What's going on with Pokémon Go's visual glitches? I asked a game developer to try and find out

I don't know about you, but I've encountered a fair few visual issues in Pokémon Go recently. For example, my avatar has been given a vibrant new appearance, menus and notifications have become a scramble of letters, and UI elements have remained on screen longer than they should.

These issues are temporary and don't break the game - if anything, they're almost always amusing, and I enjoy it when they pop up - and I'm sure most players have experienced something along these lines during their time with Pokémon Go. But with their increased frequency in recent weeks (see the many reddit posts linked throughout this article as examples), I wanted to try and understand what's going on. So I asked a game developer - someone who has worked on a range of titles for large studios and independent projects, and preferred to remain anonymous - to explain what might be happening.

They believe that, in various instances, it's the result of Pokémon Go's developers making the best of limited memory resources. Textures take up a "huge amount" of memory, they said, and it's often a case of using them in clever ways to try and fit everything in. As a result, the wrong texture can occasionally be referenced.

"The challenge for them is that the game keeps growing, but the amount of memory available for the game isn't expanding, so they have to constantly find ways to cleverly load / unload just what they need and it can lead to bugs like this," they explained.

Though the issues aren't specifically a problem with Unity (Pokémon Go's game engine), our anonymous developer suspects "they are almost definitely using Addressables [a Unity feature] to manage asset loading and unloading, and it is notoriously hard to keep track of what is and isn't loaded with that system".

With this 'eye exam' glitch, for example, it's likely a case of the wrong texture being rendered. "Instead of rendering the background texture, it's somehow rendering the font atlas," they said.

"So as you use a font, it just writes each letter to a big texture that it can then use to texture quads to make letters display. So you usually only see it piecemeal, but if you render it as a texture, it looks like that."

The below image - which features two examples where I've seen the game's opening message not appearing as it should - is another suspected issue with the font atlas.

"Something else overwrote where the letters were supposed to be generate, or they just failed to generate", the developer explained. As well as my examples above, it can also show up elsewhere, going by a reddit post:

What about other issues? In the case of avatars being given a vibrant pink and white striped appearance - a bug which is proving to be a fan favourite - this is a suspected encoding problem. Here's a breakdown of how avatar appearances work behind the scenes: "Normally on a model you have the texture map, which is what you see, but so it doesn't look flat, they add a repeated pattern called a detail map," the developer said.

"The detail map can be a texture that you just render on top, but in this case, it's more likely to be some kind of repeated normal map which is why the colours are pink and green. Normal maps encode the three cardinal directions (x, y, z) into colors (r, g, b) so you see lots of 'unexpected' colours depending on how they encode the information."

Finally, for menu options or UI elements that linger on screen longer than they should, that can be for a few reasons: sometimes it's "just the mask being set wrong for the UI layer", resulting in elements being cut off, and in others, it's perhaps because the cue to remove something was interrupted by something else, keeping it on screen.

Using this 'checkmark' glitch as an example, the developer explained that "you hide a bunch of UI and sometimes, especially if you have animations, the timings of one thing conflicts with the timing of another thing... I can imagine something like the checkmark appears and plays an animation and then disappears, but if something else is running at the same time, it might stop whatever is running that animation."

So, the next time Pokémon Go (or another game you're playing) features an unexpected visual quirk, hopefully you're a little more informed as to what might be happening under the hood. Of course, it's possible there might be things at play that our developer isn't aware of, and I've reached out to Niantic to see if there's any comment on the above issues, or if there are any specific fixes in the works.

Either way, as mentioned earlier, these visual issues are harmless and don't impact the game itself: if they happen, nothing is permanently broken or missing, and things will soon return to normal. But if something is bothering you, try restarting the app, refreshing the game data, turning off enhanced graphics and downloading the latest assets to see if that helps.

As for myself, I like it when my avatar's jazzy pink and white appearance shows up temporarily, and will be quietly sad if and when it's eventually fixed.

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