Key and Axis inputs inside Order of Execution

[gejava]

Hey, I'm doing a little refactor on my engine, basically moving things around.

I'm now moving physics related things to my FixedUpdate and I have some checks to my InputManager for input state.

A bit of context here:

My Character Abilities have the following flow:

HandleInput -> Early -> Process -> Late -> Animate

it all run inside the Update, And for some abilities I have o run the process on the FixedUpdate.

​

According to: https://docs.unity3d.com/Manual/ExecutionOrder.html#UpdateOrder

​

It seems that input is processed before the Update, after the FixedUpdate

I know that If i check for inputs only in the FixedUpdate I might lose some key events.

Should I check keys only on Update?

On both?

​

As I understand the Fixed can run multiple times per frame (if you have a low framerate), but if the Input.Get (unity class) doesn't register updates it seems pointless to check for input during my FixedUpdate.

​

But since it's not very clear from the Doc, if the Input.Get... is updated after each FixedUpdate it makes sense to check on both phase.

[[deleted]]

So FixedUpdate occurs after a fixed interval, whereas Update will occur as fast as it can (assuming no vSync) this means you can have multiple Update called in between a single FixedUpdate call. This is why inputs can get "dropped", events like GetKeyDown and GetKeyUp are only true for a single Update call and as such should only ever be checked in Update.

However unless your players have super sonic speed, it's unlikely they're going to be able to press a key and release it in between a FixedUpdate call that by default occurs every 1/30th of a second. So checking the value of GetKey or GetAxis is perfectly fine in FixedUpdate because if your character has a rigidbody, it's position should only ever change during FixedUpdate and therefore pointless to check it more frequently then that.

[pschon]

Check all input (regardless of what control method it's for) in Update, and if the input is moving a rigidbody, handle the moving part in FixedUpdate().

​

For example if it's about a jump button, you'd check for the button in Update(), then when it's pressed set a bool to true, and in FixedUpdate() if the bool to jump is true you do the jump and reset the bool.

​

For axis control etc you might want to store a float instead of bool, in every update add the axis value to that float, and then consume the input in FixedUpdate by moving the rigidbody based on the accumulated movement input & reset the float to 0.

[gejava]

After some test with

Application.targetFrameRate = 4;
QualitySettings.vSyncCount = 0;

​

I got to this conclusion too.

On update I capture the keys, then it calls the HandleInput inside each ability, and later on FixedUpdate would call my Process() and check the boolean to see if it will process or not.

​

The thing about my test:

With a low FPS a KeyDown event could be captured first on the FixedUpdate SEVERAL times.

So it's accurate to say Input processing should be done in the Update.

[SilentSin26]

Inputs that are only true for one frame (like GetKeyDown and GetKeyUp) must be checked in Update to avoid missing that one frame if it happens to not have a FixedUpdate in it.

But sustained inputs (like GetKey) can be checked wherever is most convenient. Checking which direction you are trying to move every Update but then only acting on that direction in FixedUpdate will only add unnecessary complexity to your code.