Windows: OpenXR Linking via OpenXR Loader

Adds needed headers for OpenXR, the loader from the OpenXR SDK and
JsonCpp into extern. Took a while to get this to compile/link, but on
Win10 it works fine now without patching #includes. Linux probably
needs more work.

Added a compile option WITH_OPENXR to toggle XR feature compiling.

Also does a dummy xrCreateInstance() call to test linking.

1 files changed, 11 insertions, 0 deletions

diff --git a/source/blender/windowmanager/intern/wm_init_exit.c b/source/blender/windowmanager/intern/wm_init_exit.c
index 04a3115992f..27f4fded6cf 100644
--- a/source/blender/windowmanager/intern/wm_init_exit.c
+++ b/source/blender/windowmanager/intern/wm_init_exit.c
@@ -124,6 +124,10 @@
 
 #include "DEG_depsgraph.h"
 
+#ifdef WITH_OPENXR
+#  include "openxr/openxr.h"
+#endif
+
 #include "DRW_engine.h"
 
 #ifdef WITH_OPENSUBDIV
@@ -212,6 +216,13 @@ void WM_init(bContext *C, int argc, const char **argv)
   wm_operatortype_init();
   wm_operatortypes_register();
 
+#ifdef WITH_OPENXR
+  /* Just to test OpenXR loader linking */
+  XrInstance xr_instance;
+  XrInstanceCreateInfo xr_inst_createi = {0};
+  xrCreateInstance(&xr_inst_createi, &xr_instance);
+#endif
+
   WM_paneltype_init(); /* Lookup table only. */
   WM_menutype_init();
   WM_uilisttype_init();