(I don't know what this should be called, so let me call it "Cascaded Blur".
I wanted OA's bloom effect to be more natural and smoother, so I implemented an new bloom effect for OA with "Cascaded Blur". This bloom effect spreads the glow of the image more widely and more slenderly, whereas the original one spreads it in the narrow area.
Now, what's "Cascaded Blur"?
It's an blur algorithm that adds blurred images from less blurry one to more blurry one (blurring is done with downsampling). It seems to look more nature. That's why this algorithm is used by some modern commercial games.
This bloom effect requires much less GPU power than one that is currently used in OA.
But you might see aliasing more often if you specify the large alpha value.
Sorry for my poor English skill