Add acceleration structure limits

Question

Add acceleration structure limits

Opened this issue 11 days ago · 3 comments

Is your feature request related to a problem? Please describe.
Currently users have no way to get the device limits for acceleration structures. This could be useful for users who need very large acceleration structures. We would also need to check these (we don't do anything right now).

Describe the solution you'd like
We should decide on limits names and defaults (probably just the smallest sizes, most of the sizes are beyond what most people need).

Describe alternatives you've considered
We could just set fixed values.

Additional context
see https://vulkan.gpuinfo.org/listpropertiesextensions.php and search VK_KHR_acceleration_structure

Answer 1 · 2024-12-22T06:00:01.000Z

I think the max*Counts are required to be at least 2^24 - 1.

Answer 2 · 2024-12-22T20:51:23.000Z

also see https://microsoft.github.io/DirectX-Specs/d3d/Raytracing.html#geometry-limits and https://developer.apple.com/documentation/metal/mtlaccelerationstructureusage/mtlaccelerationstructureusageextendedlimits

Answer 3 · 2024-12-22T21:47:05.000Z

I think the minimum max triangle and max instance counts are 2^24-1 (from vulkan) and minimum max primitive count is 2 ^ 28 (from non extended metal limits)