mesh_tiny_cad/VTX.py

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  15 #  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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  17 # ##### END GPL LICENSE BLOCK #####
  18
  19 # <pep8 compliant>
  20
  21
  22 import bpy
  23 import bmesh
  24 import sys
  25
  26 from . import cad_module as cm
  27
  28 messages = {
  29     'SHARED_VERTEX': 'Shared Vertex, no intersection possible',
  30     'PARALLEL_EDGES': 'Edges Parallel, no intersection possible',
  31     'NON_PLANAR_EDGES': 'Non Planar Edges, no clean intersection point'
  32 }
  33
  34
  35 def add_edges(bm, pt, idxs, fdp):
  36     '''
  37     this function is a disaster --
  38     index updates and ensure_lookup_table() are called before this function
  39     and after, and i've tried doing this less verbose but results tend to be
  40     less predictable. I'm obviously a terrible coder, but can only spend so
  41     much time figuring out this stuff.
  42     '''
  43
  44     v1 = bm.verts.new(pt)
  45
  46     bm.verts.ensure_lookup_table()
  47     bm.edges.ensure_lookup_table()
  48     bm.verts.index_update()
  49
  50     try:
  51         for e in idxs:
  52             bm.edges.index_update()
  53             v2 = bm.verts[e]
  54             bm.edges.new((v1, v2))
  55
  56         bm.edges.index_update()
  57         bm.verts.ensure_lookup_table()
  58         bm.edges.ensure_lookup_table()
  59
  60     except Exception as err:
  61         print('some failure: details')
  62         for l in fdp:
  63             print(l)
  64
  65         sys.stderr.write('ERROR: %s\n' % str(err))
  66         print(sys.exc_info()[-1].tb_frame.f_code)
  67         print('Error on line {}'.format(sys.exc_info()[-1].tb_lineno))
  68
  69
  70 def remove_earmarked_edges(bm, earmarked):
  71     edges_select = [e for e in bm.edges if e.index in earmarked]
  72     bmesh.ops.delete(bm, geom=edges_select, context=2)
  73
  74
  75 def perform_vtx(bm, pt, edges, pts, vertex_indices):
  76     idx1, idx2 = edges[0].index, edges[1].index
  77     fdp = pt, edges, pts, vertex_indices
  78
  79     # this list will hold those edges that pt lies on
  80     edges_indices = cm.find_intersecting_edges(bm, pt, idx1, idx2)
  81     mode = 'VTX'[len(edges_indices)]
  82
  83     if mode == 'V':
  84         cl_vert1 = cm.closest_idx(pt, edges[0])
  85         cl_vert2 = cm.closest_idx(pt, edges[1])
  86         add_edges(bm, pt, [cl_vert1, cl_vert2], fdp)
  87
  88     elif mode == 'T':
  89         to_edge_idx = edges_indices[0]
  90         from_edge_idx = idx1 if to_edge_idx == idx2 else idx2
  91
  92         cl_vert = cm.closest_idx(pt, bm.edges[from_edge_idx])
  93         to_vert1, to_vert2 = cm.vert_idxs_from_edge_idx(bm, to_edge_idx)
  94         add_edges(bm, pt, [cl_vert, to_vert1, to_vert2], fdp)
  95
  96     elif mode == 'X':
  97         add_edges(bm, pt, vertex_indices, fdp)
  98
  99     # final refresh before returning to user.
 100     if edges_indices:
 101         remove_earmarked_edges(bm, edges_indices)
 102
 103     bm.edges.index_update()
 104     return bm
 105
 106
 107 def do_vtx_if_appropriate(bm, edges):
 108     vertex_indices = cm.get_vert_indices_from_bmedges(edges)
 109
 110     # test 1, are there shared vers? if so return non-viable
 111     if not len(set(vertex_indices)) == 4:
 112         return {'SHARED_VERTEX'}
 113
 114     # test 2, is parallel?
 115     p1, p2, p3, p4 = [bm.verts[i].co for i in vertex_indices]
 116     point = cm.get_intersection([p1, p2], [p3, p4])
 117     if not point:
 118         return {'PARALLEL_EDGES'}
 119
 120     # test 3, coplanar edges?
 121     coplanar = cm.test_coplanar([p1, p2], [p3, p4])
 122     if not coplanar:
 123         return {'NON_PLANAR_EDGES'}
 124
 125     # point must lie on an edge or the virtual extention of an edge
 126     bm = perform_vtx(bm, point, edges, (p1, p2, p3, p4), vertex_indices)
 127     return bm
 128
 129
 130 class TCAutoVTX(bpy.types.Operator):
 131     '''Weld intersecting edges, project converging edges towards their intersection'''
 132     bl_idname = 'tinycad.autovtx'
 133     bl_label = 'VTX autoVTX'
 134
 135     @classmethod
 136     def poll(cls, context):
 137         obj = context.active_object
 138         return bool(obj) and obj.type == 'MESH'
 139
 140     def cancel_message(self, msg):
 141         print(msg)
 142         self.report({"WARNING"}, msg)
 143         return {'CANCELLED'}
 144
 145     def execute(self, context):
 146
 147         # final attempt to enter unfragmented bm/mesh
 148         # ghastly, but what can I do? it works with these
 149         # fails without.
 150         bpy.ops.object.mode_set(mode='OBJECT')
 151         bpy.ops.object.mode_set(mode='EDIT')
 152
 153         obj = context.active_object
 154         me = obj.data
 155
 156         bm = bmesh.from_edit_mesh(me)
 157         bm.verts.ensure_lookup_table()
 158         bm.edges.ensure_lookup_table()
 159
 160         edges = [e for e in bm.edges if e.select and not e.hide]
 161
 162         if len(edges) == 2:
 163             message = do_vtx_if_appropriate(bm, edges)
 164             if isinstance(message, set):
 165                 msg = messages.get(message.pop())
 166                 return self.cancel_message(msg)
 167             bm = message
 168         else:
 169             return self.cancel_message('select two edges!')
 170
 171         bm.verts.index_update()
 172         bm.edges.index_update()
 173         bmesh.update_edit_mesh(me, True)
 174
 175         return {'FINISHED'}