Tested it, there is absolutely no visual difference (end-user will not suspect anything):
And I’ve got 45 FPS instead of 35. (Without blur - 54). That’s very cool optimization!
But we still need to scale down resolution by 2 or 4 times, because it will significantly increase performance.
And I thinking what is better:
Using another post process to fake resolution downscale, which will took 4 texture samples per pixel overhead, but for blur we will only use half or quarter of resolution?
Or use a render target to render actual half resolution, but increase drawcalls and make image more dependant from triangles count?