Object: Enable transfer mode functionality for switching objects in Sculpt Mode

This implements the changes discussed in T87134 for including switch
object funcionality in 2.93. This includes:

- Remove the switch object operator experimental option
- Remove the option for switching objects in Edit Mode.
- Rename switch_object to transfer_mode.
- Enable the operator only in sculpt mode.
- Expose the operator in the Sculpt menu with an eyedropper modal
option.

On later releases, we could revisit enabling the operator in other mode
and object types as well as its place in the UI.

Reviewed By: JulienKaspar, JacquesLucke

Differential Revision: https://developer.blender.org/D10953

1 files changed, 101 insertions, 33 deletions

diff --git a/source/blender/editors/object/object_modes.c b/source/blender/editors/object/object_modes.c
index 99103cf10c7..ff1855cafc5 100644
--- a/source/blender/editors/object/object_modes.c
+++ b/source/blender/editors/object/object_modes.c
@@ -30,6 +30,8 @@
 #include "BLI_math.h"
 #include "BLI_utildefines.h"
 
+#include "BLT_translation.h"
+
 #include "BKE_context.h"
 #include "BKE_gpencil_modifier.h"
 #include "BKE_layer.h"
@@ -39,11 +41,13 @@
 #include "BKE_paint.h"
 #include "BKE_report.h"
 #include "BKE_scene.h"
+#include "BKE_screen.h"
 
 #include "WM_api.h"
 #include "WM_types.h"
 
 #include "RNA_access.h"
+#include "RNA_define.h"
 
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_query.h"
@@ -400,51 +404,59 @@ bool ED_object_mode_generic_has_data(struct Depsgraph *depsgraph, struct Object
 /** \} */
 
 /* -------------------------------------------------------------------- */
-/** \name Switch Object
+/** \name Transfer Mode
  *
  * Enters the same mode of the current active object in another object,
  * leaving the mode of the current object.
  * \{ */
 
-static bool object_switch_object_poll(bContext *C)
+static bool object_transfer_mode_poll(bContext *C)
 {
-
-  if (!U.experimental.use_switch_object_operator) {
-    return false;
-  }
-
   if (!CTX_wm_region_view3d(C)) {
     return false;
   }
   const Object *ob = CTX_data_active_object(C);
-  return ob && (ob->mode & (OB_MODE_EDIT | OB_MODE_SCULPT));
+  return ob && (ob->mode & (OB_MODE_SCULPT));
 }
 
-static int object_switch_object_invoke(bContext *C, wmOperator *op, const wmEvent *event)
+/* Update the viewport rotation origin to the mouse cursor. */
+static void object_transfer_mode_reposition_view_pivot(bContext *C, const int mval[2])
 {
   ARegion *region = CTX_wm_region(C);
   Scene *scene = CTX_data_scene(C);
-  ViewLayer *view_layer = CTX_data_view_layer(C);
 
-  Base *base_dst = ED_view3d_give_base_under_cursor(C, event->mval);
+  float global_loc[3];
+  if (!ED_view3d_autodist_simple(region, mval, global_loc, 0, NULL)) {
+    return;
+  }
+  UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
+  copy_v3_v3(ups->average_stroke_accum, global_loc);
+  ups->average_stroke_counter = 1;
+  ups->last_stroke_valid = true;
+}
+
+static bool object_transfer_mode_to_base(bContext *C, wmOperator *op, Base *base_dst)
+{
+  Scene *scene = CTX_data_scene(C);
+  ViewLayer *view_layer = CTX_data_view_layer(C);
 
   if (base_dst == NULL) {
-    return OPERATOR_CANCELLED;
+    return false;
   }
 
   Object *ob_dst = base_dst->object;
   Object *ob_src = CTX_data_active_object(C);
 
   if (ob_dst == ob_src) {
-    return OPERATOR_CANCELLED;
+    return false;
   }
 
   const eObjectMode last_mode = (eObjectMode)ob_src->mode;
   if (!ED_object_mode_compat_test(ob_dst, last_mode)) {
-    return OPERATOR_CANCELLED;
+    return false;
   }
 
-  int retval = OPERATOR_CANCELLED;
+  bool mode_transfered = false;
 
   ED_undo_group_begin(C);
 
@@ -460,42 +472,98 @@ static int object_switch_object_invoke(bContext *C, wmOperator *op, const wmEven
     ob_dst_orig = DEG_get_original_object(ob_dst);
     ED_object_mode_set_ex(C, last_mode, true, op->reports);
 
-    /* Update the viewport rotation origin to the mouse cursor. */
-    if (last_mode & OB_MODE_ALL_PAINT) {
-      float global_loc[3];
-      if (ED_view3d_autodist_simple(region, event->mval, global_loc, 0, NULL)) {
-        UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
-        copy_v3_v3(ups->average_stroke_accum, global_loc);
-        ups->average_stroke_counter = 1;
-        ups->last_stroke_valid = true;
-      }
-    }
-
     WM_event_add_notifier(C, NC_SCENE | ND_OB_SELECT, scene);
     WM_toolsystem_update_from_context_view3d(C);
-    retval = OPERATOR_FINISHED;
+    mode_transfered = true;
   }
 
   ED_undo_group_end(C);
+  return mode_transfered;
+}
 
-  return retval;
+static int object_transfer_mode_modal(bContext *C, wmOperator *op, const wmEvent *event)
+{
+  switch (event->type) {
+    case LEFTMOUSE:
+      if (event->val == KM_PRESS) {
+        WM_cursor_modal_restore(CTX_wm_window(C));
+        ED_workspace_status_text(C, NULL);
+
+        /* This ensures that the click was done in an viewport region. */
+        bScreen *screen = CTX_wm_screen(C);
+        ARegion *region = BKE_screen_find_main_region_at_xy(
+            screen, SPACE_VIEW3D, event->x, event->y);
+        if (!region) {
+          return OPERATOR_CANCELLED;
+        }
+
+        const int mval[2] = {event->x - region->winrct.xmin, event->y - region->winrct.ymin};
+        Base *base_dst = ED_view3d_give_base_under_cursor(C, mval);
+        const bool mode_transfered = object_transfer_mode_to_base(C, op, base_dst);
+        if (!mode_transfered) {
+          return OPERATOR_CANCELLED;
+        }
+
+        return OPERATOR_FINISHED;
+      }
+      break;
+    case RIGHTMOUSE: {
+      WM_cursor_modal_restore(CTX_wm_window(C));
+      ED_workspace_status_text(C, NULL);
+      return OPERATOR_CANCELLED;
+    }
+  }
+  return OPERATOR_RUNNING_MODAL;
+}
+
+static int object_transfer_mode_invoke(bContext *C, wmOperator *op, const wmEvent *event)
+{
+  const bool use_eyedropper = RNA_boolean_get(op->ptr, "use_eyedropper");
+  if (use_eyedropper) {
+    ED_workspace_status_text(C, TIP_("Click in the viewport to select an object"));
+    WM_cursor_modal_set(CTX_wm_window(C), WM_CURSOR_EYEDROPPER);
+    WM_event_add_modal_handler(C, op);
+    return OPERATOR_RUNNING_MODAL;
+  }
+
+  Object *ob_src = CTX_data_active_object(C);
+  const eObjectMode src_mode = (eObjectMode)ob_src->mode;
+
+  Base *base_dst = ED_view3d_give_base_under_cursor(C, event->mval);
+  const bool mode_transfered = object_transfer_mode_to_base(C, op, base_dst);
+  if (!mode_transfered) {
+    return OPERATOR_CANCELLED;
+  }
+
+  if (src_mode & OB_MODE_ALL_PAINT) {
+    object_transfer_mode_reposition_view_pivot(C, event->mval);
+  }
+
+  return OPERATOR_FINISHED;
 }
 
-void OBJECT_OT_switch_object(wmOperatorType *ot)
+void OBJECT_OT_transfer_mode(wmOperatorType *ot)
 {
   /* identifiers */
-  ot->name = "Switch Object";
-  ot->idname = "OBJECT_OT_switch_object";
+  ot->name = "Transfer Mode";
+  ot->idname = "OBJECT_OT_transfer_mode";
   ot->description =
       "Switches the active object and assigns the same mode to a new one under the mouse cursor, "
       "leaving the active mode in the current one";
 
   /* api callbacks */
-  ot->invoke = object_switch_object_invoke;
-  ot->poll = object_switch_object_poll;
+  ot->invoke = object_transfer_mode_invoke;
+  ot->modal = object_transfer_mode_modal;
+  ot->poll = object_transfer_mode_poll;
 
   /* Undo push is handled by the operator. */
   ot->flag = OPTYPE_REGISTER;
+
+  RNA_def_boolean(ot->srna,
+                  "use_eyedropper",
+                  false,
+                  "Use Eyedropper",
+                  "Pick the object to switch to using an eyedropper");
 }
 
 /** \} */