Custom maps: Difference between revisions

The little endian pointer to the top-left map block on the screen is stored at D35ED35F/D35FD360 (D35E/D35D/D35E in Yellow) and is adjusted when the player is walking around. This pointer can be changed to RAM by adjusting item 33 and item 33 quantity. This method while applying the changes while the menu is opened, does not immediately do so while the menu is closed (unless the player walks around to load the new data). However, the data can be applied by using glitch item [[ItemDex/Y:094|9F (0x5E)]] in English Yellow, or by swapping an X Attack x18 into item 41 in English Red/Blue (the latter forces the map script to load it).

Normally, D35ED35F/D360 points to RAM anyway and the game writes to the relevant address after a normal map is loaded. Hence, an alternative method for creating a custom map is to write to the intended RAM address (for example the region around C6F9+ in Pallet Town). To create a sense of permanency, the player can use a [[MetascriptDex|meta map script in RAM]] to call copydata to constantly write to this data, even after leaving and returning to the map (as long as the altered meta map script is kept).

*D36C-D36D (or D36B-D36C): The text pointer table location for each NPC. This two byte pointer should point to an address itself a list of two byte pointers in the map's text box index number order (readwhen reading a sign/talking to an NPC this is stored at FF8C).

*D36E-D36F (or D36D-D36F): The "level-script pointer". It is basically a little endian pointer to a script that is run continuously when the menu is closed (which is also an ideal arbitrary code execution method through adjusting item 41 in the expanded inventory). The bank of the script for pointers ranging between 4000-7FFF depends on the currently loaded map at D35E/D (see [[bp:List of locations by index number (Generation I)|this article on Bulbapedia for each map's bank]]).

*D35E (or D35D): The currently stored map. Upon changing it, this will control the palette, Town Map name/position on map; however, this will not warp the player automatically (the player can however warp instantly using the previously mentioned 9F or X Attack x18 methods but data like coordinates D361-D362 (-1), coordinate block D363-D364 (-1) may have to be adjusted with it).