src/components/look-controls.js
function (event) {
    var direction;
    var movementX;
    var movementY;
    var pitchObject = this.pitchObject;
    var previousMouseEvent = this.previousMouseEvent;
    var yawObject = this.yawObject;

    // Not dragging or not enabled.
    if (!this.data.enabled || (!this.mouseDown && !this.pointerLocked)) { return; }

    // Calculate delta.
    if (this.pointerLocked) {
      movementX = event.movementX || event.mozMovementX || 0;
      movementY = event.movementY || event.mozMovementY || 0;
    } else {
      movementX = event.screenX - previousMouseEvent.screenX;
      movementY = event.screenY - previousMouseEvent.screenY;
    }
    this.previousMouseEvent = event;

    // Calculate rotation.
    direction = this.data.reverseMouseDrag ? 1 : -1;
    yawObject.rotation.y += movementX * 0.002 * direction;
    pitchObject.rotation.x += movementY * 0.002 * direction;
    pitchObject.rotation.x = Math.max(-PI_2, Math.min(PI_2, pitchObject.rotation.x));
  }
function (event) {
    var direction;
    var movementX;
    var movementY;
    var pitchObject = this.pitchObject;
    var previousMouseEvent = this.previousMouseEvent;
    var yawObject = this.yawObject;

    // Not dragging or not enabled.
    if (!this.data.enabled || (!this.mouseDown && !this.pointerLocked)) { return; }

    // Calculate delta.
    if (this.pointerLocked) {
      movementX = event.movementX || event.mozMovementX || 0;
      movementY = event.movementY || event.mozMovementY || 0;
    } else {
      movementX = event.screenX - previousMouseEvent.screenX;
      movementY = event.screenY - previousMouseEvent.screenY;
    }
    this.previousMouseEvent = event;

    // Calculate rotation.
    direction = this.data.reverseMouseDrag ? 1 : -1;
    yawObject.rotation.y += movementX * 0.002 * direction;
    pitchObject.rotation.x += movementY * 0.002 * direction;
    pitchObject.rotation.x = Math.max(-PI_2, Math.min(PI_2, pitchObject.rotation.x));
  }
function ( event ) { var direction ; var movementX ; var movementY ; var pitchObject = this . pitchObject ; var previousMouseEvent = this . previousMouseEvent ; var yawObject = this . yawObject ; // Not dragging or not enabled. if ( ! this . data . enabled || ( ! this . mouseDown && ! this . pointerLocked ) ) { return ; } // Calculate delta. if ( this . pointerLocked ) { movementX = event . movementX || event . mozMovementX || 0 ; movementY = event . movementY || event . mozMovementY || 0 ; } else { movementX = event . screenX - previousMouseEvent . screenX ; movementY = event . screenY - previousMouseEvent . screenY ; } this . previousMouseEvent = event ; // Calculate rotation. direction = this . data . reverseMouseDrag ? 1 : - 1 ; yawObject . rotation . y += movementX * 0.002 * direction ; pitchObject . rotation . x += movementY * 0.002 * direction ; pitchObject . rotation . x = Math . max ( - PI_2 , Math . min ( PI_2 , pitchObject . rotation . x ) ) ; }
Translate mouse drag into rotation.

Dragging up and down rotates the camera around the X-axis (yaw).
Dragging left and right rotates the camera around the Y-axis (pitch).
Translate mouse drag into rotation .