XR Controller Support Step 4: Controller Drawing

Addresses T77127 (Controller Drawing).

Adds VR controller visualization and custom drawing via draw
handlers. Add-ons can draw to the XR surface (headset display) and
mirror window by adding a View3D draw handler of region type 'XR' and
draw type 'POST_VIEW'.  Controller drawing and custom overlays can be
toggled individually as XR session options, which will be added in a
future update to the VR Scene Inspection add-on.

For the actual drawing, the OpenXR XR_MSFT_controller_model extension
is used to load a glTF model provided by the XR runtime. The model's
vertex data is then used to create a GPUBatch in the XR session
state. Finally, this batch is drawn via the XR surface draw handler
mentioned above.

For runtimes that do not support the controller model extension, a
a simple fallback shape (sphere) is drawn instead.

Reviewed By: Severin, fclem

Differential Revision: https://developer.blender.org/D10948

1 files changed, 12 insertions, 2 deletions

diff --git a/source/blender/editors/space_api/spacetypes.c b/source/blender/editors/space_api/spacetypes.c
index 3da283089c5..149067a94fe 100644
--- a/source/blender/editors/space_api/spacetypes.c
+++ b/source/blender/editors/space_api/spacetypes.c
@@ -264,9 +264,9 @@ void ED_region_draw_cb_exit(ARegionType *art, void *handle)
   }
 }
 
-void ED_region_draw_cb_draw(const bContext *C, ARegion *region, int type)
+static void ed_region_draw_cb_draw(const bContext *C, ARegion *region, ARegionType *art, int type)
 {
-  LISTBASE_FOREACH_MUTABLE (RegionDrawCB *, rdc, &region->type->drawcalls) {
+  LISTBASE_FOREACH_MUTABLE (RegionDrawCB *, rdc, &art->drawcalls) {
     if (rdc->type == type) {
       rdc->draw(C, region, rdc->customdata);
 
@@ -276,6 +276,16 @@ void ED_region_draw_cb_draw(const bContext *C, ARegion *region, int type)
   }
 }
 
+void ED_region_draw_cb_draw(const bContext *C, ARegion *region, int type)
+{
+  ed_region_draw_cb_draw(C, region, region->type, type);
+}
+
+void ED_region_surface_draw_cb_draw(ARegionType *art, int type)
+{
+  ed_region_draw_cb_draw(NULL, NULL, art, type);
+}
+
 void ED_region_draw_cb_remove_by_type(ARegionType *art, void *draw_fn, void (*free)(void *))
 {
   LISTBASE_FOREACH_MUTABLE (RegionDrawCB *, rdc, &art->drawcalls) {