Issues with Keyboard Events

Game Development
1

Hey Guys,

Im a beginner in C++ and SDL and im writing a game.
Im quite done, but my problem are the Keyboard Events, when i press a key, it sometimes gets not even noticed, sometimes i have to hold it down to get it noticed as a keypress and stuff like that,
so my game isn`t working that good. I don’t know whats wrong, so i would be very happy if you guys could help me out;
The “couts” “0 was pressed” and “w was pressed” are not for the game, i just put them in there to see whats wrong, why it won’t shoot and so on^^.

Here is the Code of the Function that “recognizes events”:
void CGame::ProcessEvents()
{
SDL_Event Event;
if (SDL_PollEvent(&Event))
{
if (Event.type == SDL_QUIT)
m_bGameIsRunning = false;
if (Event.type == SDL_KEYDOWN)
{
switch (Event.key.keysym.sym)
{
case(SDLK_SPACE) :
cout << “0 was pressed” << endl;
break;
case(SDLK_w) :
cout << “w was pressed” << endl;
}
}
}
}

The SDL_PumpEvents() Function is located in g_pFramework-Update() (I think it’s needed, pls tell me if its unnecessary^^)

The SDL_QUIT part works pretty smooth, i press the “X” and the window gets closed.
As I said, I am pretty new to SDL please tell me if something could get done better in an other way.

Here is The function where its used in even if i think the problem is in the function:
void CGame::Run()
{
while (m_bGameIsRunning == true)
{
ProcessEvents();

		g_pFramework->Update();
		g_pFramework->Clear();

		m_pSpriteBackground->Render();

		m_pPlayer->Update();
		m_pPlayer->Render();

		SpawnAsteroids();

		CheckCollisions();

		RenderAsteroids();

		g_pFramework->UpdateWindow();
	}
}

And here is the main- function, but I think the problem is in the function ProcessEvents:
int main(int argc, char *args[])
{
if (g_pFramework->Init(1520, 180) == false)
return 0;

	CGame Game;
	Game.Init();
 	Game.Run();

	Game.Quit();

	g_pFramework->Quit();
	g_pFramework->Del();

	return 0;
}

I really hope you guys can help me!
Greetings Maxlof

2

On a quick glance you should have

while (SDL_PollEvent(&Event))

instead of ‘if’, since ‘if’ will only handle the first event on the queue.

3

One thing to note, besides what Christian has written, is to always break out of every switch case, to avoid weird bugs in the switch block. So add ‘break;’ after/under ‘cout << “w was pressed” << endl;’ in the SDLK_w case.

Also, if you don’t wanna write ‘if(Event.type ==’ all the time, you can change the Event.type into a switch case aswell.

The fixed event code would then look like this:

void CGame::ProcessEvents()
{
	SDL_Event Event;

	while(SDL_PollEvent(&Event))
	{
		switch(Event.type)
		{
		case SDL_QUIT:
			{
				m_bGameIsRunning = false;
				break;
			}

		case SDL_KEYDOWN:
			{
				switch(Event.key.keysym.sym)
				{
				case(SDLK_SPACE):
					{
						cout << "0 was pressed" << endl;
						break;
					}

				case(SDLK_w):
					{
						cout << "w was pressed" << endl;
						break;
					}
				}
			}
		}

		case SDL_KEYUP:
			{

			}

		// Other event types
		// case OtherEventType:
			{

			}
	}
}
4

Thanks guys. I didn`t know it should be while(SDL_PollEvent(&Event)).The “if’s” are only there for simplification, later on i will go with switch().
But the Problem is still there, Keypressed will only get noticed after several presses, or by holding the button down.

I am out of ideas and can`t find the problem.

5

I found the Problem, another Function in the Run() Function was written bad and slowed everything down.