ImageExtruder/stl_writer.py at master · telefab/ImageExtruder · GitHub

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
## {{{ http://code.activestate.com/recipes/578246/ (r1)
#!/usr/bin/env python
#coding:utf-8
# Purpose: Export 3D objects, build of faces with 3 or 4 vertices, as ASCII or Binary STL file.
# License: MIT License

import struct

ASCII_FACET = """facet normal 0 0 0
outer loop
vertex {face[0][0]:.4f} {face[0][1]:.4f} {face[0][2]:.4f}
vertex {face[1][0]:.4f} {face[1][1]:.4f} {face[1][2]:.4f}
vertex {face[2][0]:.4f} {face[2][1]:.4f} {face[2][2]:.4f}
endloop
endfacet
"""

BINARY_HEADER ="80sI"
BINARY_FACET = "12fH"

class ASCIISTLWriter:
    """ Export 3D objects build of 3 or 4 vertices as ASCII STL file.
    """
    def __init__(self, stream):
        self.fp = stream
        self._write_header()

    def _write_header(self):
        self.fp.write("solid python\n")

    def close(self):
        self.fp.write("endsolid python\n")

    def _write(self, face):
        self.fp.write(ASCII_FACET.format(face=face))

    def _split(self, face):
        p1, p2, p3, p4 = face
        return (p1, p2, p3), (p3, p4, p1)

    def add_face(self, face):
        """ Add one face with 3 or 4 vertices. """
        if len(face) == 4:
            face1, face2 = self._split(face)
            self._write(face1)
            self._write(face2)
        elif len(face) == 3:
            self._write(face)
        else:
            raise ValueError('only 3 or 4 vertices for each face')

    def add_faces(self, faces):
        """ Add many faces. """
        for face in faces:
            self.add_face(face)

class BinarySTLWriter(ASCIISTLWriter):
    """ Export 3D objects build of 3 or 4 vertices as binary STL file.
    """
    def __init__(self, stream):
        self.counter = 0
        super(Binary_STL_Writer, self).__init__(stream)

    def close(self):
        self._write_header()

    def _write_header(self):
        self.fp.seek(0)
        self.fp.write(struct.pack(BINARY_HEADER, b'Python Binary STL Writer', self.counter))

    def _write(self, face):
        self.counter += 1
        data = [
            0., 0., 0.,
            face[0][0], face[0][1], face[0][2],
            face[1][0], face[1][1], face[1][2],
            face[2][0], face[2][1], face[2][2],
            0
        ]
        self.fp.write(struct.pack(BINARY_FACET, *data))


## end of http://code.activestate.com/recipes/578246/ }}}