While the bug affects all three types of ammo in the game, it’s most impactful with heavy weapons. Their purple ammo drops are a rare sight and, more than that, there’s a high cost attached to purchasing heavy ammo packs. Even when you use one of your precious packs — they’re frequently useful during Destiny‘s dangerous raids — you always risk losing the ammo you get before you’ve even had a chance to fire off a shot.
While the problem seems simple, it’s actually very complicated, according to Bungie. Sandbox engineer Jon Cable is part of a team tasked with finding and squashing these bugs, and he offers some explanation of this issue’s complexity in Bungie’ post.
Cable starts out by explaining how the ammo disappears in the first place. The game’s inventory system creates a character’s weapons whenever they spawn or respawn, including the amount of ammo they had prior to death. The issue comes up when a piece of armor has a perk that boosts the total capacity of one ammo type or another.
It comes down to math. When the game calculates reserve ammo on a respawn, it does so before it factors in ammo boosts from armor perks. Destiny‘s inventory system uses fractions to calculate ammo totals, so when the pre-armor perk fraction is applied alongside the post-perk fraction, you end up with less ammo.
That explains why the bug happens — and it’s something both Bungie and players alike have known for some time — but Cable goes on to explain why it’s been so tricky to address. “This bug was mainly risky because it was at the intersection of a lot of different systems – player profiles, investment, sandbox, perks, and weapon management,” he said.
“There are a lot of weapon and armor perks in the game. Changing the order of how they are applied has a huge impact. It would have required a large restructuring of the way the game works to even accomplish this, because the armor perks can’t take effect until the weapon is created anyway. The application of armor perks would have to be inserted in between weapon creation and the rest of the weapon setup code.”
The chat with Cable concludes on a positive note. He’s formulated a fix, and one that doesn’t appear to break the game in other ways (which was a problem on the first few attempts). Now it’s just a matter of waiting for the patch to be written and deployed. According to Bungie, that will happen “before the end of February.”
