I think there is a small bug in the LightScatteringFilter: Implemented is
innerLightDensity = Math.max(lightDensity - Math.max(screenLightPos.x, screenLightPos.y), 0.0f);
But - as far as I understand it, the midpoint of the screen has coordinates (0.5,0.5). Thus I thiink the line shoud read something like
innerLightDensity = Math.max(0f,lightDensity - FastMath.sqrt((screenLightPos.x-0.5f)(screenLightPos.x-0.5f)+(screenLightPos.y-0.5f)(screenLightPos.y-0.5f)));
Here the distance is measured masimum senmce but with the radial distance.
I hope that helps,