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

Doom 3 GPL Source Code
Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company. 

This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).  

Doom 3 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.

Doom 3 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 Doom 3 Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the Doom 3 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 Doom 3 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.

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

#include "../../../idlib/precompiled.h"
#pragma hdrstop

#include "AASBuild_local.h"

/*
============
idAASBuild::AllGapsLeadToOtherNode
============
*/
bool idAASBuild::AllGapsLeadToOtherNode( idBrushBSPNode *nodeWithGaps, idBrushBSPNode *otherNode ) {
	int s;
	idBrushBSPPortal *p;

	for ( p = nodeWithGaps->GetPortals(); p; p = p->Next(s) ) {
		s = (p->GetNode(1) == nodeWithGaps);

		if ( !PortalIsGap( p, s ) ) {
			continue;
		}

		if ( p->GetNode(!s) != otherNode ) {
			return false;
		}
	}
	return true;
}

/*
============
idAASBuild::MergeWithAdjacentLeafNodes
============
*/
bool idAASBuild::MergeWithAdjacentLeafNodes( idBrushBSP &bsp, idBrushBSPNode *node ) {
	int s, numMerges = 0, otherNodeFlags;
	idBrushBSPPortal *p;

	do {
		for ( p = node->GetPortals(); p; p = p->Next(s) ) {
			s = (p->GetNode(1) == node);

			// both leaf nodes must have the same contents
			if ( node->GetContents() != p->GetNode(!s)->GetContents() ) {
				continue;
			}

			// cannot merge leaf nodes if one is near a ledge and the other is not
			if ( (node->GetFlags() & AREA_LEDGE) != (p->GetNode(!s)->GetFlags() & AREA_LEDGE) ) {
				continue;
			}

			// cannot merge leaf nodes if one has a floor portal and the other a gap portal
			if ( node->GetFlags() & AREA_FLOOR ) {
				if ( p->GetNode(!s)->GetFlags() & AREA_GAP ) {
					if ( !AllGapsLeadToOtherNode( p->GetNode(!s), node ) ) {
						continue;
					}
				}
			}
			else if ( node->GetFlags() & AREA_GAP ) {
				if ( p->GetNode(!s)->GetFlags() & AREA_FLOOR ) {
					if ( !AllGapsLeadToOtherNode( node, p->GetNode(!s) ) ) {
						continue;
					}
				}
			}

			otherNodeFlags = p->GetNode(!s)->GetFlags();

			// try to merge the leaf nodes
			if ( bsp.TryMergeLeafNodes( p, s ) ) {
				node->SetFlag( otherNodeFlags );
				if ( node->GetFlags() & AREA_FLOOR ) {
					node->RemoveFlag( AREA_GAP );
				}
				numMerges++;
				DisplayRealTimeString( "\r%6d", ++numMergedLeafNodes );
				break;
			}
		}
	} while( p );

	if ( numMerges ) {
		return true;
	}
	return false;
}

/*
============
idAASBuild::MergeLeafNodes_r
============
*/
void idAASBuild::MergeLeafNodes_r( idBrushBSP &bsp, idBrushBSPNode *node ) {

	if ( !node ) {
		return;
	}

	if ( node->GetContents() & AREACONTENTS_SOLID ) {
		return;
	}

	if ( node->GetFlags() & NODE_DONE ) {
		return;
	}

	if ( !node->GetChild(0) && !node->GetChild(1) ) {
		MergeWithAdjacentLeafNodes( bsp, node );
		node->SetFlag( NODE_DONE );
		return;
	}

	MergeLeafNodes_r( bsp, node->GetChild(0) );
	MergeLeafNodes_r( bsp, node->GetChild(1) );

	return;
}

/*
============
idAASBuild::MergeLeafNodes
============
*/
void idAASBuild::MergeLeafNodes( idBrushBSP &bsp ) {
	numMergedLeafNodes = 0;

	common->Printf( "[Merge Leaf Nodes]\n" );

	MergeLeafNodes_r( bsp, bsp.GetRootNode() );
	bsp.GetRootNode()->RemoveFlagRecurse( NODE_DONE );
	bsp.PruneMergedTree_r( bsp.GetRootNode() );

	common->Printf( "\r%6d leaf nodes merged\n", numMergedLeafNodes );
}
