// UdK Computational design
// Marius Watz 2003
// http://www.evolutionzone.com/udk/
//
// UDK02_02_direction_changing
//
// Changing both speed and direction every frame.

float x,y,xD,yD;
float dir,speed,minSpeed,maxSpeed;
float fract,fractD;

void setup() {
  size(300,400);
  ellipseMode(CENTER_DIAMETER);

  fractD=0.05f;
  fract=1;

  minSpeed=0.1;
  maxSpeed=2;
  speed=(maxSpeed-minSpeed)/2+minSpeed;
  dir=random(radians(360));
  x=random(width);
  y=random(height);
}

void loop() {
  background(150,140,140);

  dir=dir+random(-radians(3),radians(3));
  speed=speed+random(-0.1,0.1);
  if(speed<minSpeed) speed=minSpeed;
  else if(speed>maxSpeed) speed=maxSpeed;
  
  xD=cos(dir)*speed;
  yD=sin(dir)*speed;
  
  x=x+xD;
  y=y+yD;
  if(x<0) x=width;
  else if(x>width) x=0;
  if(y<0) y=height;
  else if(y>height) y=0;

  noStroke();
  fill(255,170,0);  
  ellipse(x,y, 20,20);
}