Nodes: Add support to mute node wires

This patch adds the ability to mute individual wires in the node editor.
This is invoked like the cut links operator but with a new shortcut.

Mute = Ctrl + Alt
Cut = Ctrl

Dragging over wires will toggle the mute state for that wire.
The muted wires are drawn in red with a bar across the center.
Red is used in the nodes context to indicate invalid links, muted links and internal links.

When a wire is muted it exposes the original node buttons which are normally hidden when a wire is connected.

Downstream and upstream links connected using reroute nodes are also muted.

Outside scope of patch:
- Add support for pynodes e.g. Animation Nodes
- Requires minor change to check for muted links using the `is_muted` link property or the `is_linked` socket property.

Maniphest Tasks: T52659

Differential Revision: https://developer.blender.org/D2807

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index 04ff181d9b5..fc1f692a8bf 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -10872,6 +10872,11 @@ static void rna_def_node_link(BlenderRNA *brna)
   RNA_def_struct_ui_text(srna, "Valid", "Link is valid");
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, NULL);
 
+  prop = RNA_def_property(srna, "is_muted", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", NODE_LINK_MUTED);
+  RNA_def_struct_ui_text(srna, "Muted", "Link is muted and can be ignored");
+  RNA_def_property_update(prop, NC_NODE | NA_EDITED, NULL);
+
   prop = RNA_def_property(srna, "from_node", PROP_POINTER, PROP_NONE);
   RNA_def_property_pointer_sdna(prop, NULL, "fromnode");
   RNA_def_property_struct_type(prop, "Node");