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

// ----------------------------------------------------------------------
// GLOBAL CONSTANTS
// ----------------------------------------------------------------------
int SCALE = 10;
int MAX_PULSES = 500;

// ----------------------------------------------------------------------
// GLOBAL VARIABLES
// ----------------------------------------------------------------------
int numPulses = 0;

int[] x = new int[MAX_PULSES];      // stores all the x-coordinates
int[] y = new int[MAX_PULSES];      // stores all the y-coordinates
float[] s = new float[MAX_PULSES];  // stores all the size values

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

void draw() {
  background(0);
  
  // draw all the pulses
  for (int i=0; i < numPulses; i++) {
    drawPulse(i); 
  }
}

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

void mouseDragged() {
  addPulse(mouseX, mouseY); 
}

void keyPressed() {
  if (key == 32) {  // space bar
    // clear all
    numPulses = 0;
  } 
}

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

/* adds a new pulse to the list */
void addPulse(int newX, int newY) {
  if (numPulses < MAX_PULSES) {
    x[numPulses] = newX;
    y[numPulses] = newY;
    s[numPulses] = 0;
    numPulses++;
  }
}