Fix T79324: Crash when changing View Layer while VR session runs

Proper handling of View Layers for the VR session was never implemented.
Now the View Layer of the VR session follows the window the session was
started in.
Note that if this window is closed, we fallback to another window. This
is done to avoid the overhead it would take to maintain a separate
depsgraph for the VR view. Instead we always share some already visible
View Layer (and hence the depsgraph).

1 files changed, 5 insertions, 1 deletions

diff --git a/source/blender/windowmanager/xr/intern/wm_xr_intern.h b/source/blender/windowmanager/xr/intern/wm_xr_intern.h
index c49e9e534b6..25e3da3ffb4 100644
--- a/source/blender/windowmanager/xr/intern/wm_xr_intern.h
+++ b/source/blender/windowmanager/xr/intern/wm_xr_intern.h
@@ -49,7 +49,11 @@ typedef struct wmXrSessionState {
 typedef struct wmXrRuntimeData {
   GHOST_XrContextHandle context;
 
-  /* Although this struct is internal, RNA gets a handle to this for state information queries. */
+  /** The window the session was started in. Stored to be able to follow its view-layer. This may
+   * be an invalid reference, i.e. the window may have been closed. */
+  wmWindow *session_root_win;
+
+  /** Although this struct is internal, RNA gets a handle to this for state information queries. */
   wmXrSessionState session_state;
   wmXrSessionExitFn exit_fn;
 } wmXrRuntimeData;