The Quest's Snapdragon GPU, like most mobile GPUs, uses a tiled rendering [1] architecture.
The basic technique for rendering gaussian splats is kryptonite for this architecture, essentially implementing every worse practice for rendering on a mobile GPU:
* Tons of overdraw (overlapping splats)
* Tons of alpha blending
* Millions of splats in the distance generate a lot of tiny triangles resolving to a single pixel
* Long thin splats in the foreground generate triangles that cover multiple tiles
These are all the ingredients you need to bring a mobile GPU to its knees! Any desktop GPU (including most laptops) will be far less sensitive to these issues, even if it's not very powerful. It's a fundamental issue of architecture rather than one of raw FLOPs.
The quest is underpowered (it's basically a midrange Android phone you wear.) More efficient coding or a simpler model would help. Inside the Scaniverse does something similar with a high framerate but the models are simple and don't look very good.
I had to power cycle mine to get out, but boy was the view great despite the motion sickness.
