Strange behaviour of chase camera

Troubleshooting General Help
1

hi there



again i have a problem. my application looks like this:







now i want that the user can view the whole scene from directly above the terrain. that means the camera should be in a perpendicular angle to the terrain. this works more or less with:



private void updateCameraPosition() {
      System.out.println(chaser.getCamera().getLocation());
      chaser.getCamera().setLocation(new Vector3f(TERRAIN_X/2,300,TERRAIN_Y/2));
      chaser.getCamera().setDirection(new Vector3f(0,-1,0));
      System.out.println(chaser.getCamera().getLocation());
   }



somehow i mixed up y and z angles i think ... but on the second screenshot one can see that it is really working:



expect for the pillars which are not displayed. can someone explain me why?? thx!
2

do they have BoundingBoxes?

3

yes

4

Use Camera.lookAt() instead of Camera.setDirection().

When you change direction, you should adjust up vector together.

5

thx i changed the code into this:


System.out.println(chaser.getCamera().getLocation());
      chaser.getCamera().setLocation(new Vector3f(TERRAIN_X/2,300,TERRAIN_Y/2));
      chaser.getCamera().lookAt(new Vector3f(0,-1,0), new Vector3f(0,1,0));
      System.out.println(chaser.getCamera().getLocation());



now the pillars are visible, but i'm not looking at the center of the terrain, but to the point where the axis cross each other (0,0,0) i think
6

i also tried it with:


System.out.println(chaser.getCamera().getLocation());
      chaser.getCamera().setLocation(new Vector3f(TERRAIN_X/2,300,TERRAIN_Y/2));
      chaser.getCamera().lookAt(new Vector3f((TERRAIN_X/2,300,TERRAIN_Y/2)), new Vector3f(0,1,0));
      System.out.println(chaser.getCamera().getLocation());



but then i can't see the terrain at all. any hints?
7

doens't really anybody knows an answer??

8

Direction, Up, Left vector should always be orthogonal.

You used up vector as UNIT_Y. That's wrong.

You can set up vector to UNIT_Y only when the direction vector is on y=0 plane

(in other words, directionVector.y = 0)


9

@mulova: thx i didn't know that. but whats the better solution?

10

no one?

11

I can't understand your last post becase of the lack of my english.  :cry:



I will just say about my solution about camera rotation.



When I rotate camera, I get Quaternion for rotating cam direction



And multiply it to up vector.



extracting Quaternion for cam direction is from Game Programming Gems



/**

*

  • @param start

    *            normalized vector
  • @param end

    *            normalized vector
  • @param store
  • @return

    */

    public static Quaternion getRotationNormalized0(final Vector3f start, final Vector3f end, final Quaternion store) {

    Vector3f temp = new Vector3f();



    // Game Programming Gems

    start.cross(end, temp);

    final float d = start.dot(end);

    if (d == -1) {

    store.fromAngleAxis(FastMath.PI, Vector3f.UNIT_Y);

    } else {

    final float s = FastMath.sqrt((1 + d) * 2);

    store.x = temp.x / s;

    store.y = temp.y / s;

    store.z = temp.z / s;

    store.w = s / 2f;

    }



    return store;

    }