UI: Multi-input node socket spacing and interaction

This commit makes links connected to multi-input sockets spread verticaly
along the socket. Sockets grow if more links are connected and the node
layout updates accordingly. Links are sorted by their incoming angle
to avoid crossing links. Also, link picking is updated to work with
spread links and bezier links.

Currently the multi-input sockets are used in the join geometry node.

The mutli-input sockets look like a vertical rounded rectangle.
Currently they do not support the other custom socket shapes.

Reviewed By Hans Goudey, with cleanup and additional edits

Differential Revision: https://developer.blender.org/D10181

1 files changed, 44 insertions, 1 deletions

diff --git a/source/blender/editors/space_node/node_edit.c b/source/blender/editors/space_node/node_edit.c
index c006889f0f7..04787748937 100644
--- a/source/blender/editors/space_node/node_edit.c
+++ b/source/blender/editors/space_node/node_edit.c
@@ -98,6 +98,25 @@ typedef struct CompoJob {
   float *progress;
 } CompoJob;
 
+float node_socket_calculate_height(const bNodeSocket *socket)
+{
+  float sock_height = NODE_SOCKSIZE * 2.0f;
+  if (socket->flag & SOCK_MULTI_INPUT) {
+    sock_height += max_ii(NODE_MULTI_INPUT_LINK_GAP * 0.5f * socket->total_inputs, NODE_SOCKSIZE);
+  }
+  return sock_height;
+}
+
+void node_link_calculate_multi_input_position(const bNodeLink *link, float r[2])
+{
+  float offset = (link->tosock->total_inputs * NODE_MULTI_INPUT_LINK_GAP -
+                  NODE_MULTI_INPUT_LINK_GAP) *
+                 0.5;
+  r[0] = link->tosock->locx - NODE_SOCKSIZE * 0.5f;
+  r[1] = link->tosock->locy - offset +
+         (link->multi_input_socket_index * NODE_MULTI_INPUT_LINK_GAP);
+}
+
 static void compo_tag_output_nodes(bNodeTree *nodetree, int recalc_flags)
 {
   LISTBASE_FOREACH (bNode *, node, &nodetree->nodes) {
@@ -1104,6 +1123,21 @@ void node_set_hidden_sockets(SpaceNode *snode, bNode *node, int set)
 }
 
 /* checks snode->mouse position, and returns found node/socket */
+static bool cursor_isect_multi_input_socket(const float cursor[2], const bNodeSocket *socket)
+{
+  const float node_socket_height = node_socket_calculate_height(socket);
+  const rctf multi_socket_rect = {
+      .xmin = socket->locx - NODE_SOCKSIZE * 4,
+      .xmax = socket->locx + NODE_SOCKSIZE,
+      .ymin = socket->locy - node_socket_height * 0.5 - NODE_SOCKSIZE * 2.0f,
+      .ymax = socket->locy + node_socket_height * 0.5 + NODE_SOCKSIZE * 2.0f,
+  };
+  if (BLI_rctf_isect_pt(&multi_socket_rect, cursor[0], cursor[1])) {
+    return true;
+  }
+  return false;
+}
+
 /* type is SOCK_IN and/or SOCK_OUT */
 int node_find_indicated_socket(
     SpaceNode *snode, bNode **nodep, bNodeSocket **sockp, float cursor[2], int in_out)
@@ -1132,7 +1166,16 @@ int node_find_indicated_socket(
     if (in_out & SOCK_IN) {
       LISTBASE_FOREACH (bNodeSocket *, sock, &node->inputs) {
         if (!nodeSocketIsHidden(sock)) {
-          if (BLI_rctf_isect_pt(&rect, sock->locx, sock->locy)) {
+          if (sock->flag & SOCK_MULTI_INPUT && !(node->flag & NODE_HIDDEN)) {
+            if (cursor_isect_multi_input_socket(cursor, sock)) {
+              if (node == visible_node(snode, &rect)) {
+                *nodep = node;
+                *sockp = sock;
+                return 1;
+              }
+            }
+          }
+          else if (BLI_rctf_isect_pt(&rect, sock->locx, sock->locy)) {
             if (node == visible_node(snode, &rect)) {
               *nodep = node;
               *sockp = sock;