root / scout / libscout / src / behaviors / maze_solve.cpp @ f878b5f9
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1 | 64ee446f | Yuyang | /**
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2 | * Copyright (c) 2011 Colony Project
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3 | *
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4 | * Permission is hereby granted, free of charge, to any person
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5 | * obtaining a copy of this software and associated documentation
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6 | * files (the "Software"), to deal in the Software without
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7 | * restriction, including without limitation the rights to use,
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8 | * copy, modify, merge, publish, distribute, sublicense, and/or sell
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9 | * copies of the Software, and to permit persons to whom the
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10 | * Software is furnished to do so, subject to the following
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11 | * conditions:
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12 | *
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13 | * The above copyright notice and this permission notice shall be
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14 | * included in all copies or substantial portions of the Software.
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15 | *
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16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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17 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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18 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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19 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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20 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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21 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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22 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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23 | * OTHER DEALINGS IN THE SOFTWARE.
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24 | */
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25 | |||
26 | #include "maze_solve.h" |
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27 | |||
28 | using namespace std; |
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29 | |||
30 | |||
31 | // want to have a minimal working thing, use a big enough
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32 | // static array and start in the middle
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33 | // we assume we are facing right, that affects where we store
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34 | // wall information
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35 | // -1 for wall, 0 for unseen, 1 for traveled, 2 for critical
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36 | static int map[60][60]; |
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37 | #define WALL -1 |
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38 | #define UNSEEN 0 |
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39 | #define SEEN 1 |
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40 | #define CRITICAL 2 |
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41 | // facings
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42 | #define UP 0 |
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43 | #define RIGHT 1 |
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44 | #define DOWN 2 |
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45 | #define LEFT 3 |
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46 | void maze_solve::run(){
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47 | |||
48 | // TODO:first initialize map to all 0's
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49 | solve(25,25, RIGHT); |
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50 | } |
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51 | f878b5f9 | Priya | |
52 | bool maze_solve::solve(int row, int col, int dir) |
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53 | { |
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54 | int intial_dir = dir;
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55 | |||
56 | 64ee446f | Yuyang | // use backtracking to solve the maze
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57 | f878b5f9 | Priya | if (at_destination())
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58 | 64ee446f | Yuyang | return true; |
59 | |||
60 | f878b5f9 | Priya | // this function should fill the adjacent cells around me with
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61 | // wall's or paths
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62 | look_around(row, col, dir); |
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63 | |||
64 | /* try go up */
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65 | if (map[row-1][col] != WALL && initial_dir != UP) |
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66 | 64ee446f | Yuyang | { |
67 | f878b5f9 | Priya | // Turn up.
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68 | turn_from_to(dir, UP); |
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69 | line_follow(); |
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70 | // Solve recursively.
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71 | bool solved = solve(row-1, col, DOWN); |
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72 | if (solved)
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73 | 64ee446f | Yuyang | { |
74 | f878b5f9 | Priya | return solved;
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75 | 64ee446f | Yuyang | } |
76 | f878b5f9 | Priya | else
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77 | 64ee446f | Yuyang | { |
78 | f878b5f9 | Priya | //Update where we are.
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79 | dir = UP; |
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80 | 64ee446f | Yuyang | } |
81 | f878b5f9 | Priya | } |
82 | /* try right */
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83 | if (map[row][col+1] != WALL && initial_dir != RIGHT) |
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84 | { |
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85 | // Turn right.
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86 | turn_from_to(dir, RIGHT); |
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87 | line_follow(); |
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88 | // Solve recursively.
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89 | bool solved = solve(row, col+1, LEFT); |
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90 | if (solved)
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91 | 64ee446f | Yuyang | { |
92 | f878b5f9 | Priya | return solved;
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93 | } |
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94 | else
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95 | { |
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96 | //Update where we are.
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97 | dir = RIGHT; |
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98 | 64ee446f | Yuyang | } |
99 | } |
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100 | f878b5f9 | Priya | /* try down */
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101 | if (map[row+1][col] != WALL && initial_dir != DOWN) |
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102 | { |
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103 | // Turn down.
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104 | turn_from_to(dir, DOWN); |
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105 | line_follow(); |
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106 | // Solve recursively.
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107 | bool solved = solve(row+1, col, UP); |
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108 | if (solved)
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109 | { |
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110 | return solved;
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111 | } |
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112 | else
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113 | { |
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114 | //Update where we are.
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115 | dir = DOWN; |
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116 | } |
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117 | } |
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118 | /* try left */
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119 | if (map[row][col-1] != WALL && initial_dir != LEFT) |
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120 | { |
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121 | // Turn down.
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122 | turn_from_to(dir, LEFT); |
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123 | line_follow(); |
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124 | // Solve recursively.
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125 | bool solved = solve(row, col-1, RIGHT); |
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126 | if (solved)
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127 | { |
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128 | return solved;
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129 | } |
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130 | else
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131 | { |
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132 | //Update where we are.
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133 | dir = LEFT; |
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134 | } |
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135 | } |
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136 | // we have exhausted all the options. This path is clearly a
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137 | // dead end. go back to where we come from and return false.
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138 | turn_from_to(dir, initial_dir); |
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139 | line_follow(); |
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140 | return false; |
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141 | 64ee446f | Yuyang | } |
142 | |||
143 | // this function takes in the current direction and turns the scout
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144 | // into it intended direction
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145 | void maze_solve::turn_from_to(int current_dir, int intended_dir) { |
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146 | switch ((4 + intended_dir - current_dir) % 4) |
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147 | case 0: |
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148 | f878b5f9 | Priya | spot_turn(); |
149 | 64ee446f | Yuyang | break;
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150 | case 1: |
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151 | turn_right(); |
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152 | break;
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153 | case 2: |
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154 | f878b5f9 | Priya | turn_straight(); |
155 | 64ee446f | Yuyang | break;
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156 | case 3: |
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157 | turn_left(); |
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158 | break;
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159 | } |
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160 | |||
161 | f878b5f9 | Priya | void maze_solve::look_around(int row, int col, int dir) |
162 | 64ee446f | Yuyang | { |
163 | // look around current place using sonar
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164 | // store whether or not
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165 | // there is a wall into the map
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166 | // stores at row col 2 if point is critical, 1 otherwise
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167 | |||
168 | f878b5f9 | Priya | int* readings = get_sonar_readings();
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169 | |||
170 | // Look to the right.
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171 | int right_distance = (readings[1] + readings[0] + readings[47])/3; |
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172 | // Look to the front.
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173 | int front_distance = (readings[11] + readings[12] + readings[13])/3; |
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174 | // Look to the left.
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175 | int left_distance = (readings[23] + readings[24] + readings[25])/3; |
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176 | switch (dir)
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177 | { |
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178 | case UP:
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179 | // If the distance is less than 500, mark the area as a wall otherwise
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180 | // mark it as seen.
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181 | map[row][col+1] = (left_distance < 500)?WALL:SEEN; |
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182 | map[row+1][col] = (front_distance < 500)?WALL:SEEN; |
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183 | map[row][col-1] = (right_distance < 500)?WALL:SEEN; |
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184 | break;
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185 | case RIGHT:
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186 | // If the distance is less than 500, mark the area as a wall otherwise
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187 | // mark it as seen.
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188 | map[row+1][col] = (left_distance < 500)?WALL:SEEN; |
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189 | map[row][col-1] = (front_distance < 500)?WALL:SEEN; |
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190 | map[row-1][col] = (right_distance < 500)?WALL:SEEN; |
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191 | break;
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192 | case DOWN:
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193 | // If the distance is less than 500, mark the area as a wall otherwise
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194 | // mark it as seen.
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195 | map[row][col-1] = (left_distance < 500)?WALL:SEEN; |
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196 | map[row-1][col] = (front_distance < 500)?WALL:SEEN; |
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197 | map[row][col+1] = (right_distance < 500)?WALL:SEEN; |
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198 | break;
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199 | case LEFT:
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200 | // If the distance is less than 500, mark the area as a wall otherwise
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201 | // mark it as seen.
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202 | map[row-1][col] = (left_distance < 500)?WALL:SEEN; |
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203 | map[row][col+1] = (front_distance < 500)?WALL:SEEN; |
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204 | map[row+1][col] = (right_distance < 500)?WALL:SEEN; |
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205 | break;
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206 | } |
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207 | 64ee446f | Yuyang | } |
208 | |||
209 | f878b5f9 | Priya | bool maze_solve::at_destination()
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210 | 64ee446f | Yuyang | { |
211 | f878b5f9 | Priya | vector<uint32_t> readings = linesensor->query(); |
212 | if ( readings[0] > 200 && |
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213 | readings[1] < 55 && |
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214 | readings[2] < 55 && |
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215 | readings[3] > 200 && |
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216 | readings[4] > 200 && |
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217 | readings[5] < 55 && |
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218 | readings[6] < 55 && |
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219 | readings[7] > 200 ) |
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220 | { |
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221 | return true; |
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222 | } |
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223 | return false; |
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224 | 64ee446f | Yuyang | } |