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, 62 insertions, 0 deletions

diff --git a/source/blender/draw/intern/draw_manager.c b/source/blender/draw/intern/draw_manager.c
index b8de92dea7f..c8900d64935 100644
--- a/source/blender/draw/intern/draw_manager.c
+++ b/source/blender/draw/intern/draw_manager.c
@@ -51,6 +51,7 @@
 #include "BKE_pbvh.h"
 #include "BKE_pointcache.h"
 #include "BKE_pointcloud.h"
+#include "BKE_screen.h"
 #include "BKE_volume.h"
 
 #include "DNA_camera_types.h"
@@ -1418,6 +1419,27 @@ void DRW_draw_callbacks_post_scene(void)
 
     ED_region_draw_cb_draw(DST.draw_ctx.evil_C, DST.draw_ctx.region, REGION_DRAW_POST_VIEW);
 
+#ifdef WITH_XR_OPENXR
+    /* XR callbacks (controllers, custom draw functions) for session mirror. */
+    if ((v3d->flag & V3D_XR_SESSION_MIRROR) != 0) {
+      if ((v3d->flag2 & V3D_XR_SHOW_CONTROLLERS) != 0) {
+        ARegionType *art = WM_xr_surface_controller_region_type_get();
+        if (art) {
+          ED_region_surface_draw_cb_draw(art, REGION_DRAW_POST_VIEW);
+        }
+      }
+      if ((v3d->flag2 & V3D_XR_SHOW_CUSTOM_OVERLAYS) != 0) {
+        SpaceType *st = BKE_spacetype_from_id(SPACE_VIEW3D);
+        if (st) {
+          ARegionType *art = BKE_regiontype_from_id(st, RGN_TYPE_XR);
+          if (art) {
+            ED_region_surface_draw_cb_draw(art, REGION_DRAW_POST_VIEW);
+          }
+        }
+      }
+    }
+#endif
+
     /* Callback can be nasty and do whatever they want with the state.
      * Don't trust them! */
     DRW_state_reset();
@@ -1464,6 +1486,46 @@ void DRW_draw_callbacks_post_scene(void)
       ED_annotation_draw_view3d(DEG_get_input_scene(depsgraph), depsgraph, v3d, region, true);
       GPU_depth_test(GPU_DEPTH_LESS_EQUAL);
     }
+
+#ifdef WITH_XR_OPENXR
+    if ((v3d->flag & V3D_XR_SESSION_SURFACE) != 0) {
+      DefaultFramebufferList *dfbl = DRW_viewport_framebuffer_list_get();
+
+      DRW_state_reset();
+
+      GPU_framebuffer_bind(dfbl->overlay_fb);
+
+      GPU_matrix_projection_set(rv3d->winmat);
+      GPU_matrix_set(rv3d->viewmat);
+
+      /* XR callbacks (controllers, custom draw functions) for session surface. */
+      if (((v3d->flag2 & V3D_XR_SHOW_CONTROLLERS) != 0) ||
+          ((v3d->flag2 & V3D_XR_SHOW_CUSTOM_OVERLAYS) != 0)) {
+        GPU_depth_test(GPU_DEPTH_NONE);
+        GPU_apply_state();
+
+        if ((v3d->flag2 & V3D_XR_SHOW_CONTROLLERS) != 0) {
+          ARegionType *art = WM_xr_surface_controller_region_type_get();
+          if (art) {
+            ED_region_surface_draw_cb_draw(art, REGION_DRAW_POST_VIEW);
+          }
+        }
+        if ((v3d->flag2 & V3D_XR_SHOW_CUSTOM_OVERLAYS) != 0) {
+          SpaceType *st = BKE_spacetype_from_id(SPACE_VIEW3D);
+          if (st) {
+            ARegionType *art = BKE_regiontype_from_id(st, RGN_TYPE_XR);
+            if (art) {
+              ED_region_surface_draw_cb_draw(art, REGION_DRAW_POST_VIEW);
+            }
+          }
+        }
+
+        DRW_state_reset();
+      }
+
+      GPU_depth_test(GPU_DEPTH_LESS_EQUAL);
+    }
+#endif
   }
 }