Node Editor: Link Drag Search Menu

This commit adds a search menu when links are dragged above empty
space. When releasing the drag, a menu displays all compatible
sockets with the source link. The "main" sockets (usually the first)
are weighted above other sockets in the search, so they appear first
when you type the name of the node.

A few special operators for creating a reroute or a group input node
are also added to the search.

Translation is started after choosing a node so it can be placed
quickly, since users would likely adjust the position after anyway.

A small "+" is displayed next to the cursor to give a hint about this.

Further improvements are possible after this first iteration:
 - Support custom node trees.
 - Better drawing of items in the search menu.
 - Potential tweaks to filtering of items, depending on user feedback.

Thanks to Juanfran Matheu for developing an initial patch.

Differential Revision: https://developer.blender.org/D8286

1 files changed, 30 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/node.cc b/source/blender/blenkernel/intern/node.cc
index a4de6730f8f..be458ed036e 100644
--- a/source/blender/blenkernel/intern/node.cc
+++ b/source/blender/blenkernel/intern/node.cc
@@ -102,6 +102,7 @@ using blender::MutableSpan;
 using blender::Set;
 using blender::Span;
 using blender::Stack;
+using blender::StringRef;
 using blender::Vector;
 using blender::VectorSet;
 using blender::nodes::FieldInferencingInterface;
@@ -1522,6 +1523,33 @@ struct bNodeSocket *nodeFindSocket(const bNode *node,
   return nullptr;
 }
 
+namespace blender::bke {
+
+bNodeSocket *node_find_enabled_socket(bNode &node,
+                                      const eNodeSocketInOut in_out,
+                                      const StringRef name)
+{
+  ListBase *sockets = (in_out == SOCK_IN) ? &node.inputs : &node.outputs;
+  LISTBASE_FOREACH (bNodeSocket *, socket, sockets) {
+    if (!(socket->flag & SOCK_UNAVAIL) && socket->name == name) {
+      return socket;
+    }
+  }
+  return nullptr;
+}
+
+bNodeSocket *node_find_enabled_input_socket(bNode &node, StringRef name)
+{
+  return node_find_enabled_socket(node, SOCK_IN, name);
+}
+
+bNodeSocket *node_find_enabled_output_socket(bNode &node, StringRef name)
+{
+  return node_find_enabled_socket(node, SOCK_OUT, name);
+}
+
+}  // namespace blender::bke
+
 /* find unique socket identifier */
 static bool unique_identifier_check(void *arg, const char *identifier)
 {
@@ -4459,7 +4487,8 @@ static void ntree_validate_links(bNodeTree *ntree)
       link->flag &= ~NODE_LINK_VALID;
     }
     else if (ntree->typeinfo->validate_link) {
-      if (!ntree->typeinfo->validate_link(ntree, link)) {
+      if (!ntree->typeinfo->validate_link((eNodeSocketDatatype)link->fromsock->type,
+                                          (eNodeSocketDatatype)link->tosock->type)) {
         link->flag &= ~NODE_LINK_VALID;
       }
     }