> Bloom level 8 in HLSL AFAIK doesn't do anything. Is this a bug?
Maybe? But maybe not.
As you know, HLSL bloom levels come from repeatedly (2x?) downsampled versions of the game texture.
And 8 levels of bloom from a normal-ish game res (320x240 or so) gets you to texture sizes of approximately 1x1 pixel. So maybe you're just seeing what happens once the bloom texture size drops below 1x1. If so, I guess it's working correctly.
At least that's my guess having not read the HLSL code in detail.
EDIT: Full disclosure -- I have no idea if HLSL bloom works with a texture at original game res as it's base level. If it doesn't then obviously I'm taking nonsense.