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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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