Render Light Shaft Bloom at lower resolution?

Is there a way to render the light shaft bloom at a lower internal resolution and then just scale it up? It’s bloom, so it’s really not a problem if it’s a bit blurry, and it’s quite expensive:


I’m fine with editing the source or global shader files or whatever is needed to change this to a lower resolution. Any idea where to look for it?

I would like to have post processing blendables have an option to be done at lower res as well. I like how we have r.SeparateTranslucencyScreenPercentageNow so something like that would be great. On all post processing, a resolution parameter 0.0-1.0 would be great.