1 | /* |
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2 | * libee ASCII-Art library |
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3 | * Copyright (c) 2002, 2003 Sam Hocevar <sam@zoy.org> |
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4 | * All Rights Reserved |
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5 | * |
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6 | * $Id: triangle.c 159 2003-11-12 21:18:50Z sam $ |
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7 | * |
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8 | * This program is free software; you can redistribute it and/or modify |
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9 | * it under the terms of the GNU General Public License as published by |
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10 | * the Free Software Foundation; either version 2 of the License, or |
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11 | * (at your option) any later version. |
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12 | * |
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13 | * This program is distributed in the hope that it will be useful, |
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14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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16 | * GNU General Public License for more details. |
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17 | * |
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18 | * You should have received a copy of the GNU General Public License |
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19 | * along with this program; if not, write to the Free Software |
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20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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21 | */ |
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22 | |
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23 | #include "config.h" |
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24 | |
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25 | #include <stdlib.h> |
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26 | |
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27 | #include "ee.h" |
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28 | #include "ee_internals.h" |
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29 | |
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30 | void ee_draw_triangle(int x1, int y1, int x2, int y2, int x3, int y3, char c) |
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31 | { |
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32 | ee_draw_line(x1, y1, x2, y2, c); |
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33 | ee_draw_line(x2, y2, x3, y3, c); |
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34 | ee_draw_line(x3, y3, x1, y1, c); |
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35 | } |
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36 | |
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37 | void ee_draw_thin_triangle(int x1, int y1, int x2, int y2, int x3, int y3) |
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38 | { |
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39 | ee_draw_thin_line(x1, y1, x2, y2); |
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40 | ee_draw_thin_line(x2, y2, x3, y3); |
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41 | ee_draw_thin_line(x3, y3, x1, y1); |
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42 | } |
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43 | |
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44 | void ee_fill_triangle(int x1, int y1, int x2, int y2, int x3, int y3, char c) |
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45 | { |
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46 | int x, y, xa, xb, xmax, ymax; |
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47 | |
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48 | /* Bubble-sort y1 <= y2 <= y3 */ |
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49 | if(y1 > y2) |
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50 | { |
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51 | ee_fill_triangle(x2, y2, x1, y1, x3, y3, c); |
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52 | return; |
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53 | } |
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54 | |
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55 | if(y2 > y3) |
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56 | { |
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57 | ee_fill_triangle(x1, y1, x3, y3, x2, y2, c); |
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58 | return; |
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59 | } |
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60 | |
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61 | /* Promote precision */ |
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62 | x1 *= 4; |
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63 | x2 *= 4; |
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64 | x3 *= 4; |
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65 | |
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66 | xmax = ee_get_width() - 1; |
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67 | ymax = ee_get_height() - 1; |
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68 | |
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69 | /* Rasterize our triangle */ |
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70 | for(y = y1 < 0 ? 0 : y1; y <= y3 && y <= ymax; y++) |
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71 | { |
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72 | if(y <= y2) |
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73 | { |
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74 | xa = (y1 == y2) ? x2 : x1 + (x2 - x1) * (y - y1) / (y2 - y1); |
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75 | xb = (y1 == y3) ? x3 : x1 + (x3 - x1) * (y - y1) / (y3 - y1); |
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76 | } |
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77 | else |
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78 | { |
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79 | xa = (y3 == y2) ? x2 : x3 + (x2 - x3) * (y - y3) / (y2 - y3); |
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80 | xb = (y3 == y1) ? x1 : x3 + (x1 - x3) * (y - y3) / (y1 - y3); |
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81 | } |
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82 | |
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83 | if(xb < xa) |
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84 | { |
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85 | int tmp = xb; |
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86 | xb = xa; xa = tmp; |
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87 | } |
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88 | |
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89 | /* Rescale xa and xb, slightly cropping */ |
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90 | xa = (xa + 2) / 4; |
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91 | xb = (xb - 2) / 4; |
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92 | |
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93 | if(xb < 0) continue; |
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94 | if(xa > xmax) continue; |
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95 | if(xa < 0) xa = 0; |
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96 | if(xb > xmax) xb = xmax; |
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97 | |
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98 | for(x = xa; x <= xb; x++) |
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99 | ee_putchar(x, y, c); |
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100 | } |
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101 | } |
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102 | |
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