rip out function into a utility file

nodes/modifier_change/mesh_separate.py

@@ -23,7 +23,7 @@
 from sverchok.node_tree import SverchCustomTreeNode
 from sverchok.data_structure import zip_long_repeat
 from sverchok.utils.nodes_mixins.sockets_config import ModifierLiteNode
-
+from sverchok.utils.modules.topology_utils import separate_loose
 
 class SvSeparateMeshNode(ModifierLiteNode, bpy.types.Node, SverchCustomTreeNode):
     '''Separate Loose mesh parts'''
@@ -42,54 +42,17 @@ def sv_init(self, context):
     def process(self):
         if not any(s.is_linked for s in self.outputs):
             return
+
         verts = self.inputs['Vertices'].sv_get(deepcopy=False)
         poly = self.inputs['Poly Egde'].sv_get(deepcopy=False)
+
         verts_out = []
         poly_edge_out = []
-        for ve, pe in zip_long_repeat(verts, poly):
-            # build links
-            node_links = {}
-            for edge_face in pe:
-                for i in edge_face:
-                    if i not in node_links:
-                        node_links[i] = set()
-                    node_links[i].update(edge_face)
 
-            nodes = set(node_links.keys())
-            n = nodes.pop()
-            node_set_list = [set([n])]
-            node_stack = collections.deque()
-            node_stack_append = node_stack.append
-            node_stack_pop = node_stack.pop
-            node_set = node_set_list[-1]
-            # find separate sets
-            while nodes:
-                for node in node_links[n]:
-                    if node not in node_set:
-                        node_stack_append(node)
-                if not node_stack:  # new mesh part
-                    n = nodes.pop()
-                    node_set_list.append(set([n]))
-                    node_set = node_set_list[-1]
-                else:
-                    while node_stack and n in node_set:
-                        n = node_stack_pop()
-                    nodes.discard(n)
-                    node_set.add(n)
-            # create new meshes from sets, new_pe is the slow line.
-            if len(node_set_list) > 1:
-                for node_set in node_set_list:
-                    mesh_index = sorted(node_set)
-                    vert_dict = {j: i for i, j in enumerate(mesh_index)}
-                    new_vert = [ve[i] for i in mesh_index]
-                    new_pe = [[vert_dict[n] for n in fe]
-                              for fe in pe
-                              if fe[0] in node_set]
-                    verts_out.append(new_vert)
-                    poly_edge_out.append(new_pe)
-            elif node_set_list:  # no reprocessing needed
-                verts_out.append(ve)
-                poly_edge_out.append(pe)
+        for ve, pe in zip_long_repeat(verts, poly):
+            nve, npe = separate_loose(ve, pe)
+            verts_out.extend(nve)
+            poly_edge_out.extend(npe)
 
         self.outputs['Vertices'].sv_set(verts_out)
         self.outputs['Poly Egde'].sv_set(poly_edge_out)

utils/modules/topology_utils.py

@@ -0,0 +1,70 @@
+# This file is part of project Sverchok. It's copyrighted by the contributors
+# recorded in the version control history of the file, available from
+# its original location https://github.com/nortikin/sverchok/commit/master
+#  
+# SPDX-License-Identifier: GPL3
+# License-Filename: LICENSE
+
+import collections
+
+def separate_loose(ve, pe):
+    """
+    this function will take verts and polygons or edges.
+    if you pass it verts and edges/polygons it will return the individual mesh islands
+    if you pass it verts and boundary edges it will return the separate boundaries per object.
+
+    """
+
+    # build links
+    node_links = {}
+    for edge_face in pe:
+        for i in edge_face:
+            if i not in node_links:
+                node_links[i] = set()
+            node_links[i].update(edge_face)
+
+    nodes = set(node_links.keys())
+    n = nodes.pop()
+    node_set_list = [set([n])]
+    node_stack = collections.deque()
+    node_stack_append = node_stack.append
+    node_stack_pop = node_stack.pop
+    node_set = node_set_list[-1]
+
+    # find separate sets
+    while nodes:
+        for node in node_links[n]:
+            if node not in node_set:
+                node_stack_append(node)
+        if not node_stack:  # new mesh part
+            n = nodes.pop()
+            node_set_list.append(set([n]))
+            node_set = node_set_list[-1]
+        else:
+            while node_stack and n in node_set:
+                n = node_stack_pop()
+            nodes.discard(n)
+            node_set.add(n)
+
+    # create new meshes from sets, new_pe is the slow line.
+    verts = []
+    poly_edges = []
+    if len(node_set_list) > 1:
+
+        for node_set in node_set_list:
+            mesh_index = sorted(node_set)
+            vert_dict = {j: i for i, j in enumerate(mesh_index)}
+            new_vert = [ve[i] for i in mesh_index]
+            new_pe = [[vert_dict[n] for n in fe]
+                      for fe in pe
+                      if fe[0] in node_set]
+
+            verts.append(new_vert)
+            poly_edges.append(new_pe)
+
+
+    elif node_set_list:  # no reprocessing needed
+        verts.append(ve)
+        poly_edges.append(pe)
+
+    return verts, poly_edges