text: /*
  ===========================================================================
  Copyright (C) 1999-2005 Id Software, Inc.
  
  This file is part of Quake III Arena source code.
  
  Quake III Arena source code is free software; you can redistribute it
  and/or modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of the License,
  or (at your option) any later version.
  
  Quake III Arena source code is distributed in the hope that it will be
  useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
  
  You should have received a copy of the GNU General Public License
  along with Foobar; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  ===========================================================================
  */
  
  #include "qbsp.h"
  #include "l_mem.h"
  
  int		c_active_portals;
  int		c_peak_portals;
  int		c_boundary;
  int		c_boundary_sides;
  int		c_portalmemory;
  
  //portal_t *portallist = NULL;
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  portal_t *AllocPortal (void)
  {
  	portal_t	*p;
  	
  	p = GetMemory(sizeof(portal_t));
  	memset (p, 0, sizeof(portal_t));
  
  	if (numthreads == 1)
  	{
  		c_active_portals++;
  		if (c_active_portals > c_peak_portals)
  		{
  			c_peak_portals = c_active_portals;
  		} //end if
  		c_portalmemory += MemorySize(p);	
  	} //end if
  
  //	p->nextportal = portallist;
  //	portallist = p;
  	
  	return p;
  } //end of the function AllocPortal
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void FreePortal (portal_t *p)
  {
  	if (p->winding) FreeWinding(p->winding);
  	if (numthreads == 1)
  	{
  		c_active_portals--;
  		c_portalmemory -= MemorySize(p);
  	} //end if
  	FreeMemory(p);
  } //end of the function FreePortal
  //===========================================================================
  // Returns the single content bit of the
  // strongest visible content present
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  int VisibleContents (int contents)
  {
  	int		i;
  
  	for (i=1 ; i<=LAST_VISIBLE_CONTENTS ; i<<=1)
  		if (contents & i )
  			return i;
  
  	return 0;
  } //end of the function VisibleContents
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  int ClusterContents (node_t *node)
  {
  	int		c1, c2, c;
  
  	if (node->planenum == PLANENUM_LEAF)
  		return node->contents;
  
  	c1 = ClusterContents(node->children[0]);
  	c2 = ClusterContents(node->children[1]);
  	c = c1|c2;
  
  	// a cluster may include some solid detail areas, but
  	// still be seen into
  	if ( ! (c1&CONTENTS_SOLID) || ! (c2&CONTENTS_SOLID) )
  		c &= ~CONTENTS_SOLID;
  	return c;
  } //end of the function ClusterContents
  
  //===========================================================================
  // Returns true if the portal is empty or translucent, allowing
  // the PVS calculation to see through it.
  // The nodes on either side of the portal may actually be clusters,
  // not leaves, so all contents should be ored together
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  qboolean Portal_VisFlood (portal_t *p)
  {
  	int		c1, c2;
  
  	if (!p->onnode)
  		return false;	// to global outsideleaf
  
  	c1 = ClusterContents(p->nodes[0]);
  	c2 = ClusterContents(p->nodes[1]);
  
  	if (!VisibleContents (c1^c2))
  		return true;
  
  	if (c1 & (CONTENTS_Q2TRANSLUCENT|CONTENTS_DETAIL))
  		c1 = 0;
  	if (c2 & (CONTENTS_Q2TRANSLUCENT|CONTENTS_DETAIL))
  		c2 = 0;
  
  	if ( (c1|c2) & CONTENTS_SOLID )
  		return false;		// can't see through solid
  
  	if (! (c1 ^ c2))
  		return true;		// identical on both sides
  
  	if (!VisibleContents (c1^c2))
  		return true;
  	return false;
  } //end of the function Portal_VisFlood
  //===========================================================================
  // The entity flood determines which areas are
  // "outside" on the map, which are then filled in.
  // Flowing from side s to side !s
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  qboolean Portal_EntityFlood (portal_t *p, int s)
  {
  	if (p->nodes[0]->planenum != PLANENUM_LEAF
  		|| p->nodes[1]->planenum != PLANENUM_LEAF)
  		Error ("Portal_EntityFlood: not a leaf");
  
  	// can never cross to a solid 
  	if ( (p->nodes[0]->contents & CONTENTS_SOLID)
  	|| (p->nodes[1]->contents & CONTENTS_SOLID) )
  		return false;
  
  	// can flood through everything else
  	return true;
  }
  
  
  //=============================================================================
  
  int		c_tinyportals;
  
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void AddPortalToNodes (portal_t *p, node_t *front, node_t *back)
  {
  	if (p->nodes[0] || p->nodes[1])
  		Error ("AddPortalToNode: allready included");
  
  	p->nodes[0] = front;
  	p->next[0] = front->portals;
  	front->portals = p;
  	
  	p->nodes[1] = back;
  	p->next[1] = back->portals;
  	back->portals = p;
  } //end of the function AddPortalToNodes
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void RemovePortalFromNode (portal_t *portal, node_t *l)
  {
  	portal_t	**pp, *t;
  
  	int s, i, n;
  	portal_t *p;
  	portal_t *portals[4096];
  	
  // remove reference to the current portal
  	pp = &l->portals;
  	while (1)
  	{
  		t = *pp;
  		if (!t)
  			Error ("RemovePortalFromNode: portal not in leaf");	
  
  		if ( t == portal )
  			break;
  
  		if (t->nodes[0] == l)
  			pp = &t->next[0];
  		else if (t->nodes[1] == l)
  			pp = &t->next[1];
  		else
  			Error ("RemovePortalFromNode: portal not bounding leaf");
  	}
  	
  	if (portal->nodes[0] == l)
  	{
  		*pp = portal->next[0];
  		portal->nodes[0] = NULL;
  	} //end if
  	else if (portal->nodes[1] == l)
  	{
  		*pp = portal->next[1];	
  		portal->nodes[1] = NULL;
  	} //end else if
  	else
  	{
  		Error("RemovePortalFromNode: mislinked portal");
  	} //end else
  //#ifdef ME
  	n = 0;
  	for (p = l->portals; p; p = p->next[s])
  	{
  		for (i = 0; i < n; i++)
  		{
  			if (p == portals[i]) Error("RemovePortalFromNode: circular linked\n");
  		} //end for
  		if (p->nodes[0] != l && p->nodes[1] != l)
  		{
  			Error("RemovePortalFromNodes: portal does not belong to node\n");
  		} //end if
  		portals[n] = p;
  		s = (p->nodes[1] == l);
  //		if (++n >= 4096) Error("RemovePortalFromNode: more than 4096 portals\n");
  	} //end for
  //#endif
  } //end of the function RemovePortalFromNode
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void PrintPortal (portal_t *p)
  {
  	int			i;
  	winding_t	*w;
  	
  	w = p->winding;
  	for (i=0 ; i<w->numpoints ; i++)
  		printf ("(%5.0f,%5.0f,%5.0f)\n",w->p[i][0]
  		, w->p[i][1], w->p[i][2]);
  } //end of the function PrintPortal
  //===========================================================================
  // The created portals will face the global outside_node
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  #define	SIDESPACE	8
  
  void MakeHeadnodePortals (tree_t *tree)
  {
  	vec3_t		bounds[2];
  	int			i, j, n;
  	portal_t	*p, *portals[6];
  	plane_t		bplanes[6], *pl;
  	node_t *node;
  
  	node = tree->headnode;
  
  // pad with some space so there will never be null volume leaves
  	for (i=0 ; i<3 ; i++)
  	{
  		bounds[0][i] = tree->mins[i] - SIDESPACE;
  		bounds[1][i] = tree->maxs[i] + SIDESPACE;
  		if ( bounds[0][i] > bounds[1][i] ) {
  			Error("empty BSP tree");
  		}
  	}
  	
  	tree->outside_node.planenum = PLANENUM_LEAF;
  	tree->outside_node.brushlist = NULL;
  	tree->outside_node.portals = NULL;
  	tree->outside_node.contents = 0;
  
  	for (i=0 ; i<3 ; i++)
  		for (j=0 ; j<2 ; j++)
  		{
  			n = j*3 + i;
  
  			p = AllocPortal ();
  			portals[n] = p;
  			
  			pl = &bplanes[n];
  			memset (pl, 0, sizeof(*pl));
  			if (j)
  			{
  				pl->normal[i] = -1;
  				pl->dist = -bounds[j][i];
  			}
  			else
  			{
  				pl->normal[i] = 1;
  				pl->dist = bounds[j][i];
  			}
  			p->plane = *pl;
  			p->winding = BaseWindingForPlane (pl->normal, pl->dist);
  			AddPortalToNodes (p, node, &tree->outside_node);
  		}
  		
  // clip the basewindings by all the other planes
  	for (i=0 ; i<6 ; i++)
  	{
  		for (j=0 ; j<6 ; j++)
  		{
  			if (j == i) continue;
  			ChopWindingInPlace (&portals[i]->winding, bplanes[j].normal, bplanes[j].dist, ON_EPSILON);
  		} //end for
  	} //end for
  } //end of the function MakeHeadNodePortals
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  #define	BASE_WINDING_EPSILON		0.001
  #define	SPLIT_WINDING_EPSILON	0.001
  
  winding_t *BaseWindingForNode (node_t *node)
  {
  	winding_t	*w;
  	node_t		*n;
  	plane_t		*plane;
  	vec3_t		normal;
  	vec_t		dist;
  
  	w = BaseWindingForPlane (mapplanes[node->planenum].normal
  		, mapplanes[node->planenum].dist);
  
  	// clip by all the parents
  	for (n=node->parent ; n && w ; )
  	{
  		plane = &mapplanes[n->planenum];
  
  		if (n->children[0] == node)
  		{	// take front
  			ChopWindingInPlace (&w, plane->normal, plane->dist, BASE_WINDING_EPSILON);
  		}
  		else
  		{	// take back
  			VectorSubtract (vec3_origin, plane->normal, normal);
  			dist = -plane->dist;
  			ChopWindingInPlace (&w, normal, dist, BASE_WINDING_EPSILON);
  		}
  		node = n;
  		n = n->parent;
  	}
  
  	return w;
  } //end of the function BaseWindingForNode
  //===========================================================================
  // create the new portal by taking the full plane winding for the cutting
  // plane and clipping it by all of parents of this node
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  qboolean WindingIsTiny (winding_t *w);
  
  void MakeNodePortal (node_t *node)
  {
  	portal_t	*new_portal, *p;
  	winding_t	*w;
  	vec3_t		normal;
  	float		dist;
  	int			side;
  
  	w = BaseWindingForNode (node);
  
  	// clip the portal by all the other portals in the node
  	for (p = node->portals; p && w; p = p->next[side])	
  	{
  		if (p->nodes[0] == node)
  		{
  			side = 0;
  			VectorCopy (p->plane.normal, normal);
  			dist = p->plane.dist;
  		} //end if
  		else if (p->nodes[1] == node)
  		{
  			side = 1;
  			VectorSubtract (vec3_origin, p->plane.normal, normal);
  			dist = -p->plane.dist;
  		} //end else if
  		else
  		{
  			Error ("MakeNodePortal: mislinked portal");
  		} //end else
  		ChopWindingInPlace (&w, normal, dist, 0.1);
  	} //end for
  
  	if (!w)
  	{
  		return;
  	} //end if
  
  	if (WindingIsTiny (w))
  	{
  		c_tinyportals++;
  		FreeWinding(w);
  		return;
  	} //end if
  
  #ifdef DEBUG
  /* //NOTE: don't use this winding ok check
  	// all the invalid windings only have a degenerate edge
  	if (WindingError(w))
  	{
  		Log_Print("MakeNodePortal: %s\n", WindingErrorString());
  		FreeWinding(w);
  		return;
  	} //end if*/
  #endif //DEBUG
  
  
  	new_portal = AllocPortal();
  	new_portal->plane = mapplanes[node->planenum];
  
  #ifdef ME
  	new_portal->planenum = node->planenum;
  #endif //ME
  
  	new_portal->onnode = node;
  	new_portal->winding = w;
  	AddPortalToNodes (new_portal, node->children[0], node->children[1]);
  } //end of the function MakeNodePortal
  //===========================================================================
  // Move or split the portals that bound node so that the node's
  // children have portals instead of node.
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void SplitNodePortals (node_t *node)
  {
  	portal_t	*p, *next_portal, *new_portal;
  	node_t *f, *b, *other_node;
  	int side;
  	plane_t *plane;
  	winding_t *frontwinding, *backwinding;
  
  	plane = &mapplanes[node->planenum];
  	f = node->children[0];
  	b = node->children[1];
  
  	for (p = node->portals ; p ; p = next_portal)	
  	{
  		if (p->nodes[0] == node) side = 0;
  		else if (p->nodes[1] == node) side = 1;
  		else Error ("SplitNodePortals: mislinked portal");
  		next_portal = p->next[side];
  
  		other_node = p->nodes[!side];
  		RemovePortalFromNode (p, p->nodes[0]);
  		RemovePortalFromNode (p, p->nodes[1]);
  
  //
  // cut the portal into two portals, one on each side of the cut plane
  //
  		ClipWindingEpsilon (p->winding, plane->normal, plane->dist,
  				SPLIT_WINDING_EPSILON, &frontwinding, &backwinding);
  
  		if (frontwinding && WindingIsTiny(frontwinding))
  		{
  			FreeWinding (frontwinding);
  			frontwinding = NULL;
  			c_tinyportals++;
  		} //end if
  
  		if (backwinding && WindingIsTiny(backwinding))
  		{
  			FreeWinding (backwinding);
  			backwinding = NULL;
  			c_tinyportals++;
  		} //end if
  
  #ifdef DEBUG
  /* 	//NOTE: don't use this winding ok check
  		// all the invalid windings only have a degenerate edge
  		if (frontwinding && WindingError(frontwinding))
  		{
  			Log_Print("SplitNodePortals: front %s\n", WindingErrorString());
  			FreeWinding(frontwinding);
  			frontwinding = NULL;
  		} //end if
  		if (backwinding && WindingError(backwinding))
  		{
  			Log_Print("SplitNodePortals: back %s\n", WindingErrorString());
  			FreeWinding(backwinding);
  			backwinding = NULL;
  		} //end if*/
  #endif //DEBUG
  
  		if (!frontwinding && !backwinding)
  		{	// tiny windings on both sides
  			continue;
  		}
  
  		if (!frontwinding)
  		{
  			FreeWinding (backwinding);
  			if (side == 0) AddPortalToNodes (p, b, other_node);
  			else AddPortalToNodes (p, other_node, b);
  			continue;
  		}
  		if (!backwinding)
  		{
  			FreeWinding (frontwinding);
  			if (side == 0) AddPortalToNodes (p, f, other_node);
  			else AddPortalToNodes (p, other_node, f);
  			continue;
  		}
  		
  	// the winding is split
  		new_portal = AllocPortal();
  		*new_portal = *p;
  		new_portal->winding = backwinding;
  		FreeWinding (p->winding);
  		p->winding = frontwinding;
  
  		if (side == 0)
  		{
  			AddPortalToNodes (p, f, other_node);
  			AddPortalToNodes (new_portal, b, other_node);
  		} //end if
  		else
  		{
  			AddPortalToNodes (p, other_node, f);
  			AddPortalToNodes (new_portal, other_node, b);
  		} //end else
  	}
  
  	node->portals = NULL;
  } //end of the function SplitNodePortals
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void CalcNodeBounds (node_t *node)
  {
  	portal_t	*p;
  	int			s;
  	int			i;
  
  	// calc mins/maxs for both leaves and nodes
  	ClearBounds (node->mins, node->maxs);
  	for (p = node->portals ; p ; p = p->next[s])	
  	{
  		s = (p->nodes[1] == node);
  		for (i=0 ; i<p->winding->numpoints ; i++)
  			AddPointToBounds (p->winding->p[i], node->mins, node->maxs);
  	}
  } //end of the function CalcNodeBounds
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  int c_numportalizednodes;
  
  void MakeTreePortals_r (node_t *node)
  {
  	int		i;
  
  #ifdef ME
  	qprintf("\r%6d", ++c_numportalizednodes);
  	if (cancelconversion) return;
  #endif //ME
  
  	CalcNodeBounds (node);
  	if (node->mins[0] >= node->maxs[0])
  	{
  		Log_Print("WARNING: node without a volume\n");
  	}
  
  	for (i=0 ; i<3 ; i++)
  	{
  		if (node->mins[i] < -MAX_MAP_BOUNDS || node->maxs[i] > MAX_MAP_BOUNDS)
  		{
  			Log_Print("WARNING: node with unbounded volume\n");
  			break;
  		}
  	}
  	if (node->planenum == PLANENUM_LEAF)
  		return;
  
  	MakeNodePortal (node);
  	SplitNodePortals (node);
  
  	MakeTreePortals_r (node->children[0]);
  	MakeTreePortals_r (node->children[1]);
  } //end of the function MakeTreePortals_r
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void MakeTreePortals(tree_t *tree)
  {
  
  #ifdef ME
  	Log_Print("---- Node Portalization ----\n");
  	c_numportalizednodes = 0;
  	c_portalmemory = 0;
  	qprintf("%6d nodes portalized", c_numportalizednodes);
  #endif //ME
  
  	MakeHeadnodePortals(tree);
  	MakeTreePortals_r(tree->headnode);
  
  #ifdef ME
  	qprintf("\n");
  	Log_Write("%6d nodes portalized\r\n", c_numportalizednodes);
  	Log_Print("%6d tiny portals\r\n", c_tinyportals);
  	Log_Print("%6d KB of portal memory\r\n", c_portalmemory >> 10);
  	Log_Print("%6i KB of winding memory\r\n", WindingMemory() >> 10);
  #endif //ME
  } //end of the function MakeTreePortals
  
  /*
  =========================================================
  
  FLOOD ENTITIES
  
  =========================================================
  */
  //#define P_NODESTACK
  
  node_t *p_firstnode;
  node_t *p_lastnode;
  
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  #ifdef P_NODESTACK
  void P_AddNodeToList(node_t *node)
  {
  	node->next = p_firstnode;
  	p_firstnode = node;
  	if (!p_lastnode) p_lastnode = node;
  } //end of the function P_AddNodeToList
  #else //it's a node queue
  //add the node to the end of the node list
  void P_AddNodeToList(node_t *node)
  {
  	node->next = NULL;
  	if (p_lastnode) p_lastnode->next = node;
  	else p_firstnode = node;
  	p_lastnode = node;
  } //end of the function P_AddNodeToList
  #endif //P_NODESTACK
  //===========================================================================
  // get the first node from the front of the node list
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  node_t *P_NextNodeFromList(void)
  {
  	node_t *node;
  
  	node = p_firstnode;
  	if (p_firstnode) p_firstnode = p_firstnode->next;
  	if (!p_firstnode) p_lastnode = NULL;
  	return node;
  } //end of the function P_NextNodeFromList
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void FloodPortals(node_t *firstnode)
  {
  	node_t *node;
  	portal_t *p;
  	int s;
  
  	firstnode->occupied = 1;
  	P_AddNodeToList(firstnode);
  
  	for (node = P_NextNodeFromList(); node; node = P_NextNodeFromList())
  	{
  		for (p = node->portals; p; p = p->next[s])
  		{
  			s = (p->nodes[1] == node);
  			//if the node at the other side of the portal is occupied already
  			if (p->nodes[!s]->occupied) continue;
  			//if it isn't possible to flood through this portal
  			if (!Portal_EntityFlood(p, s)) continue;
  			//
  			p->nodes[!s]->occupied = node->occupied + 1;
  			//
  			P_AddNodeToList(p->nodes[!s]);
  		} //end for
  	} //end for
  } //end of the function FloodPortals
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  int numrec;
  
  void FloodPortals_r (node_t *node, int dist)
  {
  	portal_t *p;
  	int s;
  //	int i;
  
  	Log_Print("\r%6d", ++numrec);
  
  	if (node->occupied) Error("FloodPortals_r: node already occupied\n");
  	if (!node)
  	{
  		Error("FloodPortals_r: NULL node\n");
  	} //end if*/
  	node->occupied = dist;
  
  	for (p = node->portals; p; p = p->next[s])
  	{
  		s = (p->nodes[1] == node);
  		//if the node at the other side of the portal is occupied already
  		if (p->nodes[!s]->occupied) continue;
  		//if it isn't possible to flood through this portal
  		if (!Portal_EntityFlood(p, s)) continue;
  		//flood recursively through the current portal
  		FloodPortals_r(p->nodes[!s], dist+1);
  	} //end for
  	Log_Print("\r%6d", --numrec);
  } //end of the function FloodPortals_r
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  qboolean PlaceOccupant (node_t *headnode, vec3_t origin, entity_t *occupant)
  {
  	node_t *node;
  	vec_t	d;
  	plane_t *plane;
  
  	//find the leaf to start in
  	node = headnode;
  	while(node->planenum != PLANENUM_LEAF)
  	{
  		if (node->planenum < 0 || node->planenum > nummapplanes)
  		{
  			Error("PlaceOccupant: invalid node->planenum\n");
  		} //end if
  		plane = &mapplanes[node->planenum];
  		d = DotProduct(origin, plane->normal) - plane->dist;
  		if (d >= 0) node = node->children[0];
  		else node = node->children[1];
  		if (!node)
  		{
  			Error("PlaceOccupant: invalid child %d\n", d < 0);
  		} //end if
  	} //end while
  	//don't start in solid
  //	if (node->contents == CONTENTS_SOLID)
  	//ME: replaced because in LeafNode in brushbsp.c
  	//    some nodes have contents solid with other contents
  	if (node->contents & CONTENTS_SOLID) return false;
  	//if the node is already occupied
  	if (node->occupied) return false;
  
  	//place the occupant in the first leaf
  	node->occupant = occupant;
  
  	numrec = 0;
  //	Log_Print("%6d recurses", numrec);
  //	FloodPortals_r(node, 1);
  //	Log_Print("\n");
  	FloodPortals(node);
  
  	return true;
  } //end of the function PlaceOccupant
  //===========================================================================
  // Marks all nodes that can be reached by entites
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  qboolean FloodEntities (tree_t *tree)
  {
  	int i;
  	int x, y;
  	vec3_t origin;
  	char *cl;
  	qboolean inside;
  	node_t *headnode;
  
  	headnode = tree->headnode;
  	Log_Print("------ FloodEntities -------\n");
  	inside = false;
  	tree->outside_node.occupied = 0;
  
  	//start at entity 1 not the world ( = 0)
  	for (i = 1; i < num_entities; i++)
  	{
  		GetVectorForKey(&entities[i], "origin", origin);
  		if (VectorCompare(origin, vec3_origin)) continue;
  
  		cl = ValueForKey(&entities[i], "classname");
  		origin[2] += 1;	//so objects on floor are ok
  
  //		Log_Print("flooding from entity %d: %s\n", i, cl);
  		//nudge playerstart around if needed so clipping hulls allways
  		//have a valid point
  		if (!strcmp(cl, "info_player_start"))
  		{
  			for (x = -16; x <= 16; x += 16)
  			{
  				for (y = -16; y <= 16; y += 16)
  				{
  					origin[0] += x;
  					origin[1] += y;
  					if (PlaceOccupant(headnode, origin, &entities[i]))
  					{
  						inside = true;
  						x = 999; //stop for this info_player_start
  						break;
  					} //end if
  					origin[0] -= x;
  					origin[1] -= y;
  				} //end for
  			} //end for
  		} //end if
  		else
  		{
  			if (PlaceOccupant(headnode, origin, &entities[i]))
  			{
  				inside = true;
  			} //end if
  		} //end else
  	} //end for
  
  	if (!inside)
  	{
  		Log_Print("WARNING: no entities inside\n");
  	} //end if
  	else if (tree->outside_node.occupied)
  	{
  		Log_Print("WARNING: entity reached from outside\n");
  	} //end else if
  
  	return (qboolean)(inside && !tree->outside_node.occupied);
  } //end of the function FloodEntities
  
  /*
  =========================================================
  
  FILL OUTSIDE
  
  =========================================================
  */
  
  int c_outside;
  int c_inside;
  int c_solid;
  
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void FillOutside_r (node_t *node)
  {
  	if (node->planenum != PLANENUM_LEAF)
  	{
  		FillOutside_r (node->children[0]);
  		FillOutside_r (node->children[1]);
  		return;
  	} //end if
  	// anything not reachable by an entity
  	// can be filled away (by setting solid contents)
  	if (!node->occupied)
  	{
  		if (!(node->contents & CONTENTS_SOLID))
  		{
  			c_outside++;
  			node->contents |= CONTENTS_SOLID;
  		} //end if
  		else
  		{
  			c_solid++;
  		} //end else
  	} //end if
  	else
  	{
  		c_inside++;
  	} //end else
  } //end of the function FillOutside_r
  //===========================================================================
  // Fill all nodes that can't be reached by entities
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void FillOutside (node_t *headnode)
  {
  	c_outside = 0;
  	c_inside = 0;
  	c_solid = 0;
  	Log_Print("------- FillOutside --------\n");
  	FillOutside_r (headnode);
  	Log_Print("%5i solid leaves\n", c_solid);
  	Log_Print("%5i leaves filled\n", c_outside);
  	Log_Print("%5i inside leaves\n", c_inside);
  } //end of the function FillOutside
  
  /*
  =========================================================
  
  FLOOD AREAS
  
  =========================================================
  */
  
  int		c_areas;
  
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void FloodAreas_r (node_t *node)
  {
  	portal_t	*p;
  	int			s;
  	bspbrush_t	*b;
  	entity_t	*e;
  
  	if (node->contents == CONTENTS_AREAPORTAL)
  	{
  		// this node is part of an area portal
  		b = node->brushlist;
  		e = &entities[b->original->entitynum];
  
  		// if the current area has allready touched this
  		// portal, we are done
  		if (e->portalareas[0] == c_areas || e->portalareas[1] == c_areas)
  			return;
  
  		// note the current area as bounding the portal
  		if (e->portalareas[1])
  		{
  			Log_Print("WARNING: areaportal entity %i touches > 2 areas\n", b->original->entitynum);
  			return;
  		}
  		if (e->portalareas[0])
  			e->portalareas[1] = c_areas;
  		else
  			e->portalareas[0] = c_areas;
  
  		return;
  	} //end if
  
  	if (node->area)
  		return;		// allready got it
  	node->area = c_areas;
  
  	for (p=node->portals ; p ; p = p->next[s])
  	{
  		s = (p->nodes[1] == node);
  #if 0
  		if (p->nodes[!s]->occupied)
  			continue;
  #endif
  		if (!Portal_EntityFlood (p, s))
  			continue;
  
  		FloodAreas_r (p->nodes[!s]);
  	} //end for
  } //end of the function FloodAreas_r
  //===========================================================================
  // Just decend the tree, and for each node that hasn't had an
  // area set, flood fill out from there
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void FindAreas_r (node_t *node)
  {
  	if (node->planenum != PLANENUM_LEAF)
  	{
  		FindAreas_r (node->children[0]);
  		FindAreas_r (node->children[1]);
  		return;
  	}
  
  	if (node->area)
  		return;		// allready got it
  
  	if (node->contents & CONTENTS_SOLID)
  		return;
  
  	if (!node->occupied)
  		return;			// not reachable by entities
  
  	// area portals are allways only flooded into, never
  	// out of
  	if (node->contents == CONTENTS_AREAPORTAL)
  		return;
  
  	c_areas++;
  	FloodAreas_r (node);
  } //end of the function FindAreas_r
  //===========================================================================
  // Just decend the tree, and for each node that hasn't had an
  // area set, flood fill out from there
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void SetAreaPortalAreas_r (node_t *node)
  {
  	bspbrush_t	*b;
  	entity_t	*e;
  
  	if (node->planenum != PLANENUM_LEAF)
  	{
  		SetAreaPortalAreas_r (node->children[0]);
  		SetAreaPortalAreas_r (node->children[1]);
  		return;
  	} //end if
  
  	if (node->contents == CONTENTS_AREAPORTAL)
  	{
  		if (node->area)
  			return;		// allready set
  
  		b = node->brushlist;
  		e = &entities[b->original->entitynum];
  		node->area = e->portalareas[0];
  		if (!e->portalareas[1])
  		{
  			Log_Print("WARNING: areaportal entity %i doesn't touch two areas\n", b->original->entitynum);
  			return;
  		} //end if
  	} //end if
  } //end of the function SetAreaPortalAreas_r
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  /*
  void EmitAreaPortals(node_t *headnode)
  {
  	int				i, j;
  	entity_t		*e;
  	dareaportal_t	*dp;
  
  	if (c_areas > MAX_MAP_AREAS)
  		Error ("MAX_MAP_AREAS");
  	numareas = c_areas+1;
  	numareaportals = 1;		// leave 0 as an error
  
  	for (i=1 ; i<=c_areas ; i++)
  	{
  		dareas[i].firstareaportal = numareaportals;
  		for (j=0 ; j<num_entities ; j++)
  		{
  			e = &entities[j];
  			if (!e->areaportalnum)
  				continue;
  			dp = &dareaportals[numareaportals];
  			if (e->portalareas[0] == i)
  			{
  				dp->portalnum = e->areaportalnum;
  				dp->otherarea = e->portalareas[1];
  				numareaportals++;
  			} //end if
  			else if (e->portalareas[1] == i)
  			{
  				dp->portalnum = e->areaportalnum;
  				dp->otherarea = e->portalareas[0];
  				numareaportals++;
  			} //end else if
  		} //end for
  		dareas[i].numareaportals = numareaportals - dareas[i].firstareaportal;
  	} //end for
  
  	Log_Print("%5i numareas\n", numareas);
  	Log_Print("%5i numareaportals\n", numareaportals);
  } //end of the function EmitAreaPortals
  */
  //===========================================================================
  // Mark each leaf with an area, bounded by CONTENTS_AREAPORTAL
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void FloodAreas (tree_t *tree)
  {
  	Log_Print("--- FloodAreas ---\n");
  	FindAreas_r (tree->headnode);
  	SetAreaPortalAreas_r (tree->headnode);
  	Log_Print("%5i areas\n", c_areas);
  } //end of the function FloodAreas
  //===========================================================================
  // Finds a brush side to use for texturing the given portal
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void FindPortalSide (portal_t *p)
  {
  	int			viscontents;
  	bspbrush_t	*bb;
  	mapbrush_t	*brush;
  	node_t		*n;
  	int			i,j;
  	int			planenum;
  	side_t		*side, *bestside;
  	float		dot, bestdot;
  	plane_t		*p1, *p2;
  
  	// decide which content change is strongest
  	// solid > lava > water, etc
  	viscontents = VisibleContents (p->nodes[0]->contents ^ p->nodes[1]->contents);
  	if (!viscontents)
  		return;
  
  	planenum = p->onnode->planenum;
  	bestside = NULL;
  	bestdot = 0;
  
  	for (j=0 ; j<2 ; j++)
  	{
  		n = p->nodes[j];
  		p1 = &mapplanes[p->onnode->planenum];
  		for (bb=n->brushlist ; bb ; bb=bb->next)
  		{
  			brush = bb->original;
  			if ( !(brush->contents & viscontents) )
  				continue;
  			for (i=0 ; i<brush->numsides ; i++)
  			{
  				side = &brush->original_sides[i];
  				if (side->flags & SFL_BEVEL)
  					continue;
  				if (side->texinfo == TEXINFO_NODE)
  					continue;		// non-visible
  				if ((side->planenum&~1) == planenum)
  				{	// exact match
  					bestside = &brush->original_sides[i];
  					goto gotit;
  				} //end if
  				// see how close the match is
  				p2 = &mapplanes[side->planenum&~1];
  				dot = DotProduct (p1->normal, p2->normal);
  				if (dot > bestdot)
  				{
  					bestdot = dot;
  					bestside = side;
  				} //end if
  			} //end for
  		} //end for
  	} //end for
  
  gotit:
  	if (!bestside)
  		Log_Print("WARNING: side not found for portal\n");
  
  	p->sidefound = true;
  	p->side = bestside;
  } //end of the function FindPortalSide
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void MarkVisibleSides_r (node_t *node)
  {
  	portal_t *p;
  	int s;
  
  	if (node->planenum != PLANENUM_LEAF)
  	{
  		MarkVisibleSides_r (node->children[0]);
  		MarkVisibleSides_r (node->children[1]);
  		return;
  	} //end if
  
  	// empty leaves are never boundary leaves
  	if (!node->contents) return;
  
  	// see if there is a visible face
  	for (p=node->portals ; p ; p = p->next[!s])
  	{
  		s = (p->nodes[0] == node);
  		if (!p->onnode)
  			continue;		// edge of world
  		if (!p->sidefound)
  			FindPortalSide (p);
  		if (p->side)
  			p->side->flags |= SFL_VISIBLE;
  	} //end for
  } //end of the function MarkVisibleSides_r
  //===========================================================================
  //
  // Parameter:				-
  // Returns:					-
  // Changes Globals:		-
  //===========================================================================
  void MarkVisibleSides(tree_t *tree, int startbrush, int endbrush)
  {
  	int		i, j;
  	mapbrush_t	*mb;
  	int		numsides;
  
  	Log_Print("--- MarkVisibleSides ---\n");
  
  	// clear all the visible flags
  	for (i=startbrush ; i<endbrush ; i++)
  	{
  		mb = &mapbrushes[i];
  
  		numsides = mb->numsides;
  		for (j=0 ; j<numsides ; j++)
  			mb->original_sides[j].flags &= ~SFL_VISIBLE;
  	}
  
  	// set visible flags on the sides that are used by portals
  	MarkVisibleSides_r (tree->headnode);
  } //end of the function MarkVisibleSides
  
  