applyMatrix4( m ) {

		const x = this.x, y = this.y, z = this.z;
		const e = m.elements;

		const w = 1 / ( e[ 3 ] * x + e[ 7 ] * y + e[ 11 ] * z + e[ 15 ] );

		this.x = ( e[ 0 ] * x + e[ 4 ] * y + e[ 8 ] * z + e[ 12 ] ) * w;
		this.y = ( e[ 1 ] * x + e[ 5 ] * y + e[ 9 ] * z + e[ 13 ] ) * w;
		this.z = ( e[ 2 ] * x + e[ 6 ] * y + e[ 10 ] * z + e[ 14 ] ) * w;

		return this;

	}
Multiplies this vector (with an implicit 1 in the 4th dimension) by m, and
divides by perspective.

@param {Matrix4} m - The matrix to apply.
@return {Vector3} A reference to this vector.