git ssb

1
function toDegrees (rad) {
2
  return rad*180/Math.PI
3
}
4
5
function dist (a, b) {
6
  return Math.sqrt(Math.pow(a[0] - b[0], 2) + Math.pow(a[1] - b[1], 2))
7
}
8
9
//given two 2d points and two distances, return a point.
10
//this has some floating point errors, probably better ways
11
//to do with without sin/cos/tan?
12
function triangulate(a, da, b, db) {
13
  var c = dist(a, b)
14
  var cos =  (da*da + c*c - db*db)/(2*da*c)
15
  var angle = Math.acos(cos)
16
  var cos2 =  (db*db + c*c - da*da)/(2*db*c)
17
  var angle2 = Math.acos(cos2)
18
  var _angle = Math.atan( (a[1]-b[1]) / (a[0]-b[0]) )
19
  var _angle2 = Math.atan( (b[1]-a[1]) / (b[0]-a[0]) )
20
21
//  console.log('ANGLE', toDegrees(angle), toDegrees(_angle),
22
//    Math.sin(angle+_angle),
23
//    Math.cos(angle+_angle),
24
//    da
25
//
26
//  )
27
  console.log('angle', toDegrees(_angle), toDegrees(_angle2))
28
  var x = [
29
    a[0] + Math.sin(angle+_angle)*da,
30
    a[1] + Math.cos(angle+_angle)*da
31
  ]
32
  var x2 = [
33
    b[0] + Math.sin(angle2+_angle2)*db,
34
    b[1] + Math.cos(angle2+_angle2)*db
35
  ]
36
  console.log(x, x2)
37
38
39
  console.log('dist a', da - dist(a, x))
40
  console.log('dist b', db - dist(b, x))
41
  if(angle2 < angle) return x2
42
  return x
43
}
44
45
//console.log(dist([0,0], [1,-1]))
46
47
//console.log(triangulate([0,0], 1, [1,1], 1))
48
//console.log(triangulate([0,0], 5, [3,0], 4))
49
50
//should be [-1, 1], or [1, 1]
51
console.log('T', triangulate([0,0], 1.414, [0,1], 1))
52
//should be [-1, 0] or [1, 0]
53
console.log('T', triangulate([0,0], 1, [0,1], 1.414))
54
55
//return
56
57
exports.triangulate = triangulate
58
59
exports.develop = function (polygon, developed) {
60
  var a, b
61
  //given
62
  //developed is a map of vertices already layed out
63
  //first find a known edge: two vertices already developed.
64
  for(var k in polygon.vertices) {
65
    var v = polygon.vertices[k]
66
    if(!a && developed[vertexId(v)])
67
      a = v
68
    else if(!b && developed[vertexId(v)])
69
      b = v
70
  }
71
  if(!a && !b) throw new Error('could not develop polygon, do not have two matching vertices')
72
73
  //calculate distance between a and b
74
//  console.log(a, b)
75
  var d = a.pos.distanceTo(b.pos)
76
  var vertices = []
77
  for(var k in polygon.vertices) {
78
    var v = polygon.vertices[k]
79
    if(developed[vertexId(v)]) //either a or b
80
      vertices.push(developed[vertexId(v)])
81
    else {
82
      var _v = triangulate(developed[vertexId(a)], a.pos.distanceTo(v.pos), developed[vertexId(b)], b.pos.distanceTo(v.pos))
83
      console.log("VERTICE", _v, a.pos.distanceTo(v.pos), b.pos.distanceTo(v.pos))
84
      vertices.push(_v)
85
      if(!developed[vertexId(v)])
86
        developed[vertexId(v)] = _v
87
    }
88
  }
89
  return vertices
90
}
91
92
var CSG = require('@jscad/csg').CSG
93
94
var square = {vertices: [
95
  new CSG.Vector3D(0, 0, 0),
96
  new CSG.Vector3D(0, 3, 0),
97
  new CSG.Vector3D(4, 3, 0),
98
//  new CSG.Vector3D(10, 0, 0)
99
].map(function (e, i) {
100
  e = new CSG.Vertex(e)
101
  e.tag = i+1
102
  return e
103
})}
104
105
//console.log(exports.develop(square, {1: [0,2], 2:[0, 5]}))
106
107
var c = CSG.cube({center: [0,0,0], size: 2})
108
console.log(c)
109
var d = {} //: [0,0], 2:[2, 0]}
110
d[vertexId(c.polygons[0].vertices[0])] = [0,0]
111
d[vertexId(c.polygons[0].vertices[1])] = [0,2]
112
113
console.log(d)
114
115
function vertexId(e) {
116
  e = e.pos || e
117
  return [e.x,e.y,e.z].join(',')
118
}
119
120
function sideId (poly) {
121
  return poly.vertices.map(vertexId).join(':')
122
}
123
124
function findUndevelopedPoly(shape, sides, developed) {
125
  for(var i = 0; i < shape.polygons.length; i++) {
126
    var poly = shape.polygons[i]
127
    if(!sides[sideId(poly)]) {
128
      var n = 0
129
      for(var j = 0; j < poly.vertices.length; j++) {
130
        if(developed[vertexId(poly.vertices[j])]) n++
131
      }
132
133
      console.log(n)
134
      if(n >= 2) return poly
135
    }
136
  }
137
//  throw new Error('could not find a polygon to develop')
138
}
139
140
141
var sides = {}
142
var side = findUndevelopedPoly(c, sides, d)
143
while(side) {
144
  sides[sideId(side)] = exports.develop(side, d)
145
//  console.log('so far', sides, d)
146
  side = findUndevelopedPoly(c, sides, d)
147
}
148
149
console.log('SIDES', sides, d)
150
151
//return
152
module.exports = function (_) {
153
  //return c
154
  sd = Object.keys(sides).map(function (k) {
155
    var side = sides[k].map(function (v) {
156
      console.log(v)
157
      return v
158
//      return new _.CSG.Vector2D(v[0], v[1])
159
    })
160
    return _.CSG
161
      .Polygon.createFromPoints(side, null, CSG.Plane.fromPoints.apply(null, side.slice().reverse()))
162
      .extrude(new CSG.Vector3D(0,0,1))
163
  })//.slice(0, 1)
164
  console.log('SIDES', sd)
165
  return sd[0]
166
//  .reduce(function (a, b) {
167
//    console.log('union', a)
168
//    return a.union(b)
169
//  })
170
}
171
172
173
174
175
176
177
178
179