/*
===========================================================================

Return to Castle Wolfenstein single player GPL Source Code
Copyright (C) 1999-2010 id Software LLC, a ZeniMax Media company. 

This file is part of the Return to Castle Wolfenstein single player GPL Source Code (RTCW SP Source Code).  

RTCW SP 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 3 of the License, or
(at your option) any later version.

RTCW SP 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 RTCW SP Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the RTCW SP Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the RTCW SP Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

===========================================================================
*/

//===========================================================================
//
// Name:				aas_areamerging.c
// Function:		Merging of Areas
// Programmer:		Mr Elusive (MrElusive@demigod.demon.nl)
// Last update:	1997-12-04
// Tab Size:		3
//===========================================================================

#include "qbsp.h"
#include "../botlib/aasfile.h"
#include "aas_create.h"
#include "aas_store.h"

#define CONVEX_EPSILON      0.3

//===========================================================================
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
tmp_node_t *AAS_RefreshMergedTree_r( tmp_node_t *tmpnode ) {
	tmp_area_t *tmparea;

	//if this is a solid leaf
	if ( !tmpnode ) {
		return NULL;
	}
	//if this is an area leaf
	if ( tmpnode->tmparea ) {
		tmparea = tmpnode->tmparea;
		while ( tmparea->mergedarea ) tmparea = tmparea->mergedarea;
		tmpnode->tmparea = tmparea;
		return tmpnode;
	} //end if
	  //do the children recursively
	tmpnode->children[0] = AAS_RefreshMergedTree_r( tmpnode->children[0] );
	tmpnode->children[1] = AAS_RefreshMergedTree_r( tmpnode->children[1] );
	return tmpnode;
} //end of the function AAS_RefreshMergedTree_r
//===========================================================================
// returns true if the two given faces would create a non-convex area at
// the given sides, otherwise false is returned
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
int NonConvex( tmp_face_t *face1, tmp_face_t *face2, int side1, int side2 ) {
	int i;
	winding_t *w1, *w2;
	plane_t *plane1, *plane2;

	w1 = face1->winding;
	w2 = face2->winding;

	plane1 = &mapplanes[face1->planenum ^ side1];
	plane2 = &mapplanes[face2->planenum ^ side2];

	//check if one of the points of face1 is at the back of the plane of face2
	for ( i = 0; i < w1->numpoints; i++ )
	{
		if ( DotProduct( plane2->normal, w1->p[i] ) - plane2->dist < -CONVEX_EPSILON ) {
			return true;
		}
	} //end for
	  //check if one of the points of face2 is at the back of the plane of face1
	for ( i = 0; i < w2->numpoints; i++ )
	{
		if ( DotProduct( plane1->normal, w2->p[i] ) - plane1->dist < -CONVEX_EPSILON ) {
			return true;
		}
	} //end for

	return false;
} //end of the function NonConvex
//===========================================================================
// try to merge the areas at both sides of the given face
//
// Parameter:				seperatingface		: face that seperates two areas
// Returns:					-
// Changes Globals:		-
//===========================================================================
int AAS_TryMergeFaceAreas( tmp_face_t *seperatingface ) {
	int side1, side2, area1faceflags, area2faceflags;
	tmp_area_t *tmparea1, *tmparea2, *newarea;
	tmp_face_t *face1, *face2, *nextface1, *nextface2;

	tmparea1 = seperatingface->frontarea;
	tmparea2 = seperatingface->backarea;

	//areas must have the same presence type
	if ( tmparea1->presencetype != tmparea2->presencetype ) {
		return false;
	}
	//areas must have the same area contents
	if ( tmparea1->contents != tmparea2->contents ) {
		return false;
	}
	//areas must have the same bsp model inside (or both none)
	if ( tmparea1->modelnum != tmparea2->modelnum ) {
		return false;
	}

	area1faceflags = 0;
	area2faceflags = 0;
	for ( face1 = tmparea1->tmpfaces; face1; face1 = face1->next[side1] )
	{
		side1 = ( face1->frontarea != tmparea1 );
		//debug: check if the area belongs to the area
		if ( face1->frontarea != tmparea1 &&
			 face1->backarea != tmparea1 ) {
			Error( "face does not belong to area1" );
		}
		//just continue if the face is seperating the two areas
		//NOTE: a result of this is that ground and gap areas can
		//      be merged if the seperating face is the gap
		if ( ( face1->frontarea == tmparea1 &&
			   face1->backarea == tmparea2 ) ||
			 ( face1->frontarea == tmparea2 &&
			   face1->backarea == tmparea1 ) ) {
			continue;
		}
		//get area1 face flags
		area1faceflags |= face1->faceflags;
		if ( AAS_GapFace( face1, side1 ) ) {
			area1faceflags |= FACE_GAP;
		}
		//
		for ( face2 = tmparea2->tmpfaces; face2; face2 = face2->next[side2] )
		{
			side2 = ( face2->frontarea != tmparea2 );
			//debug: check if the area belongs to the area
			if ( face2->frontarea != tmparea2 &&
				 face2->backarea != tmparea2 ) {
				Error( "face does not belong to area2" );
			}
			//just continue if the face is seperating the two areas
			//NOTE: a result of this is that ground and gap areas can
			//      be merged if the seperating face is the gap
			if ( ( face2->frontarea == tmparea1 &&
				   face2->backarea == tmparea2 ) ||
				 ( face2->frontarea == tmparea2 &&
				   face2->backarea == tmparea1 ) ) {
				continue;
			}
			//get area2 face flags
			area2faceflags |= face2->faceflags;
			if ( AAS_GapFace( face2, side2 ) ) {
				area2faceflags |= FACE_GAP;
			}
			//if the two faces would create a non-convex area
			if ( NonConvex( face1, face2, side1, side2 ) ) {
				return false;
			}
		} //end for
	} //end for
	  //if one area has gap faces (that aren't seperating the two areas)
	  //and the other has ground faces (that aren't seperating the two areas),
	  //the areas can't be merged
	if ( ( ( area1faceflags & FACE_GROUND ) && ( area2faceflags & FACE_GAP ) ) ||
		 ( ( area2faceflags & FACE_GROUND ) && ( area1faceflags & FACE_GAP ) ) ) {
//		Log_Print("   can't merge: ground/gap\n");
		return false;
	} //end if

//	Log_Print("merged area %d & %d to %d with %d faces\n", tmparea1->areanum, tmparea2->areanum, newarea->areanum, numfaces);
//	return false;
	//
	//AAS_CheckArea(tmparea1);
	//AAS_CheckArea(tmparea2);
	//create the new area
	newarea = AAS_AllocTmpArea();
	newarea->presencetype = tmparea1->presencetype;
	newarea->contents = tmparea1->contents;
	newarea->modelnum = tmparea1->modelnum;
	newarea->tmpfaces = NULL;

	//add all the faces (except the seperating ones) from the first area
	//to the new area
	for ( face1 = tmparea1->tmpfaces; face1; face1 = nextface1 )
	{
		side1 = ( face1->frontarea != tmparea1 );
		nextface1 = face1->next[side1];
		//don't add seperating faces
		if ( ( face1->frontarea == tmparea1 &&
			   face1->backarea == tmparea2 ) ||
			 ( face1->frontarea == tmparea2 &&
			   face1->backarea == tmparea1 ) ) {
			continue;
		} //end if
		  //
		AAS_RemoveFaceFromArea( face1, tmparea1 );
		AAS_AddFaceSideToArea( face1, side1, newarea );
	} //end for
	  //add all the faces (except the seperating ones) from the second area
	  //to the new area
	for ( face2 = tmparea2->tmpfaces; face2; face2 = nextface2 )
	{
		side2 = ( face2->frontarea != tmparea2 );
		nextface2 = face2->next[side2];
		//don't add seperating faces
		if ( ( face2->frontarea == tmparea1 &&
			   face2->backarea == tmparea2 ) ||
			 ( face2->frontarea == tmparea2 &&
			   face2->backarea == tmparea1 ) ) {
			continue;
		} //end if
		  //
		AAS_RemoveFaceFromArea( face2, tmparea2 );
		AAS_AddFaceSideToArea( face2, side2, newarea );
	} //end for
	  //free all shared faces
	for ( face1 = tmparea1->tmpfaces; face1; face1 = nextface1 )
	{
		side1 = ( face1->frontarea != tmparea1 );
		nextface1 = face1->next[side1];
		//
		AAS_RemoveFaceFromArea( face1, face1->frontarea );
		AAS_RemoveFaceFromArea( face1, face1->backarea );
		AAS_FreeTmpFace( face1 );
	} //end for
	  //
	tmparea1->mergedarea = newarea;
	tmparea1->invalid = true;
	tmparea2->mergedarea = newarea;
	tmparea2->invalid = true;
	//
	AAS_CheckArea( newarea );
	AAS_FlipAreaFaces( newarea );
//	Log_Print("merged area %d & %d to %d with %d faces\n", tmparea1->areanum, tmparea2->areanum, newarea->areanum);
	return true;
} //end of the function AAS_TryMergeFaceAreas
//===========================================================================
// try to merge areas
// merged areas are added to the end of the convex area list so merging
// will be tried for those areas as well
//
// Parameter:				-
// Returns:					-
// Changes Globals:		tmpaasworld
//===========================================================================
/*
void AAS_MergeAreas(void)
{
	int side, nummerges;
	tmp_area_t *tmparea, *othertmparea;
	tmp_face_t *face;

	nummerges = 0;
	Log_Write("AAS_MergeAreas\r\n");
	qprintf("%6d areas merged", 1);
	//first merge grounded areas only
	//NOTE: this is useless because the area settings aren't available yet
	for (tmparea = tmpaasworld.areas; tmparea; tmparea = tmparea->l_next)
	{
//		Log_Print("checking area %d\n", i);
		//if the area is invalid
		if (tmparea->invalid)
		{
//			Log_Print("   area invalid\n");
			continue;
		} //end if
		//
//		if (!(tmparea->settings->areaflags & AREA_GROUNDED)) continue;
		//
		for (face = tmparea->tmpfaces; face; face = face->next[side])
		{
			side = (face->frontarea != tmparea);
			//if the face has both a front and back area
			if (face->frontarea && face->backarea)
			{
				//
				if (face->frontarea == tmparea) othertmparea = face->backarea;
				else othertmparea = face->frontarea;
//				if (!(othertmparea->settings->areaflags & AREA_GROUNDED)) continue;
//				Log_Print("  checking area %d with %d\n", face->frontarea, face->backarea);
				if (AAS_TryMergeFaceAreas(face))
				{
					qprintf("\r%6d", ++nummerges);
					break;
				} //end if
			} //end if
		} //end for
	} //end for
	//merge all areas
	for (tmparea = tmpaasworld.areas; tmparea; tmparea = tmparea->l_next)
	{
//		Log_Print("checking area %d\n", i);
		//if the area is invalid
		if (tmparea->invalid)
		{
//			Log_Print("   area invalid\n");
			continue;
		} //end if
		//
		for (face = tmparea->tmpfaces; face; face = face->next[side])
		{
			side = (face->frontarea != tmparea);
			//if the face has both a front and back area
			if (face->frontarea && face->backarea)
			{
//				Log_Print("  checking area %d with %d\n", face->frontarea, face->backarea);
				if (AAS_TryMergeFaceAreas(face))
				{
					qprintf("\r%6d", ++nummerges);
					break;
				} //end if
			} //end if
		} //end for
	} //end for
	Log_Print("\r%6d areas merged\n", nummerges);
	//refresh the merged tree
	AAS_RefreshMergedTree_r(tmpaasworld.nodes);
} //end of the function AAS_MergeAreas*/

int AAS_GroundArea( tmp_area_t *tmparea ) {
	tmp_face_t *face;
	int side;

	for ( face = tmparea->tmpfaces; face; face = face->next[side] )
	{
		side = ( face->frontarea != tmparea );
		if ( face->faceflags & FACE_GROUND ) {
			return true;
		}
	} //end for
	return false;
} //end of the function AAS_GroundArea

void AAS_MergeAreas( void ) {
	int side, nummerges, merges, groundfirst;
	tmp_area_t *tmparea, *othertmparea;
	tmp_face_t *face;

	nummerges = 0;
	Log_Write( "AAS_MergeAreas\r\n" );
	qprintf( "%6d areas merged", 1 );
	//
	groundfirst = true;
	//for (i = 0; i < 4 || merges; i++)
	while ( 1 )
	{
		//if (i < 2) groundfirst = true;
		//else groundfirst = false;
		//
		merges = 0;
		//first merge grounded areas only
		for ( tmparea = tmpaasworld.areas; tmparea; tmparea = tmparea->l_next )
		{
			//if the area is invalid
			if ( tmparea->invalid ) {
				continue;
			} //end if
			  //
			if ( groundfirst ) {
				if ( !AAS_GroundArea( tmparea ) ) {
					continue;
				}
			} //end if
			  //
			for ( face = tmparea->tmpfaces; face; face = face->next[side] )
			{
				side = ( face->frontarea != tmparea );
				//if the face has both a front and back area
				if ( face->frontarea && face->backarea ) {
					//
					if ( face->frontarea == tmparea ) {
						othertmparea = face->backarea;
					} else { othertmparea = face->frontarea;}
					//
					if ( groundfirst ) {
						if ( !AAS_GroundArea( othertmparea ) ) {
							continue;
						}
					} //end if
					if ( AAS_TryMergeFaceAreas( face ) ) {
						qprintf( "\r%6d", ++nummerges );
						merges++;
						break;
					} //end if
				} //end if
			} //end for
		} //end for
		if ( !merges ) {
			if ( groundfirst ) {
				groundfirst = false;
			} else { break;}
		} //end if
	} //end for
	qprintf( "\n" );
	Log_Write( "%6d areas merged\r\n", nummerges );
	//refresh the merged tree
	AAS_RefreshMergedTree_r( tmpaasworld.nodes );
} //end of the function AAS_MergeAreas
