public FloatBuffer fillFloatBuffer(FloatBuffer fb) {
        return fillFloatBuffer(fb, false);
    }
Copy all elements to an existing FloatBuffer, starting at its current
position, in row-major order.

@param fb the destination buffer (not null, must have space remaining for
16 floats)
@return the destination buffer, its position advanced by 16
jme3-core/src/main/java/com/jme3/math/Matrix4f.java