The first problem was triangles with motion blur were all grouped into
one category without separating the ones with and without triangle
motion steps.
The second problem was HIP RT uses the generic motion triangle
intersection function and this function checks prim_visibility buffer.
HIP RT doesn't provide the buffer per primitive but passes it to HIP RT
core per instance.
The buffer name was changed to prim_visibility from visibility to be
the same as what Cycles uses but when the motion triangle intersection
function is called from HIP RT kernels, the instance id is passed to
the function instead of primitive id.
Pull Request: https://projects.blender.org/blender/blender/pulls/114555
HIP RT enables AMD hardware ray tracing on RDNA2 and above, and falls back to a
to shader implementation for older graphics cards. It offers an average 25%
sample rendering rate improvement in Cycles benchmarks, on a W6800 card.
The ray tracing feature functions are accessed through HIP RT SDK, available on
GPUOpen. HIP RT traversal functionality is pre-compiled in bitcode format and
shipped with the SDK.
This is not yet enabled as there are issues to be resolved, but landing the
code now makes testing and further changes easier.
Known limitations:
* Not working yet with current public AMD drivers.
* Visual artifact in motion blur.
* One of the buffers allocated for traversal has a static size. Allocating it
dynamically would reduce memory usage.
* This is for Windows only currently, no Linux support.
Co-authored-by: Brecht Van Lommel <brecht@blender.org>
Ref #105538
