Decoded: Rogue (1980) by Toy, Arnold, Wichman DOS version (1983) by Mel Sibony and Jon Lane Source file: MOVE.C Beginner friendly, line-by-line code walkthrough by MaiZure MOVE.C defines movement through the level for both players and monsters Original code: https://britzl.github.io/roguearchive/ Original code with line numbers http://www.maizure.org/projects/decoded-rogue/MOVE_linenum.txt 1 COMMENT 2 COMMENT 3 COMMENT 4 COMMENT 5 COMMENT 6 BLANK 7 Include the game header 8 Include the console management header 9 BLANK 10 COMMENT 11 COMMENT 12 COMMENT 13 BLANK 14 Declare a global to hold updated position during movement 15 BLANK 16 COMMENT 17 COMMENT 18 COMMENT 19 COMMENT ACTIVATE PLAYER RUNNING 20 Defines do_run with one argument 21 Argument 1 is the direction to run 22 BLOCK START - do_run 23 Set global player running flag 24 Don't process a turn for turning on running 25 Get the running direction 26 BLOCK END - do_run 27 BLANK 28 COMMENT 29 COMMENT 30 COMMENT 31 COMMENT 32 COMMENT MOVE PLAYER 33 Defines do_move with two arguments 34 Arguments 1 and 2 are the deltas for x and y (direction) 35 BLOCK START - do_move, processes player movement, may initiate events 36 Declares a character to hold the floor value 37 Declare an integer to hold the flags of a floor position 38 BLANK 39 Assume this isn't the first movement of a sequence 40 If the movement failed... 41 Reset failure flag 42 Print a failure message 43 Go to the next level 44 Return 45 End of check for bailout 46 If the player cannot move due to a trap or other reason... 47 Decrement the no movement counter 48 Print a message about being trapped 49 Return without moving 50 End check for being trapped 51 COMMENT 52 COMMENT 53 COMMENT 54 If the player is confused then with 20% chance... 55 Move the player in a random direction 56 Otherwise this is normal player movement 57 Label to redo movement 58 Set temporary y coordinate to the player's y plus the change in y 59 Set temporary x coordinate to the player's x plus the change in x 60 End normal player movement case 61 BLANK 62 COMMENT 63 COMMENT 64 COMMENT 65 COMMENT 66 COMMENT 67 If the updated position is not on the map 68 Jump to line 104 to process hitting the wall 69 If there are diagonal boundaries blocking this new position... 70 Don't process movement 71 End running 72 Return without updating 73 End check for diagonal boundary 74 COMMENT 75 COMMENT 76 COMMENT 77 COMMENT 78 If the player is running but this position is the same... 79 Stop all movement 80 Get the level flags at the new position 81 Get the floor character at the new position 82 COMMENT 83 COMMENT 84 COMMENT 85 COMMENT 86 If the player is at a door and the new character is a floor 87 Stop running at the room transition 88 If the floor appears to be normal but it's fake... 89 Draw a trap at the position 90 Set the position to be real now 91 End check for trap 92 Otherwise, if the player is held but they aren't attacking the fungi... 93 Print that the player cannot move 94 Return without movement 95 End check for flytrap 96 BLOCK START - Switch on the type of floor the player is moving to 97 CASE blank/unknown position (fallthrough) 98 CASE vertical wall (fallthrough) 99 CASE horizontal wall (fallthrough) 100 CASE upper-left corner wall (fallthrough) 101 CASE upper-right corner wall (fallthrough) 102 CASE lower-left corner wall (fallthrough) 103 CASE lower-right corner wall 104 Label for running in to a barrier 105 If the player is running through a passage and isn't blind... 106 Declare flags for passage state forward checks 107 BLANK 108 Switch on the player's running direction 109 BLOCK START - Switch on player run direction 110 CASE running left (fallthrough) 111 CASE running right 112 Check if the player is below the top line... 113 The next position is still in a passage 114 Or the next position is a door.. 115 Check if the player is above the bottom row... 116 The next position is a passage 117 Or the next position is a door 118 If either of the checks are different 119 Cancelling running 120 If b1 is true 121 Change player run direction to follow the wall 122 Move the player up one space 123 Otherwise.. 124 Change the player to run down 125 Move the player down 1 space 126 End check for a passage/door 127 Player stops moving left or right 128 Jump to retry to continue running 129 CASE running down (fallthrough) 130 CASE running up 131 Check if the player is not on the left edge 132 ...and that the next step is a passage 133 Or the next step is a door 134 Check if the player isn't on the right edge 135 ...and that the next step is a passage 136 or the next step is a door 137 If any of the checks are different 138 End running 139 If the player hit a passage or door on the left... 140 Change the run direction to left 141 Player is heading left 142 Otherwise the player hit a passage on the right 143 Change the run direction to right 144 Player is heading right 145 End check for a passage/door 146 Move the player 147 Retry movement 148 BLOCK END - Switch on player run direction 149 End check for passage running 150 Cancel all running move movement 151 End moevment check 152 CASE a door 153 Stop player running 154 If the player is in a passage... 155 Enter the room 156 Jump to line 175 to continue movement for door 157 CASE a trap 158 Process the trap effects 159 If the trap was either a trap door or teleport 160 Break from movement 161 CASE a passage 162 Jump to extended movement processing on line 175 163 CASE empty floor 164 If the floor is fake... 165 Process a trap 166 Jump to extended movement processing on line 175 167 CASE any other floor type 168 Stop running 169 If this is an upper case floor (monster) or any other monster (hidden) 170 Fight! 171 Otherwise this is probably an item on the floor 172 Cancel running 173 If the floor isn't stairs... 174 Prepare to take the item 175 Label for extra movement processing 176 Draw the hero at the new position 177 If the player is in a passage but was in a doorway... 178 ...or the playe ris now in a maze 179 Leave the previous room 180 If the player is now in a maze, but wasn't previously 181 End the maze room 182 Finish the move - copy the updated coordiantes to the player position 183 End check for extended movement 184 BLOCK END - Switch on the type of floor the player is moving to 185 BLOCK END - do_move 186 BLANK 187 COMMENT 188 COMMENT 189 COMMENT 190 COMMENT 191 COMMENT OPEN DOORS 192 Defines door_open with one argument 193 Argument 1 is a pointer to a room 194 BLOCK START - door_open, opens a door 195 Declare iterators 196 Declare a pointer to a floor character 197 Declare a pointer to an object 198 BLANK 199 If the player is in a real room and isn't blind (wake up some monsters!) 200 Loop through each row in the room... 201 Loop through each column in the room... 202 Get the character at the checked position 203 COMMENT 204 If the character is a monster... 205 Wake up the monster 206 If the character is unknown and the room isn't dark... 207 And the player isn't blind... 208 Store the floor position in the now awake monsters 209 End check for monster 210 Redo loop through the room until we've checked it all 211 BLOCK END - door_open 212 BLANK 213 COMMENT 214 COMMENT 215 COMMENT 216 COMMENT TRAP PLAYER 217 Defines be_trapped with one argument 218 Argument 1 is the coordinates of the trap 219 BLOCK START - be_trapped, set off a trap on the player 220 Declare a byte for the trap type 221 Declare an index for the level data array 222 BLANK 223 Reset the movement counter and stop running 224 Get the index of the position for the level data arrays 225 Set the trap type 226 Set and store the trap flag bit 227 Store that the player is trapped 228 BLOCK START - Switch on the type of trap 229 CASE trapdoor 230 Drop to the next level and print a message about the trap door 231 CASE bear trap 232 Stop the player for 2 to 3 turns 233 Print message for a bear trap 234 CASE sleep trap 235 Stop the player for 4 to 5 turns 236 Remove the player's running flag 237 Print message for a sleep trap 238 PRint an extended message 239 CASE arrow trap 240 If the arrow hits the player.. 241 Remove between 1 and 6 hitpoints 242 If the player is out of health 243 Print message for death by arrow trap 244 Player dies with cause of death as an arrow 245 Otherwise player lived 246 Print message for an arrow trap hit 247 End check for arrow hit 248 Otherwise the arrow missed 249 Declare a pointer to 250 BLANK 251 Create a new object to be an arrow 252 Set the object to type weapon 253 Set the weapon type to arrow 254 Initialize the arrow 255 There is only one arrow 256 Copy the arrow position to the player's position 257 Drop the arrow on the ground 258 End check for arrow creation 259 Print message for an arrow trap miss 260 End check for missed arrow 261 CASE teleport trap 262 Teleport the player 263 Draw the discovered trap on the ground 264 COMMENT 265 Increment the trap counter 266 CASE dart trap 267 If a dart trap hits the player... 268 Damage player health between 1 and 4 pointers 269 If the player's health is gone 270 Print message for death by dart trap 271 Cause of death is a dart 272 End check for death by dart 273 If the player isn't wearing a strength sustainment ring... 274 Remove 1 point of strength 275 Print message for a dart trap hit 276 Otherwise the dart missed 277 Print message for a dart trap miss 278 BLOCK END - Switch on trap type 279 Clear keyboard inpu 280 Return the trap type 281 BLOCK END - be_trapped 282 BLANK GO DOWN A LEVEL 283 Defines descend with one argument 284 Argument 1 is the message for level change 285 BLOCK START - descend, changes levels with an output message 286 Change game level number 287 If there is no message 288 Make it a blank space 289 Generate a new level 290 Print a blank message 291 Print the input message 292 Roll a save against luck and if it fails... 293 Print message for fall damage 294 If the player dies after taking 1 to 8 points of damage.. 295 Kill player with cause of death as a fall 296 End check for failed luck save 297 BLOCK END - descend 298 BLANK 299 COMMENT 300 COMMENT 301 COMMENT 302 COMMENT RANDOM MOVEMENT 303 Defines rndmove with two arguments 304 Argument 1 is a poiter to whoever is doing the movement 305 Argument 2 is the resulting movement position 306 BLOCK START - rndmove, randomly choose a movement destination 307 Declare x and y position offsets 308 Declare a floor character byte 309 Declare a pointer to an object 310 BLANK 311 Randomly choose a row around the input object (above, same, or below) 312 Randomly choose a column around the input object (left, same, or right) 313 COMMENT 314 COMMENT 315 COMMENT 316 COMMENT 317 If the random roll was the exact same place... 318 Return - do nothing 319 If the random position is outside of the level... 320 Jump to line 337 for a failed move 321 If the player can't move to the position due to failed diagonal checks.. 322 Jump to line 337 for a failed move 323 Otherwise the move may be ok... 324 Get the floor character at the new location 325 If there is something blocking the way... 326 Jump to line 337 for a failed move 327 If there is a scroll at the lcoation... 328 Loop through all level objects 329 If we find the matching scroll object 330 Break loop on this object 331 If there is a find and it's a scale monster scroll 332 Jump to failed move on line 337 333 End check for scroll 334 End check for valid position 335 Return with the updated position 336 BLANK 337 Label for failed movement attempt 338 Copy the object's original position in to the return value 339 Return the original position - don't move 340 BLOCK END - rndmove 341 EOFÿ