Geometry Nodes: Add default attribute name to field inputs/outputs

Geometry node group inputs and outputs get a new property that controls
the attribute name used for that field input/output when assigning the
node group to a modifier for the first time. If the default name is assigned
to an input, the default "Use attribute name" is true .

In order to properly detect when a node group is first assigned,
the modifier now clears its properties when clearing the node group.

Ref T96707

Differential Revision: https://developer.blender.org/D14761

1 files changed, 9 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/node.cc b/source/blender/blenkernel/intern/node.cc
index 4acccca322a..d3f61d381f2 100644
--- a/source/blender/blenkernel/intern/node.cc
+++ b/source/blender/blenkernel/intern/node.cc
@@ -487,6 +487,9 @@ static void write_node_socket(BlendWriter *writer, bNodeSocket *sock)
     IDP_BlendWrite(writer, sock->prop);
   }
 
+  /* This property should only be used for group node "interface" sockets. */
+  BLI_assert(sock->default_attribute_name == nullptr);
+
   write_node_socket_default_value(writer, sock);
 }
 static void write_node_socket_interface(BlendWriter *writer, bNodeSocket *sock)
@@ -497,6 +500,8 @@ static void write_node_socket_interface(BlendWriter *writer, bNodeSocket *sock)
     IDP_BlendWrite(writer, sock->prop);
   }
 
+  BLO_write_string(writer, sock->default_attribute_name);
+
   write_node_socket_default_value(writer, sock);
 }
 
@@ -650,6 +655,7 @@ static void direct_link_node_socket(BlendDataReader *reader, bNodeSocket *sock)
   sock->typeinfo = nullptr;
   BLO_read_data_address(reader, &sock->storage);
   BLO_read_data_address(reader, &sock->default_value);
+  BLO_read_data_address(reader, &sock->default_attribute_name);
   sock->total_inputs = 0; /* Clear runtime data set before drawing. */
   sock->cache = nullptr;
   sock->declaration = nullptr;
@@ -2161,6 +2167,9 @@ static void node_socket_copy(bNodeSocket *sock_dst, const bNodeSocket *sock_src,
     }
   }
 
+  sock_dst->default_attribute_name = static_cast<char *>(
+      MEM_dupallocN(sock_src->default_attribute_name));
+
   sock_dst->stack_index = 0;
   /* XXX some compositor nodes (e.g. image, render layers) still store
    * some persistent buffer data here, need to clear this to avoid dangling pointers. */