Separate world framebuffer resolution from GUI in the deferred pipeline

By default, Minecraft on Android (and possibly most other power constrained platforms) renders at the same resolution as the panel. Many mobile devices today have extremely dense PPIs with 3440 x 1440 screens that are only 6 inches or so.

With low to medium scalability settings, it is possible to achieve 10-20 fps at 1080 x 2340 even on modest devices. However, when manually changing the resolution to 720 x 1560 via OS hacks, it achieves a locked 30 FPS and the game is not only playable, but beautiful on low end mobile devices. This takes the experience of using the deferred renderer on mobile devices from unplayable to a great user experience. 

The vast majority of smartphones do not offer a per-app resolution changes and normally don't go below the panel's native resolution even globally. Even so, this is not intuitive to the average gamer as most people do not change the graphics settings when they play. For most, attempting to play Minecraft above fancy graphics will be confusingly laggy and make their device extremely hot preventing play. The pixel density is not only wasted because of the screen size but the great TAA implementation also sufficiently hides any loss in quality. 

My suggestion is to separate the canvas resolution of the reconstructed world-view from the native resolution GUI. This is beneficial for performance

Proposed change:

(each world-render axis/2) -> FSR 2 -> (reduced pixel density world-render framebuffer) -> bilinear into final native resolution framebuffer -> add UI.