The shader code output contains a little bit of plaintext such as I/O identifiers and the shader name, which was generated for the DXC backend in a way that prevents caching.
This unifies the shader name in the output code and improves the cache hit ratio for a Lyra cook from 0% to roughly 50% cache hits (for certain platforms).
#rb Jason.Nadro, Carl.Lloyd
#fyi Brian.White, Arciel.Rekman, Brandon.Schaefer
#jira FORT-548603
#preflight 63e26c6c07207b2570ba2d5b
#rnx
[CL 24050212 by Laura Hermanns in ue5-main branch]
Add ray tracing shader types
Add initial ray tracing pipeline creation
Add acceleration structure descriptor type
Add basic ray tracing pipeline, occlusion support initially
Strip reflection from ray tracing shader spirv to deal with validation warnings
Don't use an array of vk descriptor types directly, this breaks with non-contiguous enum values which are common in extensions. Using a TMap from descriptor type to values instead.
Don't store vk types in the serialized shader header, translate to and from our own internal enum types to avoid similar non-contiguous value issues.
Re-enabled ray tracing compilation on windows desktop, explicitly disable runtime support using GRHISupportsRayTracing
Todo:
We need to deal with the lack of a 1:1 mapping between shader stages and frequencies for ray tracing hit groups. This is a one to many mapping which doesn't work with how most of the Vulkan RHI is authored. For now I'm assuming a hitgroup maps to a CHS.
Ray tracing shader descriptor allocation and pending state support. While we are serializing the descriptors for ray tracing shaders, we're not allocating or updating them yet which is the last large chunk needed to trace rays.
Fix spirv binary version mismatch validation error. This basically needs a local dxc modification which explicitly sets the spirv binary version to work around incorrect assuptions in dxc which is causing validation failures.
Add another local dxc modification to allow for arbirary struct size support using VK_EXT_scalar_block_layout for ray tracing shaders.
#rb jeannoe.morissette, lukas.hermanns
[CL 16711940 by Ryan Vance in ue5-main branch]
