How to read input from keyboard using SDL?

How to read input from keyboard using SDL?

1; Loop for all events using SDL_PollEvent searching for key down/up events and saving the key states in a map so I can check for each key state in the logic of the program. Note: Alternatively, I can also use SDL_PeepEvents instead of SDL_PollEvent to take only the event types that matter; so, it would not “thrown away” the events on the queue.

Why is my keyboard not detecting SDL _ KEYDOWN event?

You’re mixing them, and it’s not working well. In your code, you’re detecting an SDL_KEYDOWN event but then you’re querying the state of the entire keyboard in an if/else chain. If you’re pressing up, for example, then you’ll never be able to detect left, right or down because you’re ignoring the information given in the event.

How does input management work in a game?

Components listen to semantic events instead of keys directly ( “PlayerJump” instead of “KeyPressedSpace” ). Then you can have an input mapping component that listens for “KeyPressedSpace” and triggers whatever action the user bound to that key. Split this into several layers. At the lowest layer you have raw input events from the OS.

What’s the best way to update the array in SDL?

When you are calling SDL_PollEvent (), it implicitly calls SDL_PumpEvents (). So, it basically updates the array for SDL_GetKeyState () anyway. By parsing these events manually, you just create a second array (well, actually a much slower map) holding the same information which SDL already collected for you.

How to check the modifier keys in SDL?

In SDL we normally use SDL_PollEvent to check for keypresses and other events. To check which modifier keys are being held down you can use SDL_GetModState. If you don’t want the code to execute multiple times for as long as you hold down the keys you should also check that the repeat value of the event is false.

Where can I find keyboard and mouse events in SDL2?

This article was originally posted as “ SDL2: Keyboard and Mouse Movement (Events) ” at Programmer’s Ranch on 12th February 2014. It is slightly updated here. The source code and spaceship bitmap are available at the Gigi Labs BitBucket repository. Hi there!

How to read events from the SDL library?

We read events using SDL_PollEvent in a while () loop and check for SDL_KEYUP and SDL_KEYDOWN events using a switch statement, like so: Example 3-10. Reading Keyboard Events SDL_Event event; . . /* Poll for events.

Which is an event in the SDL event Union?

The SDL_KeyboardEvent describes a keyboard event (obviously). The key member of the SDL_Event union is a SDL_KeyboardEvent structure. The type field specifies whether the event is a key release (SDL_KEYUP) or a key press (SDL_KEYDOWN) event.

Why is my SDL key down not working?

This causes the default case to run when I hold or press any key, so my object moves according to m_y += 1. If I remove the default case and try pressing w,a,s, or d, nothing happens. If i keep m_y += 1, but use SDL_KEYDOWN instead of 771, nothing happens.

What happens if I use SDL _ KEYDOWN instead of 771?

If i keep m_y += 1, but use SDL_KEYDOWN instead of 771, nothing happens. (I got the 771 code by printing the event.type whenever a key is being pressed).

How to update the state array in SDL?

As SDL_GetKeyState () docs point out, before using it you are expected to call SDL_PumpEvents () to update the state array. When you are calling SDL_PollEvent (), it implicitly calls SDL_PumpEvents (). So, it basically updates the array for SDL_GetKeyState () anyway.

How to handle multiple keypresses at once with SDL?

If you’re using SDL2 then use SDL_GetKeyboardState. Instead of only looking at keydown events, any solution which is going to be caring about multiple keys at once is going to have to be looking at both keydown and keyup events, and keeping track of the state of the keys in question.