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

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 __PHYSICS_BASE_H__
#define __PHYSICS_BASE_H__

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

	Physics base for a moving object using one or more collision models.

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

#define contactEntity_t		idEntityPtr<idEntity>

class idPhysics_Base : public idPhysics {

public:
	CLASS_PROTOTYPE( idPhysics_Base );

							idPhysics_Base();
							~idPhysics_Base();

	void					Save( idSaveGame *savefile ) const;
	void					Restore( idRestoreGame *savefile );

public:	// common physics interface

	void					SetSelf( idEntity *e );

	void					SetClipModel( idClipModel *model, float density, int id = 0, bool freeOld = true );
	idClipModel *			GetClipModel( int id = 0 ) const;
	int						GetNumClipModels() const;

	void					SetMass( float mass, int id = -1 );
	float					GetMass( int id = -1 ) const;

	void					SetContents( int contents, int id = -1 );
	int						GetContents( int id = -1 ) const;

	void					SetClipMask( int mask, int id = -1 );
	int						GetClipMask( int id = -1 ) const;

	const idBounds &		GetBounds( int id = -1 ) const;
	const idBounds &		GetAbsBounds( int id = -1 ) const;

	bool					Evaluate( int timeStepMSec, int endTimeMSec );
	bool					Interpolate( const float fraction );
	void					ResetInterpolationState( const idVec3 & origin, const idMat3 & axis );
	void					UpdateTime( int endTimeMSec );
	int						GetTime() const;

	void					GetImpactInfo( const int id, const idVec3 &point, impactInfo_t *info ) const;
	void					ApplyImpulse( const int id, const idVec3 &point, const idVec3 &impulse );
	void					AddForce( const int id, const idVec3 &point, const idVec3 &force );
	void					Activate();
	void					PutToRest();
	bool					IsAtRest() const;
	int						GetRestStartTime() const;
	bool					IsPushable() const;

	void					SaveState();
	void					RestoreState();

	void					SetOrigin( const idVec3 &newOrigin, int id = -1 );
	void					SetAxis( const idMat3 &newAxis, int id = -1 );

	void					Translate( const idVec3 &translation, int id = -1 );
	void					Rotate( const idRotation &rotation, int id = -1 );

	const idVec3 &			GetOrigin( int id = 0 ) const;
	const idMat3 &			GetAxis( int id = 0 ) const;

	void					SetLinearVelocity( const idVec3 &newLinearVelocity, int id = 0 );
	void					SetAngularVelocity( const idVec3 &newAngularVelocity, int id = 0 );

	const idVec3 &			GetLinearVelocity( int id = 0 ) const;
	const idVec3 &			GetAngularVelocity( int id = 0 ) const;

	void					SetGravity( const idVec3 &newGravity );
	const idVec3 &			GetGravity() const;
	const idVec3 &			GetGravityNormal() const;

	void					ClipTranslation( trace_t &results, const idVec3 &translation, const idClipModel *model ) const;
	void					ClipRotation( trace_t &results, const idRotation &rotation, const idClipModel *model ) const;
	int						ClipContents( const idClipModel *model ) const;

	void					DisableClip();
	void					EnableClip();

	void					UnlinkClip();
	void					LinkClip();

	bool					EvaluateContacts();
	int						GetNumContacts() const;
	const contactInfo_t &	GetContact( int num ) const;
	void					ClearContacts();
	void					AddContactEntity( idEntity *e );
	void					RemoveContactEntity( idEntity *e );

	bool					HasGroundContacts() const;
	bool					IsGroundEntity( int entityNum ) const;
	bool					IsGroundClipModel( int entityNum, int id ) const;

	void					SetPushed( int deltaTime );
	const idVec3 &			GetPushedLinearVelocity( const int id = 0 ) const;
	const idVec3 &			GetPushedAngularVelocity( const int id = 0 ) const;

	void					SetMaster( idEntity *master, const bool orientated = true );

	const trace_t *			GetBlockingInfo() const;
	idEntity *				GetBlockingEntity() const;

	int						GetLinearEndTime() const;
	int						GetAngularEndTime() const;

	void					WriteToSnapshot( idBitMsg &msg ) const;
	void					ReadFromSnapshot( const idBitMsg &msg );

protected:
	idEntity *				self;					// entity using this physics object
	int						clipMask;				// contents the physics object collides with
	idVec3					gravityVector;			// direction and magnitude of gravity
	idVec3					gravityNormal;			// normalized direction of gravity
	idList<contactInfo_t, TAG_IDLIB_LIST_PHYSICS>	contacts;				// contacts with other physics objects
	idList<contactEntity_t, TAG_IDLIB_LIST_PHYSICS>	contactEntities;		// entities touching this physics object

protected:
							// add ground contacts for the clip model
	void					AddGroundContacts( const idClipModel *clipModel );
							// add contact entity links to contact entities
	void					AddContactEntitiesForContacts();
							// active all contact entities
	void					ActivateContactEntities();
							// returns true if the whole physics object is outside the world bounds
	bool					IsOutsideWorld() const;
							// draw linear and angular velocity
	void					DrawVelocity( int id, float linearScale, float angularScale ) const;
};

/*
===============================================================================
Physics interpolation state
===============================================================================
*/
struct physicsInterpolationState_t {
	physicsInterpolationState_t():
		origin( 0.0f, 0.0f, 0.0f ),
		axis( 0.0f, 0.0f, 0.0f, 1.0f ) {
	}

	idVec3			origin;
	idQuat			axis;
};

/*
================
Sets the origin and axis members of stateToUpdate based on previous, next, and the fraction.
Return true if the origin or axis changed, false if they haven't.
================
*/
template< class _stateType_ >
bool InterpolatePhysicsState( _stateType_ & stateToUpdate,
							  const physicsInterpolationState_t & previous,
							  const physicsInterpolationState_t & next,
							  const float fraction ) {
	const idVec3 oldOrigin = stateToUpdate.origin;
	const idMat3 oldAxis = stateToUpdate.axis;

	stateToUpdate.origin = Lerp( previous.origin, next.origin, fraction );

	const idQuat currentQuat = Slerp( previous.axis, next.axis, fraction );
	stateToUpdate.axis = currentQuat.ToMat3();

	return ( stateToUpdate.origin != oldOrigin || stateToUpdate.axis != oldAxis );
}

#endif /* !__PHYSICS_BASE_H__ */
