How to get current frame in useFrame?

[sergidomenechguzy]

Hi I am currently trying to rebuild the threejs AR hit test example using react-three-fiber to build on top of it.

In the example they are doing something like this to run the hit test on every frame:

renderer.setAnimationLoop((timestamp, frame) => {
  // run the hit test on the current frame
});

Now in react-three-fiber I am using a Canvas and setting vr={true} so that it internally switches to setAnimationLoop() instead of requestAnimationFrame(). To overwrite the animation loop I am using useFrame() and want to pass it a function that handles the hit test.

The problem is in useFrame() I only have access to the same state objects as in useThree() and a clock delta (API documentation). But I didn't find any way to access the current frame in the same way the threejs example does and I definitely need this frame to perform the hit test

So is there a way that I can get that same frame object in useFrame() that is accessible when passing a function directly into renderer.setAnimationLoop()?

I hope someone can help me with this as I really want to use react-three-fiber instead of plain threejs.

[drcmda]

what is a "frame"? setAnimationLoop((timestamp, frame) seems undocumented, i dont see it mentioned anywhere. is this simply the delta perhaps?

[sergidomenechguzy]

The frame is an XRFrame that is passed into the requestAnimationFrame() and setAnimationLoop() callbacks when running in an XRSession in addition to the frame time. I am using the WebXR API to create an ARSession just like in the plain threejs example I mentioned above.

So apparently this frame object is only available when an XRSession is running but I wasn't really able to find a lot of further information about it as there is generally not a lot of information about the WebXR API.

[drcmda]

if you want make a PR so that it gets forwarded, i have no experience with AR and wouldnt know how to test it myself. and have you looked into react-xr? it seems to me they have abstracted such things already: https://github.com/react-spring/react-xr they're doing this https://twitter.com/dubenko_/status/1221109131890872320 and more, hit testing is definitvely included.

[sergidomenechguzy]

Yes I have looked into it but found no alternative to react-three-fibers useFrame() that lets me access the XRFrame. But it is very well possible that there exists a way in react-xr that let's me do this.

I will look into it more when I have the time and look if it is possible to somehow forward it.
Thank you a lot for your time and patience though.