/*! 
    \file IPhys.h
    \brief Interface to physics engine
*/

#ifndef IPHYS_H
#define IPHYS_H

#include "stdincl.h"

//! Avaiable types of behaviour for a physical object. Mainly determines which
//! attributes are used and what calculations are done.
enum IPHYS_BEHAVIOUR {
	//	Bodies
 	B_MASS_POINT,			//!< Body: No orientation, just a inf. small mass
 	B_RIGID_BODY,			//!< Body: Rigid Body, lossless bumping
 	B_ELAST_BODY,			//!< Body: Rigid, lossy bumping
 	//	Interactions
  	I_SPRING_LINEAR,		//!< Interaction: Linear, ideal spring
  	I_DMPSPR_LINEAR,		//!< Interaction: Linear, damped spring
	I_SPRING_MOMENTUM, 		//!< Interaction: Momentum spring, ideal
	I_DMPSPR_MOMENTUM,		//!< Interaction: Momentum spring, damped
	//  Fields
	F_GRAVITY,				//!< Field: Gravity field in some direction
	F_HOVER,				//!< Field: Something like antigravity (hover drive)
	F_SHOCKWAVE,			//!< Field: Cylindrical Shockwave
	F_BEAM					//!< Field: Electromagnetic beam (exerts pressure on intersecting objects)
};

class IPhys
{
  public:
	IPhys ();
	~IPhys ();
		
	// Simulation
	void simIterate(Uint32 deltaT);
	
	// Exertion of external forces
	void exertForce( Vector force );
	void exertMomentum( Vector Momentum );

	// set attributes	
	void setBehaviour( IPHYS_BEHAVIOUR desiredBehaviour );
	void setBody( float mass );
	void setBody( float mass, float inertMoment[] );
	void setBody( float mass, float inertMoment[], float YoungsModulus );
	
	void setMounts( WorldEntity *point1, WorldEntity *point2 );
	void setSpring( float neutralLength, float springConst );
	void setSpring( float neutralLength, float springConst, float damping );
	void setSpring( Quaternion neutralOrientation, float springConst );
	void setSpring( Quaternion neutralOrientation, float springConst, float damping );

	//void setInfluence
	//void setGravity
	
	// get attributes	
	Placement getPlacement() ;
	float getMass();
	float* getInertMoment();

		
  private:
	IPHYS_BEHAVIOUR behav;		//!< Behaviour
	Vector pos;					//!< Position
	Quaternion ori;				//!< Orientation
	
	Vector vel;					//!< Velocity
	Quaternion rot;				//!< Rotation
	
	Vector resForce;			//!< Resulting force
	Vector resMomentum;			//!< Resulting Momentum
	
	// Attributes for bodies
    float m;					//!< Mass
    float inertM[3,3];			//!< Inertial Moment Matrix
    float YE;					//!< Youngs Modulus E (Elasticity)
    
    // Attributes for interactions
    WorldEntity* mounts[2];		//!< Mounts; meaning depends on obj. behaviour
    float spNeutralL;			//!< Spring neutral length
    float spConst;				//!< Spring constant k
    float dmp;					//!< Damping  	
    Quaternion mspNeutralOri;	//!< Momentum spring neutral orientation
    
	
};

#endif