Support Window-less (offscreen) VR session on Windows

Uses the new wmSurface type (non-window drawable container) to manage
the OpenGL, DirectX and GPU module contexts. The draw callback of the XR
surface calls the GHOST_Xr session drawing routines.

What you should see when starting a VR session now (using the WMR
runtime): The Windows Mixed Reality Portal pops up, and a blue
background is drawn on the HMD. This is from the blue color clear call
we do in the drawing preparations of the GHOST_Xr session drawing.

1 files changed, 3 insertions, 2 deletions

diff --git a/source/blender/windowmanager/intern/wm_xr.c b/source/blender/windowmanager/intern/wm_xr.c
index e02aee7beb2..cad02fc20c2 100644
--- a/source/blender/windowmanager/intern/wm_xr.c
+++ b/source/blender/windowmanager/intern/wm_xr.c
@@ -104,14 +104,15 @@ wmSurface *wm_xr_session_surface_create(wmWindowManager *wm, unsigned int gpu_bi
 
   wm_window_clear_drawable(wm);
   wm_surface_clear_drawable();
+  surface->ghost_ctx = WM_opengl_context_create();
+  WM_opengl_context_activate(surface->ghost_ctx);
 
   switch (gpu_binding_type) {
     case GHOST_kXrGraphicsOpenGL:
-      surface->ghost_ctx = WM_opengl_context_create();
-      WM_opengl_context_activate(surface->ghost_ctx);
       break;
 #ifdef WIN32
     case GHOST_kXrGraphicsD3D11:
+      surface->secondary_ghost_ctx = WM_directx_context_create();
       break;
 #endif
   }