processing4/java/examples/Topics/Advanced Data/ArrayListClass/Ball.pde

// Simple bouncing ball class

class Ball {
  
  float x;
  float y;
  float speed;
  float gravity;
  float w;
  float life = 255;
  
  Ball(float tempX, float tempY, float tempW) {
    x = tempX;
    y = tempY;
    w = tempW;
    speed = 0;
    gravity = 0.1;
  }
  
    void move() {
    // Add gravity to speed
    speed = speed + gravity;
    // Add speed to y location
    y = y + speed;
    // If square reaches the bottom
    // Reverse speed
    if (y > height) {
      // Dampening
      speed = speed * -0.8;
      y = height;
    }
  }
  
  boolean finished() {
    // Balls fade out
    life--;
    if (life < 0) {
      return true;
    } else {
      return false;
    }
  }
  
  void display() {
    // Display the circle
    fill(0,life);
    //stroke(0,life);
    ellipse(x,y,w,w);
  }
}