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, 11 insertions, 0 deletions

diff --git a/source/blender/nodes/shader/nodes/node_shader_math.cc b/source/blender/nodes/shader/nodes/node_shader_math.cc
index a10124460ff..51c94b10c8b 100644
--- a/source/blender/nodes/shader/nodes/node_shader_math.cc
+++ b/source/blender/nodes/shader/nodes/node_shader_math.cc
@@ -24,6 +24,7 @@
 #include "node_shader_util.h"
 
 #include "NOD_math_functions.hh"
+#include "NOD_socket_search_link.hh"
 
 /* **************** SCALAR MATH ******************** */
 
@@ -44,6 +45,15 @@ static void sh_node_math_declare(NodeDeclarationBuilder &b)
   b.add_output<decl::Float>(N_("Value"));
 };
 
+static void sh_node_math_gather_link_searches(GatherLinkSearchOpParams &params)
+{
+  /* For now, do something very basic (only exposing "Add", and a single "Value" socket). */
+  params.add_item(IFACE_("Value"), [](LinkSearchOpParams &params) {
+    bNode &node = params.add_node("ShaderNodeMath");
+    params.update_and_connect_available_socket(node, "Value");
+  });
+}
+
 }  // namespace blender::nodes
 
 static const char *gpu_shader_get_name(int mode)
@@ -171,6 +181,7 @@ void register_node_type_sh_math()
   node_type_gpu(&ntype, gpu_shader_math);
   node_type_update(&ntype, node_math_update);
   ntype.build_multi_function = sh_node_math_build_multi_function;
+  ntype.gather_link_search_ops = blender::nodes::sh_node_math_gather_link_searches;
 
   nodeRegisterType(&ntype);
 }