Make GsplatRenderer Loading Async

[busiyg]

When loading the GsplatRenderer or setting its enable property to true, there’s a brief lag.
Can this be changed to run asynchronously?

[wuyize25]

You're right, it can be made asynchronous. I'll implement this feature when I have time.

[TokyoWarfare]

Yep certainly, I think async and load unload of data would make theese splats much more tempting. It could allow from aerial reconstructions to be used, large scans etc...
I think Cesium is planning to add support for this in the 3D tiles but I don´t use Cesium and may have other shortocomings I'm unaware.

[TokyoWarfare]

This other project using gsplat has implemented streaming
HiFi-Human/DynGsplat-unity@4d7509c
so may have already been solved

[wuyize25]

This other project using gsplat has implemented streaming HiFi-Human/DynGsplat-unity@4d7509c so may have already been solved

That project uses Addressables to asynchronously load data from disk into RAM. My new commit (9d27ffb) implements streaming data from RAM to VRAM. For the disk-to-RAM loading stage, I recommend marking the Game Object that contains the Gsplat Renderer as an Addressable prefab and using Addressables’ standard asynchronous loading APIs. This way, no changes to the Gsplat Renderer are required.

At the moment, there is still a small lag, which is likely caused by the creation of large Graphics Buffers. I am also considering switching these Graphics Buffers to Textures, so that we may be able to directly leverage Unity’s asynchronous upload pipeline.