#ifndef _PARTICLE_H_
#define _PARTICLE_H_

#include "vectors.h"

// ================================================================
//
// stores the information for a particle

class Particle {

public:

  // CONSTRUCTOR & DESTRUCTOR
  Particle(Vec3f p, Vec3f v, Vec3f _color, Vec3f _dead_color, float m, float lifespan) {
    position = p;
    last_position = p;
    velocity = v;
    color = _color;
    dead_color = _dead_color;
    mass = m;
    timeToDeath = lifespan; }
  ~Particle() {}

  // ACCESSORS
  Vec3f getPosition() const { return position; }
  Vec3f getVelocity() const { return velocity; }
  Vec3f getColor() const { return color; }
  float getMass() const { return mass; }  
  int isDead() const { if (timeToDeath <= 0) return 1; else return 0; }

  // MODIFIER
  void setPosition(Vec3f p) { last_position = position; position = p; }
  void setVelocity(Vec3f v) { velocity = v; }
  void setColor(Vec3f c) { color = c; }
  void setMass(float m) { mass = m; }
  void increaseAge(float a);

  // Paint
  void Paint(float dt, int integrator_color, int draw_vectors, int motion_blur) const;
  
private:

  Particle() { assert(0); } // don't use this constructor

  // REPRESENTATION
  Vec3f position;
  Vec3f last_position; 
  Vec3f velocity;
  Vec3f color;
  Vec3f dead_color; // color interpolates from color to dead_color as clock ticks down
  float mass;
  float timeToDeath;

};

// ================================================================

#endif