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

2 files changed, 57 insertions, 1 deletions

diff --git a/source/blender/nodes/function/node_function_util.cc b/source/blender/nodes/function/node_function_util.cc
index ac48322c269..83f5b571695 100644
--- a/source/blender/nodes/function/node_function_util.cc
+++ b/source/blender/nodes/function/node_function_util.cc
@@ -17,6 +17,8 @@
 #include "node_function_util.hh"
 #include "node_util.h"
 
+#include "NOD_socket_search_link.hh"
+
 static bool fn_node_poll_default(bNodeType *UNUSED(ntype),
                                  bNodeTree *ntree,
                                  const char **r_disabled_hint)
@@ -34,4 +36,5 @@ void fn_node_type_base(bNodeType *ntype, int type, const char *name, short nclas
   node_type_base(ntype, type, name, nclass, flag);
   ntype->poll = fn_node_poll_default;
   ntype->insert_link = node_insert_link_default;
+  ntype->gather_link_search_ops = blender::nodes::search_link_ops_for_basic_node;
 }
diff --git a/source/blender/nodes/function/nodes/node_fn_random_value.cc b/source/blender/nodes/function/nodes/node_fn_random_value.cc
index e2efae68001..b053482c99d 100644
--- a/source/blender/nodes/function/nodes/node_fn_random_value.cc
+++ b/source/blender/nodes/function/nodes/node_fn_random_value.cc
@@ -19,6 +19,8 @@
 
 #include "node_function_util.hh"
 
+#include "NOD_socket_search_link.hh"
+
 #include "UI_interface.h"
 #include "UI_resources.h"
 
@@ -43,7 +45,8 @@ static void fn_node_random_value_declare(NodeDeclarationBuilder &b)
       .max(1.0f)
       .default_value(0.5f)
       .subtype(PROP_FACTOR)
-      .supports_field();
+      .supports_field()
+      .make_available([](bNode &node) { node_storage(node).data_type = CD_PROP_BOOL; });
   b.add_input<decl::Int>(N_("ID")).implicit_field();
   b.add_input<decl::Int>(N_("Seed")).default_value(0).min(-10000).max(10000).supports_field();
 
@@ -97,6 +100,55 @@ static void fn_node_random_value_update(bNodeTree *ntree, bNode *node)
   nodeSetSocketAvailability(ntree, sock_out_bool, data_type == CD_PROP_BOOL);
 }
 
+static std::optional<CustomDataType> node_type_from_other_socket(const bNodeSocket &socket)
+{
+  switch (socket.type) {
+    case SOCK_FLOAT:
+      return CD_PROP_FLOAT;
+    case SOCK_BOOLEAN:
+      return CD_PROP_BOOL;
+    case SOCK_INT:
+      return CD_PROP_INT32;
+    case SOCK_VECTOR:
+      return CD_PROP_FLOAT3;
+    case SOCK_RGBA:
+      return CD_PROP_COLOR;
+    default:
+      return {};
+  }
+}
+
+static void fn_node_random_value_gather_link_search(GatherLinkSearchOpParams &params)
+{
+  const NodeDeclaration &declaration = *params.node_type().fixed_declaration;
+  const std::optional<CustomDataType> type = node_type_from_other_socket(params.other_socket());
+  if (!type) {
+    return;
+  }
+  if (params.in_out() == SOCK_IN) {
+    if (ELEM(*type, CD_PROP_INT32, CD_PROP_FLOAT3, CD_PROP_FLOAT)) {
+      params.add_item(IFACE_("Min"), [type](LinkSearchOpParams &params) {
+        bNode &node = params.add_node("FunctionNodeRandomValue");
+        node_storage(node).data_type = *type;
+        params.update_and_connect_available_socket(node, "Min");
+      });
+      params.add_item(IFACE_("Max"), [type](LinkSearchOpParams &params) {
+        bNode &node = params.add_node("FunctionNodeRandomValue");
+        node_storage(node).data_type = *type;
+        params.update_and_connect_available_socket(node, "Max");
+      });
+    }
+    search_link_ops_for_declarations(params, declaration.inputs().take_back(3));
+  }
+  else {
+    params.add_item(IFACE_("Value"), [type](LinkSearchOpParams &params) {
+      bNode &node = params.add_node("FunctionNodeRandomValue");
+      node_storage(node).data_type = *type;
+      params.update_and_connect_available_socket(node, "Value");
+    });
+  }
+}
+
 class RandomVectorFunction : public fn::MultiFunction {
  public:
   RandomVectorFunction()
@@ -297,6 +349,7 @@ void register_node_type_fn_random_value()
   ntype.draw_buttons = blender::nodes::fn_node_random_value_layout;
   ntype.declare = blender::nodes::fn_node_random_value_declare;
   ntype.build_multi_function = blender::nodes::fn_node_random_value_build_multi_function;
+  ntype.gather_link_search_ops = blender::nodes::fn_node_random_value_gather_link_search;
   node_type_storage(
       &ntype, "NodeRandomValue", node_free_standard_storage, node_copy_standard_storage);
   nodeRegisterType(&ntype);