Replace InMemoryAssetResolver with DynamicTextureProvider

[lilleyse]

Fixes #116

Removes InMemoryAssetResolver and uses Omniverse's built-in DynamicTextureProvider instead. This has several benefits:

• No longer need to convert raw pixels to BMP
• Textures now work when Cesium for Omniverse is first installed, without a restart ¹
• Compressed textures and mipmaps are supported in DynamicTextureProvider. That can be a follow up PR.
• Pixel data can be swapped out dynamically. This means we don't need to create a new material when higher detail imagery comes in. Going a step further, this allows us to do basic material pooling which could significantly improve performance. I haven't actually tested this yet, it will be a follow up PR.
• I no longer see cyan flashes (texture loading) for 3D Tiles input. Red flashes still happen, but that's expected.
• Removed /rtx-transient/resourcemanager/enableTextureStreaming = false workaround from InMemoryAssetResolver plugin not being called #95

This doesn't fix the crashes / hangs we've noticed. At least not all of them. I can still trigger hangs by reloading agi.usda repeatedly.

One potential blocker is that each time a texture is loaded a warning gets printed. I reached out to the Nvidia team about this.

2023-03-29 19:50:32  [Warning] [omni.hydra] Material parameter 'tex' was assigned an incompatible texture: 'dynamic://imagery_ion_2__11718102_184221417_4827478_456288989__11717949_310164846_4827677_90915967'

To do:

• Fix Windows CI

Footnotes

1. Though a restart is still required to register Cesium USD schemas ↩

[weegeekps]

Looks good. One open question.

[weegeekps]

As discussed, please raise this up to Nvidia so we can understand if this is an expected dependency.

[weegeekps]

As long as found is held it blocks other threads, correct? I'm concerned about if there's a case where we could run into a situation where reference count could go negative.

[lilleyse]

I believe accessor acts as a lock guard, so we shouldn't see any race conditions

[weegeekps]

Sounds good. This is good to go once you fix the Windows builds. I'll give it a quick once over when that's done.

[weegeekps]

🚀

[weegeekps]

As discussed offline. Blocking this due to the perceived performance issues and warning spam. We'll revisit this with either the next Kit release or if we get a workaround.

[lilleyse]

This PR doesn't seem to fix the blue dots artifact that shows up in Create when a material is loaded. Interestingly this doesn't happen in cesium.omniverse.app.kit.

This is different from the cyan placeholder when loading textures, which is fixed in this PR.

[weegeekps]

Good to go.