/*! 
    \file particle_emitter.h
    \brief Definition of a ParticleEmitter
*/

#ifndef _PARTICLE_EMITTER_H
#define _PARTICLE_EMITTER_H

#include "p_node.h"

// FORWARD DEFINITION 
struct Particle;
class ParticleSystem;

//! The form of the Emitter to emit from
typedef enum EMITTER_TYPE {EMITTER_DOT   = 1,
			   EMITTER_PLANE = 2,
			   EMITTER_SPHERE= 4,
			   EMITTER_CUBE  = 8};

//! A class to handle an Emitter.
class ParticleEmitter : public PNode {

 public:
  ParticleEmitter(const Vector& direction, float angle = .5,
		  float emissionRate = 1.0, float velocity = 1.0);
  virtual ~ParticleEmitter(void);

  /* controlling the emitter: interface */
  void start();
  void stop();
  void tick(float dt, ParticleSystem* system);

  /* controlling the behavour: these can be used as Animation interfaces */
  void setType(EMITTER_TYPE type);
  void setSize(float emitterSize);
  void setEmissionRate(float emissionRate);
  void setSpread(float angle, float randomAngle = 0.0);
  void setEmissionVelocity(float velocity, float randomVelocity = 0.0);

  /** \returns the type of the emitter */
  inline EMITTER_TYPE getType(void) const { return this->type; };
  /** \returns the Size of the emitter */
  inline float getSize(void) const { return this->emitterSize; };
  /** \returns the emissionRate */
  inline float getEmissionRate(void) const { return this->emissionRate; };
  /** \returns the SpreadAngle of the emitter */
  inline float getSpread(void) { return this->angle; };
  /** \returns the EmissionVelocity of the emitter */
  inline float getEmissionVelocity(void) { return this->velocity; };

  void debug(void);

 private:
  EMITTER_TYPE type;    //!< The type of emitter this is
  float emitterSize;    //!< The size of the emitter (not for EMITTER_DOT)
  Vector direction;     //!< emition direction
  float angle;          //!< max angle from the direction of the emitter
  float randomAngle;    //!< random emission angle (angle +- angleRandom is the emitted angle.
  float emissionRate;   //!< amount of particles per seconds emitted by emitter.
  float velocity;       //!< the initial speed of a Particles.
  float randomVelocity; //!< the random variation from the initial Speed.

  float saveTime;       //!< The time that was missing by the last Tick (otherwise there would be no emission when framefate is too big).
};

#endif /* _PARTICLE_EMITTER_H */