public Vector3f multLocal(Vector3f vec) {
        if (vec == null) {
            return null;
        }
        float x = vec.x;
        float y = vec.y;
        vec.x = m00 * x + m01 * y + m02 * vec.z;
        vec.y = m10 * x + m11 * y + m12 * vec.z;
        vec.z = m20 * x + m21 * y + m22 * vec.z;
        return vec;
    }
Applies the linear transformation to the vector argument and returns the
(modified) argument. If the argument is null, null is returned.

<p>Despite the name, the current instance is unaffected.

@param vec the vector to transform (modified if not null)
@return {@code vec} or null
jme3-core/src/main/java/com/jme3/math/Matrix3f.java