Method getNormalMatrix

src/math/Matrix3.js:352–356

* Computes the normal matrix which is the inverse transpose of the upper * left 3x3 portion of the given 4x4 matrix. * * @param {Matrix4} matrix4 - The 4x4 matrix. * @return {Matrix3} A reference to this matrix.

( matrix4 )

	 * @return {Matrix3} A reference to this matrix.
	 */
	getNormalMatrix( matrix4 ) {

		return this.setFromMatrix4( matrix4 ).invert().transpose();

	}

	/**
	 * Transposes this matrix into the supplied array, and returns itself unchanged.