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/windowmanager/xr/intern/wm_xr_intern.h b/source/blender/windowmanager/xr/intern/wm_xr_intern.h
index 8fb5424b8c2..2cd0ba5c056 100644
--- a/source/blender/windowmanager/xr/intern/wm_xr_intern.h
+++ b/source/blender/windowmanager/xr/intern/wm_xr_intern.h
@@ -88,6 +88,11 @@ typedef struct wmXrViewportPair {
 typedef struct {
   /** Off-screen buffers/viewports for each view. */
   ListBase viewports; /* #wmXrViewportPair */
+
+  /** Dummy region type for controller draw callback. */
+  struct ARegionType *controller_art;
+  /** Controller draw callback handle. */
+  void *controller_draw_handle;
 } wmXrSurfaceData;
 
 typedef struct wmXrDrawData {
@@ -114,12 +119,16 @@ typedef struct wmXrController {
   /input/trigger/value, interaction_path = /user/hand/left/input/trigger/value).
   */
   char subaction_path[64];
-  /* Pose (in world space) that represents the user's hand when holding the controller.*/
+
+  /** Pose (in world space) that represents the user's hand when holding the controller. */
   GHOST_XrPose grip_pose;
   float grip_mat[4][4];
-  /* Pose (in world space) that represents the controller's aiming source. */
+  /** Pose (in world space) that represents the controller's aiming source. */
   GHOST_XrPose aim_pose;
   float aim_mat[4][4];
+
+  /** Controller model. */
+  struct GPUBatch *model;
 } wmXrController;
 
 typedef struct wmXrAction {
@@ -207,3 +216,4 @@ void wm_xr_session_controller_data_clear(wmXrSessionState *state);
 void wm_xr_pose_to_mat(const GHOST_XrPose *pose, float r_mat[4][4]);
 void wm_xr_pose_to_imat(const GHOST_XrPose *pose, float r_imat[4][4]);
 void wm_xr_draw_view(const GHOST_XrDrawViewInfo *draw_view, void *customdata);
+void wm_xr_draw_controllers(const struct bContext *C, struct ARegion *region, void *customdata);