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

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_facemerging.c
// Function:		Merging of Faces
// 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"

//===========================================================================
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
int AAS_TryMergeFaces( tmp_face_t *face1, tmp_face_t *face2 ) {
	winding_t *neww;

#ifdef DEBUG
	if ( !face1->winding ) {
		Error( "face1 %d without winding", face1->num );
	}
	if ( !face2->winding ) {
		Error( "face2 %d without winding", face2->num );
	}
#endif //DEBUG
	   //
	if ( face1->faceflags != face2->faceflags ) {
		return false;
	}
	//NOTE: if the front or back area is zero this doesn't mean there's
	//a real area. It means there's solid at that side of the face
	//if both faces have the same front area
	if ( face1->frontarea == face2->frontarea ) {
		//if both faces have the same back area
		if ( face1->backarea == face2->backarea ) {
			//if the faces are in the same plane
			if ( face1->planenum == face2->planenum ) {
				//if they have both a front and a back area (no solid on either side)
				if ( face1->frontarea && face1->backarea ) {
					neww = MergeWindings( face1->winding, face2->winding,
										  mapplanes[face1->planenum].normal );
				} //end if
				else
				{
					//this function is to be found in l_poly.c
					neww = TryMergeWinding( face1->winding, face2->winding,
											mapplanes[face1->planenum].normal );
				} //end else
				if ( neww ) {
					FreeWinding( face1->winding );
					face1->winding = neww;
					if ( face2->frontarea ) {
						AAS_RemoveFaceFromArea( face2, face2->frontarea );
					}
					if ( face2->backarea ) {
						AAS_RemoveFaceFromArea( face2, face2->backarea );
					}
					AAS_FreeTmpFace( face2 );
					return true;
				} //end if
			} //end if
			else if ( ( face1->planenum & ~1 ) == ( face2->planenum & ~1 ) ) {
				Log_Write( "face %d and %d, same front and back area but flipped planes\r\n",
						   face1->num, face2->num );
			} //end if
		} //end if
	} //end if
	return false;
} //end of the function AAS_TryMergeFaces
/*
int AAS_TryMergeFaces(tmp_face_t *face1, tmp_face_t *face2)
{
	winding_t *neww;

#ifdef DEBUG
	if (!face1->winding) Error("face1 %d without winding", face1->num);
	if (!face2->winding) Error("face2 %d without winding", face2->num);
#endif //DEBUG
	//if the faces are in the same plane
	if ((face1->planenum & ~1) != (face2->planenum & ~1)) return false;
//	if (face1->planenum != face2->planenum) return false;
	//NOTE: if the front or back area is zero this doesn't mean there's
	//a real area. It means there's solid at that side of the face
	//if both faces have the same front area
	if (face1->frontarea != face2->frontarea ||
		face1->backarea != face2->backarea)
	{
		if (!face1->frontarea || !face1->backarea ||
				!face2->frontarea || !face2->backarea) return false;
		else if (face1->frontarea != face2->backarea ||
					face1->backarea != face2->frontarea) return false;
//		return false;
	} //end if
	//this function is to be found in l_poly.c
	neww = TryMergeWinding(face1->winding, face2->winding,
					mapplanes[face1->planenum].normal);
	if (!neww) return false;
	//
	FreeWinding(face1->winding);
	face1->winding = neww;
	//remove face2
	if (face2->frontarea)
		AAS_RemoveFaceFromArea(face2, &tmpaasworld.areas[face2->frontarea]);
	if (face2->backarea)
		AAS_RemoveFaceFromArea(face2, &tmpaasworld.areas[face2->backarea]);
	return true;
} //end of the function AAS_TryMergeFaces*/
//===========================================================================
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
void AAS_MergeAreaFaces( void ) {
	int num_facemerges = 0;
	int side1, side2, restart;
	tmp_area_t *tmparea, *lasttmparea;
	tmp_face_t *face1, *face2;

	Log_Write( "AAS_MergeAreaFaces\r\n" );
	qprintf( "%6d face merges", num_facemerges );
	//NOTE: first convex area is a dummy
	lasttmparea = tmpaasworld.areas;
	for ( tmparea = tmpaasworld.areas; tmparea; tmparea = tmparea->l_next )
	{
		restart = false;
		//
		if ( tmparea->invalid ) {
			continue;
		}
		//
		for ( face1 = tmparea->tmpfaces; face1; face1 = face1->next[side1] )
		{
			side1 = face1->frontarea != tmparea;
			for ( face2 = face1->next[side1]; face2; face2 = face2->next[side2] )
			{
				side2 = face2->frontarea != tmparea;
				//if succesfully merged
				if ( AAS_TryMergeFaces( face1, face2 ) ) {
					//start over again after merging two faces
					restart = true;
					num_facemerges++;
					qprintf( "\r%6d", num_facemerges );
					AAS_CheckArea( tmparea );
					break;
				} //end if
			} //end for
			if ( restart ) {
				tmparea = lasttmparea;
				break;
			} //end if
		} //end for
		lasttmparea = tmparea;
	} //end for
	qprintf( "\n" );
	Log_Write( "%6d face merges\r\n", num_facemerges );
} //end of the function AAS_MergeAreaFaces
//===========================================================================
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
void AAS_MergePlaneFaces( tmp_area_t *tmparea, int planenum ) {
	tmp_face_t *face1, *face2, *nextface2;
	winding_t *neww;
	int side1, side2;

	for ( face1 = tmparea->tmpfaces; face1; face1 = face1->next[side1] )
	{
		side1 = face1->frontarea != tmparea;
		if ( face1->planenum != planenum ) {
			continue;
		}
		//
		for ( face2 = face1->next[side1]; face2; face2 = nextface2 )
		{
			side2 = face2->frontarea != tmparea;
			nextface2 = face2->next[side2];
			//
			if ( ( face2->planenum & ~1 ) != ( planenum & ~1 ) ) {
				continue;
			}
			//
			neww = MergeWindings( face1->winding, face2->winding,
								  mapplanes[face1->planenum].normal );
			FreeWinding( face1->winding );
			face1->winding = neww;
			if ( face2->frontarea ) {
				AAS_RemoveFaceFromArea( face2, face2->frontarea );
			}
			if ( face2->backarea ) {
				AAS_RemoveFaceFromArea( face2, face2->backarea );
			}
			AAS_FreeTmpFace( face2 );
			//
			nextface2 = face1->next[side1];
		} //end for
	} //end for
} //end of the function AAS_MergePlaneFaces
//===========================================================================
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
int AAS_CanMergePlaneFaces( tmp_area_t *tmparea, int planenum ) {
	tmp_area_t *frontarea, *backarea;
	tmp_face_t *face1;
	int side1, merge, faceflags = 0; // TTimo: init

	frontarea = backarea = NULL;
	merge = false;
	for ( face1 = tmparea->tmpfaces; face1; face1 = face1->next[side1] )
	{
		side1 = face1->frontarea != tmparea;
		if ( ( face1->planenum & ~1 ) != ( planenum & ~1 ) ) {
			continue;
		}
		if ( !frontarea && !backarea ) {
			frontarea = face1->frontarea;
			backarea = face1->backarea;
			faceflags = face1->faceflags;
		} //end if
		else
		{
			if ( frontarea != face1->frontarea ) {
				return false;
			}
			if ( backarea != face1->backarea ) {
				return false;
			}
			if ( faceflags != face1->faceflags ) {
				return false;
			}
			merge = true;
		} //end else
	} //end for
	return merge;
} //end of the function AAS_CanMergePlaneFaces
//===========================================================================
//
// Parameter:				-
// Returns:					-
// Changes Globals:		-
//===========================================================================
void AAS_MergeAreaPlaneFaces( void ) {
	int num_facemerges = 0;
	int side1;
	tmp_area_t *tmparea, *nexttmparea;
	tmp_face_t *face1;

	Log_Write( "AAS_MergePlaneFaces\r\n" );
	qprintf( "%6d plane face merges", num_facemerges );
	//NOTE: first convex area is a dummy
	for ( tmparea = tmpaasworld.areas; tmparea; tmparea = nexttmparea )
	{
		nexttmparea = tmparea->l_next;
		//
		if ( tmparea->invalid ) {
			continue;
		}
		//
		for ( face1 = tmparea->tmpfaces; face1; face1 = face1->next[side1] )
		{
			side1 = face1->frontarea != tmparea;
			//
			if ( AAS_CanMergePlaneFaces( tmparea, face1->planenum ) ) {
				AAS_MergePlaneFaces( tmparea, face1->planenum );
				nexttmparea = tmparea;
				num_facemerges++;
				qprintf( "\r%6d", num_facemerges );
				break;
			} //end if
		} //end for
	} //end for
	qprintf( "\n" );
	Log_Write( "%6d plane face merges\r\n", num_facemerges );
} //end of the function AAS_MergeAreaPlaneFaces