I'm creating a script that causes a box to approach the camera, but in a spiral. I thought the idea would look neat, but for some reason it disappears after about half way and then reappears. Does anyone understand why it would do this? I have no problem creating boxes anywhere I want but once I start using the spirals, it starts doing this:

Code:

import processing.opengl.*;
import javax.media.opengl.*; 
//import peasy.*;

//PeasyCam cam;

void setup() {
  size(800, 600, OPENGL);
//  cam = new PeasyCam(this, width);
  location = new PVector(100, 100, 0);
}

PVector location;

void draw() {
  background(0);
  location.z += 5;
  float distance = sqrt(location.x*location.x + location.y*location.y);
  float angle    = atan(location.y/location.x);
  location.x     = distance*cos(angle+PI/48);
  location.y     = distance*sin(angle+PI/48);  
  translate(location.x, location.y, location.z);
  box(50);
}