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

Doom 3 BFG Edition GPL Source Code
Copyright (C) 1993-2012 id Software LLC, a ZeniMax Media company.

This file is part of the Doom 3 BFG Edition GPL Source Code ("Doom 3 BFG Edition Source Code").

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

In addition, the Doom 3 BFG Edition 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 BFG Edition 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 __PUSH_H__
#define __PUSH_H__

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

  Allows physics objects to be pushed geometrically.

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

#define PUSHFL_ONLYMOVEABLE			1		// only push moveable entities
#define PUSHFL_NOGROUNDENTITIES		2		// don't push entities the clip model rests upon
#define PUSHFL_CLIP					4		// also clip against all non-moveable entities
#define PUSHFL_CRUSH				8		// kill blocking entities
#define PUSHFL_APPLYIMPULSE			16		// apply impulse to pushed entities

//#define NEW_PUSH

class idPush
{
public:
	// Try to push other entities by moving the given entity.
	// If results.fraction < 1.0 the move was blocked by results.c.entityNum
	// Returns total mass of all pushed entities.
	float			ClipTranslationalPush( trace_t& results, idEntity* pusher, const int flags,
										   const idVec3& newOrigin, const idVec3& move );
										   
	float			ClipRotationalPush( trace_t& results, idEntity* pusher, const int flags,
										const idMat3& newAxis, const idRotation& rotation );
										
	float			ClipPush( trace_t& results, idEntity* pusher, const int flags,
							  const idVec3& oldOrigin, const idMat3& oldAxis,
							  idVec3& newOrigin, idMat3& newAxis );
							  
	// initialize saving the positions of entities being pushed
	void			InitSavingPushedEntityPositions();
	// move all pushed entities back to their previous position
	void			RestorePushedEntityPositions();
	// returns the number of pushed entities
	int				GetNumPushedEntities() const
	{
		return numPushed;
	}
	// get the ith pushed entity
	idEntity* 		GetPushedEntity( int i ) const
	{
		assert( i >= 0 && i < numPushed );
		return pushed[i].ent;
	}
	
private:
	struct pushed_s
	{
		idEntity* 	ent;					// pushed entity
		idAngles	deltaViewAngles;		// actor delta view angles
	}				pushed[MAX_GENTITIES];	// pushed entities
	int				numPushed;				// number of pushed entities
	
	struct pushedGroup_s
	{
		idEntity* 	ent;
		float		fraction;
		bool		groundContact;
		bool		test;
	}				pushedGroup[MAX_GENTITIES];
	int				pushedGroupSize;
	
private:
	void			SaveEntityPosition( idEntity* ent );
	bool			RotateEntityToAxial( idEntity* ent, idVec3 rotationPoint );
#ifdef NEW_PUSH
	bool			CanPushEntity( idEntity* ent, idEntity* pusher, idEntity* initialPusher, const int flags );
	void			AddEntityToPushedGroup( idEntity* ent, float fraction, bool groundContact );
	bool			IsFullyPushed( idEntity* ent );
	bool			ClipTranslationAgainstPusher( trace_t& results, idEntity* ent, idEntity* pusher, const idVec3& translation );
	int				GetPushableEntitiesForTranslation( idEntity* pusher, idEntity* initialPusher, const int flags,
			const idVec3& translation, idEntity* entityList[], int maxEntities );
	bool			ClipRotationAgainstPusher( trace_t& results, idEntity* ent, idEntity* pusher, const idRotation& rotation );
	int				GetPushableEntitiesForRotation( idEntity* pusher, idEntity* initialPusher, const int flags,
			const idRotation& rotation, idEntity* entityList[], int maxEntities );
#else
	void			ClipEntityRotation( trace_t& trace, const idEntity* ent, const idClipModel* clipModel,
										idClipModel* skip, const idRotation& rotation );
	void			ClipEntityTranslation( trace_t& trace, const idEntity* ent, const idClipModel* clipModel,
										   idClipModel* skip, const idVec3& translation );
	int				TryTranslatePushEntity( trace_t& results, idEntity* check, idClipModel* clipModel, const int flags,
											const idVec3& newOrigin, const idVec3& move );
	int				TryRotatePushEntity( trace_t& results, idEntity* check, idClipModel* clipModel, const int flags,
										 const idMat3& newAxis, const idRotation& rotation );
	int				DiscardEntities( idEntity* entityList[], int numEntities, int flags, idEntity* pusher );
#endif
};

#endif /* !__PUSH_H__ */