1 | /* |
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2 | * libcaca 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 | * This library is free software; you can redistribute it and/or |
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7 | * modify it under the terms of the GNU Lesser General Public |
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8 | * License as published by the Free Software Foundation; either |
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9 | * version 2 of the License, or (at your option) any later version. |
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10 | * |
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11 | * This library is distributed in the hope that it will be useful, |
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 | * Lesser General Public License for more details. |
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15 | * |
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16 | * You should have received a copy of the GNU Lesser General Public |
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17 | * License along with this library; if not, write to the Free Software |
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18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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19 | * 02111-1307 USA |
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20 | */ |
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21 | |
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22 | /** \file triangle.c |
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23 | * \version \$Id: triangle.c 298 2003-12-31 14:21:08Z sam $ |
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24 | * \author Sam Hocevar <sam@zoy.org> |
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25 | * \brief Triangle drawing |
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26 | * |
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27 | * This file contains triangle drawing functions, both filled and outline. |
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28 | */ |
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29 | |
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30 | #include "config.h" |
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31 | |
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32 | #include <stdlib.h> |
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33 | |
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34 | #include "caca.h" |
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35 | #include "caca_internals.h" |
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36 | |
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37 | /** |
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38 | * \brief Draw a triangle on the screen using the given character. |
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39 | * |
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40 | * \param x1 X coordinate of the first point. |
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41 | * \param y1 Y coordinate of the first point. |
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42 | * \param x2 X coordinate of the second point. |
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43 | * \param y2 Y coordinate of the second point. |
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44 | * \param x3 X coordinate of the third point. |
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45 | * \param y3 Y coordinate of the third point. |
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46 | * \param c Character to draw the triangle outline with. |
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47 | * \return void |
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48 | */ |
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49 | void caca_draw_triangle(int x1, int y1, int x2, int y2, int x3, int y3, char c) |
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50 | { |
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51 | caca_draw_line(x1, y1, x2, y2, c); |
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52 | caca_draw_line(x2, y2, x3, y3, c); |
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53 | caca_draw_line(x3, y3, x1, y1, c); |
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54 | } |
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55 | |
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56 | /** |
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57 | * \brief Draw a thin triangle on the screen. |
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58 | * |
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59 | * \param x1 X coordinate of the first point. |
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60 | * \param y1 Y coordinate of the first point. |
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61 | * \param x2 X coordinate of the second point. |
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62 | * \param y2 Y coordinate of the second point. |
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63 | * \param x3 X coordinate of the third point. |
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64 | * \param y3 Y coordinate of the third point. |
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65 | * \return void |
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66 | */ |
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67 | void caca_draw_thin_triangle(int x1, int y1, int x2, int y2, int x3, int y3) |
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68 | { |
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69 | caca_draw_thin_line(x1, y1, x2, y2); |
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70 | caca_draw_thin_line(x2, y2, x3, y3); |
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71 | caca_draw_thin_line(x3, y3, x1, y1); |
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72 | } |
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73 | |
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74 | /** |
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75 | * \brief Fill a triangle on the screen using the given character. |
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76 | * |
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77 | * \param x1 X coordinate of the first point. |
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78 | * \param y1 Y coordinate of the first point. |
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79 | * \param x2 X coordinate of the second point. |
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80 | * \param y2 Y coordinate of the second point. |
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81 | * \param x3 X coordinate of the third point. |
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82 | * \param y3 Y coordinate of the third point. |
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83 | * \param c Character to fill the triangle with. |
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84 | * \return void |
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85 | */ |
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86 | void caca_fill_triangle(int x1, int y1, int x2, int y2, int x3, int y3, char c) |
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87 | { |
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88 | int x, y, xa, xb, xmax, ymax; |
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89 | |
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90 | /* Bubble-sort y1 <= y2 <= y3 */ |
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91 | if(y1 > y2) |
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92 | { |
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93 | caca_fill_triangle(x2, y2, x1, y1, x3, y3, c); |
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94 | return; |
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95 | } |
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96 | |
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97 | if(y2 > y3) |
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98 | { |
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99 | caca_fill_triangle(x1, y1, x3, y3, x2, y2, c); |
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100 | return; |
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101 | } |
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102 | |
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103 | /* Promote precision */ |
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104 | x1 *= 4; |
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105 | x2 *= 4; |
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106 | x3 *= 4; |
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107 | |
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108 | xmax = _caca_width - 1; |
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109 | ymax = _caca_height - 1; |
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110 | |
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111 | /* Rasterize our triangle */ |
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112 | for(y = y1 < 0 ? 0 : y1; y <= y3 && y <= ymax; y++) |
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113 | { |
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114 | if(y <= y2) |
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115 | { |
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116 | xa = (y1 == y2) ? x2 : x1 + (x2 - x1) * (y - y1) / (y2 - y1); |
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117 | xb = (y1 == y3) ? x3 : x1 + (x3 - x1) * (y - y1) / (y3 - y1); |
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118 | } |
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119 | else |
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120 | { |
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121 | xa = (y3 == y2) ? x2 : x3 + (x2 - x3) * (y - y3) / (y2 - y3); |
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122 | xb = (y3 == y1) ? x1 : x3 + (x1 - x3) * (y - y3) / (y1 - y3); |
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123 | } |
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124 | |
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125 | if(xb < xa) |
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126 | { |
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127 | int tmp = xb; |
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128 | xb = xa; xa = tmp; |
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129 | } |
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130 | |
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131 | /* Rescale xa and xb, slightly cropping */ |
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132 | xa = (xa + 2) / 4; |
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133 | xb = (xb - 2) / 4; |
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134 | |
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135 | if(xb < 0) continue; |
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136 | if(xa > xmax) continue; |
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137 | if(xa < 0) xa = 0; |
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138 | if(xb > xmax) xb = xmax; |
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139 | |
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140 | for(x = xa; x <= xb; x++) |
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141 | caca_putchar(x, y, c); |
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142 | } |
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143 | } |
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144 | |
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