Intel Vulkan Driver Wires Up Image Compression Control For VKD3D-Proton

In addition to Vulkan explicit sync under X11, another merge request hitting Mesa 24.1 overnight that's worth mentioning is the open-source Intel "ANV" Vulkan driver now supporting VK_EXT_image_compression_control.

VK_EXT_image_compression_control is the nearly year-old Vulkan extension that enables fixed-rate image compression and the ability to control it. Per the Khronos Registry:

"This extension enables fixed-rate image compression and adds the ability to control when this kind of compression can be applied. Many implementations support some form of framebuffer compression. This is typically transparent to applications as lossless compression schemes are used. With fixed-rate compression, the compression is done at a defined bitrate. Such compression algorithms generally produce results that are visually lossless, but the results are typically not bit-exact when compared to a non-compressed result. The implementation may not be able to use the requested compression rate in all cases. This extension adds a query that can be used to determine the compression scheme and rate that was applied to an image."

In the Mesa merge request it's noted that Intel worked on this extension in collaborating with Valve's Hans-Kristian Arntzen. The commit notes that VKD3D-Proton is interested in this extension.

For now though the code is limiting VK_EXT_image_compression_control support to VKD3D/VKD3D-Proton. Intel's Lionel Landwerlin noted:

"Limited to vkd3d right now, there are specific use cases there.

We don't want any app to disable compression, it should be mostly transparent and we better be aware of potential bugs."

VKD3D-Proton allows using the VK_EXT_image_compression_control extension to allow for more fine-grained workarounds for otherwise broken games. The Intel Vulkan driver support for VK_EXT_image_compression_control will be in this quarter's Mesa 24.1 release.