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Source at commit c5f54df created 10 years 5 months ago. By Werner Almesberger, cameo/stl.c: generate real STL (WIP) | |
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1 | /* |
2 | * stl.c - Genererate STL slice from polygon set |
3 | * |
4 | * Written 2013 by Werner Almesberger |
5 | * Copyright 2013 Werner Almesberger |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify |
8 | * it under the terms of the GNU General Public License as published by |
9 | * the Free Software Foundation; either version 2 of the License, or |
10 | * (at your option) any later version. |
11 | */ |
12 | |
13 | |
14 | #include <stdlib.h> |
15 | #include <stdio.h> |
16 | #include <math.h> |
17 | |
18 | #include "poly2d.h" |
19 | |
20 | #include "path.h" |
21 | #include "stl.h" |
22 | |
23 | |
24 | static void facet(FILE *file, const struct f2d *f, int a, int b, int c, |
25 | double za, double zb, double zc, double nx, double ny, double nz) |
26 | { |
27 | double d; |
28 | |
29 | d = sqrt(nx*nx+ny*ny+nz*nz); |
30 | if (!d) |
31 | d = 1; |
32 | |
33 | fprintf(file, "facet normal %e %e %e\n", nx/d, ny/d, nz/d); |
34 | fprintf(file, "\touter loop\n"); |
35 | fprintf(file, "\t\tvertex %e %e %e\n", f->x[a], f->y[a], za); |
36 | fprintf(file, "\t\tvertex %e %e %e\n", f->x[b], f->y[b], zb); |
37 | fprintf(file, "\t\tvertex %e %e %e\n", f->x[c], f->y[c], zc); |
38 | fprintf(file, "\tendloop\n"); |
39 | fprintf(file, "endfacet\n"); |
40 | } |
41 | |
42 | |
43 | static void surface(FILE *file, const struct f2d *f) |
44 | { |
45 | facet(file, f, 0, 1, 2, 1, 1, 1, 0, 0, 1); |
46 | facet(file, f, 2, 1, 0, 0, 0, 0, 0, 0, -1); |
47 | } |
48 | |
49 | |
50 | static void side(FILE *file, const struct f2d *f, int a, int b) |
51 | { |
52 | double nx, ny; |
53 | |
54 | nx = f->y[b]-f->y[a]; |
55 | ny = f->x[a]-f->x[b]; |
56 | facet(file, f, a, b, b, 0, 0, 1, nx, ny, 0); |
57 | facet(file, f, b, a, a, 1, 1, 0, nx, ny, 0); |
58 | } |
59 | |
60 | |
61 | static void stl_write(FILE *file, const struct path *paths) |
62 | { |
63 | struct p2d *polys; |
64 | struct f2d *faces; |
65 | const struct f2d *f; |
66 | int i; |
67 | |
68 | fprintf(file, "solid cameo\n"); |
69 | polys = paths_to_polys(paths); |
70 | faces = f2d_tri(polys); |
71 | for (f = faces; f; f = f->next) { |
72 | surface(file, f); |
73 | for (i = 0; i != 3; i++) |
74 | if (f->side[i]) |
75 | side(file, f, i, (i+1) % 3); |
76 | } |
77 | p2d_free_all(polys); |
78 | f2d_free_all(faces); |
79 | fprintf(file, "endsolid cameo\n"); |
80 | } |
81 | |
82 | |
83 | void stl(const char *name, const struct path *paths) |
84 | { |
85 | FILE *file = stdout; |
86 | |
87 | if (name) { |
88 | file = fopen(name, "w"); |
89 | if (!file) { |
90 | perror(name); |
91 | exit(1); |
92 | } |
93 | } |
94 | stl_write(file, paths); |
95 | if (name && fclose(file)) { |
96 | perror(name); |
97 | exit(1); |
98 | } |
99 | } |
100 |
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