CODEWITHSUNDEEP
c++eventskeyboardgtksdl
Scott
Scott

Reputation: 448

SDL Get Keyboard State without using Events

Does anyone know how to get SDL_GetKeyState to work properly, without having to setup a loop which polls the SDL Events?

int *keystates;
keystates = SDL_GetKeyState(NULL);
SDL_PumpEvents();
std::cout << "Test 1\n";
if (keystates[SDLK_F1]) {
    std::cout << "Test 1 Okay\n";
    key_ac = true;
    emu->setPower(true);
}

This code is run over 100 times a second, however even when I hold down the F1 key, I still do not get any output to say it was successful.

I have no SDL event loop, so could this be that events are being discarded because I'm not using them? In which case, how could I get SDL to filter out all events?

Upvotes: 3

Views: 8357

Answers (1)

user1944441
user1944441

Reputation:

SDL_GetKeyState() only has to be called once at the start of your program.

unsigned char * keys = SDL_GetKeyState(NULL);

Then the value it returns, a unsigned char pointer to an array is stored internally. To to update the state of the array call the function SDL_PumpEvents().

To update array keys in your main loop:

SDL_PumpEvents();

if( keys[ SDLK_m ] )
{
    //do stuff
}

EDIT: You can call SDL_GetKeyState() as much as you want after the first call and you won't create a memory leak. The function is always returning the same pointer.

Upvotes: 7

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