Android Native (C++) OpenXR Application. HTC Vive Focus 3

[ste-phil]

Hello,

I am trying to build an Android app that initializes the OpenXR Runtime in C++ for the HTC Vive Focus 3

The problem is that the application fails at the xrCreateInstance() method provided by the OpenXR loader, which should pass the requested function to the runtime.  The encountered error seems to be an access violation (SIGSEV) due to a nullptr, when trying to find the xrCreateInstance method in the runtime. (maybe the function does not exist?).

The stacktrace of the error:

art_sigsegv_fault 0x00000077a19766dc
art::FaultManager::HandleFault(int, siginfo*, void*) 0x00000077a1976be0
art::SignalChain::Handler(int, siginfo*, void*) 0x000000566c858ec4
__kernel_rt_sigreturn 0x0000007828ce8678
<unknown> 0x0000007734936ae8
RuntimeInterface::CreateInstance(const XrInstanceCreateInfo *, XrInstance_T **) runtime_interface.cpp:457
LoaderXrTermCreateInstance(const XrInstanceCreateInfo *, XrInstance_T **) loader_core.cpp:423
LoaderInstance::CreateInstance(XrResult (*)(XrInstance_T *, const char *, void (**)()), XrResult (*)(const XrInstanceCreateInfo *, XrInstance_T **), XrResult (*)(const XrInstanceCreateInfo *, const XrApiLayerCreateInfo *, XrInstance_T **), std::__ndk1::vector<…>, const XrInstanceCreateInfo *, std::__ndk1::unique_ptr<…> *) loader_instance.cpp:250
LoaderXrCreateInstance(const XrInstanceCreateInfo *, XrInstance_T **) loader_core.cpp:275
xrCreateInstance(const XrInstanceCreateInfo *, XrInstance *) loader_core.cpp:835
main_body() list_json.cpp:137

 

The basics steps I took were:

• Grabbed an OpenXR loader

  • According to https://developer.vive.com/resources/openxr/unity/download/latest/ is is compatible with the OpenXR loader v1.0.26

• Created an Android studio project with a native plugin in c++
• Created a project according to https://registry.khronos.org/OpenXR/specs/1.0/loader.html#runtime-interaction
  • This explains how to setup the android manifest so that the loader is able to load a runtime.
•  Added a few lines of code to enumerate OpenXR features and then start the instance.

 

What I already tried:

• Created my own Android app with a Native side.
  • Error encountered.
• Built the Android sample app by Khronos using this repo: https://github.com/KhronosGroup/OpenXR-SDK-Source.
  • Same error.
• Enumerating the features creating the instance.
  • This works fine, the runtime lists a total 22 supported features.
• Used a selection of different OpenXR loaders.
  • All of them encounter the same issue.
• Running a the handtracking unity sample to see if it is an issue with the device. 
  • Works.

 

If anybody has already done something similar I would be glad on some insight about what I might have missed. Does it maybe need some preconfiguration?

 

Kind regards

Philipp

 

[Alex_HTC]

@ste-phil
Hi Philipp!

Creating a C++ application using the open source loader is something that has been done by a few folks, so I'm a little confused as to what the error may be.

Using the hello_xr app that's a part of https://github.com/KhronosGroup/OpenXR-SDK-Source seems to work just fine for me, does that also work for you?

What other functionality other than what is in hello_xr sample above are you using? Can you fork and create a branch with these changes?

Thanks,
Alex