1 | /* |
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2 | * libcucul Unicode canvas library |
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3 | * Copyright (c) 2002-2006 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 Do What The Fuck You Want To |
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8 | * Public License, Version 2, as published by Sam Hocevar. See |
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9 | * http://sam.zoy.org/wtfpl/COPYING for more details. |
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10 | */ |
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11 | |
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12 | /** \file triangle.c |
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13 | * \version \$Id: triangle.c 568 2006-03-09 12:47:37Z sam $ |
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14 | * \author Sam Hocevar <sam@zoy.org> |
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15 | * \brief Triangle drawing |
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16 | * |
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17 | * This file contains triangle drawing functions, both filled and outline. |
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18 | */ |
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19 | |
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20 | #include "config.h" |
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21 | |
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22 | #if !defined(__KERNEL__) |
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23 | # include <stdlib.h> |
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24 | #endif |
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25 | |
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26 | #include "cucul.h" |
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27 | #include "cucul_internals.h" |
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28 | |
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29 | /** |
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30 | * \brief Draw a triangle on the screen using the given character. |
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31 | * |
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32 | * \param x1 X coordinate of the first point. |
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33 | * \param y1 Y coordinate of the first point. |
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34 | * \param x2 X coordinate of the second point. |
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35 | * \param y2 Y coordinate of the second point. |
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36 | * \param x3 X coordinate of the third point. |
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37 | * \param y3 Y coordinate of the third point. |
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38 | * \param c Character to draw the triangle outline with. |
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39 | * \return void |
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40 | */ |
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41 | void cucul_draw_triangle(cucul_t *qq, int x1, int y1, int x2, int y2, int x3, int y3, char c) |
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42 | { |
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43 | cucul_draw_line(qq, x1, y1, x2, y2, c); |
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44 | cucul_draw_line(qq, x2, y2, x3, y3, c); |
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45 | cucul_draw_line(qq, x3, y3, x1, y1, c); |
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46 | } |
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47 | |
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48 | /** |
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49 | * \brief Draw a thin triangle on the screen. |
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50 | * |
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51 | * \param x1 X coordinate of the first point. |
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52 | * \param y1 Y coordinate of the first point. |
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53 | * \param x2 X coordinate of the second point. |
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54 | * \param y2 Y coordinate of the second point. |
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55 | * \param x3 X coordinate of the third point. |
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56 | * \param y3 Y coordinate of the third point. |
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57 | * \return void |
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58 | */ |
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59 | void cucul_draw_thin_triangle(cucul_t *qq, int x1, int y1, int x2, int y2, int x3, int y3) |
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60 | { |
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61 | cucul_draw_thin_line(qq, x1, y1, x2, y2); |
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62 | cucul_draw_thin_line(qq, x2, y2, x3, y3); |
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63 | cucul_draw_thin_line(qq, x3, y3, x1, y1); |
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64 | } |
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65 | |
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66 | /** |
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67 | * \brief Fill a triangle on the screen using the given character. |
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68 | * |
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69 | * \param x1 X coordinate of the first point. |
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70 | * \param y1 Y coordinate of the first point. |
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71 | * \param x2 X coordinate of the second point. |
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72 | * \param y2 Y coordinate of the second point. |
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73 | * \param x3 X coordinate of the third point. |
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74 | * \param y3 Y coordinate of the third point. |
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75 | * \param c Character to fill the triangle with. |
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76 | * \return void |
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77 | */ |
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78 | void cucul_fill_triangle(cucul_t *qq, int x1, int y1, int x2, int y2, int x3, int y3, char c) |
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79 | { |
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80 | int x, y, xa, xb, xmax, ymax; |
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81 | |
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82 | /* Bubble-sort y1 <= y2 <= y3 */ |
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83 | if(y1 > y2) |
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84 | { |
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85 | cucul_fill_triangle(qq, x2, y2, x1, y1, x3, y3, c); |
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86 | return; |
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87 | } |
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88 | |
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89 | if(y2 > y3) |
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90 | { |
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91 | cucul_fill_triangle(qq, x1, y1, x3, y3, x2, y2, c); |
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92 | return; |
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93 | } |
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94 | |
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95 | /* Promote precision */ |
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96 | x1 *= 4; |
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97 | x2 *= 4; |
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98 | x3 *= 4; |
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99 | |
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100 | xmax = qq->width - 1; |
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101 | ymax = qq->height - 1; |
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102 | |
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103 | /* Rasterize our triangle */ |
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104 | for(y = y1 < 0 ? 0 : y1; y <= y3 && y <= ymax; y++) |
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105 | { |
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106 | if(y <= y2) |
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107 | { |
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108 | xa = (y1 == y2) ? x2 : x1 + (x2 - x1) * (y - y1) / (y2 - y1); |
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109 | xb = (y1 == y3) ? x3 : x1 + (x3 - x1) * (y - y1) / (y3 - y1); |
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110 | } |
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111 | else |
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112 | { |
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113 | xa = (y3 == y2) ? x2 : x3 + (x2 - x3) * (y - y3) / (y2 - y3); |
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114 | xb = (y3 == y1) ? x1 : x3 + (x1 - x3) * (y - y3) / (y1 - y3); |
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115 | } |
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116 | |
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117 | if(xb < xa) |
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118 | { |
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119 | int tmp = xb; |
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120 | xb = xa; xa = tmp; |
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121 | } |
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122 | |
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123 | /* Rescale xa and xb, slightly cropping */ |
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124 | xa = (xa + 2) / 4; |
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125 | xb = (xb - 2) / 4; |
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126 | |
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127 | if(xb < 0) continue; |
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128 | if(xa > xmax) continue; |
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129 | if(xa < 0) xa = 0; |
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130 | if(xb > xmax) xb = xmax; |
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131 | |
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132 | for(x = xa; x <= xb; x++) |
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133 | cucul_putchar(qq, x, y, c); |
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134 | } |
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135 | } |
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136 | |
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