setFromRotationMatrix( m, order = this._order, update = true ) {

		const te = m.elements;
		const m11 = te[ 0 ], m12 = te[ 4 ], m13 = te[ 8 ];
		const m21 = te[ 1 ], m22 = te[ 5 ], m23 = te[ 9 ];
		const m31 = te[ 2 ], m32 = te[ 6 ], m33 = te[ 10 ];

		switch ( order ) {

			case 'XYZ':

				this._y = Math.asin( clamp( m13, -1, 1 ) );

				if ( Math.abs( m13 ) < 0.9999999 ) {

					this._x = Math.atan2( - m23, m33 );
					this._z = Math.atan2( - m12, m11 );

				} else {

					this._x = Math.atan2( m32, m22 );
					this._z = 0;

				}

				break;

			case 'YXZ':

				this._x = Math.asin( - clamp( m23, -1, 1 ) );

				if ( Math.abs( m23 ) < 0.9999999 ) {

					this._y = Math.atan2( m13, m33 );
					this._z = Math.atan2( m21, m22 );

				} else {

					this._y = Math.atan2( - m31, m11 );
					this._z = 0;

				}

				break;

			case 'ZXY':

				this._x = Math.asin( clamp( m32, -1, 1 ) );

				if ( Math.abs( m32 ) < 0.9999999 ) {

					this._y = Math.atan2( - m31, m33 );
					this._z = Math.atan2( - m12, m22 );

				} else {

					this._y = 0;
					this._z = Math.atan2( m21, m11 );

				}

				break;

			case 'ZYX':

				this._y = Math.asin( - clamp( m31, -1, 1 ) );

				if ( Math.abs( m31 ) < 0.9999999 ) {

					this._x = Math.atan2( m32, m33 );
					this._z = Math.atan2( m21, m11 );

				} else {

					this._x = 0;
					this._z = Math.atan2( - m12, m22 );

				}

				break;

			case 'YZX':

				this._z = Math.asin( clamp( m21, -1, 1 ) );

				if ( Math.abs( m21 ) < 0.9999999 ) {

					this._x = Math.atan2( - m23, m22 );
					this._y = Math.atan2( - m31, m11 );

				} else {

					this._x = 0;
					this._y = Math.atan2( m13, m33 );

				}

				break;

			case 'XZY':

				this._z = Math.asin( - clamp( m12, -1, 1 ) );

				if ( Math.abs( m12 ) < 0.9999999 ) {

					this._x = Math.atan2( m32, m22 );
					this._y = Math.atan2( m13, m11 );

				} else {

					this._x = Math.atan2( - m23, m33 );
					this._y = 0;

				}

				break;

			default:

				console.warn( 'THREE.Euler: .setFromRotationMatrix() encountered an unknown order: ' + order );

		}

		this._order = order;

		if ( update === true ) this._onChangeCallback();

		return this;

	}
Sets the angles of this Euler instance from a pure rotation matrix.

@param {Matrix4} m - A 4x4 matrix of which the upper 3x3 of matrix is a pure rotation matrix (i.e. unscaled).
@param {string} [order] - A string representing the order that the rotations are applied.
@param {boolean} [update=true] - Whether the internal `onChange` callback should be executed or not.
@return {Euler} A reference to this Euler instance.