//------------------------------------------------------------ 
// Metaball Class 
//------------------------------------------------------------ 

class Metaball 
{ 
  private Vector3D loc;
  private Vector3D vel;
  private Vector3D acc;
  private float maxvel;

  // These need to be replaced by loc.x & loc.y
  float center_x, center_y;
  
  int center_i, center_j; 
  int scan_iMin, scan_iMax, scan_jMin, scan_jMax; 
  float dx, dy; 
  float strength = 30000; 
  float isoValue = 16.0f;
  float R; 
  int sqR; 
  float timer;

  /*
	Metaball(float isoV) 
   	{ 
   		this.isoValue = isoV; 
   		this.getRadius(); 
   		this.center_x = 0; 
   		this.center_y = 0; 
   	} 
   */

  Metaball(Vector3D a, Vector3D v, Vector3D l) 
  {
    
    acc = a.copy();
    vel = v.copy();
    loc = l.copy();
    
    /*
    acc = a;
    vel = v;
    loc = l;
    */
    maxvel = 8;
    //this.isoValue = isoV;
    this.getRadius();
    //this.center_x = l.x; 
    //this.center_y = l.y; 
    //timer = 400.0;
  }

  /*Add functions to our thing object to access the location, velocity and acceleration from outside the class*/
  Vector3D getVel() {
    return vel.copy();
  }

  Vector3D getAcc() {
    return acc.copy();
  }

  Vector3D getLoc() {
    return loc.copy();
  }

  void setLoc(Vector3D v) {
    loc = v.copy();
  }

  void setVel(Vector3D v) {
    vel = v.copy();
  }

  void setAcc(Vector3D v) {
    acc = v.copy();
  }

  //function to update location
  void update() {
    vel.add(acc);
    loc.add(vel);
    //limit speed to max
    if (vel.magnitude() > maxvel) {
      vel.normalize();
      vel.mult(maxvel);
    }
    timer -= 1.0;
  }

  void setStrength(float s)
  {
    this.strength = s;
    this.getRadius();
  }

  /*
	void setCenterTo(Vector3D loc) 
   	{ 
   		this.center_x = loc.x;
   		this.center_y = loc.y;
   	} 
   */

  void setCenterTo(float x, float y) 
  {
    this.center_x = x;
    this.center_y = y;
  }

  void getRadius() 
  { 
    this.R = (float) Math.sqrt( (double) (strength/isoValue) ); 
    this.sqR = (int) R/(256/64);
  } 

  float getFieldAt(float x, float y)
  {
    dx = (loc.x - x);
    dy = (loc.y - y);

    return strength/(dx*dx + dy*dy+0.01f);
  }

  void SquareCoords(float res_x, float res_y) 
  { 
    center_i = (int)(center_x/res_x); 
    center_j = (int)(center_y/res_y); 
  } 

  int getSquareCoords_i(float res_x, float res_y) 
  { 
    center_i = (int)(center_x/res_x); 
    return center_i; 
  } 

  int getSquareCoords_j(float res_x, float res_y) 
  { 
    center_j = (int)(center_y/res_y);
    return center_j;
  }
  
    // Is the particle still useful?
  boolean dead() {
    if (timer <= 0.0) {
      return true;
    } else {
      return false;
    }
  }
  
  
}