Deus Ex – Exploiting Inventory Management Bug

En esta guía, I will describe how to make the most of your inventory space by exploiting a bug that allows inventory items to occupy the same slots as one another.

Lo esencial

The bug itself is simple enough. Para demostrar, I’ll walk through a basic version of the bug to get 2 heavy weapons in the lower 2 rows of JC’s inventory. para empezar, we’ll put one heavy weapon on the ground and get our inventory looking like this:

The specific items/locations aren’t too important, all that matters is that if the heavy weapon in your inventory were not there, you would be able to pick up the one on the floor and have it enter 1 slot to the left of where the one in your inventory is now. (items will always enter the highest row they can fit in, and the leftmost column in that row) Próximo, click and drag the one in your inventory onto somewhere on the screen that doesn’t have any inventory slots, como esto:

Ahora, exit the inventory without letting go of the item and pick up the heavy weapon sitting on the floor. Your inventory will look something like this:

You’ll notice the floor weapon is now sitting behind the weapon that you already had. Clicking anywhere on the front weapon will select it, while clicking the 2 slots to the left of it will select the back one.

If you just want a basic breakdown of how it works, then dragging and closing with an item will mean the game will treat your inventory as though it isn’t there until you open it again. Any items you pick up will be behind the item you dragged. If you don’t care to look into the details, then just hop straight to the applications of the bug. De lo contrario…

Item Slots

I haven’t looked in the game code, so all of this is based on my own observations, but as far as I can tell the game stores the items in your inventory separately from the slots they occupy. Under normal circumstances, an empty slot will always be tagged as empty, and an occupied slot will always be tagged as occupied. Sin embargo, items that are clicked and dragged out of slots will mark their respective slots as empty without actually removing the item from those slots, and exiting the inventory before putting the item somewhere else will cause them not to be marked as occupied again.

Opening the inventory will reset all slots to empty/occupied as appropriate, so if you were to attempt the glitch mentioned above, but opened and closed the menu after dragging and closing with the inventory item, then you would be unable to pick up the item on the floor. Básicamente, if you have some item slots which are occupied but technically empty, cycling your inventory will fix them.

In case this isn’t making sense, let’s run through the previous example, while showing what the item slots think is happening. «oh» will mean a slot is occupied, while a «_» means it’s vacant. A «- » means it’s technically considered vacant, but there is an item in it. Those won’t show up until the inventory is bugged.

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[_][oh][oh][oh][oh]
[_][oh][oh][oh][oh]

En este punto, all slots are accurately showing which ones have an item in them and which ones do not. Nothing out of the ordinary, let’s see what happens next…

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[_][_][_][_][_]
[_][_][_][_][_]

Está bien, we’ve moved the flamethrower out of the slots it was already occupying and as a result, those slots have become vacant. De nuevo, nothing out of the ordinary, but the interesting thing happens when we close the inventory. The items themselves revert to how they were in the first screenshot…

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[_][- ][- ][- ][- ]
[_][- ][- ][- ][- ]

…while the item slots stay the same. Note the screenshot is just the first one again, not actually the items in this state, since as I said previously, opening the inventory will fix any broken slots.
Ahora, we pick up the GEP gun…

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[oh][oh][oh][oh][- ]
[oh][oh][oh][oh][- ]

…and the slots it moves into are occupied. When you open your inventory, sin embargo…

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]

the slots which the flamethrower occupy are tagged correctly.

Something worth noting is that slots being occupied is a purely binary system, a slot cannot be «multi occupied», which is to say there is no real difference between 1 item occupying a slot, y 100 items occupying it. The game’s inventory system was designed around items never being able to stack like this, so items being removed from their slots will always flag those slots as empty, regardless of whether those slots still contain more items.

sabiendo esto, and starting at the end of the previous example, we could now drop the GEP gun…

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[_][- ][- ][- ][oh]
[_][- ][- ][- ][oh]

…and know that the slots it occupied are vacant, despite the flamethrower still being in some of them. Since they’re technically vacant now, we can drag and drop an item right on top of the flamethrower.

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[_][- ][- ][oh][oh]
[_][- ][- ][- ][oh]

Note dragging and dropping items onto psuedo-vacant slots is a bit buggy, and may or may not even work at all. If it’s just being finnicky, dragging from the top to the bottom and from the left to the right will get the item into the right slot consistently.

Item Order

Ahora, I should talk about what determines whether a given item will be behind or in front of another one, and what is affected by that. (y de nuevo, I haven’t looked at anything in the game code so this is just educated guesses based on what I’ve seen while experimenting with this bug)

What determines it is simple, the more recently an item has entered your inventory, the farther back it will be behind others.

Dragging and dropping an item will never place an item behind another, even if the item slot is vacant. Por ejemplo, if the soy packet I had moved had been picked up after I grabbed the flamethrower, I wouldn’t have been able to drag and drop it onto the flamethrower.

Clicking a given slot will always select the farthest front item in that slot. Repeating a similar trick to the one detailed above, but using a sniper rifle and picking up the flamethrower after dragging and closing on the rifle, my inventory ends up in this state:

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[oh][oh][oh][oh][_]
[oh][oh][oh][oh][_]

Since the rifle was in my inventory first, it’s in front.

Sin embargo, if I were instead to drag and close on the flamethrower and pick up the rifle, it would end up like this:

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[oh][oh][oh][oh][_]
[oh][oh][oh][oh][_]

The sniper rifle is now completely behind the flamethrower, leaving it inaccessible.

Sin embargo, by simply dropping the flamethrower, closing my inventory, and picking it back up again, it will end up in the same location (unless there was room farther up and to the left in my inventory) but at the very back end of the item order. This means items too far forward can be easily sent to the back of the order without fiddling with other items.

Applications

The most straightforward use of the bug is to put items that don’t need to be selected to be used behind other items so that they take up no real inventory space. Fuera de mi cabeza, augmentation canisters are only used with medbots, biocells and aug upgrades can be used from the «augs» page inventory, and the ambrosia vial you get in the PRCS Wall Cloud only needs to be in your inventory to give it to Stanton Dowd. Medkits can be used on specific body parts without using them in the inventory but when used as an item will distribute healing to all parts of the body, y el «heal all» option will distribute heals but will use as many medkits as possible to heal as much damage as possible, even if it means wasting one to heal off 1 health or something, so it might be good to have these still usable through the inventory.

If you want to make good use of all of the weird mechanics this bug has, you can cram a very large amount of items into a very small place, por ejemplo:

If you want a play by play of the item slots as this video takes place, aquí:

>Initial setup
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][_][_][oh]
[_][_][_][_][_]
[_][_][_][_][_]

>Picking up the first couple items

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][_][_][oh]
[oh][oh][oh][_][_]
[_][_][_][_][_]

>Re-organize

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[oh][oh][oh][_][_]
[oh][oh][_][_][_]

>Drop shotgun, move pistol

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[oh][_][_][_][_]
[_][oh][_][_][_]

>Drag/Close with pistol

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[- ][_][_][_][_]
[_][oh][_][_][_]

>Pick up shotgun, now stacked with pistol

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[oh][oh][oh][_][_]
[_][oh][_][_][_]

>Drop shotgun(pistol’s slot is empty without being drop/closed, meaning I can drop/close another item)

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[- ][_][_][_][_]
[_][oh][_][_][_]

>Move crossbow

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[- ][oh][_][_][_]
[_][_][_][_][_]

>Drag/Close with crossbow

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[- ][- ][_][_][_]
[_][_][_][_][_]

>Pick up shotgun, now stacked with crossbow:

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[oh][oh][oh][_][_]
[_][_][_][_][_]

>Fiddling with soy food is not relevant to the glitch, just me getting my self confused
>Drag/Close with shotgun

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[- ][- ][- ][_][_]
[_][_][_][_][_]

>Pick up sniper rifle, now stacked with shotgun

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][oh][_][_]
[oh][oh][oh][oh][_]
[_][_][_][_][_]

>Move soy food (not relevant to the bug, I could have left it in the same place the whole time)

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][_][oh][_]
[oh][oh][oh][oh][_]
[_][_][_][_][_]

>Drag/Close on sniper rifle

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][_][oh][_]
[- ][- ][- ][- ][_]
[_][_][_][_][_]

>Pick up GEP gun, now stacked with sniper rifle

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][_][oh][_]
[oh][oh][oh][oh][_]
[oh][oh][oh][oh][_]

>Drag/Close GEP gun

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][_][oh][_]
[- ][- ][- ][- ][_]
[- ][- ][- ][- ][_]

>Pick up flamethrower, now stacked with GEP gun

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][_][oh][_]
[oh][oh][oh][oh][_]
[oh][oh][oh][oh][_]

>Drag GEP gun

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][_][oh][_]
[- ][- ][- ][- ][_]
[- ][- ][- ][- ][_]

>Place GEP gun

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[_][_][_][oh][_]
[- ][oh][oh][oh][oh]
[- ][oh][oh][oh][oh]

>Open/Close, Re-organize

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][_][_]
[oh][oh][oh][_][_]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]

>Pick up assault rifle

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]

>Drop GEP gun

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][- ][- ][- ][_]
[oh][- ][- ][- ][_]

>Move assault rifle

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][_][_]
[oh][oh][oh][_][_]
[oh][- ][- ][oh][oh]
[oh][- ][- ][oh][oh]

>Drag/Close assault rifle

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][_][_]
[oh][oh][oh][_][_]
[oh][- ][- ][- ][- ]
[oh][- ][- ][- ][- ]

>Pick up GEP gun (tough to see, it’s behind everything else since it was picked up most recently)

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][_][_]
[oh][oh][oh][_][_]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]

>Drop flamethrower

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][_][_]
[oh][oh][oh][_][_]
[- ][- ][- ][- ][oh]
[_][- ][- ][- ][oh]

>Pick up flamethrower (now the most recent pickup, so it’s behind the GEP gun)

[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]
[oh][oh][oh][_][_]
[oh][oh][oh][_][_]
[oh][oh][oh][oh][oh]
[oh][oh][oh][oh][oh]

Next little bit is just me showing that each item is selectable.