Implement poses functions with "seconds from now"

[xytovl]

OpenXR doesn't natively have a concept of "now", but has extensions to convert OS time to XrTime so that we can implement relative time ourselves.

GetPoseActionDataRelativeToNow is used for instance in The Lab, the change does however not fix the hand movement which is still not smooth.

[xytovl]

I could test GetPoseActionDataRelativeToNow in The Lab, which doesn't make any visible change.
I don't know of games that use GetDeviceToAbsoluteTrackingPose, so I'm not sure how to test that change.

[Supreeeme]

This could use a test if you're up to writing one, if not I'll write it myself.

[Supreeeme]

Why not have the pose cache be Mutex<HashMap<xr::Time, TrackedDevicePose>>?

[xytovl]

It complained that xr::Time was not hashable:

   Compiling xrizer v0.3.0 (/home/xytovl/projects/xrizer)
error[E0599]: the method `get` exists for struct `std::sync::MutexGuard<'_, HashMap<openxr::Time, TrackedDevicePose_t>>`, but its trait bounds were not satisfied
  --> src/input/devices.rs:91:40
   |
91 |         if let Some(pose) = pose_cache.get(xr_time) {
   |                                        ^^^ method cannot be called due to unsatisfied trait bounds
   |
  ::: /home/xytovl/.cargo/git/checkouts/openxrs-419b52284129469d/d0afdd3/sys/src/lib.rs:46:1
   |
46 | pub struct Time(i64);
   | --------------- doesn't satisfy `openxr::Time: Hash`
   |
   = note: the following trait bounds were not satisfied:
           `openxr::Time: Hash`

[Supreeeme]

Ah. In this case I'd prefer if a type like this was defined:

#[derive(PartialEq, Eq, derive_more::From, Copy, Clone)]
struct Time(xr::Time);

impl Hash for Time {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.0.as_nanos().hash(state);
    }
}

Then you should be able to use it like:

pose_cache.get(&Time(xr_time))
pose_cache.insert(Time(xr_time))
// etc

[xytovl]

This could use a test if you're up to writing one, if not I'll write it myself.

What would you test? The cache mechanism, relative time, fallback if openxr now is not available?
I am not familiar with rust yet, so I'm not sure how to mock the instance method.

[Supreeeme]

What would you test?

Relative time. Check that the poses returned from GetPoseActionDataRelativeToNow( and GetPoseActionDataForNextFrame actually differ, and that it returns the right pose basically.

The way xrizer handles tests is primarily unit testing each interface with a mocked OpenXR runtime, this fake runtime lives in the fakexr directory. If you look at the code in there you can see it's just implementing all of the relevant OpenXR functions from the runtime side. So you can add whatever helpers you need and just call the OpenVR functions like an application would. The input tests specifically live in src/input/tests.rs, they should be insightful at least.

[Supreeeme]

Sorry I keep accidentally closing it lol