Hey there,
I’m trying to implement this QR code tracking method:
I have tried it in unreal 4.27.2, I have all the required plugins and have made other applications in the hololens that work and use the openXR plugins. When I want to preview in vr I keep getting this crash.
"Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000080000000
UE4Editor_MicrosoftOpenXR!winrt::Windows::Foundation::IUnknown::unconditional_release_ref() [D:\build\U5M-Marketplace\Sync\LocalBuilds\PluginTemp\HostProject\Plugins\MicrosoftOpenXR\Intermediate\Microsoft.Windows.CppWinRT.2.0.201217.4\NuGetModule\winrt\base.h:2037]
UE4Editor_MicrosoftOpenXR!MicrosoftOpenXR::FQRTrackingPlugin::UpdateDeviceLocations() [D:\build\U5M-Marketplace\Sync\LocalBuilds\PluginTemp\HostProject\Plugins\MicrosoftOpenXR\Source\MicrosoftOpenXR\Private\QRTrackingPlugin.cpp:258]
UE4Editor_OpenXRHMD
UE4Editor_OpenXRHMD
UE4Editor_Engine
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor
UE4Editor
UE4Editor
UE4Editor
UE4Editor
UE4Editor
kernel32
ntdll"
It seems to occur when the “Toggle ARCapture” node is triggered, because when I remove it from the open level blueprint below, it does not crash.
Ive tried setting a delay for it too, which only delays the same error.
In terms of how its all set up, the open level blueprint is shown above, and I added an actor blueprint according to the tutorial, mine is shown below:
The rest of it is set up based on the microsoft tutorials: 3. Setting up your project for mixed reality - Mixed Reality | Microsoft Learn
this includes the MRPawn and creating the game mode base.
I’m not sure where I’m going wrong here. Any help would be appreciated.
Thanks