HiddenItemCoords's 0 x or y coordinate design flaw (Generation I)

HiddenItemCoords's 0 x or y coordinate design flaw (Generation I)

Channel:
Evie (ChickasaurusGL) 🌺
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Published on ● Video Link: https://www.youtube.com/watch?v=2WgzwjOSDNU


Duration: 3:34
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Notes: Documented by jojobear13 in 2019 https://github.com/pret/pokered/pull/232/commits/9c2f1a4edf95461c5218f9763fc5fbe1201884e5


The ItemFinder can't detect an item if it has an x or y coordinate of 0. Note this doesn't refer to an out of bounds coordinate, as the valid coordinates start at 0 (so in counting terms the 0 is like x=1 or y=1 etc.). If x or y=0, the carry bit won't be set and even if you're close to the item, it will give a false negative. This also applies to where the item is according to the ItemFinder, as adjusting the database ( https://github.com/pret/pokered/blob/2954013da1f10e11db4ec96f9586b7c01706ae1a/data/events/hidden_item_coords.asm ) won't automatically change where the item actually is.


Using Game Genie code XX6-BA9-E6E, you can adjust the x coordinate of the hidden Potion near the north-most Bug Catcher in Viridian Forest. So 006-BA9-E6E will break ItemFinder even if you're on x=00 (where the left-most tree is), and when used alone (though not necessarily related to a coordinate of 0, as you could use a far away coordinate as well) you can fool ItemFinder into thinking the Potion isn't there when it is. If you like, you can also change the y coordinate of that Potion with XX6-B99-A22.


See also: https://bulbapedia.bulbagarden.net/wiki/Broken_hidden_items - unlike this design flaw the broken hidden items glitch affects real items in Red/Green and is related to the mismatches described at the end of the paragraph above and also invalid item flag 255.



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