1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
|
%%
%% wings_edge.erl --
%%
%% This module contains most edge command and edge utility functions.
%%
%% Copyright (c) 2001-2008 Bjorn Gustavsson.
%%
%% See the file "license.terms" for information on usage and redistribution
%% of this file, and for a DISCLAIMER OF ALL WARRANTIES.
%%
%% $Id: wings_edge.erl,v 1.1 2009/01/25 18:55:33 kostis Exp $
%%
-module(wings_edge).
-export([dissolve_edges/2]).
-include("wings.hrl").
%%%
%%% Dissolve.
%%%
dissolve_edges(Edges0, We0) when is_list(Edges0) ->
#we{es=Etab} = We1 = lists:foldl(fun internal_dissolve_edge/2, We0, Edges0),
case [E || E <- Edges0, gb_trees:is_defined(E, Etab)] of
Edges0 ->
%% No edge was deleted in the last pass. We are done.
We = wings_we:rebuild(We0#we{vc=undefined}),
wings_we:validate_mirror(We);
Edges ->
dissolve_edges(Edges, We1)
end;
dissolve_edges(Edges, We) ->
dissolve_edges(gb_sets:to_list(Edges), We).
internal_dissolve_edge(Edge, #we{es=Etab}=We0) ->
case gb_trees:lookup(Edge, Etab) of
none -> We0;
{value,#edge{ltpr=Same,ltsu=Same,rtpr=Same,rtsu=Same}} ->
Empty = gb_trees:empty(),
We0#we{vc=Empty,vp=Empty,es=Empty,fs=Empty,he=gb_sets:empty()};
{value,#edge{rtpr=Back,ltsu=Back}=Rec} ->
merge_edges(backward, Edge, Rec, We0);
{value,#edge{rtsu=Forward,ltpr=Forward}=Rec} ->
merge_edges(forward, Edge, Rec, We0);
{value,Rec} ->
try dissolve_edge_1(Edge, Rec, We0) of
We -> We
catch
throw:hole -> We0
end
end.
%% dissolve_edge_1(Edge, EdgeRecord, We) -> We
%% Remove an edge and a face. If one of the faces is degenerated
%% (only consists of two edges), remove that one. Otherwise, it
%% doesn't matter which face we remove.
dissolve_edge_1(Edge, #edge{lf=Remove,rf=Keep,ltpr=Same,ltsu=Same}=Rec, We) ->
dissolve_edge_2(Edge, Remove, Keep, Rec, We);
dissolve_edge_1(Edge, #edge{lf=Keep,rf=Remove}=Rec, We) ->
dissolve_edge_2(Edge, Remove, Keep, Rec, We).
dissolve_edge_2(Edge, FaceRemove, FaceKeep,
#edge{ltpr=LP,ltsu=LS,rtpr=RP,rtsu=RS},
#we{fs=Ftab0,es=Etab0,he=Htab0}=We0) ->
%% First change face for all edges surrounding the face we will remove.
Etab1 = wings_face:fold(
fun (_, E, _, IntEtab) when E =:= Edge -> IntEtab;
(_, E, R, IntEtab) ->
case R of
#edge{lf=FaceRemove,rf=FaceKeep} ->
throw(hole);
#edge{rf=FaceRemove,lf=FaceKeep} ->
throw(hole);
#edge{lf=FaceRemove} ->
gb_trees:update(E, R#edge{lf=FaceKeep}, IntEtab);
#edge{rf=FaceRemove} ->
gb_trees:update(E, R#edge{rf=FaceKeep}, IntEtab)
end
end, Etab0, FaceRemove, We0),
%% Patch all predecessors and successor of the edge we will remove.
Etab2 = patch_edge(LP, RS, Edge, Etab1),
Etab3 = patch_edge(LS, RP, Edge, Etab2),
Etab4 = patch_edge(RP, LS, Edge, Etab3),
Etab5 = patch_edge(RS, LP, Edge, Etab4),
%% Remove the edge.
Etab = gb_trees:delete(Edge, Etab5),
Htab = hardness(Edge, soft, Htab0),
%% Remove the face. Patch the face entry for the remaining face.
Ftab1 = gb_trees:delete(FaceRemove, Ftab0),
We1 = wings_facemat:delete_face(FaceRemove, We0),
Ftab = gb_trees:update(FaceKeep, LP, Ftab1),
%% Return result.
We = We1#we{es=Etab,fs=Ftab,vc=undefined,he=Htab},
AnEdge = gb_trees:get(FaceKeep, Ftab),
case gb_trees:get(AnEdge, Etab) of
#edge{lf=FaceKeep,ltpr=Same,ltsu=Same} ->
internal_dissolve_edge(AnEdge, We);
#edge{rf=FaceKeep,rtpr=Same,rtsu=Same} ->
internal_dissolve_edge(AnEdge, We);
_Other ->
case wings_we:is_face_consistent(FaceKeep, We) of
true ->
We;
false ->
io:format("Dissolving would cause a badly formed face.")
end
end.
%%
%% We like winged edges, but not winged vertices (a vertex with
%% only two edges connected to it). We will remove the winged vertex
%% by joining the two edges connected to it.
%%
merge_edges(Dir, Edge, Rec, #we{es=Etab}=We) ->
{Va,Vb,_,_,_,_,To,To} = half_edge(Dir, Rec),
case gb_trees:get(To, Etab) of
#edge{vs=Va,ve=Vb} ->
del_2edge_face(Dir, Edge, Rec, To, We);
#edge{vs=Vb,ve=Va} ->
del_2edge_face(Dir, Edge, Rec, To, We);
_Other ->
merge_1(Dir, Edge, Rec, To, We)
end.
merge_1(Dir, Edge, Rec, To, #we{es=Etab0,fs=Ftab0,he=Htab0}=We) ->
OtherDir = reverse_dir(Dir),
{Vkeep,Vdelete,Lf,Rf,A,B,L,R} = half_edge(OtherDir, Rec),
Etab1 = patch_edge(L, To, Edge, Etab0),
Etab2 = patch_edge(R, To, Edge, Etab1),
Etab3 = patch_half_edge(To, Vkeep, Lf, A, L, Rf, B, R, Vdelete, Etab2),
Htab = hardness(Edge, soft, Htab0),
Etab = gb_trees:delete(Edge, Etab3),
#edge{lf=Lf,rf=Rf} = Rec,
Ftab1 = update_face(Lf, To, Edge, Ftab0),
Ftab = update_face(Rf, To, Edge, Ftab1),
merge_2(To, We#we{es=Etab,fs=Ftab,he=Htab,vc=undefined}).
merge_2(Edge, #we{es=Etab}=We) ->
%% If the merged edge is part of a two-edge face, we must
%% remove that edge too.
case gb_trees:get(Edge, Etab) of
#edge{ltpr=Same,ltsu=Same} ->
internal_dissolve_edge(Edge, We);
#edge{rtpr=Same,rtsu=Same} ->
internal_dissolve_edge(Edge, We);
_Other -> We
end.
update_face(Face, Edge, OldEdge, Ftab) ->
case gb_trees:get(Face, Ftab) of
OldEdge -> gb_trees:update(Face, Edge, Ftab);
_Other -> Ftab
end.
del_2edge_face(Dir, EdgeA, RecA, EdgeB,
#we{es=Etab0,fs=Ftab0,he=Htab0}=We) ->
{_,_,Lf,Rf,_,_,_,_} = half_edge(reverse_dir(Dir), RecA),
RecB = gb_trees:get(EdgeB, Etab0),
Del = gb_sets:from_list([EdgeA,EdgeB]),
EdgeANear = stabile_neighbor(RecA, Del),
EdgeBNear = stabile_neighbor(RecB, Del),
Etab1 = patch_edge(EdgeANear, EdgeBNear, EdgeA, Etab0),
Etab2 = patch_edge(EdgeBNear, EdgeANear, EdgeB, Etab1),
Etab3 = gb_trees:delete(EdgeA, Etab2),
Etab = gb_trees:delete(EdgeB, Etab3),
%% Patch hardness table.
Htab1 = hardness(EdgeA, soft, Htab0),
Htab = hardness(EdgeB, soft, Htab1),
%% Patch the face table.
#edge{lf=Klf,rf=Krf} = gb_trees:get(EdgeANear, Etab),
KeepFaces = ordsets:from_list([Klf,Krf]),
EdgeAFaces = ordsets:from_list([Lf,Rf]),
[DelFace] = ordsets:subtract(EdgeAFaces, KeepFaces),
Ftab1 = gb_trees:delete(DelFace, Ftab0),
[KeepFace] = ordsets:intersection(KeepFaces, EdgeAFaces),
Ftab2 = update_face(KeepFace, EdgeANear, EdgeA, Ftab1),
Ftab = update_face(KeepFace, EdgeBNear, EdgeB, Ftab2),
%% Return result.
We#we{vc=undefined,es=Etab,fs=Ftab,he=Htab}.
stabile_neighbor(#edge{ltpr=Ea,ltsu=Eb,rtpr=Ec,rtsu=Ed}, Del) ->
[Edge] = lists:foldl(fun(E, A) ->
case gb_sets:is_member(E, Del) of
true -> A;
false -> [E|A]
end
end, [], [Ea,Eb,Ec,Ed]),
Edge.
%%%
%%% Setting hard/soft edges.
%%%
hardness(Edge, soft, Htab) -> gb_sets:delete_any(Edge, Htab);
hardness(Edge, hard, Htab) -> gb_sets:add(Edge, Htab).
%%%
%%% Utilities.
%%%
reverse_dir(forward) -> backward;
reverse_dir(backward) -> forward.
half_edge(backward, #edge{vs=Va,ve=Vb,lf=Lf,rf=Rf,a=A,b=B,ltsu=L,rtpr=R}) ->
{Va,Vb,Lf,Rf,A,B,L,R};
half_edge(forward, #edge{ve=Va,vs=Vb,lf=Lf,rf=Rf,a=A,b=B,ltpr=L,rtsu=R}) ->
{Va,Vb,Lf,Rf,A,B,L,R}.
patch_half_edge(Edge, V, FaceA, A, Ea, FaceB, B, Eb, OrigV, Etab) ->
New = case gb_trees:get(Edge, Etab) of
#edge{vs=OrigV,lf=FaceA,rf=FaceB}=Rec ->
Rec#edge{a=A,vs=V,ltsu=Ea,rtpr=Eb};
#edge{vs=OrigV,lf=FaceB,rf=FaceA}=Rec ->
Rec#edge{a=B,vs=V,ltsu=Eb,rtpr=Ea};
#edge{ve=OrigV,lf=FaceA,rf=FaceB}=Rec ->
Rec#edge{b=B,ve=V,ltpr=Ea,rtsu=Eb};
#edge{ve=OrigV,lf=FaceB,rf=FaceA}=Rec ->
Rec#edge{b=A,ve=V,ltpr=Eb,rtsu=Ea}
end,
gb_trees:update(Edge, New, Etab).
patch_edge(Edge, ToEdge, OrigEdge, Etab) ->
New = case gb_trees:get(Edge, Etab) of
#edge{ltsu=OrigEdge}=R ->
R#edge{ltsu=ToEdge};
#edge{ltpr=OrigEdge}=R ->
R#edge{ltpr=ToEdge};
#edge{rtsu=OrigEdge}=R ->
R#edge{rtsu=ToEdge};
#edge{rtpr=OrigEdge}=R ->
R#edge{rtpr=ToEdge}
end,
gb_trees:update(Edge, New, Etab).
|
