root / scout / libscout / src / behaviors / smart_runaround.cpp @ 2fd5122a
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1 | 2fd5122a | viki | /**
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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 | #define WALL -1 |
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37 | #define UNSEEN 0 |
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38 | #define SEEN 1 |
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39 | #define CRITICAL 2 |
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40 | // facings on map, NOT on robot
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41 | #define UP 0 |
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42 | #define RIGHT 1 |
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43 | #define DOWN 2 |
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44 | #define LEFT 3 |
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45 | // number of pixels on one row/column of map block
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46 | #define BLOCK_LENGTH 13 |
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47 | |||
48 | // robot control variables
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49 | #define BASESPEED 50 |
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50 | |||
51 | // robots row and column on map, starting at center
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52 | int row = MAP_LENGTH/2+1; // add 1 because we know MAP_LENGTH is odd |
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53 | int col = MAP_LENGTH/2+1; |
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54 | |||
55 | // utility functions
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56 | // pixels to meters
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57 | float pix_to_m(int pixels) |
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58 | { |
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59 | return pixels/200.0; |
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60 | } |
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61 | |||
62 | // meters to pixels
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63 | int m_to_idx(float meters) |
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64 | { |
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65 | float pixels = meters*200.0; |
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66 | float idx = pixels/BLOCK_LENGTH;
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67 | return floor(idx+0.5); |
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68 | } |
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69 | |||
70 | /* return a direction (if any) where adjacent block
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71 | * is labeled "info" on map. Searches clockwise
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72 | * starting at up. Returns -1 if no direction valid.
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73 | */
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74 | int maze_solve::choose_direc(int row, int col, int info) |
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75 | { |
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76 | if (map[row-1][col] == info) |
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77 | return UP;
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78 | else if (map[row][col+1] == info) |
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79 | return RIGHT;
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80 | else if (map[row+1][col] == info) |
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81 | return DOWN;
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82 | else if (map[row][col-1] == info) |
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83 | return LEFT;
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84 | return -1; |
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85 | } |
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86 | |||
87 | Duration sonar_update_time(1.5); |
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88 | |||
89 | // THIS VERSION MODIFIED BY ZANE
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90 | void maze_solve::run(){
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91 | |||
92 | ROS_INFO("Starting to solve the maze");
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93 | // Go up to the first line.
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94 | //follow_line();
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95 | // Turn the sonar on.
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96 | sonar->set_on(); |
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97 | sonar->set_range(0, 23); |
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98 | // initialize map to all UNSEEN
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99 | for(int r = 0; r < MAP_LENGTH; r++) { |
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100 | for(int c = 0; c < MAP_LENGTH; c++) |
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101 | map[r][c] = UNSEEN; |
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102 | } |
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103 | |||
104 | // Wait for the sonar to initialize.
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105 | while(!look_around(25, 25, RIGHT) && ok()) |
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106 | { |
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107 | spinOnce(); |
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108 | } |
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109 | |||
110 | /* Assumptions:
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111 | * Grid has a fixed size
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112 | * Start location unknown
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113 | * When robot moves forward, it moves to exact center
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114 | * of the block in front.
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115 | */
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116 | |||
117 | |||
118 | int dir = RIGHT; // current direction |
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119 | int new_dir = RIGHT; // direction in which to turn after a scan |
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120 | bool success = false; // true when maze solved |
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121 | while(ok())
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122 | { |
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123 | // Look left, right, and forward
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124 | look_around(row, col, dir); |
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125 | // Try moving in each direction
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126 | new_dir = choose_direc(row, col, UNSEEN); |
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127 | if(new_dir < 0) |
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128 | new_dir = choose_direc(row, col, SEEN); |
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129 | if(new_dir >= 0) { |
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130 | turn_from_to(dir, new_dir); |
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131 | dir = new_dir; |
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132 | } |
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133 | } |
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134 | |||
135 | // Check and report final condition.
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136 | if (success)
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137 | ROS_INFO("YAY! I have solved the maze");
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138 | else
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139 | ROS_INFO("NO! The maze is unsolvable");
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140 | } |
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141 | |||
142 | // NOT CURRENTLY USED!!!
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143 | bool maze_solve::solve(int row, int col, int dir) |
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144 | { |
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145 | int initial_dir = dir;
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146 | |||
147 | ROS_INFO("I am at direction %d", dir);
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148 | |||
149 | // use backtracking to solve the maze
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150 | if (at_destination())
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151 | return true; |
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152 | |||
153 | // Wait for sonar to update.
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154 | sonar_update_time.sleep(); |
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155 | |||
156 | // this function should fill the adjacent cells around me with
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157 | // wall's or paths
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158 | while(!look_around(row, col, dir) && ok())
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159 | { |
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160 | spinOnce(); |
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161 | } |
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162 | |||
163 | /* try go up */
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164 | if (map[row-1][col] != WALL && initial_dir != UP) |
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165 | { |
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166 | ROS_INFO("GOING UP!");
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167 | // Turn up.
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168 | turn_from_to(dir, UP); |
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169 | follow_line(); |
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170 | // Solve recursively.
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171 | bool solved = solve(row-1, col, DOWN); |
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172 | if (solved)
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173 | { |
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174 | return solved;
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175 | } |
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176 | else
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177 | { |
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178 | //Update where we are.
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179 | dir = UP; |
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180 | } |
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181 | } |
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182 | /* try right */
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183 | if (map[row][col+1] != WALL && initial_dir != RIGHT) |
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184 | { |
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185 | ROS_INFO("GOING RIGHT!");
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186 | // Turn right.
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187 | turn_from_to(dir, RIGHT); |
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188 | follow_line(); |
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189 | // Solve recursively.
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190 | bool solved = solve(row, col+1, LEFT); |
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191 | if (solved)
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192 | { |
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193 | return solved;
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194 | } |
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195 | else
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196 | { |
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197 | //Update where we are.
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198 | dir = RIGHT; |
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199 | } |
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200 | } |
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201 | /* try down */
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202 | if (map[row+1][col] != WALL && initial_dir != DOWN) |
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203 | { |
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204 | ROS_INFO("GOING DOWN!");
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205 | // Turn down.
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206 | turn_from_to(dir, DOWN); |
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207 | follow_line(); |
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208 | // Solve recursively.
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209 | bool solved = solve(row+1, col, UP); |
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210 | if (solved)
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211 | { |
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212 | return solved;
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213 | } |
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214 | else
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215 | { |
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216 | //Update where we are.
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217 | dir = DOWN; |
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218 | } |
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219 | } |
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220 | /* try left */
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221 | if (map[row][col-1] != WALL && initial_dir != LEFT) |
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222 | { |
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223 | ROS_INFO("GOING LEFT!");
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224 | // Turn down.
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225 | turn_from_to(dir, LEFT); |
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226 | follow_line(); |
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227 | // Solve recursively.
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228 | bool solved = solve(row, col-1, RIGHT); |
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229 | if (solved)
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230 | { |
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231 | return solved;
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232 | } |
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233 | else
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234 | { |
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235 | //Update where we are.
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236 | dir = LEFT; |
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237 | } |
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238 | } |
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239 | |||
240 | ROS_INFO("DEAD END FOUND, TURNING BACK.");
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241 | // we have exhausted all the options. This path is clearly a
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242 | // dead end. go back to where we come from and return false.
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243 | turn_from_to(dir, initial_dir); |
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244 | follow_line(); |
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245 | return false; |
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246 | } |
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247 | |||
248 | /* this function takes in the current direction,
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249 | * and turns the scout to the intended direction
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250 | */
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251 | void maze_solve::turn_from_to(int current_dir, int intended_dir) { |
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252 | switch ((4 + intended_dir - current_dir) % 4) // TODO: Try without "4 +" at start |
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253 | { |
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254 | case 0: |
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255 | turn_straight(intended_dir); |
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256 | break;
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257 | case 1: |
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258 | turn_right(); |
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259 | break;
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260 | case 2: |
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261 | spot_turn(); |
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262 | break;
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263 | case 3: |
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264 | turn_left(); |
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265 | break;
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266 | } |
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267 | } |
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268 | |||
269 | bool maze_solve::look_around(int row, int col, int dir) |
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270 | { |
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271 | // look around current place using sonar
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272 | // store whether or not
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273 | // there is a wall into the map
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274 | // stores at row col 2 if point is critical, 1 otherwise
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275 | |||
276 | int* readings = sonar->get_sonar_readings();
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277 | spinOnce(); |
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278 | |||
279 | // Assumption: readings are given in millimeters - Zane
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280 | |||
281 | // distances with respect to robot, NOT map
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282 | // Look to the left.
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283 | float left_distance = readings[0]/1000.0; |
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284 | int left_idx = m_to_idx(left_distance);
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285 | // Look to the front.
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286 | float front_distance = readings[36]/1000.0; |
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287 | int front_idx = m_to_idx(front_distance);
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288 | // Look to the right.
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289 | float right_distance = readings[24]/1000.0; |
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290 | int right_idx = m_to_idx(right_distance);
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291 | |||
292 | ROS_INFO("front: %d left: %d right: %d", front_distance, left_distance, right_distance);
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293 | if (right_distance == 0 || front_distance == 0 || left_distance == 0) |
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294 | return false; |
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295 | |||
296 | // determine relative distances on map, based on robot position
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297 | int up_d, right_d, down_d, left_d;
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298 | // determine upward distance
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299 | switch (dir)
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300 | { |
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301 | case UP:
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302 | up_d = front_idx; |
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303 | right_d = right_idx; |
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304 | down_d = 0; // unknown |
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305 | left_d = left_idx; |
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306 | break;
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307 | case RIGHT:
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308 | up_d = left_idx; |
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309 | right_d = front_idx; |
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310 | down_d = right_idx; |
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311 | left_d = 0; // unknown |
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312 | break;
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313 | case DOWN:
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314 | up_d = 0; // unknown |
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315 | right_d = left_idx; |
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316 | down_d = front_idx; |
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317 | left_d = right_idx; |
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318 | break;
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319 | case LEFT:
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320 | up_d = right_idx; |
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321 | right_d = 0; // unknown |
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322 | down_d = left_idx; |
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323 | left_d = front_idx; |
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324 | break;
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325 | } |
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326 | |||
327 | // change map until wall index, or until reading < 500
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328 | // reading < 500 <=> left_idx < 8 (approx.)
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329 | |||
330 | // map blocks above robot (on map)
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331 | for(int u = 0; u < 8; u++) |
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332 | { |
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333 | if(u = up_d) {
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334 | map[row-u][col] = (up_d)?WALL:SEEN; |
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335 | break;
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336 | } |
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337 | map[row-u][col] = SEEN; |
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338 | } |
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339 | |||
340 | // map blocks to right of robot
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341 | for(int r = 0; r < 8; r++) |
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342 | { |
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343 | if(r = right_d) {
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344 | map[row][col+r] = (right_d)?WALL:SEEN; |
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345 | break;
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346 | } |
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347 | map[row][col+r] = SEEN; |
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348 | } |
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349 | |||
350 | // map blocks under robot (on map)
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351 | for(int d = 0; d < 8; d++) |
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352 | { |
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353 | if(d = down_d) {
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354 | map[row+d][col] = (down_d)?WALL:SEEN; |
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355 | break;
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356 | } |
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357 | map[row+d][col] = SEEN; |
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358 | } |
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359 | |||
360 | // map blocks to left of robot
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361 | for(int l = 0; l < 8; l++) |
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362 | { |
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363 | if(l = left_d) {
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364 | map[row][col-l] = (left_d)?WALL:SEEN; |
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365 | break;
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366 | } |
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367 | map[row][col-l] = SEEN; |
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368 | } |
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369 | |||
370 | return true; |
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371 | } |
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372 | |||
373 | // TODO: test this function
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374 | // return true iff the map has been completely explored
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375 | // and only true if it "returned" to home destination after solving
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376 | bool maze_solve::at_destination()
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377 | { |
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378 | // check whether there is a square portion with
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379 | // only SEEN or WALL blocks, of the size of the map.
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380 | int start_row = -1; |
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381 | int start_col = -1; |
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382 | int seen_width = 0; |
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383 | int seen_height = 0; |
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384 | for(int r = 0; r < MAP_LENGTH; r++) { |
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385 | for(int c = 0; c < MAP_LENGTH; c++) { |
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386 | if(map[r][c] == UNSEEN) {
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387 | start_row = -1;
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388 | start_col = -1;
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389 | seen_width = 0;
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390 | seen_height = 0;
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391 | } |
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392 | else {
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393 | start_row = r; |
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394 | start_col = c; |
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395 | seen_width++; |
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396 | seen_height++; |
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397 | } |
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398 | if(seen_width >= 15) |
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399 | return true; |
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400 | } |
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401 | } |
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402 | return false; |
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403 | } |
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404 | |||
405 | // TODO: test these functions to make sure robot moves well
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406 | // move forward one block in direction "dir"
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407 | void maze_solve::turn_straight(int dir) |
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408 | { |
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409 | // TODO: try to use motor encoder values to move forward enough
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410 | motors->set_sides(BASESPEED, BASESPEED, MOTOR_ABSOLUTE); |
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411 | spinOnce(); |
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412 | Duration moveTime(1.0); |
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413 | moveTime.sleep(); |
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414 | |||
415 | // update robot's position on map
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416 | switch(dir)
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417 | { |
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418 | case UP:
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419 | row--; |
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420 | break;
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421 | case RIGHT:
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422 | col++; |
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423 | break;
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424 | case DOWN:
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425 | row++; |
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426 | break;
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427 | case LEFT:
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428 | col--; |
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429 | break;
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430 | } |
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431 | } |
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432 | |||
433 | // turn clockwise (right)
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434 | void maze_solve::turn_right()
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435 | { |
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436 | motors->set_sides(BASESPEED, -BASESPEED, MOTOR_ABSOLUTE); |
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437 | spinOnce(); |
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438 | Duration moveTime(3.3); |
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439 | moveTime.sleep(); |
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440 | } |
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441 | |||
442 | // do a 180 deg turn, NOT a barrel roll
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443 | void maze_solve::spot_turn()
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444 | { |
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445 | motors->set_sides(BASESPEED, -BASESPEED, MOTOR_ABSOLUTE); |
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446 | spinOnce(); |
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447 | Duration moveTime(6.6); |
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448 | moveTime.sleep(); |
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449 | } |
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450 | |||
451 | // turn counter-clockwise (left)
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452 | void maze_solve::turn_left()
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453 | { |
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454 | motors->set_sides(-BASESPEED, BASESPEED, MOTOR_ABSOLUTE); |
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455 | spinOnce(); |
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456 | Duration moveTime(3.3); |
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457 | moveTime.sleep(); |
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458 | } |