6 OpenXR Controller Support¶

The controller part mainly contains event and extension.

6.1 Event of Controller¶

The event is defined as follows:

enum xrt_device_eventtype
{
    XRT_DEVICE_CONNECTCHANGED = 0,
    XRT_DEVICE_MAIN_CHANGED = 1,
    XRT_DEVICE_VERSION = 2,
    XRT_DEVICE_SN = 3,
    XRT_DEVICE_BIND_STATUS = 4,
    XRT_STATION_STATUS = 5,
    XRT_DEVICE_IOBUSY = 6,
    XRT_DEVICE_OTASTAUS = 7,
    XRT_DEVICE_ID = 8,
    XRT_DEVICE_HANDNESS_CHANGED = 15,
    XRT_DEVICE_CHANNEL = 16,
    XRT_DEVICE_LOSSRATE = 17,
    XRT_DEVICE_THREAD_STARTED = 18
};
typedef struct XrControllerEventChanged {
     XrStructureType              type;
     const void* XR_MAY_ALIAS     next;
     enum xrt_device_eventtype    eventtype;
     uint8_t                      controller;
     uint8_t                      status;
     uint8_t                      varying[400];
     uint16_t                     length;
} XrControllerEventChanged;

The bottom layer notifies the top layer via xrPollevent when the controller state changes, and the corresponding type is XR_TYPE_EVENT_CONTROLLER_STATE_CHANGED.

The xrt_device_eventtype is commented as follows:

XRT_DEVICE_CONNECTCHANGED  //the connection of controller has changed
XRT_DEVICE_MAIN_CHANGED   //the main controller has changed
XRT_DEVICE_VERSION   //return controller version
XRT_DEVICE_SN  //return controller SN
XRT_DEVICE_BIND_STATUS //the binding status of controller has changed
XRT_STATION_STATUS  //the station status of controller has changed
XRT_DEVICE_IOBUSY   //the serial port is busy
XRT_DEVICE_OTASTAUS  //the OTA status of controller has changed
XRT_DEVICE_ID //return controller ID
XRT_DEVICE_HANDNESS_CHANGED  //the handness has changed
XRT_DEVICE_CHANNEL //the electronic channel has changed
XRT_DEVICE_LOSSRATE  //packet loss rate of controller
XRT_DEVICE_THREAD_STARTED //the controller binding thread has started

6.2 Extension of Controller¶

To use the feature of controller, you need to enable the extension XR_PICO_android_controller_function_ext_enable at xrCreateInstance, and then use xrGetInstanceProcAddress to get the function pointer to the extension function after successful creation of xrInstance .

It is as follows:

PFN_xrGetControllerConnectionStatePico pfnXrGetControllerConnectionStatePico;
xrGetInstanceProcAddr(up.mInstance,"xrGetControllerConnectionStatePico",reinterpret_cast<PFN_xrVoidFunction*>(&pfnXrGetControllerConnectionStatePico));

For the extended use of controller, you can refer to the HelloXR Sample, which shows the use of controller vibration extension ( xrVibrateControllerPico ). In this Sample, the vibration of controller is realized by long pressing the Trigger button.

The extension function definition is detailed as follows:

xrGetControllerConnectionStatePico¶

Function name: XrResult XRAPI_CALL xrGetControllerConnectionStatePico(XrInstance instance,uint8_t controllerhandle,uint8_t* status)

Function: getting the connection status of controller

Parameters: controllerhandle 0 - left controller; 1 - right controller

status - connection status 0 - disconnected; 1 - connected