Geometry Nodes: Link error when implicit conversion isn't possible

This turns links red if no implicit conversion can be made between the
from socket and the to socket. For geometry nodes this happens with
object, geometry, collection, and string sockets that are connected to
a different type. The change is simply implementing a callback that is
already implemented for other node tree types.

Differential Revision: https://developer.blender.org/D11229

1 files changed, 11 insertions, 0 deletions

diff --git a/source/blender/nodes/geometry/node_geometry_tree.cc b/source/blender/nodes/geometry/node_geometry_tree.cc
index afb86ff57b8..f13ddabbf2c 100644
--- a/source/blender/nodes/geometry/node_geometry_tree.cc
+++ b/source/blender/nodes/geometry/node_geometry_tree.cc
@@ -84,6 +84,16 @@ static void foreach_nodeclass(Scene *UNUSED(scene), void *calldata, bNodeClassCa
   func(calldata, NODE_CLASS_LAYOUT, N_("Layout"));
 }
 
+static bool geometry_node_tree_validate_link(bNodeTree *UNUSED(ntree), bNodeLink *link)
+{
+  /* Geometry, string, object and collection sockets can only be connected to themselves. */
+  if (ELEM(link->fromsock->type, SOCK_GEOMETRY, SOCK_STRING, SOCK_OBJECT, SOCK_COLLECTION) ||
+      ELEM(link->tosock->type, SOCK_GEOMETRY, SOCK_STRING, SOCK_OBJECT, SOCK_COLLECTION)) {
+    return (link->tosock->type == link->fromsock->type);
+  }
+  return true;
+}
+
 static bool geometry_node_tree_socket_type_valid(eNodeSocketDatatype socket_type,
                                                  bNodeTreeType *UNUSED(ntreetype))
 {
@@ -113,6 +123,7 @@ void register_node_tree_type_geo(void)
   tt->get_from_context = geometry_node_tree_get_from_context;
   tt->foreach_nodeclass = foreach_nodeclass;
   tt->valid_socket_type = geometry_node_tree_socket_type_valid;
+  tt->validate_link = geometry_node_tree_validate_link;
 
   ntreeTypeAdd(tt);
 }