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

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.

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

#ifndef __GAME_PVS_H__
#define __GAME_PVS_H__

#include "idlib/geometry/Winding.h"
#include "idlib/math/Vector.h"
#include "idlib/bv/Bounds.h"

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

	PVS

	Note: mirrors and other special view portals are not taken into account

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


typedef struct pvsHandle_s {
	int					i;			// index to current pvs
	unsigned int		h;			// handle for current pvs
} pvsHandle_t;


typedef struct pvsCurrent_s {
	pvsHandle_t			handle;		// current pvs handle
	byte *				pvs;		// current pvs bit string
} pvsCurrent_t;

#define MAX_CURRENT_PVS		8		// must be a power of 2

typedef enum {
	PVS_NORMAL				= 0,	// PVS through portals taking portal states into account
	PVS_ALL_PORTALS_OPEN	= 1,	// PVS through portals assuming all portals are open
	PVS_CONNECTED_AREAS		= 2		// PVS considering all topologically connected areas visible
} pvsType_t;


class idPVS {
public:
						idPVS( void );
						~idPVS( void );
						// setup for the current map
	void				Init( void );
	void				Shutdown( void );
						// get the area(s) the source is in
	int					GetPVSArea( const idVec3 &point ) const;		// returns the area number
	int					GetPVSAreas( const idBounds &bounds, int *areas, int maxAreas ) const;	// returns number of areas
						// setup current PVS for the source
	pvsHandle_t			SetupCurrentPVS( const idVec3 &source, const pvsType_t type = PVS_NORMAL ) const;
	pvsHandle_t			SetupCurrentPVS( const idBounds &source, const pvsType_t type = PVS_NORMAL ) const;
	pvsHandle_t			SetupCurrentPVS( const int sourceArea, const pvsType_t type = PVS_NORMAL ) const;
	pvsHandle_t			SetupCurrentPVS( const int *sourceAreas, const int numSourceAreas, const pvsType_t type = PVS_NORMAL ) const;
	pvsHandle_t			MergeCurrentPVS( pvsHandle_t pvs1, pvsHandle_t pvs2 ) const;
	void				FreeCurrentPVS( pvsHandle_t handle ) const;
						// returns true if the target is within the current PVS
	bool				InCurrentPVS( const pvsHandle_t handle, const idVec3 &target ) const;
	bool				InCurrentPVS( const pvsHandle_t handle, const idBounds &target ) const;
	bool				InCurrentPVS( const pvsHandle_t handle, const int targetArea ) const;
	bool				InCurrentPVS( const pvsHandle_t handle, const int *targetAreas, int numTargetAreas ) const;
						// draw all portals that are within the PVS of the source
	void				DrawPVS( const idVec3 &source, const pvsType_t type = PVS_NORMAL ) const;
	void				DrawPVS( const idBounds &source, const pvsType_t type = PVS_NORMAL ) const;
						// visualize the PVS the handle points to
	void				DrawCurrentPVS( const pvsHandle_t handle, const idVec3 &source ) const;

#if ASYNC_WRITE_PVS
	void				WritePVS( const pvsHandle_t handle, idBitMsg &msg );
	void				ReadPVS( const pvsHandle_t handle, const idBitMsg &msg );
#endif

private:
	int					numAreas;
	int					numPortals;
	bool *				connectedAreas;
	int *				areaQueue;
	byte *				areaPVS;
						// current PVS for a specific source possibly taking portal states (open/closed) into account
	mutable pvsCurrent_t currentPVS[MAX_CURRENT_PVS];
						// used to create PVS
	int					portalVisBytes;
	int					portalVisInts;
	int					areaVisBytes;
	int					areaVisInts;
	struct pvsPortal_s *pvsPortals;
	struct pvsArea_s *	pvsAreas;

private:
	int					GetPortalCount( void ) const;
	void				CreatePVSData( void );
	void				DestroyPVSData( void );
	void				CopyPortalPVSToMightSee( void ) const;
	void				FloodFrontPortalPVS_r( struct pvsPortal_s *portal, int areaNum ) const;
	void				FrontPortalPVS( void ) const;
	struct pvsStack_s *	FloodPassagePVS_r( struct pvsPortal_s *source, const struct pvsPortal_s *portal, struct pvsStack_s *prevStack ) const;
	void				PassagePVS( void ) const;
	void				AddPassageBoundaries( const idWinding &source, const idWinding &pass, bool flipClip, idPlane *bounds, int &numBounds, int maxBounds ) const;
	void				CreatePassages( void ) const;
	void				DestroyPassages( void ) const;
	int					AreaPVSFromPortalPVS( void ) const;
	void				GetConnectedAreas( int srcArea, bool *connectedAreas ) const;
	pvsHandle_t			AllocCurrentPVS( unsigned int h ) const;
};

#endif /* !__GAME_PVS_H__ */
