solved VR fixed sight

[devAxeon]

Hi !

I'm looking for a sight that is not following the scene's geometry like the gaze tracker mesh.

So I tried to create a plane with a texture, child of the VR camera, that is at the center and in front of this camera.

Here's what I've tried: https://www.babylonjs-playground.com/#Q1VRX3#2

But it isn't always in the center, or doesn't work without a headset connected (like for google cardboard).

Furthermore, It would be nice if we can have the good scene.activeCamera on the 'onEnteringVR' event 

Thank you so much for your help !!

[Sebavan]

Adding @trevordev our own VR guru ?

[trevordev]

@devAxeon Valid concerns.

There is an odd quirk with the webVR camera that it's position is not actually your head, instead it is stationary and it's sub cameras are the ones that move (left/right eye cameras). See https://doc.babylonjs.com/how_to/webvr_helper#accessing-vr-device-position-and-rotation , I would update the position of your plane on every frame like done in the example there. This is definitely not ideal as you will have to have separate logic for a vr camera vs non vr camera.

The way onEnteringVR looks to be designed is that it fires right before VR is entered. This also seems odd to me, I can add an onEnteredVR event if desired.

With the introduction of the webXR apis/phasing out of webVR coming to browsers we are thinking of adding new webXR support (Maybe as webXR camera) to babylon that addresses many of the existing concerns raised about the webVR apis. https://github.com/BabylonJS/Babylon.js/issues/3899 . 

[devAxeon]

@trevordev Thanks for those explanations !

Here's what I tried next, but I'm missing something, dunno what... https://www.babylonjs-playground.com/#Q1VRX3#3
onEnteredVR event could help in some cases yep !!

Btw, good "luck" for the the webXR implementation, can't wait to test it !!

[trevordev]

Try this https://www.babylonjs-playground.com/#Q1VRX3#7. It looked like your issue was that sight was still a child of the camera. I undid that and positioned it at cameraPos + cameraForward*distance and it worked.

[devAxeon]

Great !! Thank you very much @trevordev !!
Just one last question: do you have any idea why this doesn't work without a headset (eg: chrome)?

I would like to make it work with google cardbords, but I don't know why it doesn't have the same behavior...

[trevordev]

Give this a shot https://www.babylonjs-playground.com/#Q1VRX3#10

Also note that using babylon objects ._variables are private which means they should not be used in production code and could be changed in the next release.

[devAxeon]

That works perfectly !! Thank you so much for your help @trevordev !!