public class Missile {
  private float x, y, xv, yv, a, adir;
  boolean setForDestruction = false; // sets to true once, and only once in a missiles life time.
  private final float accelRate = 0.25;

  public Missile(float initx, float inity, float initxv, float inityv, float dir) {
    x = initx;
    y = inity;
    xv = initxv;
    yv = inityv;
    adir = dir;
    a = 0.1;
  }
  
  // Returns false if outside of visible screen
  public boolean move() {
    a += accelRate;
    float dx = a * cos(adir);
    float dy = a * sin(adir);
    xv += dx;
    yv += dy;
    x += xv;
    y += yv;
    if((x>=width-1) || (x<=0) || (y>=height-1) || (y<=0)) {
      return false;
    }
    else return true;
  }
  
  public void render() {
    stroke(255);
    fill(255);
    ellipse(x, y, 2, 2);
  }
  
  // Did the missile hit a roid?
  public Roid checkHit(){
    Roid retRoid = null;
    // check current point AND past trajectory path
    float step = 0.5;
    float cx = this.x - xv;
    float cy = this.y - yv;
    boolean checkFinished = false;
    Roid hitRoid = null;
    
    while(!checkFinished && hitRoid==null) {
      hitRoid = roidHandler.whichRoid( cx, cy, 7 ); // radius was 2, then 10
      if(cx <= x)
        cx+=step;
      if(cy <= y)
        cy+=step;
      if(cx > x && cy > y)
        checkFinished = true;       
    }
    
    
    if(hitRoid != null) {
      // Split target roid
      roidHandler.splitRoid(hitRoid, this.getAngle());
      retRoid = hitRoid;
    }
    return hitRoid;
  }
  
  public float getAngle() {
    return adir;
  }
  
}