tiny steps from the current node to the nodes that it links to, one at a time.
					// pev->angles.y = flYaw;
					for( step = 0; step < flDist && !fWalkFailed; step += HULL_STEP_SIZE )
					{
						float stepSize = HULL_STEP_SIZE;

						if( ( step + stepSize ) >= ( flDist - 1 ) )
							stepSize = ( flDist - step ) - 1;

						if( !WALK_MOVE( ENT( pev ), flYaw, stepSize, MoveMode ) )
						{
							// can't take the next step
							fWalkFailed = TRUE;
							break;
						}
					}

					if( !fWalkFailed && ( pev->origin - vecSpot ).Length() > 64 )
					{
						// ALERT( at_console, "bogus walk\n" );
						// we thought we 
						fWalkFailed = TRUE;
					}

					if( fWalkFailed )
					{
						//pTempPool[pSrcNode->m_iFirstLink + j] = pTempPool[pSrcNode->m_iFirstLink + ( pSrcNode->m_cNumLinks - 1 )];

						// now me must eliminate the hull that couldn't walk this connection
						switch( hull )
						{
						case NODE_SMALL_HULL:	// if this hull can't fit, nothing can, so drop the connection
							fprintf( file, "NODE_SMALL_HULL step %d\n", step );
							pTempPool[pSrcNode->m_iFirstLink + j].m_afLinkInfo &= ~( bits_LINK_SMALL_HULL | bits_LINK_HUMAN_HULL | bits_LINK_LARGE_HULL );
							fSkipRemainingHulls = TRUE;// don't bother checking larger hulls
							break;
						case NODE_HUMAN_HULL:
							fprintf( file, "NODE_HUMAN_HULL step %d\n", step );
							pTempPool[pSrcNode->m_iFirstLink + j].m_afLinkInfo &= ~( bits_LINK_HUMAN_HULL | bits_LINK_LARGE_HULL );
							fSkipRemainingHulls = TRUE;// don't bother checking larger hulls
							break;
						case NODE_LARGE_HULL:
							fprintf( file, "NODE_LARGE_HULL step %d\n", step );
							pTempPool[pSrcNode->m_iFirstLink + j].m_afLinkInfo &= ~bits_LINK_LARGE_HULL;
							break;
						}
					}
					pev->flags = SaveFlags;
				}
				else
				{
					TraceResult tr;

					UTIL_TraceHull( pSrcNode->m_vecOrigin + Vector( 0, 0, 32 ), pDestNode->m_vecOriginPeek + Vector( 0, 0, 32 ), ignore_monsters, large_hull, ENT( pev ), &tr );
					if( tr.fStartSolid || tr.flFraction < 1.0f )
					{
						pTempPool[pSrcNode->m_iFirstLink + j].m_afLinkInfo &= ~bits_LINK_FLY_HULL;
					}
				}
			}

			if( pTempPool[pSrcNode->m_iFirstLink + j].m_afLinkInfo == 0 )
			{
				fprintf( file, "Rejected Node %3d - Unreachable by ", pTempPool[ pSrcNode->m_iFirstLink + j].m_iDestNode );
				pTempPool[pSrcNode->m_iFirstLink + j] = pTempPool[pSrcNode->m_iFirstLink + ( pSrcNode->m_cNumLinks - 1 )];
				fprintf( file, "Any Hull\n" );

				pSrcNode->m_cNumLinks--;
				cPoolLinks--;// we just removed a link, so decrement the total number of links in the pool.
				j--;
			}

		}
	}
	fprintf( file, "-------------------------------------------------------------------------------\n\n\n" );

	cPoolLinks -= WorldGraph.RejectInlineLinks( pTempPool, file );

	// now malloc a pool just large enough to hold the links that are actually used
	WorldGraph.m_pLinkPool = (CLink *)calloc( sizeof(CLink), cPoolLinks );

	if( !WorldGraph.m_pLinkPool )
	{
		// couldn't make the link pool!
		ALERT( at_aiconsole, "Couldn't malloc LinkPool!\n" );
		if( pTempPool )
		{
			free( pTempPool );
		}
		if( file )
		{
			// close the file
			fclose( file );
		}

		return;
	}
	WorldGraph.m_cLinks = cPoolLinks;

	//copy only the used portions of the TempPool into the graph's link pool
	int iFinalPoolIndex = 0;
	int iOldFirstLink;

	for( i = 0; i < WorldGraph.m_cNodes; i++ )
	{
		iOldFirstLink = WorldGraph.m_pNodes[i].m_iFirstLink;// store this, because we have to re-assign it before entering the copy loop

		WorldGraph.m_pNodes[i].m_iFirstLink = iFinalPoolIndex;

		for( j = 0; j < WorldGraph.m_pNodes[i].m_cNumLinks; j++ )
		{
			WorldGraph.m_pLinkPool[iFinalPoolIndex++] = pTempPool[iOldFirstLink + j];
		}
	}

	// Node sorting numbers linked nodes close to each other
	//
	WorldGraph.SortNodes();

	// This is used for HashSearch
	//
	WorldGraph.BuildLinkLookups();

	fPairsValid = TRUE; // assume that the connection pairs are all valid to start

	fprintf( file, "\n\n-------------------------------------------------------------------------------\n" );
	fprintf( file, "Link Pairings:\n" );

	// link integrity check. The idea here is that if Node A links to Node B, node B should
	// link to node A. If not, we have a situation that prevents us from using a basic 
	// optimization in the FindNearestLink function. 
	for( i = 0; i < WorldGraph.m_cNodes; i++ )
	{
		for( j = 0; j < WorldGraph.m_pNodes[i].m_cNumLinks; j++ )
		{
			int iLink;
			WorldGraph.HashSearch( WorldGraph.INodeLink( i, j ), i, iLink );
			if( iLink < 0 )
			{
				fPairsValid = FALSE;// unmatched link pair.
				fprintf( file, "WARNING: Node %3d does not connect back to Node %3d\n", WorldGraph.INodeLink( i, j ), i );
			}
		}
	}

	// !!!LATER - if all connections are properly paired, when can enable an optimization in the pathfinding code
	// (in the find nearest line function)
	if( fPairsValid )
	{
		fprintf( file, "\nAll Connections are Paired!\n" );
	}

#ifdef _MSC_VER
#define SIZET_FMT "%Iu"
#else
#define SIZET_FMT "%zu"
#endif
	fprintf( file, "-------------------------------------------------------------------------------\n" );
	fprintf( file, "\n\n-------------------------------------------------------------------------------\n" );
	fprintf( file, "Total Number of Connections in Pool: %d\n", cPoolLinks );
	fprintf( file, "-------------------------------------------------------------------------------\n" );
	fprintf( file, "Connection Pool: " SIZET_FMT " bytes\n", sizeof(CLink) * cPoolLinks );
	fprintf( file, "-------------------------------------------------------------------------------\n" );

	ALERT( at_aiconsole, "%d Nodes, %d Connections\n", WorldGraph.m_cNodes, cPoolLinks );

	// This is used for FindNearestNode
	//
	WorldGraph.BuildRegionTables();

	// Push all of the LAND nodes down to the ground now. Leave the water and air nodes alone.
	//
	for( i = 0; i < WorldGraph.m_cNodes; i++ )
	{
		if( ( WorldGraph.m_pNodes[i].m_afNodeInfo & bits_NODE_LAND ) )
		{
			WorldGraph.m_pNodes[i].m_vecOrigin.z -= NODE_HEIGHT;
		}
	}

	if( pTempPool )
	{
		// free the temp pool
		free( pTempPool );
	}

	if( file )
	{
		fclose( file );
	}

	// We now have some graphing capabilities.
	//
	WorldGraph.m_fGraphPresent = TRUE;//graph is in memory.
	WorldGraph.m_fGraphPointersSet = TRUE;// since the graph was generated, the pointers are ready
	WorldGraph.m_fRoutingComplete = FALSE; // Optimal routes aren't computed, yet.

	// Compute and compress the routing information.
	//
	WorldGraph.ComputeStaticRoutingTables();

	// save the node graph for this level	
	WorldGraph.FSaveGraph( STRING( gpGlobals->mapname ) );
	ALERT( at_console, "Done.\n" );
}

//=========================================================
// returns a hardcoded path.
//=========================================================
void CTestHull::PathFind( void )
{
	int iPath[50];
	int iPathSize;
	int i;
	CNode *pNode, *pNextNode;

	if( !WorldGraph.m_fGraphPresent || !WorldGraph.m_fGraphPointersSet )
	{
		// protect us in the case that the node graph isn't available
		ALERT( at_aiconsole, "Graph not ready!\n" );
		return;
	}

	iPathSize = WorldGraph.FindShortestPath( iPath, 0, 19, 0, 0 ); // UNDONE use hull constant

	if( !iPathSize )
	{
		ALERT( at_aiconsole, "No Path!\n" );
		return;
	}
	
	ALERT( at_aiconsole, "%d\n", iPathSize );

	pNode = &WorldGraph.m_pNodes[iPath[0]];

	for( i = 0; i < iPathSize - 1; i++ )
	{
		pNextNode = &WorldGraph.m_pNodes[iPath[i + 1]];

		MESSAGE_BEGIN( MSG_BROADCAST, SVC_TEMPENTITY );
			WRITE_BYTE( TE_SHOWLINE );

			WRITE_COORD( pNode->m_vecOrigin.x );
			WRITE_COORD( pNode->m_vecOrigin.y );
			WRITE_COORD( pNode->m_vecOrigin.z + NODE_HEIGHT );

			WRITE_COORD( pNextNode->m_vecOrigin.x );
			WRITE_COORD( pNextNode->m_vecOrigin.y );
			WRITE_COORD( pNextNode->m_vecOrigin.z + NODE_HEIGHT );
		MESSAGE_END();

		pNode = pNextNode;
	}
}

//=========================================================
// CStack Constructor
//=========================================================
CStack::CStack( void )
{
	m_level = 0;
}

//=========================================================
// pushes a value onto the stack
//=========================================================
void CStack::Push( int value )
{
	if( m_level >= MAX_STACK_NODES )
	{
		printf( "Error!\n" );
		return;
	}
	m_stack[m_level] = value;
	m_level++;
}

//=========================================================
// pops a value off of the stack
//=========================================================
int CStack::Pop( void )
{
	if( m_level <= 0 )
		return -1;

	m_level--;
	return m_stack[m_level];
}

//=========================================================
// returns the value on the top of the stack
//=========================================================
int CStack::Top( void )
{
	return m_stack[m_level - 1];
}

//=========================================================
// copies every element on the stack into an array LIFO 
//=========================================================
void CStack::CopyToArray( int *piArray )
{
	int i;

	for( i = 0; i < m_level; i++ )
	{
		piArray[i] = m_stack[i];
	}
}

//=========================================================
// CQueue constructor
//=========================================================
CQueue::CQueue( void )
{
	m_cSize = 0;
	m_head = 0;
	m_tail = -1;
}

//=========================================================
// inserts a value into the queue
//=========================================================
void CQueue::Insert( int iValue, float fPriority )
{
	if( Full() )
	{
		printf( "Queue is full!\n" );
		return;
	}

	m_tail++;

	if( m_tail == MAX_STACK_NODES )
	{
		//wrap around
		m_tail = 0;
	}

	m_queue[m_tail].Id = iValue;
	m_queue[m_tail].Priority = fPriority;
	m_cSize++;
}

//=========================================================
// removes a value from the queue (FIFO)
//=========================================================
int CQueue::Remove( float &fPriority )
{
	if( m_head == MAX_STACK_NODES )
	{
		// wrap
		m_head = 0;
	}

	m_cSize--;
	fPriority = m_queue[m_head].Priority;
	return m_queue[m_head++].Id;
}

//=========================================================
// CQueue constructor
//=========================================================
CQueuePriority::CQueuePriority( void )
{
	m_cSize = 0;
}

//=========================================================
// inserts a value into the priority queue
//=========================================================
void CQueuePriority::Insert( int iValue, float fPriority )
{
	if( Full() )
	{
		printf( "Queue is full!\n" );
		return;
	}

	m_heap[m_cSize].Priority = fPriority;
	m_heap[m_cSize].Id = iValue;
	m_cSize++;
	Heap_SiftUp();
}

//=========================================================
// removes the smallest item from the priority queue
//
//=========================================================
int CQueuePriority::Remove( float &fPriority )
{
	int iReturn = m_heap[0].Id;
	fPriority = m_heap[0].Priority;

	m_cSize--;

	m_heap[0] = m_heap[m_cSize];

	Heap_SiftDown( 0 );
	return iReturn;
}

#define HEAP_LEFT_CHILD(x) ( 2 * ( x ) + 1 )
#define HEAP_RIGHT_CHILD(x) ( 2 * ( x ) + 2 )
#define HEAP_PARENT(x) ( ( ( x ) - 1 ) / 2 )

void CQueuePriority::Heap_SiftDown( int iSubRoot )
{
	int parent = iSubRoot;
	int child = HEAP_LEFT_CHILD( parent );

	struct tag_HEAP_NODE Ref = m_heap[parent];

	while( child < m_cSize )
	{
		int rightchild = HEAP_RIGHT_CHILD( parent );
		if( rightchild < m_cSize )
		{
			if( m_heap[rightchild].Priority < m_heap[child].Priority )
			{
				child = rightchild;
			}
		}
		if( Ref.Priority <= m_heap[child].Priority )
			break;

		m_heap[parent] = m_heap[child];
		parent = child;
		child = HEAP_LEFT_CHILD( parent );
	}
	m_heap[parent] = Ref;
}

void CQueuePriority::Heap_SiftUp( void )
{
	int child = m_cSize - 1;
	while( child )
	{
		int parent = HEAP_PARENT( child );
		if( m_heap[parent].Priority <= m_heap[child].Priority )
			break;

		struct tag_HEAP_NODE Tmp;
		Tmp = m_heap[child];
		m_heap[child] = m_heap[parent];
		m_heap[parent] = Tmp;

		child = parent;
	}
}

//=========================================================
// CGraph - FLoadGraph - attempts to load a node graph from disk.
// if the current level is maps/snar.bsp, maps/graphs/snar.nod
// will be loaded. If file cannot be loaded, the node tree
// will be created and saved to disk.
//=========================================================
int CGraph::FLoadGraph( const char *szMapName )
{
	char szFilename[MAX_PATH];
	int iVersion;
	int length;
	byte *aMemFile;
	byte *pMemFile;

	// make sure the directories have been made
	char szDirName[MAX_PATH];
	GET_GAME_DIR( szDirName );
	strcat( szDirName, "/maps" );
	CreateDirectoryA( szDirName, NULL );
	strcat( szDirName, "/graphs" );
	CreateDirectoryA( szDirName, NULL );

	strcpy( szFilename, "maps/graphs/" );
	strcat( szFilename, szMapName );
	strcat( szFilename, ".nod" );

	pMemFile = aMemFile = LOAD_FILE_FOR_ME( szFilename, &length );

	if( !aMemFile )
		return FALSE;

	// Read the graph version number
	//
	length -= sizeof(int);
	if( length < 0 )
		goto ShortFile;
	iVersion = *(int *) pMemFile;
	pMemFile += sizeof(int);

	if( iVersion == GRAPH_VERSION || iVersion == GRAPH_VERSION_RETAIL )
	{
		// Read the graph class
		//
		if ( iVersion == GRAPH_VERSION )
		{
			length -= sizeof(CGraph);
			if( length < 0 )
				goto ShortFile;
			memcpy( this, pMemFile, sizeof(CGraph) );
			pMemFile += sizeof(CGraph);

			// Set the pointers to zero, just in case we run out of memory.
			//
			m_pNodes = NULL;
			m_pLinkPool = NULL;
			m_di = NULL;
			m_pRouteInfo = NULL;
			m_pHashLinks = NULL;
		}
#if _GRAPH_VERSION != _GRAPH_VERSION_RETAIL
		else
		{
			ALERT( at_aiconsole, "Loading CGraph in GRAPH_VERSION 16 compatibility mode\n" );
			length -= sizeof(CGraph_Retail);
			if( length < 0 )
				goto ShortFile;
			reinterpret_cast<CGraph_Retail*>(pMemFile) -> copyOverTo(this);
			pMemFile += sizeof(CGraph_Retail);
		}
#endif

		// Malloc for the nodes
		//
		m_pNodes = (CNode *)calloc( sizeof(CNode), m_cNodes );

		if( !m_pNodes )
		{
			ALERT( at_aiconsole, "**ERROR**\nCouldn't malloc %d nodes!\n", m_cNodes );
			goto NoMemory;
		}

		// Read in all the nodes
		//
		length -= sizeof(CNode) * m_cNodes;
		if( length < 0 )
			goto ShortFile;
		memcpy( m_pNodes, pMemFile, sizeof(CNode) * m_cNodes );
		pMemFile += sizeof(CNode) * m_cNodes;

		// Malloc for the link pool
		//
		m_pLinkPool = (CLink *)calloc( sizeof(CLink), m_cLinks );

		if( !m_pLinkPool )
		{
			ALERT( at_aiconsole, "**ERROR**\nCouldn't malloc %d link!\n", m_cLinks );
			goto NoMemory;
		}

		// Read in all the links
		//
		if( iVersion == GRAPH_VERSION )
		{
			length -= sizeof(CLink) * m_cLinks;
			if( length < 0 )
				goto ShortFile;
			memcpy( m_pLinkPool, pMemFile, sizeof(CLink) * m_cLinks );
			pMemFile += sizeof(CLink) * m_cLinks;
		}
#if _GRAPH_VERSION != _GRAPH_VERSION_RETAIL
		else
		{
			ALERT( at_aiconsole, "Loading CLink array in GRAPH_VERSION 16 compatibility mode\n" );
			length -= sizeof(CLink_Retail) * m_cLinks;
			if( length < 0 )
				goto ShortFile;
			reinterpret_cast<CLink_Retail*>(pMemFile) -> copyOverTo(m_pLinkPool);
			pMemFile += sizeof(CLink_Retail) * m_cLinks;
		}
#endif

		// Malloc for the sorting info.
		//
		m_di = (DIST_INFO *)calloc( sizeof(DIST_INFO), m_cNodes );
		if( !m_di )
		{
			ALERT( at_aiconsole, "***ERROR**\nCouldn't malloc %d entries sorting nodes!\n", m_cNodes );
			goto NoMemory;
		}

		// Read it in.
		//
		length -= sizeof(DIST_INFO) * m_cNodes;
		if( length < 0 )
			goto ShortFile;
		memcpy( m_di, pMemFile, sizeof(DIST_INFO) * m_cNodes );
		pMemFile += sizeof(DIST_INFO) * m_cNodes;

		// Malloc for the routing info.
		//
		m_fRoutingComplete = FALSE;
		m_pRouteInfo = (signed char *)calloc( sizeof(signed char), m_nRouteInfo );
		if( !m_pRouteInfo )
		{
			ALERT( at_aiconsole, "***ERROR**\nCouldn't malloc %d route bytes!\n", m_nRouteInfo );
			goto NoMemory;
		}
		m_CheckedCounter = 0;
		for(int i = 0; i < m_cNodes; i++ )
		{
			m_di[i].m_CheckedEvent = 0;
		}

		// Read in the route information.
		//
		length -= sizeof(char) * m_nRouteInfo;
		if( length < 0 )
			goto ShortFile;
		memcpy( m_pRouteInfo, pMemFile, sizeof(char) * m_nRouteInfo );
		pMemFile += sizeof(char) * m_nRouteInfo;
		m_fRoutingComplete = TRUE;

		// malloc for the hash links
		//
		m_pHashLinks = (short *)calloc( sizeof(short), m_nHashLinks );
		if( !m_pHashLinks )
		{
			ALERT( at_aiconsole, "***ERROR**\nCouldn't malloc %d hash link bytes!\n", m_nHashLinks );
			goto NoMemory;
		}

		// Read in the hash link information
		//
		length -= sizeof(short) * m_nHashLinks;
		if( length < 0 )
			goto ShortFile;
		memcpy( m_pHashLinks, pMemFile, sizeof(short) * m_nHashLinks );
		// pMemFile += sizeof(short) * m_nHashLinks;

		// Set the graph present flag, clear the pointers set flag
		//
		m_fGraphPresent = TRUE;
		m_fGraphPointersSet = FALSE;

		FREE_FILE( aMemFile );

		if( length != 0 )
		{
			ALERT( at_aiconsole, "***WARNING***:Node graph was longer than expected by %d bytes.!\n", length );
		}

		return TRUE;
	}
	else
	{
		// This file was written by a different build of the dll!
		//
		ALERT( at_aiconsole, "**ERROR** Graph version is %d, expected %d\n", iVersion, GRAPH_VERSION );
		goto ShortFile;
	}

ShortFile:
NoMemory:
	FREE_FILE( aMemFile );
	return FALSE;
}

//=========================================================
// CGraph - FSaveGraph - It's not rocket science.
// this WILL overwrite existing files.
//=========================================================
int CGraph::FSaveGraph( const char *szMapName )
{
	int iVersion = GRAPH_VERSION;
	char szFilename[MAX_PATH];
	FILE *file;

	if( !m_fGraphPresent || !m_fGraphPointersSet )
	{
		// protect us in the case that the node graph isn't available or built
		ALERT( at_aiconsole, "Graph not ready!\n" );
		return FALSE;
	}

	// make sure directories have been made
	GET_GAME_DIR( szFilename );
	strcat( szFilename, "/maps" );
	CreateDirectoryA( szFilename, NULL );
	strcat( szFilename, "/graphs" );
	CreateDirectoryA( szFilename, NULL );

	strcat( szFilename, "/" );
	strcat( szFilename, szMapName );
	strcat( szFilename, ".nod" );

	file = fopen( szFilename, "wb" );

	ALERT( at_aiconsole, "Created: %s\n", szFilename );

	if( !file )
	{
		// couldn't create
		ALERT( at_aiconsole, "Couldn't Create: %s\n", szFilename );
		return FALSE;
	}
	else
	{
		// write the version
		fwrite( &iVersion, sizeof(int), 1, file );

		// write the CGraph class
		fwrite( this, sizeof(CGraph), 1, file );

		// write the nodes
		fwrite( m_pNodes, sizeof(CNode), m_cNodes, file );

		// write the links
		fwrite( m_pLinkPool, sizeof(CLink), m_cLinks, file );

		fwrite( m_di, sizeof(DIST_INFO), m_cNodes, file );

		// Write the route info.
		//
		if( m_pRouteInfo && m_nRouteInfo )
		{
			fwrite( m_pRouteInfo, sizeof(signed char), m_nRouteInfo, file );
		}

		if( m_pHashLinks && m_nHashLinks )
		{
			fwrite( m_pHashLinks, sizeof(short), m_nHashLinks, file );
		}
		fclose( file );
		return TRUE;
	}
}

//=========================================================
// CGraph - FSetGraphPointers - Takes the modelnames of 
// all of the brush ents that block connections in the node
// graph and resolves them into pointers to those entities.
// this is done after loading the graph from disk, whereupon
// the pointers are not valid.
//=========================================================
int CGraph::FSetGraphPointers( void )
{
	int i;
	edict_t	*pentLinkEnt;

	for( i = 0; i < m_cLinks; i++ )
	{
		// go through all of the links
		if( m_pLinkPool[i].m_pLinkEnt != NULL )
		{
			char name[5];
			// when graphs are saved, any valid pointers are will be non-zero, signifying that we should
			// reset those pointers upon reloading. Any pointers that were NULL when the graph was saved
			// will be NULL when reloaded, and will ignored by this function.

			// m_szLinkEntModelname is not necessarily NULL terminated (so we can store it in a more alignment-friendly 4 bytes)
			memcpy( name, m_pLinkPool[i].m_szLinkEntModelname, 4 );
			name[4] = 0;
			pentLinkEnt =  FIND_ENTITY_BY_STRING( NULL, "model", name );

			if( FNullEnt( pentLinkEnt ) )
			{
				// the ent isn't around anymore? Either there is a major problem, or it was removed from the world
				// ( like a func_breakable that's been destroyed or something ). Make sure that LinkEnt is null.
				ALERT( at_aiconsole, "**Could not find model %s\n", name );
				m_pLinkPool[i].m_pLinkEnt = NULL;
			}
			else
			{
				m_pLinkPool[i].m_pLinkEnt = VARS( pentLinkEnt );

				if( !FBitSet( m_pLinkPool[i].m_pLinkEnt->flags, FL_GRAPHED ) )
				{
					m_pLinkPool[i].m_pLinkEnt->flags += FL_GRAPHED;
				}
			}
		}
	}

	// the pointers are now set.
	m_fGraphPointersSet = TRUE;
	return TRUE;
}

//=========================================================
// CGraph - CheckNODFile - this function checks the date of 
// the BSP file that was just loaded and the date of the a
// ssociated .NOD file. If the NOD file is not present, or 
// is older than the BSP file, we rebuild it.
//
// returns FALSE if the .NOD file doesn't qualify and needs
// to be rebuilt.
//
// !!!BUGBUG - the file times we get back are 20 hours ahead!
// since this happens consistantly, we can still correctly 
// determine which of the 2 files is newer. This needs fixed,
// though. ( I now suspect that we are getting GMT back from
// these functions and must compensate for local time ) (sjb)
//=========================================================
int CGraph::CheckNODFile( const char *szMapName )
{
	int retValue;

	char szBspFilename[MAX_PATH];
	char szGraphFilename[MAX_PATH];

	strcpy( szBspFilename, "maps/" );
	strcat( szBspFilename, szMapName );
	strcat( szBspFilename, ".bsp" );

	strcpy( szGraphFilename, "maps/graphs/" );
	strcat( szGraphFilename, szMapName );
	strcat( szGraphFilename, ".nod" );

	retValue = TRUE;

	int iCompare;
	if( COMPARE_FILE_TIME( szBspFilename, szGraphFilename, &iCompare ) )
	{
		if( iCompare > 0 )
		{
			// BSP file is newer.
			ALERT( at_aiconsole, ".NOD File will be updated\n\n" );
			retValue = FALSE;
		}
	}
	else
	{
		retValue = FALSE;
	}

	return retValue;
}

#define ENTRY_STATE_EMPTY -1

struct tagNodePair
{
	short iSrc;
	short iDest;
};

void CGraph::HashInsert( int iSrcNode, int iDestNode, int iKey )
{
	struct tagNodePair np;

	np.iSrc  = iSrcNode;
	np.iDest = iDestNode;
	CRC32_t dwHash;
	CRC32_INIT( &dwHash );
	CRC32_PROCESS_BUFFER( &dwHash, &np, sizeof(np) );
	dwHash = CRC32_FINAL( dwHash );

	int di = m_HashPrimes[dwHash&15];
	int i = ( dwHash >> 4 ) % m_nHashLinks;
	while( m_pHashLinks[i] != ENTRY_STATE_EMPTY )
	{
		i += di;
		if( i >= m_nHashLinks )
			i -= m_nHashLinks;
	}
	m_pHashLinks[i] = iKey;
}

void CGraph::HashSearch( int iSrcNode, int iDestNode, int &iKey )
{
	struct tagNodePair np;

	np.iSrc = iSrcNode;
	np.iDest = iDestNode;
	CRC32_t dwHash;
	CRC32_INIT( &dwHash );
	CRC32_PROCESS_BUFFER( &dwHash, &np, sizeof(np) );
	dwHash = CRC32_FINAL( dwHash );

	int di = m_HashPrimes[dwHash&15];
	int i = ( dwHash >> 4 ) % m_nHashLinks;
	while( m_pHashLinks[i] != ENTRY_STATE_EMPTY )
	{
		CLink &link = Link( m_pHashLinks[i] );
		if( iSrcNode == link.m_iSrcNode && iDestNode == link.m_iDestNode )
		{
			break;
		}
		else
		{
			i += di;
			if( i >= m_nHashLinks )
				i -= m_nHashLinks;
		}
	}
	iKey = m_pHashLinks[i];
}

#define NUMBER_OF_PRIMES 177

int Primes[NUMBER_OF_PRIMES] =
{ 1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67,
71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151,
157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239,
241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337,
347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433,
439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541,
547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641,
643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743,
751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857,
859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971,
977, 983, 991, 997, 1009, 1013, 1019, 1021, 1031, 1033, 1039, 0 };

void CGraph::HashChoosePrimes( int TableSize )
{
	int iPrime, iZone;
	int LargestPrime = TableSize / 2;
	if( LargestPrime > Primes[NUMBER_OF_PRIMES - 2] )
	{
		LargestPrime = Primes[NUMBER_OF_PRIMES - 2];
	}
	int Spacing = LargestPrime / 16;

	// Pick a set primes that are evenly spaced from (0 to LargestPrime)
	// We divide this interval into 16 equal sized zones. We want to find
	// one prime number that best represents that zone.
	//
	for( iZone = 1, iPrime = 0; iPrime < 16; iZone += Spacing )
	{
		// Search for a prime number that is less than the target zone
		// number given by iZone.
		//
		int Lower = Primes[0];
		for( int jPrime = 0; Primes[jPrime] != 0; jPrime++ )
		{
			if( jPrime != 0 && TableSize % Primes[jPrime] == 0 )
				continue;
			int Upper = Primes[jPrime];
			if( Lower <= iZone && iZone <= Upper )
			{
				// Choose the closest lower prime number.
				//
				if( iZone - Lower <= Upper - iZone )
				{
					m_HashPrimes[iPrime++] = Lower;
				}
				else
				{
					m_HashPrimes[iPrime++] = Upper;
				}
				break;
			}
			Lower = Upper;
		}
	}

	// Alternate negative and positive numbers
	//
	for( iPrime = 0; iPrime < 16; iPrime += 2 )
	{
		m_HashPrimes[iPrime] = TableSize - m_HashPrimes[iPrime];
	}

	// Shuffle the set of primes to reduce correlation with bits in
	// hash key.
	//
	for( iPrime = 0; iPrime < 16 - 1; iPrime++ )
	{
		int Pick = RANDOM_LONG( 0, 15 - iPrime);
		int Temp = m_HashPrimes[Pick];
		m_HashPrimes[Pick] = m_HashPrimes[15 - iPrime];
		m_HashPrimes[15 - iPrime] = Temp;
	}
}

// Renumber nodes so that nodes that link together are together.
//
#define UNNUMBERED_NODE -1

void CGraph::SortNodes( void )
{
	// We are using m_iPreviousNode to be the new node number.
	// After assigning new node numbers to everything, we move
	// things and patchup the links.
	//
	int i, iNodeCnt = 0;
	m_pNodes[0].m_iPreviousNode = iNodeCnt++;
	for( i = 1; i < m_cNodes; i++ )
	{
		m_pNodes[i].m_iPreviousNode = UNNUMBERED_NODE;
	}

	for( i = 0; i < m_cNodes; i++ )
	{
		// Run through all of this node's neighbors
		//
		for( int j = 0; j < m_pNodes[i].m_cNumLinks; j++ )
		{
			int iDestNode = INodeLink( i, j );
			if( m_pNodes[iDestNode].m_iPreviousNode == UNNUMBERED_NODE )
			{
				m_pNodes[iDestNode].m_iPreviousNode = iNodeCnt++;
			}
		}
	}

	// Assign remaining node numbers to unlinked nodes.
	//
	for( i = 0; i < m_cNodes; i++ )
	{
		if( m_pNodes[i].m_iPreviousNode == UNNUMBERED_NODE )
		{
			m_pNodes[i].m_iPreviousNode = iNodeCnt++;
		}
	}

	// Alter links to reflect new node numbers.
	//
	for( i = 0; i < m_cLinks; i++ )
	{
		m_pLinkPool[i].m_iSrcNode  = m_pNodes[m_pLinkPool[i].m_iSrcNode].m_iPreviousNode;
		m_pLinkPool[i].m_iDestNode = m_pNodes[m_pLinkPool[i].m_iDestNode].m_iPreviousNode;
	}

	// Rearrange nodes to reflect new node numbering.
	//
	for( i = 0; i < m_cNodes; i++ )
	{
		while( m_pNodes[i].m_iPreviousNode != i )
		{
			// Move current node off to where it should be, and bring
			// that other node back into the current slot.
			//
			int iDestNode = m_pNodes[i].m_iPreviousNode;
			CNode TempNode = m_pNodes[iDestNode];
			m_pNodes[iDestNode] = m_pNodes[i];
			m_pNodes[i] = TempNode;
		}
	}
}

void CGraph::BuildLinkLookups( void )
{
	int i;
	m_nHashLinks = 3 * m_cLinks / 2 + 3;

	HashChoosePrimes( m_nHashLinks );
	m_pHashLinks = (short *)calloc( sizeof(short), m_nHashLinks );
	if( !m_pHashLinks )
	{
		ALERT( at_aiconsole, "Couldn't allocated Link Lookup Table.\n" );
		return;
	}
	for( i = 0; i < m_nHashLinks; i++ )
	{
		m_pHashLinks[i] = ENTRY_STATE_EMPTY;
	}

	for( i = 0; i < m_cLinks; i++ )
	{
		CLink &link = Link( i );
		HashInsert( link.m_iSrcNode, link.m_iDestNode, i );
	}
#if 0
	for( i = 0; i < m_cLinks; i++ )
	{
		CLink &link = Link( i );
		int iKey;
		HashSearch( link.m_iSrcNode, link.m_iDestNode, iKey );
		if( iKey != i )
		{
			ALERT( at_aiconsole, "HashLinks don't match (%d versus %d)\n", i, iKey );
		}
	}
#endif
}

void CGraph::BuildRegionTables( void )
{
	int i, j;
	if( m_di )
		free( m_di );

	// Go ahead and setup for range searching the nodes for FindNearestNodes
	//
	m_di = (DIST_INFO *)calloc( sizeof(DIST_INFO), m_cNodes );
	if( !m_di )
	{
		ALERT( at_aiconsole, "Couldn't allocated node ordering array.\n" );
		return;
	}

	// Calculate regions for all the nodes.
	//
	//
	for( i = 0; i < 3; i++ )
	{
		m_RegionMin[i] =  999999999.0; // just a big number out there;
		m_RegionMax[i] = -999999999.0; // just a big number out there;
	}
	for( i = 0; i < m_cNodes; i++ )
	{
		if( m_pNodes[i].m_vecOrigin.x < m_RegionMin[0] )
			m_RegionMin[0] = m_pNodes[i].m_vecOrigin.x;
		if( m_pNodes[i].m_vecOrigin.y < m_RegionMin[1] )
			m_RegionMin[1] = m_pNodes[i].m_vecOrigin.y;
		if( m_pNodes[i].m_vecOrigin.z < m_RegionMin[2] )
			m_RegionMin[2] = m_pNodes[i].m_vecOrigin.z;

		if( m_pNodes[i].m_vecOrigin.x > m_RegionMax[0] )
			m_RegionMax[0] = m_pNodes[i].m_vecOrigin.x;
		if( m_pNodes[i].m_vecOrigin.y > m_RegionMax[1] )
			m_RegionMax[1] = m_pNodes[i].m_vecOrigin.y;
		if( m_pNodes[i].m_vecOrigin.z > m_RegionMax[2] )
			m_RegionMax[2] = m_pNodes[i].m_vecOrigin.z;
	}
	for( i = 0; i < m_cNodes; i++ )
	{
		m_pNodes[i].m_Region[0] = CALC_RANGE( m_pNodes[i].m_vecOrigin.x, m_RegionMin[0], m_RegionMax[0] );
		m_pNodes[i].m_Region[1] = CALC_RANGE( m_pNodes[i].m_vecOrigin.y, m_RegionMin[1], m_RegionMax[1] );
		m_pNodes[i].m_Region[2] = CALC_RANGE( m_pNodes[i].m_vecOrigin.z, m_RegionMin[2], m_RegionMax[2] );
	}

	for( i = 0; i < 3; i++ )
	{
		for( j = 0; j < NUM_RANGES; j++ )
		{
			m_RangeStart[i][j] = 255;
			m_RangeEnd[i][j] = 0;
		}
		for( j = 0; j < m_cNodes; j++ )
		{
			m_di[j].m_SortedBy[i] = j;
		}

		for( j = 0; j < m_cNodes - 1; j++ )
		{
			int jNode = m_di[j].m_SortedBy[i];
			int jCodeX = m_pNodes[jNode].m_Region[0];
			int jCodeY = m_pNodes[jNode].m_Region[1];
			int jCodeZ = m_pNodes[jNode].m_Region[2];
			int jCode;
			switch( i )
			{
			case 0:
				jCode = ( jCodeX << 16 ) + ( jCodeY << 8 ) + jCodeZ;
				break;
			case 1:
				jCode = ( jCodeY << 16 ) + ( jCodeZ << 8 ) + jCodeX;
				break;
			case 2:
				jCode = ( jCodeZ << 16 ) + ( jCodeX << 8 ) + jCodeY;
				break;
			}

			for( int k = j + 1; k < m_cNodes; k++ )
			{
				int kNode = m_di[k].m_SortedBy[i];
				int kCodeX = m_pNodes[kNode].m_Region[0];
				int kCodeY = m_pNodes[kNode].m_Region[1];
				int kCodeZ = m_pNodes[kNode].m_Region[2];
				int kCode;
				switch( i )
				{
				case 0:
					kCode = ( kCodeX << 16 ) + ( kCodeY << 8 ) + kCodeZ;
					break;
				case 1:
					kCode = ( kCodeY << 16 ) + ( kCodeZ << 8 ) + kCodeX;
					break;
				case 2:
					kCode = ( kCodeZ << 16 ) + ( kCodeX << 8 ) + kCodeY;
					break;
				}

				if( kCode < jCode )
				{
					// Swap j and k entries.
					//
					int Tmp = m_di[j].m_SortedBy[i];
					m_di[j].m_SortedBy[i] = m_di[k].m_SortedBy[i];
					m_di[k].m_SortedBy[i] = Tmp;
				}
			}
		}
	}

	// Generate lookup tables.
	//
	for( i = 0; i < m_cNodes; i++ )
	{
		int CodeX = m_pNodes[m_di[i].m_SortedBy[0]].m_Region[0];
		int CodeY = m_pNodes[m_di[i].m_SortedBy[1]].m_Region[1];
		int CodeZ = m_pNodes[m_di[i].m_SortedBy[2]].m_Region[2];

		if( i < m_RangeStart[0][CodeX] )
		{
			m_RangeStart[0][CodeX] = i;
		}
		if( i < m_RangeStart[1][CodeY] )
		{
			m_RangeStart[1][CodeY] = i;
		}
		if( i < m_RangeStart[2][CodeZ] )
		{
			m_RangeStart[2][CodeZ] = i;
		}
		if( m_RangeEnd[0][CodeX] < i )
		{
			m_RangeEnd[0][CodeX] = i;
		}
		if( m_RangeEnd[1][CodeY] < i )
		{
			m_RangeEnd[1][CodeY] = i;
		}
		if( m_RangeEnd[2][CodeZ] < i )
		{
			m_RangeEnd[2][CodeZ] = i;
		}
	}

	// Initialize the cache.
	//
	memset( m_Cache, 0, sizeof(m_Cache) );
}

void CGraph::ComputeStaticRoutingTables( void )
{
	int iFrom;
	int nRoutes = m_cNodes * m_cNodes;
#define FROM_TO(x,y) ( ( x ) * m_cNodes + ( y ) )
	short *Routes = new short[nRoutes];

	int *pMyPath = new int[m_cNodes];
	unsigned short *BestNextNodes = new unsigned short[m_cNodes];
	signed char *pRoute = new signed char[m_cNodes*2];

	if( Routes && pMyPath && BestNextNodes && pRoute )
	{
		int nTotalCompressedSize = 0;
		for( int iHull = 0; iHull < MAX_NODE_HULLS; iHull++ )
		{
			for( int iCap = 0; iCap < 2; iCap++ )
			{
				int iCapMask;
				switch( iCap )
				{
				case 0:
					iCapMask = 0;
					break;
				case 1:
					iCapMask = bits_CAP_OPEN_DOORS | bits_CAP_AUTO_DOORS | bits_CAP_USE;
					break;
				}

				// Initialize Routing table to uncalculated.
				//
				for( iFrom = 0; iFrom < m_cNodes; iFrom++ )
				{
					for( int iTo = 0; iTo < m_cNodes; iTo++ )
					{
						Routes[FROM_TO( iFrom, iTo )] = -1;
					}
				}

				for( iFrom = 0; iFrom < m_cNodes; iFrom++ )
				{
					for( int iTo = m_cNodes - 1; iTo >= 0; iTo-- )
					{
						if( Routes[FROM_TO( iFrom, iTo )] != -1 )
							continue;

						int cPathSize = FindShortestPath( pMyPath, iFrom, iTo, iHull, iCapMask );

						// Use the computed path to update the routing table.
						//
						if( cPathSize > 1 )
						{
							for( int iNode = 0; iNode < cPathSize - 1; iNode++ )
							{
								int iStart = pMyPath[iNode];
								int iNext  = pMyPath[iNode + 1];
								for( int iNode1 = iNode + 1; iNode1 < cPathSize; iNode1++ )
								{
									int iEnd = pMyPath[iNode1];
									Routes[FROM_TO(iStart, iEnd)] = iNext;
								}
							}
#if 0
							// Well, at first glance, this should work, but actually it's safer
							// to be told explictly that you can take a series of node in a
							// particular direction. Some links don't appear to have links in
							// the opposite direction.
							//
							for( iNode = cPathSize-1; iNode >= 1; iNode-- )
							{
								int iStart = pMyPath[iNode];
								int iNext = pMyPath[iNode - 1];
								for( int iNode1 = iNode-1; iNode1 >= 0; iNode1-- )
								{
									int iEnd = pMyPath[iNode1];
									Routes[FROM_TO( iStart, iEnd )] = iNext;
								}
							}
#endif
						}
						else
						{
							Routes[FROM_TO( iFrom, iTo )] = iFrom;
							Routes[FROM_TO( iTo, iFrom )] = iTo;
						}
					}
				}

				for( iFrom = 0; iFrom < m_cNodes; iFrom++ )
				{
					for( int iTo = 0; iTo < m_cNodes; iTo++ )
					{
						BestNextNodes[iTo] = Routes[FROM_TO( iFrom, iTo )];
					}

					// Compress this node's routing table.
					//
					int iLastNode = 9999999; // just really big.
					int cSequence = 0;
					int cRepeats = 0;
					int CompressedSize = 0;
					signed char *p = pRoute;
					for( int i = 0; i < m_cNodes; i++ )
					{
						BOOL CanRepeat = ( ( BestNextNodes[i] == iLastNode ) && cRepeats < 127 );
						BOOL CanSequence = ( BestNextNodes[i] == i && cSequence < 128 );

						if( cRepeats )
						{
							if( CanRepeat )
							{
								cRepeats++;
							}
							else
							{
								// Emit the repeat phrase.
								//
								CompressedSize += 2; // (count-1, iLastNode-i)
								*p++ = cRepeats - 1;
								int a = iLastNode - iFrom;
								int b = iLastNode - iFrom + m_cNodes;
								int c = iLastNode - iFrom - m_cNodes;
								if( -128 <= a && a <= 127 )
								{
									*p++ = a;
								}
								else if( -128 <= b && b <= 127 )
								{
									*p++ = b;
								}
								else if( -128 <= c && c <= 127 )
								{
									*p++ = c;
								}
								else
								{
									ALERT( at_aiconsole, "Nodes need sorting (%d,%d)!\n", iLastNode, iFrom );
								}
								cRepeats = 0;

								if( CanSequence )
								{
									// Start a sequence.
									//
									cSequence++;
								}
								else
								{
									// Start another repeat.
									//
									cRepeats++;
								}
							}
						}
						else if( cSequence )
						{
							if( CanSequence )
							{
								cSequence++;
							}
							else
							{
								// It may be advantageous to combine
								// a single-entry sequence phrase with the
								// next repeat phrase.
								//
								if( cSequence == 1 && CanRepeat )
								{
									// Combine with repeat phrase.
									//
									cRepeats = 2;
									cSequence = 0;
								}
								else
								{
									// Emit the sequence phrase.
									//
									CompressedSize += 1; // (-count)
									*p++ = -cSequence;
									cSequence = 0;

									// Start a repeat sequence.
									//
									cRepeats++;
								}
							}
						}
						else
						{
							if( CanSequence )
							{
								// Start a sequence phrase.
								//
								cSequence++;
							}
							else
							{
								// Start a repeat sequence.
								//
								cRepeats++;
							}
						}
						iLastNode = BestNextNodes[i];
					}
					if( cRepeats )
					{
						// Emit the repeat phrase.
						//
						CompressedSize += 2;
						*p++ = cRepeats - 1;
#if 0
						iLastNode = iFrom + *pRoute;
						if( iLastNode >= m_cNodes )
							iLastNode -= m_cNodes;
						else if( iLastNode < 0 )
							iLastNode += m_cNodes;
#endif
						int a = iLastNode - iFrom;
						int b = iLastNode - iFrom + m_cNodes;
						int c = iLastNode - iFrom - m_cNodes;
						if( -128 <= a && a <= 127 )
						{
							*p++ = a;
						}
						else if( -128 <= b && b <= 127 )
						{
							*p++ = b;
						}
						else if( -128 <= c && c <= 127 )
						{
							*p++ = c;
						}
						else
						{
							ALERT( at_aiconsole, "Nodes need sorting (%d,%d)!\n", iLastNode, iFrom );
						}
					}
					if( cSequence )
					{
						// Emit the Sequence phrase.
						//
						CompressedSize += 1;
						*p++ = -cSequence;
					}

					// Go find a place to store this thing and point to it.
					//
					int nRoute = p - pRoute;
					if( m_pRouteInfo )
					{
						int i;
						for( i = 0; i < m_nRouteInfo - nRoute; i++ )
						{
							if( memcmp( m_pRouteInfo + i, pRoute, nRoute ) == 0 )
							{
								break;
							}
						}
						if( i < m_nRouteInfo - nRoute )
						{
							m_pNodes[iFrom].m_pNextBestNode[iHull][iCap] = i;
						}
						else
						{
							signed char *Tmp = (signed char *)calloc( sizeof(signed char), ( m_nRouteInfo + nRoute ) );
							memcpy( Tmp, m_pRouteInfo, m_nRouteInfo );
							free( m_pRouteInfo );
							m_pRouteInfo = Tmp;
							memcpy( m_pRouteInfo + m_nRouteInfo, pRoute, nRoute );
							m_pNodes[iFrom].m_pNextBestNode[iHull][iCap] = m_nRouteInfo;
							m_nRouteInfo += nRoute;
							nTotalCompressedSize += CompressedSize;
						}
					}
					else
					{
						m_nRouteInfo = nRoute;
						m_pRouteInfo = (signed char *)calloc( sizeof(signed char), nRoute );
						memcpy( m_pRouteInfo, pRoute, nRoute );
						m_pNodes[iFrom].m_pNextBestNode[iHull][iCap] = 0;
						nTotalCompressedSize += CompressedSize;
					}
				}
			}
		}
		ALERT( at_aiconsole, "Size of Routes = %d\n", nTotalCompressedSize );
	}
	if( Routes )
		delete[] Routes;
	if( BestNextNodes )
		delete[] BestNextNodes;
	if( pRoute )
		delete[] pRoute;
	if( pMyPath )
		delete[] pMyPath;
	Routes = 0;
	BestNextNodes = 0;
	pRoute = 0;
	pMyPath = 0;
#if 0
	TestRoutingTables();
#endif
	m_fRoutingComplete = TRUE;
}

// Test those routing tables. Doesn't really work, yet.
//
void CGraph::TestRoutingTables( void )
{
	int i;
	int *pMyPath = new int[m_cNodes];
	int *pMyPath2 = new int[m_cNodes];
	if( pMyPath && pMyPath2 )
	{
		for( int iHull = 0; iHull < MAX_NODE_HULLS; iHull++ )
		{
			for( int iCap = 0; iCap < 2; iCap++ )
			{
				int iCapMask;
				switch( iCap )
				{
				case 0:
					iCapMask = 0;
					break;
				case 1:
					iCapMask = bits_CAP_OPEN_DOORS | bits_CAP_AUTO_DOORS | bits_CAP_USE;
					break;
				}

				for( int iFrom = 0; iFrom < m_cNodes; iFrom++ )
				{
					for( int iTo = 0; iTo < m_cNodes; iTo++ )
					{
						m_fRoutingComplete = FALSE;
						int cPathSize1 = FindShortestPath( pMyPath, iFrom, iTo, iHull, iCapMask );
						m_fRoutingComplete = TRUE;
						int cPathSize2 = FindShortestPath( pMyPath2, iFrom, iTo, iHull, iCapMask );

						// Unless we can look at the entire path, we can verify that it's correct.
						//
						if( cPathSize2 == MAX_PATH_SIZE )
							continue;

						// Compare distances.
						//
#if 1
						float flDistance1 = 0.0;
						for( i = 0; i < cPathSize1 - 1; i++ )
						{
							// Find the link from pMyPath[i] to pMyPath[i+1]
							//
							if( pMyPath[i] == pMyPath[i + 1] )
								continue;
							int iVisitNode;
							BOOL bFound = FALSE;
							for( int iLink = 0; iLink < m_pNodes[pMyPath[i]].m_cNumLinks; iLink++ )
							{
								iVisitNode = INodeLink( pMyPath[i], iLink );
								if( iVisitNode == pMyPath[i + 1] )
								{
									flDistance1 += m_pLinkPool[m_pNodes[pMyPath[i]].m_iFirstLink + iLink].m_flWeight;
									bFound = TRUE;
									break;
								}
							}
							if( !bFound )
							{
								ALERT( at_aiconsole, "No link.\n" );
							}
						}

						float flDistance2 = 0.0;
						for( i = 0; i < cPathSize2 - 1; i++ )
						{
							// Find the link from pMyPath2[i] to pMyPath2[i+1]
							//
							if( pMyPath2[i] == pMyPath2[i + 1] )
								continue;
							int iVisitNode;
							BOOL bFound = FALSE;
							for( int iLink = 0; iLink < m_pNodes[pMyPath2[i]].m_cNumLinks; iLink++ )
							{
								iVisitNode = INodeLink( pMyPath2[i], iLink );
								if( iVisitNode == pMyPath2[i + 1] )
								{
									flDistance2 += m_pLinkPool[m_pNodes[pMyPath2[i]].m_iFirstLink + iLink].m_flWeight;
									bFound = TRUE;
									break;
								}
							}
							if( !bFound )
							{
								ALERT( at_aiconsole, "No link.\n" );
							}
						}
						if( fabs( flDistance1 - flDistance2 ) > 0.1f )
						{
#else
						if( cPathSize1 != cPathSize2 || memcmp( pMyPath, pMyPath2, sizeof(int) * cPathSize1 ) != 0 )
						{
#endif
							ALERT( at_aiconsole, "Routing is inconsistent!!!\n" );
							ALERT( at_aiconsole, "(%d to %d |%d/%d)1:", iFrom, iTo, iHull, iCap );
							for( i = 0; i < cPathSize1; i++ )
							{
								ALERT( at_aiconsole, "%d ", pMyPath[i] );
							}
							ALERT( at_aiconsole, "\n(%d to %d |%d/%d)2:", iFrom, iTo, iHull, iCap );
							for( i = 0; i < cPathSize2; i++ )
							{
								ALERT( at_aiconsole, "%d ", pMyPath2[i] );
							}
							ALERT( at_aiconsole, "\n" );
							m_fRoutingComplete = FALSE;
							cPathSize1 = FindShortestPath( pMyPath, iFrom, iTo, iHull, iCapMask );
							m_fRoutingComplete = TRUE;
							cPathSize2 = FindShortestPath( pMyPath2, iFrom, iTo, iHull, iCapMask );
							goto EnoughSaid;
						}
					}
				}
			}
		}
	}

EnoughSaid:
	if( pMyPath )
		delete[] pMyPath;
	if( pMyPath2 )
		delete[] pMyPath2;
	pMyPath = 0;
	pMyPath2 = 0;
}

//=========================================================
// CNodeViewer - Draws a graph of the shorted path from all nodes
// to current location (typically the player).  It then draws
// as many connects as it can per frame, trying not to overflow the buffer
//=========================================================
class CNodeViewer : public CBaseEntity
{
public:
	void Spawn( void );

	int m_iBaseNode;
	int m_iDraw;
	int m_nVisited;
	int m_aFrom[128];
	int m_aTo[128];
	int m_iHull;
	int m_afNodeType;
	Vector m_vecColor;

	void FindNodeConnections( int iNode );
	void AddNode( int iFrom, int iTo );
	void EXPORT DrawThink( void );
};

LINK_ENTITY_TO_CLASS( node_viewer, CNodeViewer )
LINK_ENTITY_TO_CLASS( node_viewer_human, CNodeViewer )
LINK_ENTITY_TO_CLASS( node_viewer_fly, CNodeViewer )
LINK_ENTITY_TO_CLASS( node_viewer_large, CNodeViewer )

void CNodeViewer::Spawn()
{
	if( !WorldGraph.m_fGraphPresent || !WorldGraph.m_fGraphPointersSet )
	{
		// protect us in the case that the node graph isn't available or built
		ALERT( at_console, "Graph not ready!\n" );
		UTIL_Remove( this );
		return;
	}

	if( FClassnameIs( pev, "node_viewer_fly" ) )
	{
		m_iHull = NODE_FLY_HULL;
		m_afNodeType = bits_NODE_AIR;
		m_vecColor = Vector( 160, 100, 255 );
	}
	else if( FClassnameIs( pev, "node_viewer_large" ) )
	{
		m_iHull = NODE_LARGE_HULL;
		m_afNodeType = bits_NODE_LAND | bits_NODE_WATER;
		m_vecColor = Vector( 100, 255, 160 );
	}
	else
	{
		m_iHull = NODE_HUMAN_HULL;
		m_afNodeType = bits_NODE_LAND | bits_NODE_WATER;
		m_vecColor = Vector( 255, 160, 100 );
	}

	m_iBaseNode = WorldGraph.FindNearestNode( pev->origin, m_afNodeType );

	if( m_iBaseNode < 0 )
	{
		ALERT( at_console, "No nearby node\n" );
		return;
	}

	m_nVisited = 0;

	ALERT( at_aiconsole, "basenode %d\n", m_iBaseNode );

	if( WorldGraph.m_cNodes < 128 )
	{
		for( int i = 0; i < WorldGraph.m_cNodes; i++ )
		{
			AddNode( i, WorldGraph.NextNodeInRoute( i, m_iBaseNode, m_iHull, 0 ) );
		}
	}
	else
	{
		// do a depth traversal
		FindNodeConnections( m_iBaseNode );

		int start = 0;
		int end;
		do{
			// end = m_nVisited;
			// ALERT( at_console, "%d :", m_nVisited );
			for( end = m_nVisited; start < end; start++ )
			{
				FindNodeConnections( m_aFrom[start] );
				FindNodeConnections( m_aTo[start] );
			}
		} while( end != m_nVisited );
	}

	ALERT( at_aiconsole, "%d nodes\n", m_nVisited );

	m_iDraw = 0;
	SetThink( &CNodeViewer::DrawThink );
	pev->nextthink = gpGlobals->time;
}

void CNodeViewer::FindNodeConnections( int iNode )
{
	AddNode( iNode, WorldGraph.NextNodeInRoute( iNode, m_iBaseNode, m_iHull, 0 ) );
	for( int i = 0; i < WorldGraph.m_pNodes[iNode].m_cNumLinks; i++ )
	{
		CLink *pToLink = &WorldGraph.NodeLink( iNode, i );
		AddNode( pToLink->m_iDestNode, WorldGraph.NextNodeInRoute( pToLink->m_iDestNode, m_iBaseNode, m_iHull, 0 ) );
	}
}

void CNodeViewer::AddNode( int iFrom, int iTo )
{
	if( m_nVisited >= 128 )
	{
		return;
	}
	else
	{
		if( iFrom == iTo )
			return;

		for( int i = 0; i < m_nVisited; i++ )
		{
			if( m_aFrom[i] == iFrom && m_aTo[i] == iTo )
				return;
			if( m_aFrom[i] == iTo && m_aTo[i] == iFrom )
				return;
		}
		m_aFrom[m_nVisited] = iFrom;
		m_aTo[m_nVisited] = iTo;
		m_nVisited++;
	}
}

void CNodeViewer::DrawThink( void )
{
	pev->nextthink = gpGlobals->time;

	for( int i = 0; i < 10; i++ )
	{
		if( m_iDraw == m_nVisited )
		{
			UTIL_Remove( this );
			return;
		}

		extern short g_sModelIndexLaser;
		MESSAGE_BEGIN( MSG_BROADCAST, SVC_TEMPENTITY );
			WRITE_BYTE( TE_BEAMPOINTS );
			WRITE_COORD( WorldGraph.m_pNodes[m_aFrom[m_iDraw]].m_vecOrigin.x );
			WRITE_COORD( WorldGraph.m_pNodes[m_aFrom[m_iDraw]].m_vecOrigin.y );
			WRITE_COORD( WorldGraph.m_pNodes[m_aFrom[m_iDraw]].m_vecOrigin.z + NODE_HEIGHT );

			WRITE_COORD( WorldGraph.m_pNodes[m_aTo[m_iDraw]].m_vecOrigin.x );
			WRITE_COORD( WorldGraph.m_pNodes[m_aTo[m_iDraw]].m_vecOrigin.y );
			WRITE_COORD( WorldGraph.m_pNodes[m_aTo[m_iDraw]].m_vecOrigin.z + NODE_HEIGHT );
			WRITE_SHORT( g_sModelIndexLaser );
			WRITE_BYTE( 0 ); // framerate
			WRITE_BYTE( 0 ); // framerate
			WRITE_BYTE( 250 ); // life
			WRITE_BYTE( 40 );  // width
			WRITE_BYTE( 0 );   // noise
			WRITE_BYTE( m_vecColor.x );   // r, g, b
			WRITE_BYTE( m_vecColor.y );   // r, g, b
			WRITE_BYTE( m_vecColor.z );   // r, g, b
			WRITE_BYTE( 128 );	// brightness
			WRITE_BYTE( 0 );		// speed
		MESSAGE_END();

		m_iDraw++;
	}
}