CODEWITHSUNDEEP
c++inputglfw
GDN9
GDN9

Reputation: 339

GLFW Input States

I'm having a hard time with GLFW's input system, figuring out how to make it work the way I want it, so I've come to people with more experience for wisdom. Using GLFW 3.

There are 3 states 0 Release, 1 Press and 2 Repeat. This is exactly what I would want, only, the key state from Press to Repeat takes about a second to change. Ideally, I would want it to have a state "Press" only for 1 frame, and then change into a repeat state.

The goal: Be able to easily call functions based on what state my key is as follows:

LINK

Please have a look in the files on the link above, and let me know if there's another way around it. Or is the approach itself rubbish, the way I do it? Thanks guys, all feedback and help appreiated.

Upvotes: 2

Views: 10963

Answers (2)

Nicol Bolas
Nicol Bolas

Reputation: 474116

It is very important that there is a delay between "press" and "repeat". Most human beings are incapable of pressing and releasing a key, such that your game only registers the key being pressed for exactly one frame. And the few who are capable of that cannot do so consistently, with any accuracy.

So a user will never be able to "do once". They will be doing it for multiple frames. That's generally bad.

Also, there is a conceptual difference between pressing, holding, and repeating. Holding is just what happens when you hold down the key. Repeating is a facility that is governed by the OS (which is why GLFW doesn't give you a way to set the repeat rate). Key repeating is typically meant for text input (which GLFW takes care of for you anyway via its text-based callback).

Essentially, you should ignore it. In a game situation, a key has 4 possible useful states: not pressed, was just pressed, being held down, and was just released. You can infer this from the button's previous state (which you can store) and the button's current state provided by the callback.

If all you want to do is take an action when a button "was just pressed", then you need to know that the button was not pressed in the previous frame. If the key is pressed now but not in the previous frame, take the action.

Upvotes: 5

Some programmer dude
Some programmer dude

Reputation: 409404

One way is to simply ignore the "repeat" event, and only go with the "press" and "release" events.

When you get the "press" event set a flag, and clear the flag on the "release" event. Then simply check this flag every frame.

Upvotes: 7

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