Godot Game Engine Has Been Backing "Betsy" As A GPU-Based Texture Compressor
Betsy is the open-source project being worked on for the Godot Engine. Betsy implements BC6, ETC1, ETC2, and EAC algorithms among others using GLSL compute shaders. This compressor is implemented as GLSL compute shaders so the work can be offloaded to the graphics processor either via OpenGL or Vulkan usage as well.
Betsy can be driven via a command-line program for compressing textures or the compute shaders can be used directly such as how the Godot Game Engine is preparing to make use of them with Vulkan. Betsy is purely focused on GPU texture compression and doesn't implement any CPU-based path, short of using the likes of LLVMpipe for ultimately running the shaders on a CPU.
Betsy is still young in development but is making good progress so far. The code can be found via GitHub. Over on the Godot Engine Blog is a write-up about Betsy and the early results thus far and why speedy texture compression is important for the game engine.
Finding this interesting, I did add Betsy to the Phoronix Test Suite / OpenBenchmarking.org for benchmarking this GPU texture compressor on various drivers/GPUs moving forward with different algorithm/quality options. Betsy did indeed perform very well with the newest Radeon dGPUs but did encounter some troubles particularly on older generations of Intel Gen9 graphics and Polaris and older AMD hardware hitting some hangs. Renoir as well happened to be troublesome as well. So it looks like Betsy may be a useful test case as well for the Mesa drivers. On the GPUs where it does work well, some results will begin to accumulate soon on OpenBenchmarking.org.