Geometry Nodes: Initial socket visualization for fields.

This implements the update logic for the vizualization of which
sockets pass data or constants directly, and which pass functions.
The socket shapes may still have to be updated. That should be
done separately, because it might be a bit more involved, because
socket shapes are currently linked to keyframe shapes. Currently
the circle and diamond shapes are used with the following meanings:

 - Input Sockets:
    - Circle: Required to be a single value.
    - Diamond: This input supports fields.
 - Output Sockets:
    - Circle: This output is a single value.
    - Diamond: This output may be a field.

Connecting a field to a circle input socket is an error, since a
field cannot be converted to a single value. If the socket shape
is a diamond with a dot in the middle, it means it is currently
a single value, but could be a field.

In addition to socket shapes, the intention is to draw node links
differently based on the field status. However, the exact method for
conveying that isn't decided yet.

Differential Revision: https://developer.blender.org/D12584

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/editors/space_node/node_relationships.cc b/source/blender/editors/space_node/node_relationships.cc
index 7d95659e403..b69e7e98bca 100644
--- a/source/blender/editors/space_node/node_relationships.cc
+++ b/source/blender/editors/space_node/node_relationships.cc
@@ -220,6 +220,7 @@ static LinkData *create_drag_link(Main *bmain, SpaceNode *snode, bNode *node, bN
   if (node_connected_to_output(bmain, snode->edittree, node)) {
     oplink->flag |= NODE_LINK_TEST;
   }
+  oplink->flag |= NODE_LINK_DRAGGED;
   return linkdata;
 }
 
@@ -894,6 +895,8 @@ static void node_link_exit(bContext *C, wmOperator *op, bool apply_links)
      */
     do_tag_update |= (link->flag & NODE_LINK_TEST) != 0;
 
+    link->flag &= ~NODE_LINK_DRAGGED;
+
     if (apply_links && link->tosock && link->fromsock) {
       /* before actually adding the link,
        * let nodes perform special link insertion handling
@@ -1097,6 +1100,7 @@ static bNodeLinkDrag *node_link_init(Main *bmain, SpaceNode *snode, float cursor
           *oplink = *link;
           oplink->next = oplink->prev = nullptr;
           oplink->flag |= NODE_LINK_VALID;
+          oplink->flag |= NODE_LINK_DRAGGED;
 
           /* The link could be disconnected and in that case we
            * wouldn't be able to check whether tag update is
@@ -1150,6 +1154,7 @@ static bNodeLinkDrag *node_link_init(Main *bmain, SpaceNode *snode, float cursor
         *oplink = *link_to_pick;
         oplink->next = oplink->prev = nullptr;
         oplink->flag |= NODE_LINK_VALID;
+        oplink->flag |= NODE_LINK_DRAGGED;
         oplink->flag &= ~NODE_LINK_TEST;
         if (node_connected_to_output(bmain, snode->edittree, link_to_pick->tonode)) {
           oplink->flag |= NODE_LINK_TEST;