mesh_tiny_cad/XALL.py

   1 # SPDX-License-Identifier: GPL-2.0-or-later
   2
   3
   4 import bpy
   5 import bmesh
   6 from mathutils.geometry import intersect_line_line as LineIntersect
   7
   8 import itertools
   9 from collections import defaultdict
  10 from . import cad_module as cm
  11
  12
  13 def order_points(edge, point_list):
  14     ''' order these edges from distance to v1, then
  15     sandwich the sorted list with v1, v2 '''
  16     v1, v2 = edge
  17
  18     def dist(co):
  19         return (v1 - co).length
  20     point_list = sorted(point_list, key=dist)
  21     return [v1] + point_list + [v2]
  22
  23
  24 def remove_permutations_that_share_a_vertex(bm, permutations):
  25     ''' Get useful Permutations '''
  26     final_permutations = []
  27     for edges in permutations:
  28         raw_vert_indices = cm.vertex_indices_from_edges_tuple(bm, edges)
  29         if cm.duplicates(raw_vert_indices):
  30             continue
  31
  32         # reaches this point if they do not share.
  33         final_permutations.append(edges)
  34
  35     return final_permutations
  36
  37
  38 def get_valid_permutations(bm, edge_indices):
  39     raw_permutations = itertools.permutations(edge_indices, 2)
  40     permutations = [r for r in raw_permutations if r[0] < r[1]]
  41     return remove_permutations_that_share_a_vertex(bm, permutations)
  42
  43
  44 def can_skip(closest_points, vert_vectors):
  45     '''this checks if the intersection lies on both edges, returns True
  46     when criteria are not met, and thus this point can be skipped'''
  47     if not closest_points:
  48         return True
  49     if not isinstance(closest_points[0].x, float):
  50         return True
  51     if cm.num_edges_point_lies_on(closest_points[0], vert_vectors) < 2:
  52         return True
  53
  54     # if this distance is larger than than VTX_PRECISION, we can skip it.
  55     cpa, cpb = closest_points
  56     return (cpa - cpb).length > cm.CAD_prefs.VTX_PRECISION
  57
  58
  59 def get_intersection_dictionary(bm, edge_indices):
  60
  61     bm.verts.ensure_lookup_table()
  62     bm.edges.ensure_lookup_table()
  63
  64     permutations = get_valid_permutations(bm, edge_indices)
  65
  66     k = defaultdict(list)
  67     d = defaultdict(list)
  68
  69     for edges in permutations:
  70         raw_vert_indices = cm.vertex_indices_from_edges_tuple(bm, edges)
  71         vert_vectors = cm.vectors_from_indices(bm, raw_vert_indices)
  72
  73         points = LineIntersect(*vert_vectors)
  74
  75         # some can be skipped.    (NaN, None, not on both edges)
  76         if can_skip(points, vert_vectors):
  77             continue
  78
  79         # reaches this point only when an intersection happens on both edges.
  80         [k[edge].append(points[0]) for edge in edges]
  81
  82     # k will contain a dict of edge indices and points found on those edges.
  83     for edge_idx, unordered_points in k.items():
  84         tv1, tv2 = bm.edges[edge_idx].verts
  85         v1 = bm.verts[tv1.index].co
  86         v2 = bm.verts[tv2.index].co
  87         ordered_points = order_points((v1, v2), unordered_points)
  88         d[edge_idx].extend(ordered_points)
  89
  90     return d
  91
  92
  93 def update_mesh(bm, d):
  94     ''' Make new geometry (delete old first) '''
  95
  96     oe = bm.edges
  97     ov = bm.verts
  98
  99     new_verts = []
 100     collect = new_verts.extend
 101     for old_edge, point_list in d.items():
 102         num_edges_to_add = len(point_list)-1
 103         for i in range(num_edges_to_add):
 104             a = ov.new(point_list[i])
 105             b = ov.new(point_list[i+1])
 106             oe.new((a, b))
 107             bm.normal_update()
 108             collect([a, b])
 109
 110     bmesh.ops.delete(bm, geom=[edge for edge in bm.edges if edge.select], context='EDGES')
 111
 112     #bpy.ops.mesh.remove_doubles(
 113     #    threshold=cm.CAD_prefs.VTX_DOUBLES_THRSHLD,
 114     #    use_unselected=False)
 115
 116     bmesh.ops.remove_doubles(bm, verts=new_verts, dist=cm.CAD_prefs.VTX_DOUBLES_THRSHLD)
 117
 118
 119 def unselect_nonintersecting(bm, d_edges, edge_indices):
 120     if len(edge_indices) > len(d_edges):
 121         reserved_edges = set(edge_indices) - set(d_edges)
 122         for edge in reserved_edges:
 123             bm.edges[edge].select = False
 124         print("unselected {}, non intersecting edges".format(reserved_edges))
 125
 126
 127 class TCIntersectAllEdges(bpy.types.Operator):
 128     '''Adds a vertex at the intersections of all selected edges'''
 129     bl_idname = 'tinycad.intersectall'
 130     bl_label = 'XALL intersect all edges'
 131     bl_options = {'REGISTER', 'UNDO'}
 132
 133     @classmethod
 134     def poll(cls, context):
 135         obj = context.active_object
 136         return obj is not None and obj.type == 'MESH' and obj.mode == 'EDIT'
 137
 138     def execute(self, context):
 139         # must force edge selection mode here
 140         bpy.context.tool_settings.mesh_select_mode = (False, True, False)
 141
 142         obj = context.active_object
 143         if obj.mode == "EDIT":
 144             bm = bmesh.from_edit_mesh(obj.data)
 145
 146             selected_edges = [edge for edge in bm.edges if edge.select]
 147             edge_indices = [i.index for i in selected_edges]
 148
 149             d = get_intersection_dictionary(bm, edge_indices)
 150
 151             unselect_nonintersecting(bm, d.keys(), edge_indices)
 152             update_mesh(bm, d)
 153
 154             bmesh.update_edit_mesh(obj.data)
 155         else:
 156             print('must be in edit mode')
 157
 158         return {'FINISHED'}