Routines
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32291: Draw Room
Used by the routine at MainLoop.
Reached at the end of every pass of MainLoop. Looks up the list of items for the current room in RoomTable and runs the handler of each one through ProcessRoomItem. Each entry in a list is the address of an item record in the initial entity data at Initialisation_Player. Once the list is finished the counter at CounterLow is incremented and, on the first pass, DrawRoomEntities draws all of the entities in the room and bit 0 of GameFlags is set. The random number seed at RandomSeed is then stirred, the pick-up key, the pause keys and the food are dealt with and the main loop is restarted, unless the player is in room 142 which ends the game with GameComplete.
Before After
draw-room-before draw-room-after
DrawRoom 32291 LD A,(60049) Fetch the room of the player.
32294 LD L,A Double the room number to create an offset in HL.
32295 LD H,0
32297 ADD HL,HL
32298 LD BC,30077 Find the entry for the room in the table of item lists at RoomTable.
32301 ADD HL,BC
32302 LD A,(HL) Fetch the address of the list of items for the room.
32303 INC HL
32304 LD H,(HL)
32305 LD L,A
32306 LD (24091),HL Update the room pointer in CurrentRoom.
Each pass of this loop reads one item from the list.
Decor_Loop 32309 LD HL,(24091) Fetch the pointer to the next entry in the list of items.
32312 LD A,(HL) Fetch the low byte of the item address.
32313 INC HL Move on to the next entry in the list and write the pointer to CurrentRoom.
32314 INC HL
32315 LD (24091),HL
32318 DEC HL Fetch the address of the item.
32319 LD H,(HL)
32320 LD L,A
32321 OR H Jump to ProcessRoomItem to process the item if the list has not ended (the item address is not zero).
32322 JR NZ,ProcessRoomItem
The list is finished (it is terminated by an address of 0).
32324 LD HL,(24082) Increment the counter held in CounterLow by one.
32327 INC HL
32328 LD (24082),HL
32331 LD HL,24084 Jump to DrawRoom_Finish if bit 0 of GameFlags is set (the entities are drawn).
32334 BIT 0,(HL)
32336 JR NZ,DrawRoom_Finish
32338 CALL DrawRoomEntities Call DrawRoomEntities to draw the entities in this room.
DrawRoom_Finish 32341 LD HL,24084 Set bit 0 of GameFlags.
32344 SET 0,(HL)
Stir the random number seed with FRAMES and the counter.
32346 LD HL,(24069) Fetch the random seed.
32349 LD DE,(23672) Fetch FRAMES.
32353 ADD HL,DE Add FRAMES to the random seed.
32354 LD A,(24082) Fetch the low byte of the counter.
32357 ADD A,L Add the counter to the random seed.
32358 LD L,A
32359 LD (24069),HL Store the new random seed.
Read the pick-up key, check for the game being paused and spawn food.
32362 CALL ReadPickupKey Call ReadPickupKey to read the key to pick up an item.
32365 CALL PauseGame Call PauseGame to check whether the game is paused.
32368 CALL SpawnFood Call SpawnFood to spawn the food.
Finish the game if the player has reached the final room.
32371 LD A,(60049) Fetch the room of the player.
32374 CP 142 Jump to GameComplete if the player is in room 142.
32376 JP Z,GameComplete
32379 JP MainLoop Jump back to MainLoop to run the next pass of the main loop.
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