crunch

Have you considered compressed texture formats, perhaps DXT5? Fixed compression ratio (1 byte per pixel for DXT5), arbitrary random access, decompress the pixels you need on the fly. Can be further compressed for efficient storage to about 1-2 bits per pixel with https://github.com/BinomialLLC/crunch.

I wouldn't call Oodle Texture a hack. But there's also https://github.com/BinomialLLC/crunch and https://github.com/BinomialLLC/basis_universal. The latter has the advantage that it can be decoded to multiple different compressed texture formats, so that all GPUs can be supported from a single file (different GPUs support different formats so you can't necessarily send the same compressed texture to any GPU).

From this [1] it sounds like the texture is a modified variant of ETC1, which gets loaded up from disk into memory as such, and transcoded on the CPU into target GPU format (DXT, PVRTC, etc), and then uploaded to VRAM. If so that sounds similar to their previous Crunch library [2], in that it does transcoding on the CPU before moving the texture to the GPU - but most likely much faster than Crunch because it starts with ETC as shared basis. (And artifacts are a common with transcoding between compressed formats, especially when transparency is present, but I have high hopes for this one considering the authors! :) ) Authors suggest that a version that transcodes on the GPU would be possible - that would be really interesting, I would imagine that would be even faster, although at the cost of higher texture memory usage. [1] https://githu