rotate( axis, angle ) {

		const point = this._gizmos.position; //rotation center
		this._translationMatrix.makeTranslation( - point.x, - point.y, - point.z );
		this._rotationMatrix.makeRotationAxis( axis, - angle );

		//rotate camera
		this._m4_1.makeTranslation( point.x, point.y, point.z );
		this._m4_1.multiply( this._rotationMatrix );
		this._m4_1.multiply( this._translationMatrix );

		this.setTransformationMatrices( this._m4_1 );

		return _transformation;

	}
Rotates the camera around an axis passing by trackball's center.

@private
@param {Vector3} axis - Rotation axis.
@param {number} angle - Angle in radians.
@returns {Object} Object with 'camera' field containing transformation matrix resulting from the operation to be applied to the camera.