Revisiting asset bundles

[yaustar]

We have a bundle feature in the Engine and behind a feature flag on the Editor.

https://github.com/playcanvas/engine/blob/main/src/framework/bundle/bundle-registry.js

The expected format is a .tar file and decompression happens on the client after it downloads, at which point all the assets are loaded and processed.

Issues arise from this:

• Decompressing the .tar is expensive and negates any saving we have from latency on multiple requests and varies based on device
• Assets cannot be processed until the whole asset bundle is downloaded

• It requires extra care from the developer to load the bundle first before using any assets inside it (ie trying to load a single asset won't trigger the load of the bundle (should it?))

  What would be great if:

• We could package it up in a way where it doesn't require a separate decompression step (could we gzip it and have the browser do the decompression?)
• Could it be streamable so that we can process assets when that part of the bundle is downloaded?

[yaustar]

I was thinking this morning that rather than tar-ing it, can we make a binary blob that is uncompressed and therefore has no decompression time. We can still rely on server/browser based gzipping to make the package smaller.

Or could we tar this in a way that has no compression (except on network delivery with gzip) and therefore is very quick to open?