Curves: Add edit mode tilt control

Adds support for the tilt transform operator and a "Clear Tilt"
operator to mirror the functionality from the legacy curve type.

scripts/presets/keyconfig/keymap_data/blender_default.py

@@ -6084,6 +6084,10 @@ def km_edit_curves(params):
         ("curves.select_less", {"type": 'NUMPAD_MINUS', "value": 'PRESS', "ctrl": True, "repeat": True}, None),
         *_template_items_proportional_editing(
             params, connected=True, toggle_data_path='tool_settings.use_proportional_edit'),
+        ("curves.tilt_clear", {"type": 'T', "value": 'PRESS', "alt": True}, None),
+        op_tool_optional(
+            ("transform.tilt", {"type": 'T', "value": 'PRESS', "ctrl": True}, None),
+            (op_tool_cycle, "builtin.tilt"), params),
         ("transform.transform", {"type": 'S', "value": 'PRESS', "alt": True},
          {"properties": [("mode", 'CURVE_SHRINKFATTEN')]}),
     ])

scripts/startup/bl_ui/space_toolsystem_toolbar.py

@@ -3026,8 +3026,10 @@ class VIEW3D_PT_tools_active(ToolSelectPanelHelper, Panel):
         'EDIT_CURVES': [
             *_tools_default,
             None,
-            _defs_edit_curve.curve_radius,
             _defs_edit_curves.draw,
+            None,
+            _defs_edit_curve.curve_radius,
+            _defs_edit_curve.tilt,
         ],
         'EDIT_SURFACE': [
             *_tools_default,

source/blender/editors/curves/intern/curves_ops.cc

@@ -1282,6 +1282,46 @@ static void CURVES_OT_duplicate(wmOperatorType *ot)
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
+namespace clear_tilt {
+
+static int exec(bContext *C, wmOperator * /*op*/)
+{
+  for (Curves *curves_id : get_unique_editable_curves(*C)) {
+    bke::CurvesGeometry &curves = curves_id->geometry.wrap();
+    IndexMaskMemory memory;
+    const IndexMask selection = retrieve_selected_points(*curves_id, memory);
+    if (selection.is_empty()) {
+      continue;
+    }
+
+    if (selection.size() == curves.points_num()) {
+      curves.attributes_for_write().remove("tilt");
+    }
+    else {
+      index_mask::masked_fill(curves.tilt_for_write(), 0.0f, selection);
+    }
+
+    curves.tag_normals_changed();
+    DEG_id_tag_update(&curves_id->id, ID_RECALC_GEOMETRY);
+    WM_event_add_notifier(C, NC_GEOM | ND_DATA, curves_id);
+  }
+  return OPERATOR_FINISHED;
+}
+
+}  // namespace clear_tilt
+
+static void CURVES_OT_tilt_clear(wmOperatorType *ot)
+{
+  ot->name = "Clear Tilt";
+  ot->idname = __func__;
+  ot->description = "Clear the tilt of selected control points";
+
+  ot->exec = clear_tilt::exec;
+  ot->poll = editable_curves_in_edit_mode_poll;
+
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+}
+
 }  // namespace blender::ed::curves
 
 void ED_operatortypes_curves()
@@ -1302,6 +1342,7 @@ void ED_operatortypes_curves()
   WM_operatortype_append(CURVES_OT_surface_set);
   WM_operatortype_append(CURVES_OT_delete);
   WM_operatortype_append(CURVES_OT_duplicate);
+  WM_operatortype_append(CURVES_OT_tilt_clear);
 }
 
 void ED_operatormacros_curves()

source/blender/editors/transform/transform_convert_curves.cc

@@ -105,7 +105,11 @@ static void createTransCurvesVerts(bContext * /*C*/, TransInfo *t)
           "radius",
           ATTR_DOMAIN_POINT,
           bke::AttributeInitVArray(VArray<float>::ForSingle(0.01f, curves.points_num())));
-
+      value_attribute = attribute_writer.span;
+    }
+    else if (t->mode == TFM_TILT) {
+      bke::MutableAttributeAccessor attributes = curves.attributes_for_write();
+      attribute_writer = attributes.lookup_or_add_for_write_span<float>("tilt", ATTR_DOMAIN_POINT);
       value_attribute = attribute_writer.span;
     }
 
@@ -117,6 +121,8 @@ static void createTransCurvesVerts(bContext * /*C*/, TransInfo *t)
                                       curves.curves_range(),
                                       use_connected_only,
                                       0 /* No data offset for curves. */);
+
+    /* TODO: This is wrong. The attribute writer should live at least as long as the span. */
     attribute_writer.finish();
   }
 }
@@ -127,9 +133,16 @@ static void recalcData_curves(TransInfo *t)
   for (const TransDataContainer &tc : trans_data_contrainers) {
     Curves *curves_id = static_cast<Curves *>(tc.obedit->data);
     bke::CurvesGeometry &curves = curves_id->geometry.wrap();
-
-    curves.calculate_bezier_auto_handles();
-    curves.tag_positions_changed();
+    if (t->mode == TFM_CURVE_SHRINKFATTEN) {
+      /* No cache to update currently. */
+    }
+    else if (t->mode == TFM_TILT) {
+      curves.tag_normals_changed();
+    }
+    else {
+      curves.tag_positions_changed();
+      curves.calculate_bezier_auto_handles();
+    }
     DEG_id_tag_update(&curves_id->id, ID_RECALC_GEOMETRY);
   }
 }

source/blender/editors/transform/transform_ops.cc

@@ -8,6 +8,7 @@
 
 #include "MEM_guardedalloc.h"
 
+#include "DNA_curve_types.h"
 #include "DNA_object_types.h"
 #include "DNA_scene_types.h"
 
@@ -960,6 +961,22 @@ static void TRANSFORM_OT_rotate(wmOperatorType *ot)
                            P_GEO_SNAP | P_GPENCIL_EDIT | P_CENTER);
 }
 
+static bool tilt_poll(bContext *C)
+{
+  Object *obedit = CTX_data_edit_object(C);
+  if (!obedit) {
+    return false;
+  }
+  if (obedit->type == OB_CURVES_LEGACY) {
+    Curve *cu = (Curve *)obedit->data;
+    return (cu->flag & CU_3D) && (nullptr != cu->editnurb);
+  }
+  if (obedit->type == OB_CURVES) {
+    return true;
+  }
+  return true;
+}
+
 static void TRANSFORM_OT_tilt(wmOperatorType *ot)
 {
   /* identifiers */
@@ -976,7 +993,7 @@ static void TRANSFORM_OT_tilt(wmOperatorType *ot)
   ot->exec = transform_exec;
   ot->modal = transform_modal;
   ot->cancel = transform_cancel;
-  ot->poll = ED_operator_editcurve_3d;
+  ot->poll = tilt_poll;
   ot->poll_property = transform_poll_property;
 
   RNA_def_float_rotation(