Turnip now exposes Vulkan 1.3

RB3 development board with Adreno 630 GPU

It is a major milestone for a driver that is created without any hardware documentation.

The last major roadblocks were VK_KHR_dynamic_rendering and, to a much lesser extent, VK_EXT_inline_uniform_block. Huge props to Connor Abbott for implementing them both!

VK_KHR_dynamic_rendering was an especially nasty extension to implement on tiling GPUs because dynamic rendering allows splitting a render pass between several command buffers.

For desktop GPUs there are no issues with this. They could just record and execute commands in the same order they are submitted without any additional post-processing. Desktop GPUs don’t have render passes internally, they are just a sequence of commands for them.

On the other hand, tiling GPUs have the internal concept of a render pass: they do binning of the whole render pass geometry first, load part of the framebuffer into the tile memory, execute all render pass commands, store framebuffer contents into the main memory, then repeat load_framebufer -> execute_renderpass -> store_framebuffer for all tiles. In Turnip the required glue code is created at the end of a render pass, while the whole render pass contents (when the render pass is split across several command buffers) are known only at the submit time. Therefore we have to stitch the final render pass right there.

What’s next?

Implementing Vulkan 1.3 was necessary to support the latest DXVK (Direct3D 9-11 translation layer). VK_KHR_dynamic_rendering itself was also necessary for the latest VKD3D (Direct3D 12 translation layer).

For now my plan is:

• Continue implementing new extensions for DXVK, VKD3D, and Zink as they come out.
• Focus more on performance.
• Improvements to driver debug tooling so it works better with internal and external debugging utilities.