title: Shapes disappear when I change camera settings
body: <p>flow-ers! I'm learning a fascinating language: <strong>Processing</strong>. I started to use <strong>P3D</strong> and tried to make <strong>'First-person' camera</strong> in 3D world. The matter is, when I move my mouse(means I changed my camera option), 3D shapes such as spheres and cubes seem to be cut by a transparent plane. </p>
  
  <p>I made some attempts to deal with my problem, (e.g. changing 3rd factor of camera()) but it still doesn't work. Let me show my codes.</p>
  
  <p>This is the main drawing part of my program.</p>
  
  <pre><code>pushMatrix();
  translate(width/2, height, 0);
  
  // P is player-class, and view method controls the camera option
  P.view(P.looking_at());
  
  fill(0); stroke(255);
  for (int i=0; i&lt;1000; i+=1) {
    if (isNear(shapes[i])) // just checking for distance, it doesn't matter
      shapes[i].locate();
  }
  
  popMatrix(); // now, the origin is top left
  </code></pre>
  
  <p>and this is locating function of the shapes.</p>
  
  <pre><code>void locate() {
    // these are coordinate of the shape
    translate(location.x, location.y, location.z); 
    // sphere or cube
    translate(-location.x, -location.y, -location.z);
  }
  </code></pre>
  
  <p>finally, this is what I wrote for P.view():</p>
  
  <pre><code>void view(PVector watch_point) { // camera setting
    hint(ENABLE_DEPTH_TEST);
    camera(location.x, location.y, location.z, // these are coordinate of player
      watch_point.x, watch_point.y, watch_point.z, // sight direction, updated when the mouse is moved
      0, -1, 0); // 3rd factor for camera
    lights();
  }
  </code></pre>
  
  <p>I expect the "normal view" as in real world, but when I look at some shapes squarely, they disappear! <strong>They only seem normally when I leer at them, and the sculpture steadily fades away when I move my sight to them</strong>; more specifically, it it looks like it was cut by a plane. Please help me solving this problem. (Or is there any mis-coding in my codes?)</p>