How can i block block X and Z axis rotation ?

[tiagoernst]

Is there a simple way to block the rotations on X and Z axis ? I'm using the trackball and managed somewhat to block thoose axis by converting the rotation (in quaternion ) to euler angles and putting x=0 and y=0, the problem is at some point the y doesn't go further (it looks like it's glitching and can't continue the rotation),I believe it's when the value of the y axis gets close to -1 or 1 (180° -180°).

code snippet from modified LeapTrackballControls.js:

 THREE.LeapTrackballControls = function ( object , controller , params, domElement ) {
    //initializing euler angle
    rot3D_blocked = new THREE.Euler(0,0,0,'XYZ');
    ....
    //later on the update function
      rot3D_blocked.setFromQuaternion(rotation);
      rot3D_blocked.z=0;
      rot3D_blocked.x=0;

      rotation.setFromEuler(rot3D_blocked);

      this.rotation = rotation;
      this.rotatingObject.rotation.setFromQuaternion(rotation);