1 files changed, 11 insertions, 0 deletions
diff --git a/source/blender/editors/space_view3d/view3d_project.c b/source/blender/editors/space_view3d/view3d_project.c
index 49da1764660..8a900a4e898 100644
--- a/source/blender/editors/space_view3d/view3d_project.c
+++ b/source/blender/editors/space_view3d/view3d_project.c
@@ -330,6 +330,17 @@ float ED_view3d_calc_zfac(const RegionView3D *rv3d, const float co[3], bool *r_f
   return zfac;
 }
 
+/**
+ * Calculate a depth value from `co` (result should only be used for comparison).
+ */
+float ED_view3d_calc_depth_for_comparison(const RegionView3D *rv3d, const float co[3])
+{
+  if (rv3d->is_persp) {
+    return ED_view3d_calc_zfac(rv3d, co, NULL);
+  }
+  return -dot_v3v3(rv3d->viewinv[2], co);
+}
+
 static void view3d_win_to_ray_segment(struct Depsgraph *depsgraph,
                                       const ARegion *region,
                                       const View3D *v3d,