QR Code Tracking on HoloLens 2 with Unity

1. XR Plugin

   → Project Setting ⇒ XR Plugin Manager ⇒ Select “Windows Mixed Reality”

   → NOTE: MUST use “Windows Mixed Reality” ⇒ “OpenXR” will NOT work with QRCode

2. Install Microsoft.MixedReality.QR package

   → have NuGet for Unity installed

   → Package Manager ⇒ Add package from git URL ⇒ https://github.com/GlitchEnzo/NuGetForUnity.git?path=/src/NuGetForUnity

   → install Microsoft.MixedReality.QR from NuGet

   → NOTE: install Microsoft.MixedReality.QR will also automatically install Microsoft.VCRTForwarders.140 as dependency

3. Enable Webcam

   → Project Setting ⇒ Player ⇒ Publish Settings ⇒ Capabilities ⇒ Select “Webcam”

→ reference to https://github.com/microsoft/MixedReality-QRCode-Sample

→ have all the QR Code script in this zip file

• QRCode.cs (can edit)

  → attached to the QR code object/prefab

  → determine what will be displayed in the scene with the QR code

• QRCodesManager.cs (do NOT edit)

  → main class for handling the QR SDK

  → attached to QRCodeManager object

  → functions:

  • StartQRTracking() & StopQRTracking()

    → start & stop QR code tracking

  • Start()

    → to initialize QR Code tracking

    → QRCodeWatcher.IsSupportted(): check if QR Code scanning is supported on device

    → QRCodeWatcher.RequestAccessAsync(): get permission for webcam

  • SetUpQRTracking()

    → IsTrackerRunning: check if tracker is running

    → qrTracker.Added, qrTracker.Update, qrTracker.Removed: event listeners for new, updated, removed QR codes

    → qrTracker.EnumerationCompleted: list of QR Code added in same session

• QRCodesSetup.cs (do NOT edit)

  → starts the tracking functionality in QRCodesManager object

• QRCodesVisualizer.cs (can edit)

  → handles all QR code visualizing in the scene and instantiates all QR codes in the local list kept in QRCodesManager

• SpatialGraphNodeTracker.cs (do NOT edit)

  → attached to the QR code object/prefab

  → to transform real-world QR code coordinates into the Unity coordinate system

  → also places the virtual QR code object in the scene at the same location as the real-world QR code

• SpatialGraphNode.cs (do NOT edit)

  → abstract the tracking of a spatial graph static node ⇒ represent tracking info of QR code in a GUID id

→ about MyQRCodeManager in https://codeholo.com/2021/03/27/qrcode-tracking-with-hololens-2-xr-sdk-and-mrtk-v2-5/

→ NOTE: QR Code object == object displayed after detecting the QR Code