(Meta issue) Improve sample load times

[SaschaWillems]

Doing a full batch run in debug mode can take up to 20 minutes. This is especially cumbersome for maintainers, as doing a batch run is now a requirement when doing changes to the framework. One culprit are assets that store textures in ASTC format. This is only supported on mobile and on desktop (where samples are actually developed) those samples need to transcode those textures. This can take a long time, and for a batch run this is done for each and every sample that uses those assets.

We should improve load times of the samples, esp. the ones that use complex scenes.

Related:

• Store Assets in Raw and Compressed formats #860

[SaschaWillems]

Just came up on our reddit: https://www.reddit.com/r/vulkan/comments/1ghalw9/vulkan_samples_slow_loading/

[tomadamatkinson]

@SaschaWillems step one would be to add non compressed versions of our current assets to the asset submodule

I think @JoseEmilio-ARM may be able to help with the scenes provided by ARM. The only other option would be to decompress the ASTC (lossy compressed, so would not advise this)

In terms of compressing assets per platform we could use a python script that compressed images (added to the assets repo) and then add an image resolver to the gltf loader that looks for compressed alternatives if they exist.

There may be better options but this seems inline with the shader work where we do as much offline as possible

[JoseEmilio-ARM]

We have an internal solution to cache the decompressed textures locally, will share a PR for review