/*
  Sample processing program for CS112
  Spring 2015
  it would be a good idea to add an x velocity and have the ball bounce off the sides
*/

float x;  // keep track of the ball's x and y position
float y;
float yvelocity;  // keep track of the ball's y veloicity

void setup(){   // setup() is run once to setup the program
  size(500,300);  // create the window
  x = 10;    // set the ball's initial x and y position
  y = 10;
  yvelocity = 2;  // set the ball's initial y velocity
}

void draw(){  // draw() is run in an infinite loop
  fill(random(0,255),random(0,255),random(0,255));  // amount of red, green, and blue from 0 - 255 to fill the ball
  background(100,200,100);  // draw in the background
  stroke(100,100,0);   // set the color of the ball's outline
  ellipse(x,y,40,20);  // draw the ball
  x = x + 1;   // change the ball's x position
  y = y + yvelocity;  // change the ball's y position
  if(y > height){  // bounce off the bottom of the screen
    yvelocity = yvelocity * -1;
  }
  if(y < 0){  // bounce off the top of the screen
    yvelocity = yvelocity * -1;
  }

}