/**
 * Animating a square.
 *
 * <p>Elie Zananiri<br>
 * CART 253, Winter 2008</p>
 */

/* global variables */
int rectX;
int rectY;
int rectSize = 50;

/* built-in functions */
void setup() {
  size(300, 300);
  noStroke();
  smooth();
  
  resetSquare();
}

void draw() {
  background(0);
  moveSquare();
  drawSquare();
}

/* custom functions */
// resets the square's position
void resetSquare() {
  rectX = 0;
  rectY = 50; 
}

// moves the square erratically
void moveSquare() {
  if (rectX < width && rectY < height) {
    // random() returns a float, so we have to transform it into an integer;
    // this is done with casting, using the (int) operator.
    rectX = rectX+(int)random(0, 5);
    rectY = rectY+(int)random(0, 5);
  } else {
    resetSquare();
  }
}

// draws the square
void drawSquare() {
  fill(255, 128, 0);  // orange
  rect(rectX, rectY, rectSize, rectSize);
}