Nodes: add button in switch nodes to add inputs

This is a small usability feature to simplify adding additional inputs in the
Index Switch and Menu Switch nodes without having to go to the sidebar.

Technically, something similar can be done for other extend-sockets. However,
here it works best, because one does not have to choose the socket type. For
other inputs we could use a quick popup when pressing the button, but that seems
outside of the scope of this patch.

Later we might also want add the ability to remove existing inputs. But just
adding an icon for that doesn't work so well for socket types that have an input
property.

Co-authored-by: Brady Johnston <36021261+BradyAJohnston@users.noreply.github.com>
Pull Request: https://projects.blender.org/blender/blender/pulls/145915

source/blender/editors/space_node/drawnode.cc

@@ -1458,7 +1458,7 @@ void ED_init_standard_node_socket_type(blender::bke::bNodeSocketType *stype)
 void ED_init_node_socket_type_virtual(blender::bke::bNodeSocketType *stype)
 {
   using namespace blender::ed::space_node;
-  stype->draw = node_socket_button_label;
+  stype->draw = std_node_socket_draw;
   stype->draw_color = node_socket_virtual_draw_color;
   stype->draw_color_simple = node_socket_virtual_draw_color_simple;
 }

source/blender/nodes/NOD_socket_items_ops.hh

@@ -24,7 +24,9 @@
 
 namespace blender::nodes::socket_items::ops {
 
-inline PointerRNA get_active_node_to_operate_on(bContext *C, const StringRef node_idname)
+inline PointerRNA get_active_node_to_operate_on(bContext *C,
+                                                wmOperator *op,
+                                                const StringRef node_idname)
 {
   SpaceNode *snode = CTX_wm_space_node(C);
   if (!snode) {
@@ -40,20 +42,28 @@ inline PointerRNA get_active_node_to_operate_on(bContext *C, const StringRef nod
   if (!zones) {
     return PointerRNA_NULL;
   }
-  bNode *active_node = bke::node_get_active(*snode->edittree);
-  if (!active_node) {
+
+  bNode *node = nullptr;
+  if (RNA_struct_property_is_set(op->ptr, "node_identifier")) {
+    const int id = RNA_int_get(op->ptr, "node_identifier");
+    node = snode->edittree->node_by_id(id);
+  }
+  else {
+    node = bke::node_get_active(*snode->edittree);
+  }
+  if (!node) {
     return PointerRNA_NULL;
   }
-  if (const bke::bNodeTreeZone *zone = zones->get_zone_by_node(active_node->identifier)) {
-    if (zone->input_node() == active_node) {
+  if (const bke::bNodeTreeZone *zone = zones->get_zone_by_node(node->identifier)) {
+    if (zone->input_node() == node) {
       /* Assume the data is generally stored on the output and not the input node. */
-      active_node = const_cast<bNode *>(zone->output_node());
+      node = const_cast<bNode *>(zone->output_node());
     }
   }
-  if (active_node->idname != node_idname) {
+  if (node->idname != node_idname) {
     return PointerRNA_NULL;
   }
-  return RNA_pointer_create_discrete(&snode->edittree->id, &RNA_Node, active_node);
+  return RNA_pointer_create_discrete(&snode->edittree->id, &RNA_Node, node);
 }
 
 inline void update_after_node_change(bContext *C, const PointerRNA node_ptr)
@@ -68,7 +78,30 @@ inline void update_after_node_change(bContext *C, const PointerRNA node_ptr)
 
 template<typename Accessor> inline bool editable_node_active_poll(bContext *C)
 {
-  return get_active_node_to_operate_on(C, Accessor::node_idname).data != nullptr;
+  SpaceNode *snode = CTX_wm_space_node(C);
+  if (!snode) {
+    return false;
+  }
+  if (!snode->edittree) {
+    return false;
+  }
+  if (!ID_IS_EDITABLE(snode->edittree)) {
+    return false;
+  }
+  return true;
+}
+
+inline void add_node_identifier_property(wmOperatorType *ot)
+{
+  RNA_def_int(ot->srna,
+              "node_identifier",
+              0,
+              0,
+              INT32_MAX,
+              "Node Identifier",
+              "Optional identifier of the node to operate on",
+              0,
+              INT32_MAX);
 }
 
 template<typename Accessor>
@@ -82,8 +115,8 @@ inline void remove_active_item(wmOperatorType *ot,
   ot->description = description;
   ot->poll = editable_node_active_poll<Accessor>;
 
-  ot->exec = [](bContext *C, wmOperator * /*op*/) -> wmOperatorStatus {
-    PointerRNA node_ptr = get_active_node_to_operate_on(C, Accessor::node_idname);
+  ot->exec = [](bContext *C, wmOperator *op) -> wmOperatorStatus {
+    PointerRNA node_ptr = get_active_node_to_operate_on(C, op, Accessor::node_idname);
     bNode &node = *static_cast<bNode *>(node_ptr.data);
     SocketItemsRef ref = Accessor::get_items_from_node(node);
     if (*ref.items_num > 0) {
@@ -93,6 +126,8 @@ inline void remove_active_item(wmOperatorType *ot,
     }
     return OPERATOR_FINISHED;
   };
+
+  add_node_identifier_property(ot);
 }
 
 template<typename Accessor>
@@ -107,7 +142,7 @@ inline void remove_item_by_index(wmOperatorType *ot,
   ot->poll = editable_node_active_poll<Accessor>;
 
   ot->exec = [](bContext *C, wmOperator *op) -> wmOperatorStatus {
-    PointerRNA node_ptr = get_active_node_to_operate_on(C, Accessor::node_idname);
+    PointerRNA node_ptr = get_active_node_to_operate_on(C, op, Accessor::node_idname);
     bNode &node = *static_cast<bNode *>(node_ptr.data);
     const int index_to_remove = RNA_int_get(op->ptr, "index");
     SocketItemsRef ref = Accessor::get_items_from_node(node);
@@ -132,8 +167,11 @@ inline void add_item(wmOperatorType *ot,
   ot->description = description;
   ot->poll = editable_node_active_poll<Accessor>;
 
-  ot->exec = [](bContext *C, wmOperator * /*op*/) -> wmOperatorStatus {
-    PointerRNA node_ptr = get_active_node_to_operate_on(C, Accessor::node_idname);
+  ot->exec = [](bContext *C, wmOperator *op) -> wmOperatorStatus {
+    PointerRNA node_ptr = get_active_node_to_operate_on(C, op, Accessor::node_idname);
+    if (node_ptr.data == nullptr) {
+      return OPERATOR_CANCELLED;
+    }
     bNode &node = *static_cast<bNode *>(node_ptr.data);
     SocketItemsRef ref = Accessor::get_items_from_node(node);
     const typename Accessor::ItemT *active_item = nullptr;
@@ -180,6 +218,8 @@ inline void add_item(wmOperatorType *ot,
     update_after_node_change(C, node_ptr);
     return OPERATOR_FINISHED;
   };
+
+  add_node_identifier_property(ot);
 }
 
 enum class MoveDirection {
@@ -199,7 +239,7 @@ inline void move_active_item(wmOperatorType *ot,
   ot->poll = editable_node_active_poll<Accessor>;
 
   ot->exec = [](bContext *C, wmOperator *op) -> wmOperatorStatus {
-    PointerRNA node_ptr = get_active_node_to_operate_on(C, Accessor::node_idname);
+    PointerRNA node_ptr = get_active_node_to_operate_on(C, op, Accessor::node_idname);
     bNode &node = *static_cast<bNode *>(node_ptr.data);
     const MoveDirection direction = MoveDirection(RNA_enum_get(op->ptr, "direction"));
 
@@ -225,6 +265,7 @@ inline void move_active_item(wmOperatorType *ot,
   };
 
   RNA_def_enum(ot->srna, "direction", direction_items, 0, "Direction", "Move direction");
+  add_node_identifier_property(ot);
 }
 
 /**

source/blender/nodes/geometry/nodes/node_geo_index_switch.cc

@@ -2,6 +2,7 @@
  *
  * SPDX-License-Identifier: GPL-2.0-or-later */
 
+#include "UI_interface_c.hh"
 #include "node_geometry_util.hh"
 
 #include "UI_interface_layout.hh"
@@ -65,7 +66,12 @@ static void node_declare(NodeDeclarationBuilder &b)
   }
   output.structure_type(structure_type);
 
-  b.add_input<decl::Extend>("", "__extend__");
+  b.add_input<decl::Extend>("", "__extend__").custom_draw([](CustomSocketDrawParams &params) {
+    uiLayout &layout = params.layout;
+    layout.emboss_set(ui::EmbossType::None);
+    PointerRNA op_ptr = layout.op("node.index_switch_item_add", IFACE_(""), ICON_ADD);
+    RNA_int_set(&op_ptr, "node_identifier", params.node.identifier);
+  });
 }
 
 static void node_layout(uiLayout *layout, bContext * /*C*/, PointerRNA *ptr)

source/blender/nodes/geometry/nodes/node_geo_menu_switch.cc

@@ -103,7 +103,14 @@ static void node_declare(blender::nodes::NodeDeclarationBuilder &b)
     }
   }
 
-  b.add_input<decl::Extend>("", "__extend__").structure_type(StructureType::Dynamic);
+  b.add_input<decl::Extend>("", "__extend__")
+      .structure_type(StructureType::Dynamic)
+      .custom_draw([](CustomSocketDrawParams &params) {
+        uiLayout &layout = params.layout;
+        layout.emboss_set(ui::EmbossType::None);
+        PointerRNA op_ptr = layout.op("node.enum_definition_item_add", "", ICON_ADD);
+        RNA_int_set(&op_ptr, "node_identifier", params.node.identifier);
+      });
 }
 
 static void node_layout(uiLayout *layout, bContext * /*C*/, PointerRNA *ptr)