Intel Vulkan Driver Lands ASTC LDR Emulation For Latest GPUs

Similar to the Radeon RADV driver recently implementing software-based decoding for Adaptive Scalable Texture Compression (ASTC), the Intel "ANV" Vulkan driver within Mesa has also now wired up ASTC LDR emulation.

Intel's Gen12.5 graphics and newer drop ASTC hardware support. While ASTC is an open standard and has been seeing more use these days as a better alternative to the likes of S3TC, built-in hardware support hasn't proved worthwhile for GPU vendors. Intel Gen12.5 graphics such as the latest integrated and discrete graphics processors go without the ASTC hardware decoding and thus leaving it up to ASTC decoding using compute shaders.

The Intel Iris Gallium3D (OpenGL) driver has made use of this emulated ASTC support for a while on Gen12.5+ hardware while now the Intel ANV Vulkan driver is following a similar route. This merge adds ASTC low dynamic range (LDR) emulation in a similar approach to RADV. This code was merged for the upcoming Mesa 23.3 release.

ASTC is a lossy block-based texture compression algorithm that has been around for more than one decade. Intel graphics supported ASTC in hardware since Skylake (Gen9 graphics) but ended it with Arc / Gen12.5.