// Ball class

class Ball { 
  float x, y;
  float yspeed = 0;
  float xspeed = random(8)-4;
  float r;
  float gravity = 0.1;
  int redvalue = 255;
  int bluevalue = 255;
  int greenvalue = 255;
  int bouncecount = 0;
  
  // three states for alive:  
  //  0 = dead, do nothing
  //  1 = alive, move normally
  //  2 = dead, ready to be archived
  int alive = 0;
  float px, py;

  // initialize a new Ball instance  
  Ball(float inx, float iny, float inr) {
    x = inx;
    y = iny;
    r = inr;
  }
  
  // reset a Ball after it has ben deactivated
  void reset()
    {
    x = 0;
    y = 0;
    yspeed = 0;
    xspeed = 0;
    alive = 0;
    bouncecount = 0;
    }

  // manual color reset
  void colorreset()
    {
    if (y > 0 && redvalue >= 0 && redvalue <= 255) { redvalue = 255 - floor(0.3 * y); }
    if (y > 0 && bluevalue >= 0 && bluevalue <= 255) { bluevalue = 255-floor(0.4 * y); }
    if (x > 0 && greenvalue >=0 && greenvalue <= 255) { greenvalue = 255-floor(0.5 * x); }          
    }

  // attempt to move a ball    
  void move() 
    { 
    // if the ball hits the right edge of the screen
    if (x > width-25) {
      xspeed = -1 * xspeed / 1.2;
      x = width-25;
    }
    
    // if the ball hits the left edge of the screen
    if (x < 25) {
      xspeed = -1 * xspeed / 1.2;
      x = 25;
    }
      
    // if the ball is at the bottom of the screen and moving downwards
    if (y > height-25 && yspeed > 0) 
      {
      // if speed is high enough, bounce
      if (yspeed > 0.5) {
        yspeed = -1 * yspeed / 2;
      }
      // otherwise deactivate this ball
      else {
        alive = 2;
      }
     }

    // if the ball is active and moving normally, continue it along it's path    
    if (alive == 1) 
      {
      px = x;
      py = y;
      y = y + yspeed;
      x = x + xspeed;
      yspeed = yspeed + gravity;
      //if (bluevalue > yspeed && bluevalue <= 255) { bluevalue = bluevalue - floor(yspeed); }
      //if (greenvalue > yspeed && greenvalue <= 255) { greenvalue = greenvalue - floor(yspeed); }
      if (y > 0 && redvalue >= 0 && redvalue <= 255) { redvalue = 255 - floor(0.3 * y); }
      if (y > 0 && bluevalue >= 0 && bluevalue <= 255) { bluevalue = 255-floor(0.4 * y); }
      //if (y > 0 && greenvalue >= 0 && greenvalue <= 255) { greenvalue = 255-floor(0.5 * y); }
      
      if (x > 0 && greenvalue >=0 && greenvalue <= 255) { greenvalue = 255-floor(0.5 * x); }
      
      
      fill (redvalue, bluevalue, greenvalue);
      
      
      ellipse (x, y, r, r);
      }
    }
  }