float angle;
float radius;
float lastX;
float lastY;
float h;

void setup() {
  size(800,600);
  colorMode(HSB);
  background(255);
  smooth();
  angle = 0;
  radius = 10;
  lastX = mouseX;
  lastY = mouseY;
  h = random(0,255);
}

void draw() {
  if (mousePressed && mouseButton == LEFT) {
    float strength = dist(lastX, lastY, mouseX, mouseY) + 40;
    float sat = random(63,255);
    float bright = random(63,255);
    stroke(h, sat, bright, strength);
    strokeWeight(strength/100);
    noFill();
    drawline();
    angle += PI/20;
    drawline();
    angle += PI/20;
    drawline();
    angle += PI/20;
  }
  lastX = mouseX;
  lastY = mouseY;
}

void drawline() {
  float ax = lastX + cos(angle)*radius;
  float ay = lastY + sin(angle)*radius;
  float bx = mouseX + cos(angle+PI/2)*radius;
  float by = mouseY + sin(angle+PI/2)*radius;
  line(ax, ay, bx, by);

}

void mousePressed() {
  if (mouseButton == RIGHT) {
    // this might be a cool place to toggle between colors?
    h = random(255);
  }
}

void keyPressed() {
  if (key == 's' || key == 'S') { // save an image
    save("CE3-drawing" + year() +"-"+ month() +"-"+ day() +"-" + hour() +"-" + minute() + ".png");
  } 
  else if (key == ENTER) {
    h = random(0,255);
    background(255);
  }
}