// UdK Computational design
// Marius Watz 2003
// http://www.evolutionzone.com/udk/
//
// UDK02_02_direction
//
// Avoid behavior.

float x,y,x2,y2,xD,yD,radius;
float dist,angle;

void setup() {
  size(400,400);
  x=random(width);
  y=random(height);
  x2=random(width);
  y2=random(height);
  x2=200;
  y2=200;
  ellipseMode(CENTER_DIAMETER);
}

void loop() {
  background(200,200,200);
  xD=x2-x;
  yD=y2-y;
  radius=150;
  
  dist=sqrt(xD*xD+yD*yD);
  angle=degrees(atan2(yD,xD));

  
  x=x+random(-10,10);
  y=y+random(-10,10);
  if(x<0) x=width;
  else if(x>width) x=0;
  if(y<0) y=height;
  else if(y>height) y=0;
  
  // Check to see if dist-(radius of green sphere) is less than radius
  // If so, avoid by moving some distance in the opposite direction.
  if((dist-5)<radius) {
    x=x-xD/20;
    y=y-yD/20;
  }

  // Red sphere
  fill(255,0,0);
  ellipse(x2,y2, radius*2,radius*2);
  
  // Green sphere
  fill(0,255,0);
  ellipse(x,y, 10,10);
}