It should be, but it might not the right spot. How about this and the next line? Both seem to have effect on the rendertarget size to reach lower resolution. But as you can see there’s no simple way to just set the scale here, it is pretty much designed to always generate halved sizes. It’s a logical way, tho not optimal as per VR requirements. I’d try to extend this class to add more configurable options, so the bloom could request the very small maps optionally. Size .25 or .33 should be fine.
It also worth to point out, that the comments in the bloom will mention that eyeadaptation is also use these maps to measure the lumen, so i’d advise to check the function regularly to see if it’s still working as it should.
Edit:
Try r.UseMobileBloom 1, that’s a different bloom and might have a lesser cost. But as the name suggests, it was not designed for desktops.