Fix T78959: Show current frame indicator when interface is locked

When the playhead drawing moved to an overlay, a check was added to keep
it from drawing with a locked interface. This is necessary for some overlays,
but not this one, so this removes the check, making it the responsibility of
the editor.

A context function is added to make that check easier in the future.

Differential Revision: https://developer.blender.org/D8313

1 files changed, 7 insertions, 1 deletions

diff --git a/source/blender/blenkernel/BKE_screen.h b/source/blender/blenkernel/BKE_screen.h
index 91f241018ec..13716ddb5c6 100644
--- a/source/blender/blenkernel/BKE_screen.h
+++ b/source/blender/blenkernel/BKE_screen.h
@@ -142,7 +142,13 @@ typedef struct ARegionType {
   void (*exit)(struct wmWindowManager *wm, struct ARegion *region);
   /* draw entirely, view changes should be handled here */
   void (*draw)(const struct bContext *C, struct ARegion *region);
-  /* Handler to draw overlays. This handler is called every draw loop. */
+  /**
+   * Handler to draw overlays. This handler is called every draw loop.
+   *
+   * \note Some editors should return early if the interface is locked
+   * (check with #CTX_wm_interface_locked) to avoid accessing scene data
+   * that another thread may be modifying
+   */
   void (*draw_overlay)(const struct bContext *C, struct ARegion *region);
   /* optional, compute button layout before drawing for dynamic size */
   void (*layout)(const struct bContext *C, struct ARegion *region);