Decoded: Rogue (1980) by Toy, Arnold, Wichman DOS version (1983) by Mel Sibony and Jon Lane Source file: SCROLLS.C Beginner friendly, line-by-line code walkthrough by MaiZure SCROLLS.C implements scroll usage and the associated effects Original code: https://britzl.github.io/roguearchive/ Original code with line numbers http://www.maizure.org/projects/decoded-rogue/SCROLLS_linenum.txt 1 COMMENT 2 COMMENT 3 COMMENT 4 COMMENT 5 COMMENT 6 BLANK 7 Include game header 8 Include console management header 9 BLANK 10 Declare a string used when reading a scare monster scroll 11 Declare an extra string for scare monster scrolls (non-terse extension) 12 COMMENT 13 COMMENT 14 COMMENT 15 COMMENT READ A SCROLL The largest procedure in the game! 16 Defines read_scroll with no arguments 17 BLOCK START - read_scroll, invokes scroll magic 18 Declare a pointer to the scroll 19 Declare position iterators 20 Declare a character to hold map values 21 Declare a pointer to a monster 22 Declare an array index 23 Declare a flag for destroying a scroll 24 BLANK 25 Query the player for a scroll to read 26 If the player didn't choose anything 27 Do nothing 28 If the player didn't choose a scroll 29 Print failure message 30 Return failure 31 End check for non-scroll reading 32 Print out a message that the scroll has been used 33 COMMENT 34 COMMENT 35 COMMENT 36 If the player read his weapon...? 37 Remove the weapon (still in inventory) 38 BLOCK START - Switch on scroll type CONFUSION SCROLL 39 CASE confusion scroll 40 COMMENT 41 COMMENT 42 COMMENT 43 The player can now confuse monsters 44 Print a message for the player ARMOR SCROLL 45 CASE armor scroll 46 If the player is wearing armor 47 Reduce (improve) the armor class 48 Remove the cursed flag 49 Print a message for the player 50 End check for wearing armor HOLD MONSTER SCROLL 51 CASE hold monster scroll 52 COMMENT 53 COMMENT 54 COMMENT 55 COMMENT 56 BLANK 57 Loop across the nearest 7 columns around the player 58 ..as long as it's not off the map.. 59 And loop through the 7 rows around the player.. 60 If this position is on the map and there is a monster... 61 Remove the monster's run flag 62 Add the monster held flag 63 End check for monster SLEEP SCROLL 64 CASE sleep scroll 65 COMMENT 66 COMMENT 67 COMMENT 68 Player now knows about the sleep scroll 69 Put the player to sleep for 9 or 10 turns 70 Player is no longer runner 71 Print a message for the player CREATE MONSTER SCROLL 72 CASE create monster scroll 73 BLOCK START - create monster 74 Declare a coordinate for a new monster 75 BLANK 76 If we successfully create a new monster near the player... 77 Initialize the monster in the new location 78 Otherwise... 79 Print a terse message for the player 80 Print an extended message for the player 81 BLOCK END - create monster IDENTIFY SCROLL 82 CASE identify scroll 83 COMMENT 84 COMMENT 85 COMMENT 86 The player now knows the identify scroll 87 Print a message for the player 88 IF the player selects an item... 89 Wait for more input 90 Reveal the identify of the target MAP SCROLL 91 CASE show map scroll 92 COMMENT 93 COMMENT 94 COMMENT 95 The player now knows the map scroll 96 Print a message for the player 97 COMMENT 98 COMMENT 99 COMMENT 100 Loop through all map rows 101 And loop through all map columns 102 Get the data array position 103 Switch on the map position character 104 BLOCK START - Switch on map location type 105 CASE vertical wall (fallthrough) 106 CASE horizontal wall (fallthrough) 107 CASE upper-left corner wall (fallthrough) 108 CASE upper-right corner wall (fallthrough) 109 CASE lower-left corner wall (fallthrough) 110 CASE lower-right corner wall 111 If the wall position is fake 112 Reveal the door in that position 113 Remove the fake flag 114 End check for fake walls 115 CASE door (fallthrough) 116 CASE passage (fallthrough) 117 CASE stairs 118 If there is a monster at this position 119 And the monster hasn't buffered the proper floor character 120 Buffer it now 121 Break on floor type 122 CASE any other floor type 123 Character is blank 124 BLOCK END - Switch on map location type 125 If the character is a door 126 Move cursor to the door 127 If the actual charater there isn't a door 128 Emphasize the output (invert) 129 End check for door 130 If the character isn't a blank 131 Draw the actual character 132 End extended output formatting 133 End loop through the whole map DETECT FOOD SCROLL 134 CASE detect food scroll 135 COMMENT 136 COMMENT 137 COMMENT 138 Clear the character variable 139 Loop through all objects on the level 140 If there is an object of type food 141 Set the character variable to true 142 Emphasize output 143 Draw the food in it's real position 144 End printing emphasis 145 Otherwise this isn't food but... 146 If the object is the amulet 147 Set character flag to true 148 Emphasize printing output 149 Draw the amulet 150 End printing emphasis 151 End check for amulet 152 Retry loop through level 153 If any food or the amulet was detected on the level... 154 The player now knows about detect food scrolls 155 Print a successful message for the player 156 Otherwise 157 Print an unsuccessful message for the player TELEPORT SCROLL 158 CASE teleport scroll 159 COMMENT 160 COMMENT 161 COMMENT 162 COMMENT 163 BLOCK START - Teleport player 164 Declare a pointer to a room 165 BLANK 166 Get the current room 167 Teleport! 168 If the room changed 169 Player now knows about the teleport scroll 170 BLOCK END - Teleport player ENCHANTMENT SCROLL 171 CASE enchantment scroll 172 If the player has no weapon or isn't using a weapon 173 Print a failure message for the unwise player 174 Otherwise 175 BLOCK START - Enchant wepaon 176 Remove curse flag 177 Roll a 50% chance... 178 To improve hit bonus 179 Otherwise 180 Boost damage bonus 181 Print a message for the player 182 BLOCK END - Enchant weapon SCARE MONSTER SCROLL 183 CASE scare monster scroll 184 COMMENT 185 COMMENT 186 COMMENT 187 COMMENT 188 Laugh mercilessly at the player REMOVE CURSE SCROLL 189 CASE remove curse scroll 190 If the player is wearing armor 191 Remove armor curse 192 If the player is wearing a weapon 193 Remove weapon curse 194 If the player is wearing a left ring 195 Remove left ring curse 196 If the player is wearing a right ring 197 Remove right ring curse 198 Print a message for the player AGGRAVATE MONSTER SCROLL 199 CASE aggravate monster scroll 200 COMMENT 201 COMMENT 202 COMMENT 203 COMMENT 204 Activate all monsters! 205 Print a message for the player 206 Print a message for the player USELESS SCROLL 207 CASE useless scroll 208 Print an equally useless message VORPAL SCROLL 209 CASE vorpal enchantment scroll 210 COMMENT 211 COMMENT 212 COMMENT 213 COMMENT 214 COMMENT 215 COMMENT 216 COMMENT 217 COMMENT 218 COMMENT 219 COMMENT 220 COMMENT 221 COMMENT 222 COMMENT 223 COMMENT 224 If the player is not wearing a weapon... 225 Laugh mercilessly at the poor guy 226 Otherwise.... 227 COMMENT 228 COMMENT 229 COMMENT 230 If the weapon already has a vorpal enchantment 231 Print a bad message for the player 232 Include the name of the weapon 233 Steal the weapon from the player 234 Destroy it forever 235 Leave the player with empty hands 236 Otherwise... 237 Choose a random monster to vorpalize 238 Add a hit bonus to the weapon 239 Add a damage bonus to the weapon 240 Add charges to the weapon 241 Print a message about a blinding flash 242 A very blinding flash! 243 BLANK 244 COMMENT 245 COMMENT 246 COMMENT 247 COMMENT 248 COMMENT 249 COMMENT 250 COMMENT 251 COMMENT 252 COMMENT 253 COMMENT 254 COMMENT 255 COMMENT 256 End vorpal enchantment 257 End check for current weapon UNKNOWN SCROLL 258 CASE unknown scroll type 259 Print message about the unknown scroll type 260 Return without anything happening 261 BLOCK END - Switch on scroll type 262 Full update of the screen 263 Update status bar 264 COMMENT 265 COMMENT 266 COMMENT 267 Decrement inventory counter 268 If there is more than one scroll on the stack 269 Decrement th stack counter 270 Otherwise there was only one scroll of this type 271 BLOCK START - Remove inventory stack 272 Remove from inventory 273 Set discard flag to true 274 BLOCK END - Remove inventory stack 275 Update player's knowledge about the scroll 276 BLANK 277 If we're discarding the object 278 Free the memory 279 BLOCK END - read_scroll 280 EOFÿ