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

2 files changed, 41 insertions, 12 deletions

diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index f68a4d78a00..bedc24a6287 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -1798,5 +1798,10 @@ void ED_spacetype_view3d(void)
   art = ED_area_type_hud(st->spaceid);
   BLI_addhead(&st->regiontypes, art);
 
+  /* regions: xr */
+  art = MEM_callocN(sizeof(ARegionType), "spacetype view3d xr region");
+  art->regionid = RGN_TYPE_XR;
+  BLI_addhead(&st->regiontypes, art);
+
   BKE_spacetype_register(st);
 }
diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index 733ec7e81cd..4da24888e1d 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -339,7 +339,16 @@ static void view3d_xr_mirror_setup(const wmWindowManager *wm,
   }
   view3d_main_region_setup_view(depsgraph, scene, v3d, region, viewmat, NULL, rect);
 
-  /* Reset overridden View3D data */
+  /* Set draw flags. */
+  SET_FLAG_FROM_TEST(v3d->flag2,
+                     (wm->xr.session_settings.draw_flags & V3D_OFSDRAW_XR_SHOW_CONTROLLERS) != 0,
+                     V3D_XR_SHOW_CONTROLLERS);
+  SET_FLAG_FROM_TEST(v3d->flag2,
+                     (wm->xr.session_settings.draw_flags & V3D_OFSDRAW_XR_SHOW_CUSTOM_OVERLAYS) !=
+                         0,
+                     V3D_XR_SHOW_CUSTOM_OVERLAYS);
+
+  /* Reset overridden View3D data. */
   v3d->lens = lens_old;
 }
 #endif /* WITH_XR_OPENXR */
@@ -1757,6 +1766,7 @@ void ED_view3d_draw_offscreen_simple(Depsgraph *depsgraph,
                                      const float winmat[4][4],
                                      float clip_start,
                                      float clip_end,
+                                     bool is_xr_surface,
                                      bool is_image_render,
                                      bool draw_background,
                                      const char *viewname,
@@ -1786,23 +1796,37 @@ void ED_view3d_draw_offscreen_simple(Depsgraph *depsgraph,
     v3d.shading.flag = V3D_SHADING_SCENE_WORLD | V3D_SHADING_SCENE_LIGHTS;
   }
 
-  if (draw_flags & V3D_OFSDRAW_SHOW_ANNOTATION) {
-    v3d.flag2 |= V3D_SHOW_ANNOTATION;
+  if ((draw_flags & ~V3D_OFSDRAW_OVERRIDE_SCENE_SETTINGS) == V3D_OFSDRAW_NONE) {
+    v3d.flag2 = V3D_HIDE_OVERLAYS;
   }
-  if (draw_flags & V3D_OFSDRAW_SHOW_GRIDFLOOR) {
-    v3d.gridflag |= V3D_SHOW_FLOOR | V3D_SHOW_X | V3D_SHOW_Y;
-    v3d.grid = 1.0f;
-    v3d.gridlines = 16;
-    v3d.gridsubdiv = 10;
-
-    /* Show grid, disable other overlays (set all available _HIDE_ flags). */
+  else {
+    if (draw_flags & V3D_OFSDRAW_SHOW_ANNOTATION) {
+      v3d.flag2 |= V3D_SHOW_ANNOTATION;
+    }
+    if (draw_flags & V3D_OFSDRAW_SHOW_GRIDFLOOR) {
+      v3d.gridflag |= V3D_SHOW_FLOOR | V3D_SHOW_X | V3D_SHOW_Y;
+      v3d.grid = 1.0f;
+      v3d.gridlines = 16;
+      v3d.gridsubdiv = 10;
+    }
+    if (draw_flags & V3D_OFSDRAW_SHOW_SELECTION) {
+      v3d.flag |= V3D_SELECT_OUTLINE;
+    }
+    if (draw_flags & V3D_OFSDRAW_XR_SHOW_CONTROLLERS) {
+      v3d.flag2 |= V3D_XR_SHOW_CONTROLLERS;
+    }
+    if (draw_flags & V3D_OFSDRAW_XR_SHOW_CUSTOM_OVERLAYS) {
+      v3d.flag2 |= V3D_XR_SHOW_CUSTOM_OVERLAYS;
+    }
+    /* Disable other overlays (set all available _HIDE_ flags). */
     v3d.overlay.flag |= V3D_OVERLAY_HIDE_CURSOR | V3D_OVERLAY_HIDE_TEXT |
                         V3D_OVERLAY_HIDE_MOTION_PATHS | V3D_OVERLAY_HIDE_BONES |
                         V3D_OVERLAY_HIDE_OBJECT_XTRAS | V3D_OVERLAY_HIDE_OBJECT_ORIGINS;
     v3d.flag |= V3D_HIDE_HELPLINES;
   }
-  else {
-    v3d.flag2 = V3D_HIDE_OVERLAYS;
+
+  if (is_xr_surface) {
+    v3d.flag |= V3D_XR_SESSION_SURFACE;
   }
 
   rv3d.persp = RV3D_PERSP;