How to create contextual VR Menu

Hi,
I am trying to understand how to create a dynamic contextual menu in VR for Cardboard.

For example, I have a scene of an interior of a house. Now when the user turns their head and the reticle points at a surface, say a wall, the entire wall is interactive. When the user activates a click, I want a menu to appear.

Since the user could be looking in any direction, I cannot pre-define the position of the menu, it should just appear in front of the user wherever they are looking.

When the menu appears, the user should be still able to move their head to focus on a particular menu item and select it.

I tried using the Screen Space style menu, but when the user moves the head, the menu also moves with it and hence the user can select only one item.

Is there something I am missing here? Should I not be using screen space on my canvas? What is the right way to do it?

Thanks.

 

Screen space draws directly over the camera.
Since VR cameras behave differently and is all about moving around freely, UI can't be drawn with the same methods you would use in a typical game / app. It was to be drawn somewhere in 3D space where the user can focus. (IE in world space) https://docs.unity3d.com/ScriptReference/Canvas-renderMode.html

This article should have all the information you need on UI in VR :
https://unity3d.com/learn/tutorials/topics/virtual-reality/user-interfaces-vr

And here's a sample code that will place an object directly in front of the camera, looking at the camera. However, some shader tweaking should be done for the object to draw on top of other objects. Note that this may cause some visual strain.

Code (CSharp):

1. private void OnEnable()
2.         {
3.             if (_camera == null)
4.             {
5.                 _camera = Camera.main.transform;
6.             }
7.             if (_transform == null)
8.             {
9.                 _transform = transform;
10.             }
11.             // Director vector
12.             Vector3 director = _camera.forward;
13.  
14.             // Look at rotation
15.             Quaternion inverseRot = Quaternion.LookRotation(director);
16.             _transform.rotation = inverseRot;
17.  
18.             // Position
19.             Vector3 newPos = _camera.position + (director * _distanceToSpawn);
20.             _transform.position = newPos;
21.         }

 

You need to use a world space UI, and instantiate it when the user clicks the button. The position where it spawns could be a transform that is a child of Main Camera, and moved forward on the Z axis. The parent of the UI should be null, it will be a root transform.

I show how that works here:
youtu.be/JzrhU3SDo3Y?t=9m33s

 

Thanks a lot.
Trying to understand your example code.
What does _camera and _transform refer to?

Pardon my basic questions, still in early stages of learning

 

I would start out by checking basic unity tutorials in that case along with the VR Samples project

here's what they both are : https://docs.unity3d.com/ScriptReference/Transform.html

 

Does anyone knows how to do this step in Creating a VR Menu tutorial?