Problems With GetVisibilityMask

[DougChism]

After checking for the extension, I believe I am correctly obtaining the function address via

xrGetInstanceProcAddr(xr_instance, "xrGetVisibilityMaskKHR", (PFN_xrVoidFunction*)(&ext_xrGetVisibilityMaskKHR));

and calling the function via

XrVisibilityMaskKHR VisMask;
if (ext_xrGetVisibilityMaskKHR(xr_session, app_config_view, iView, XR_VISIBILITY_MASK_TYPE_HIDDEN_TRIANGLE_MESH_KHR, &VisMask) == XR_SUCCESS)
{
	int debug = 0;
}

However I get the error

ERROR (OpenXR) : Invalid XrStructureType -858993460 at address 0x5e3b2a8. Expected 'XR_TYPE_VISIBILITY_MASK_KHR'.

Which does not make sense, as I have provided a structure, and it is complaining that it is expecting a structure, but XR_TYPE_VISIBILITY_MASK_KHR is actually an enumeration, that identifies the structure I am passing down.

There no samples or code anywhere on the net demonstrating this capability so I am at a loss as to how to proceed. Clearly giving it the address of an enumeration will not work. The visibility mask is essential for performance.

[carsten_neumann]

@DougChism

Which does not make sense, as I have provided a structure,

Yes, but you have not initialized any of the structure members, in particular you have not initialized the .type and .next members:

XrVisibilityMaskKHR VisMask;
VisMask.type = XR_TYPE_VISIBILITY_MASK_KHR;
VisMaks.next = nullptr;
// initialize the remaining members of VisMask

This is very much idiomatic for OpenXR and used everywhere in the API, please take a look at what any other piece of code that passes any type of struct to OpenXR does.

[ryliepavlik]

Yep, that’s the issue. You have to initialize the structures before you pass them in. For reference, here’s the relevant part of the spec: for the type field, https://www.khronos.org/registry/OpenXR/specs/1.0/html/xrspec.html#valid-usage-for-structure-types for the next pointer, https://www.khronos.org/registry/OpenXR/specs/1.0/html/xrspec.html#valid-usage-for-structure-pointer-chains

[DougChism]

Thanks for the help all I appreciate it.