jogl cameras

OpenGL Development JOGL Development
#1

Hi,

I’m not happy with the rotation control that I get from using an arcball implementation that took me quite a bit of time to develop.

So I’m wondering if anyone knows of other completed cameras using jogl that would provide better camera control, zooms, panning, etc… good for viewing models.

#2

Maybe there is something wrong because of gimbal lock.

#3

I find that the easiest camera control to get good is to just support a rotation around X followed by a rotation around Y; this gives you pitch and yaw. For a model viewer camera, you have a distance from origin as well. Something like this might work:

public class ArcBallCamera {
  float pitch;
  float yaw;
  float distance = 40.0f;
  public void update(float dx, float dy) {
    yaw += dx;
    pitch += dy;
    if (pitch > 80.f) pitch = 80.f;
    if (pitch < -80.f) pitch = -80.f;
    yaw = (float) Math.mod(yaw, 360.f);
  }
  public void setDistance(float d) {
    distance = d;
  }
  public void loadCameraMatrix(GL gl) {
    gl.glMatrixMode(GL.GL_MODELVIEW);
    gl.glLoadIdentity();
    gl.glRotatef(yaw, 0, 1, 0);
    gl.glRotatef(pitch, 1, 0, 0);
    gl.glTranslatef(0, 0, -distance);
  }
}

You call update() with dx and dy from mouse movement. You call loadCameraMatrix() to load the camera matrix into the MODELVIEW matrix.