/**
 * Pulses
 *
 * <p>Elie Zananiri<br>
 * CART 253, Winter 2008</p>
 */

// ----------------------------------------------------------------------
// GLOBAL CONSTANTS
// ----------------------------------------------------------------------
int SCALE = 10;

// ----------------------------------------------------------------------
// GLOBAL VARIABLES
// ----------------------------------------------------------------------
int x;    // x-coordinate of the pulse
int y;    // y-coordinate of the pulse
float s;  // size of the pulse

// ----------------------------------------------------------------------
// BUILT-IN FUNCTIONS
// ----------------------------------------------------------------------
void setup() {
  size(400, 400);
  smooth();
  noStroke();
}

void draw() {
  background(0);

  // draw the pulse
  drawPulse(); 
}

void mousePressed() {
  movePulse(mouseX, mouseY); 
}

// ----------------------------------------------------------------------
// USER FUNCTIONS
// ----------------------------------------------------------------------
/* draws a pulse and updates its size */
void drawPulse() {
  fill(255);
  ellipse(x, y, sin(s)*SCALE, sin(s)*SCALE);
  s += 0.1;
}

/* moves the pulse to the given position */
void movePulse(int newX, int newY) {
  x = newX;
  y = newY;
}