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| 1 | /* |
| 2 | * shape.c - Toolpaths for basic shapes |
| 3 | * |
| 4 | * Written 2010-2011 by Werner Almesberger |
| 5 | * Copyright 2010-2011 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 <math.h> |
| 15 | |
| 16 | #include "path.h" |
| 17 | #include "shape.h" |
| 18 | |
| 19 | |
| 20 | static double arc2angle(double arc, double r) |
| 21 | { |
| 22 | return acos(1-arc*arc/(r*r)/2); |
| 23 | } |
| 24 | |
| 25 | |
| 26 | static void half_circle(struct path *path, |
| 27 | double cx, double cy, double rx, double ry, double z, double s) |
| 28 | { |
| 29 | double m[4]; |
| 30 | double x = rx, y = ry, tmp; |
| 31 | double a; |
| 32 | |
| 33 | m[0] = cos(s); |
| 34 | m[1] = -sin(s); |
| 35 | m[2] = -m[1]; |
| 36 | m[3] = m[0]; |
| 37 | |
| 38 | for (a = 0; a < M_PI; a += s) { |
| 39 | path_add(path, cx+x, cy+y, z); |
| 40 | tmp = x*m[0]+y*m[1]; |
| 41 | y = x*m[2]+y*m[3]; |
| 42 | x = tmp; |
| 43 | } |
| 44 | path_add(path, cx-rx, cy-ry, z); |
| 45 | } |
| 46 | |
| 47 | |
| 48 | struct path *slot(double xa, double ya, double xb, double yb, double z, |
| 49 | double sr, double tr, double step, const char *id) |
| 50 | { |
| 51 | struct path *path; |
| 52 | double dx = xb-xa; |
| 53 | double dy = yb-ya; |
| 54 | double s = arc2angle(step, sr); |
| 55 | double nx, ny; |
| 56 | double f; |
| 57 | |
| 58 | path = path_new(tr, id); |
| 59 | if (sr <= tr) { |
| 60 | path_add(path, xa, ya, z); |
| 61 | path_add(path, xb, yb, z); |
| 62 | } else { |
| 63 | f = (sr-tr)/hypot(dx, dy); |
| 64 | nx = -dy*f; |
| 65 | ny = dx*f; |
| 66 | |
| 67 | half_circle(path, xa, ya, nx, ny, z, s); |
| 68 | half_circle(path, xb, yb, -nx, -ny, z, s); |
| 69 | path_add(path, xa+nx, ya+ny, z); |
| 70 | } |
| 71 | return path; |
| 72 | } |
| 73 | |
| 74 | |
| 75 | struct path *circle(double cx, double cy, double cz, double cr, double tr, |
| 76 | double step, const char *id) |
| 77 | { |
| 78 | struct path *path; |
| 79 | double s = arc2angle(step, cr); |
| 80 | double a; |
| 81 | |
| 82 | path = path_new(tr, id); |
| 83 | if (cr <= tr) { |
| 84 | path_add(path, cx, cy, cz); |
| 85 | } else { |
| 86 | for (a = 0; a < 2*M_PI; a += s) |
| 87 | path_add(path, |
| 88 | cx+(cr-tr)*cos(a), cy+(cr-tr)*sin(a), cz); |
| 89 | path_add(path, cx+(cr-tr), cy, cz); |
| 90 | } |
| 91 | return path; |
| 92 | } |
| 93 |
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