Fix T92099: No undo when moving viewport with camera locked to view

Supports undo step generation while navigating in locked camera view.
NDOF & track-pad navigation are not included for now.

Actions that uses smooth view can be supported but are outside
the scope of this change, includes undo push for:

- VIEW3D_OT_view_pan
- VIEW3D_OT_dolly
- VIEW3D_OT_fly
- VIEW3D_OT_move
- VIEW3D_OT_rotate
- VIEW3D_OT_walk
- VIEW3D_OT_zoom

Reviewed by: campbellbarton

Ref D15345

1 files changed, 38 insertions, 0 deletions

diff --git a/source/blender/editors/space_view3d/view3d_utils.c b/source/blender/editors/space_view3d/view3d_utils.c
index 85b1af8e55d..99f8cbc975b 100644
--- a/source/blender/editors/space_view3d/view3d_utils.c
+++ b/source/blender/editors/space_view3d/view3d_utils.c
@@ -44,6 +44,7 @@
 
 #include "ED_keyframing.h"
 #include "ED_screen.h"
+#include "ED_undo.h"
 #include "ED_view3d.h"
 
 #include "UI_resources.h"
@@ -688,6 +689,43 @@ bool ED_view3d_camera_lock_autokey(View3D *v3d,
   return false;
 }
 
+/**
+ * Create a MEMFILE undo-step for locked camera movement when transforming the view.
+ * Edit and texture paint mode don't use MEMFILE undo so undo push is skipped for them.
+ * NDOF and track-pad navigation would create an undo step on every gesture and we may end up with
+ * unnecessary undo steps so undo push for them is not supported for now. Also operators that uses
+ * smooth view for navigation are excluded too, but they can be supported, see: D15345.
+ */
+static bool view3d_camera_lock_undo_ex(
+    const char *str, View3D *v3d, RegionView3D *rv3d, struct bContext *C, bool undo_group)
+{
+  if (ED_view3d_camera_lock_check(v3d, rv3d)) {
+    if (ED_undo_is_memfile_compatible(C)) {
+      if (undo_group) {
+        ED_undo_grouped_push(C, str);
+      }
+      else {
+        ED_undo_push(C, str);
+      }
+      return true;
+    }
+  }
+  return false;
+}
+
+bool ED_view3d_camera_lock_undo_push(const char *str, View3D *v3d, RegionView3D *rv3d, bContext *C)
+{
+  return view3d_camera_lock_undo_ex(str, v3d, rv3d, C, false);
+}
+
+bool ED_view3d_camera_lock_undo_grouped_push(const char *str,
+                                             View3D *v3d,
+                                             RegionView3D *rv3d,
+                                             bContext *C)
+{
+  return view3d_camera_lock_undo_ex(str, v3d, rv3d, C, true);
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */