/**
 * Bounce. 
 * 
 * When the shape hits the edge of the window, it reverses its direction. 
 * 
 * Updated 1 September 2002
 */
 
import processing.serial.*;

String portname = "/dev/tty.usbserial-A4001qa8";
Serial port;  // Create object from Serial class

int size = 60;       // Width of the shape
float xpos, ypos;    // Starting position of shape    

float xspeed = 3.9;  // Speed of the shape
float yspeed = 3.1;  // Speed of the shape

int xdirection = 1;  // Left or Right
int ydirection = 1;  // Top to Bottom


void setup() 
{
  size(400, 400);
  colorMode(HSB, 255);
  noStroke();
  frameRate(30);
  ellipseMode(CENTER);   // draw from center out
  smooth();
  // Set the starting position of the shape
  xpos = width/2;
  ypos = height/2;
  
  // Open the port that the board is connected to and use the same speed (19200 bps)
  port = new Serial(this, portname, 19200);

}

void draw() 
{
  
 if (port.available() > 0) {  // If data is available,
    size = port.read();         // read it and store it as the new size
  }

  background(102);
  
  // Update the position of the shape
  xpos = xpos + ( xspeed * xdirection );
  ypos = ypos + ( yspeed * ydirection );
  
  // Test to see if the shape exceeds the boundaries of the screen
  // If it does, reverse its direction by multiplying by -1
  int halfsize = size/2;  // because we're drawing from the circle's center
  if (xpos + halfsize > width || xpos - halfsize < 0) {
    xdirection *= -1;
  }
  if (ypos + halfsize > height || ypos - halfsize < 0) {
    ydirection *= -1;
  }

  // Draw the shape
  fill(size,255,255);  // we're in HSB mode, so first value is color
  ellipse(xpos, ypos, size, size);
}