GH-727 Add constant variable support

src/editor/component_panels/variables_panel.cpp

@@ -74,6 +74,15 @@ void OrchestratorScriptVariablesComponentPanel::_create_variable_item(TreeItem*
         item->set_button_tooltip_text(0, index, "Variable is exported and visible outside the orchestration.");
         item->set_button_disabled(0, index, false);
     }
+    else if (p_variable->is_constant())
+    {
+        String tooltip = "Variable is a constant.";
+
+        int32_t index = item->get_button_count(0);
+        item->add_button(0, SceneUtils::get_editor_icon("MemberConstant"), 4);
+        item->set_button_tooltip_text(0, index, tooltip);
+        item->set_button_disabled(0, index, false);
+    }
     else
     {
         String tooltip = "Variable is private and not exported.";

src/editor/graph/actions/default_action_registrar.cpp

@@ -699,6 +699,10 @@ void OrchestratorDefaultGraphActionRegistrar::_register_orchestration_variables(
             Ref<OrchestratorGraphActionHandler> getter_handler(memnew(OrchestratorGraphNodeSpawnerVariableGet(variable_name)));
             _context->list->push_back(memnew(OrchestratorGraphActionMenuItem(getter_spec, getter_handler)));
 
+            // Constants don't allow spawning using setters
+            if (variable->is_constant())
+                continue;
+
             OrchestratorGraphActionSpec setter_spec;
             setter_spec.category = vformat("Variables/set_%s", variable_name);
             setter_spec.tooltip = vformat("Set the value of of variable '%s'", variable_name);

src/editor/graph/graph_edit.cpp

@@ -618,8 +618,12 @@ bool OrchestratorGraphEdit::_can_drop_data(const Vector2& p_position, const Vari
     if (allowed_types.has(type))
     {
         if (type == "variable")
-            _show_drag_hint("Use Ctrl to drop a Setter, Shift to drop a Getter");
-
+        {
+            const String variable_name = String(Array(data["variables"])[0]);
+            const Ref<OScriptVariable> variable = _script_graph->get_orchestration()->get_variable(variable_name);
+            if (variable.is_valid() && !variable->is_constant())
+                _show_drag_hint("Use Ctrl to drop a Setter, Shift to drop a Getter");
+        }
         return true;
     }
 
@@ -737,36 +741,46 @@ void OrchestratorGraphEdit::_drop_data(const Vector2& p_position, const Variant&
         _hide_drag_hint();
 
         const String variable_name = String(Array(data["variables"])[0]);
-        if (Input::get_singleton()->is_key_pressed(Key::KEY_CTRL))
+
+        Ref<OScriptVariable> variable = get_orchestration()->get_variable(variable_name);
+        if (!variable.is_valid())
+            return;
+
+        const bool is_constant = variable->is_constant();
+        const bool is_validated = variable->get_variable_type() == Variant::OBJECT;
+
+        if (Input::get_singleton()->is_key_pressed(KEY_CTRL))
         {
-            OrchestratorGraphNodeSpawnerVariableSet setter(variable_name);
-            setter.execute(this, _saved_mouse_position);
+            if (!is_constant)
+            {
+                Ref<OrchestratorGraphNodeSpawnerVariableSet> setter(memnew(OrchestratorGraphNodeSpawnerVariableSet(variable_name)));
+                setter->execute(this, _saved_mouse_position);
+            }
         }
-        else if (Input::get_singleton()->is_key_pressed(Key::KEY_SHIFT))
+        else if (Input::get_singleton()->is_key_pressed(KEY_SHIFT))
         {
-            OrchestratorGraphNodeSpawnerVariableGet getter(variable_name);
-            getter.execute(this, _saved_mouse_position);
+            Ref<OrchestratorGraphNodeSpawnerVariableGet> getter(memnew(OrchestratorGraphNodeSpawnerVariableGet(variable_name)));
+            getter->execute(this, _saved_mouse_position);
         }
         else
         {
-            const bool validated = get_orchestration()->get_variable(variable_name)->get_variable_type() == Variant::OBJECT;
-
-            // Create context-menu handlers
-            Ref<OrchestratorGraphActionHandler> get_handler(memnew(OrchestratorGraphNodeSpawnerVariableGet(variable_name)));
-            Ref<OrchestratorGraphActionHandler> set_handler(memnew(OrchestratorGraphNodeSpawnerVariableSet(variable_name)));
-            Ref<OrchestratorGraphActionHandler> get_validated_handler(memnew(OrchestratorGraphNodeSpawnerVariableGet(variable_name, true)));
-
-            // Create context-menu to specify variable get or set choice
             _context_menu->clear();
             _context_menu->add_separator("Variable " + variable_name);
             _context_menu->add_item("Get " + variable_name, CM_VARIABLE_GET);
-            if (validated)
+            _context_menu->set_item_metadata(_context_menu->get_item_index(CM_VARIABLE_GET), memnew(OrchestratorGraphNodeSpawnerVariableGet(variable_name)));
+
+            if (is_validated)
+            {
                 _context_menu->add_item("Get " + variable_name + " with validation", CM_VARIABLE_GET_VALIDATED);
-            _context_menu->add_item("Set " + variable_name, CM_VARIABLE_SET);
-            _context_menu->set_item_metadata(_context_menu->get_item_index(CM_VARIABLE_GET), get_handler);
-            if (validated)
-                _context_menu->set_item_metadata(_context_menu->get_item_index(CM_VARIABLE_GET_VALIDATED), get_validated_handler);
-            _context_menu->set_item_metadata(_context_menu->get_item_index(CM_VARIABLE_SET), set_handler);
+                _context_menu->set_item_metadata(_context_menu->get_item_index(CM_VARIABLE_GET_VALIDATED), memnew(OrchestratorGraphNodeSpawnerVariableGet(variable_name, true)));
+            }
+
+            if (!is_constant)
+            {
+                _context_menu->add_item("Set " + variable_name, CM_VARIABLE_SET);
+                _context_menu->set_item_metadata(_context_menu->get_item_index(CM_VARIABLE_SET), memnew(OrchestratorGraphNodeSpawnerVariableSet(variable_name)));
+            }
+
             _context_menu->reset_size();
             _context_menu->set_position(get_screen_position() + p_position);
             _context_menu->popup();

src/script/nodes/variables/variable_set.cpp

@@ -24,10 +24,17 @@ class OScriptNodeVariableSetInstance : public OScriptNodeInstance
 {
     DECLARE_SCRIPT_NODE_INSTANCE(OScriptNodeVariableSet);
     StringName _variable_name;
+    bool _constant{ false };
 
 public:
     int step(OScriptExecutionContext& p_context) override
     {
+        if (_constant)
+        {
+            p_context.set_error(vformat("Cannot modify a constant variable '%s'", _variable_name));
+            return -1 | STEP_FLAG_END;
+        }
+
         Variant value = p_context.get_input(0);
 
         Variant current_value;
@@ -150,10 +157,19 @@ void OScriptNodeVariableSet::reallocate_pins_during_reconstruction(const Vector<
     }
 }
 
+void OScriptNodeVariableSet::validate_node_during_build(BuildLog& p_log) const
+{
+    if (_variable.is_valid() && _variable->is_constant())
+        p_log.error(this, "Cannot modify constant variable value.");
+
+    super::validate_node_during_build(p_log);
+}
+
 OScriptNodeInstance* OScriptNodeVariableSet::instantiate()
 {
     OScriptNodeVariableSetInstance *i = memnew(OScriptNodeVariableSetInstance);
     i->_node = this;
     i->_variable_name = _variable->get_variable_name();
+    i->_constant = _variable->is_constant();
     return i;
 }

src/script/nodes/variables/variable_set.h

@@ -40,6 +40,7 @@ class OScriptNodeVariableSet : public OScriptNodeVariable
     String get_tooltip_text() const override;
     String get_node_title() const override;
     void reallocate_pins_during_reconstruction(const Vector<Ref<OScriptNodePin>>& p_old_pins) override;
+    void validate_node_during_build(BuildLog& p_log) const override;
     OScriptNodeInstance* instantiate() override;
     //~ End OScriptNode Interface
 };

src/script/variable.cpp

@@ -35,6 +35,10 @@ void OScriptVariable::_bind_methods()
     ClassDB::bind_method(D_METHOD("get_category"), &OScriptVariable::get_category);
     ADD_PROPERTY(PropertyInfo(Variant::STRING, "category"), "set_category", "get_category");
 
+    ClassDB::bind_method(D_METHOD("set_constant", "constant"), &OScriptVariable::set_constant);
+    ClassDB::bind_method(D_METHOD("is_constant"), &OScriptVariable::is_constant);
+    ADD_PROPERTY(PropertyInfo(Variant::BOOL, "constant"), "set_constant", "is_constant");
+
     ClassDB::bind_method(D_METHOD("set_exported", "exported"), &OScriptVariable::set_exported);
     ClassDB::bind_method(D_METHOD("is_exported"), &OScriptVariable::is_exported);
     ADD_PROPERTY(PropertyInfo(Variant::BOOL, "exported"), "set_exported", "is_exported");
@@ -97,7 +101,7 @@ void OScriptVariable::_validate_property(PropertyInfo& p_property) const
 
 bool OScriptVariable::_property_can_revert(const StringName& p_name) const
 {
-    static Array properties = Array::make("name", "category", "exported", "classification", "default_value", "description");
+    static Array properties = Array::make("name", "category", "exported", "classification", "default_value", "description", "constant");
     return properties.has(p_name);
 }
 
@@ -133,11 +137,20 @@ bool OScriptVariable::_property_get_revert(const StringName& p_name, Variant& r_
         r_property = "";
         return true;
     }
+    else if (p_name.match("constant"))
+    {
+        r_property = false;
+        return true;
+    }
     return false;
 }
 
 bool OScriptVariable::_is_exportable_type(const PropertyInfo& p_property) const
 {
+    // Constants cannot be exported
+    if (_constant)
+        return false;
+
     switch (p_property.type)
     {
         // These are all not exportable
@@ -396,3 +409,18 @@ void OScriptVariable::set_default_value(const Variant& p_default_value)
         emit_changed();
     }
 }
+
+void OScriptVariable::set_constant(bool p_constant)
+{
+    if (_constant != p_constant)
+    {
+        _constant = p_constant;
+
+        _exportable = _is_exportable_type(_info);
+        if (!_exportable && _constant)
+            _exported = false;
+
+        notify_property_list_changed();
+        emit_changed();
+    }
+}

src/script/variable.h

@@ -49,6 +49,7 @@ class OScriptVariable : public Resource
     int _type_category{ 0 };                   //! Defaults to basic
     Variant _type_subcategory;                 //! Subcategory type
     String _value_list;                        //! Enum/Bitfield custom value list
+    bool _constant{ false };                   //! Whether variable is a constant
 
 protected:
     //~ Begin Wrapped Interface
@@ -160,6 +161,14 @@ class OScriptVariable : public Resource
     /// Set the variable's default value
     /// @param p_default_value the default value
     void set_default_value(const Variant& p_default_value);
+
+    /// Return whether the variable is a constant value
+    /// @return true if the variable is a constant and cannot be set, false otherwise
+    bool is_constant() const { return _constant; }
+
+    /// Sets whether the variable is a constant
+    /// @param p_constant whether the variable is constant
+    void set_constant(bool p_constant);
 };
 
 #endif  // ORCHESTRATOR_SCRIPT_VARIABLE_H