Why mac os sdl2 program window is not responding? - c++

Question

I have just set up the SDL2 framework on my mac but however compilation and running the program succeeds, the window is not responding (I copied code that creates some rectangle).
I use xcode and I followed tutorial from here http://lazyfoo.net/tutorials/SDL/01_hello_SDL/mac/xcode/index.php
step by step.
SDL_Window* window = NULL;
//The surface contained by the window
SDL_Surface* screenSurface = NULL;
//Initialize SDL
if( SDL_Init( SDL_INIT_VIDEO ) < 0 )
{
printf( "SDL could not initialize! SDL_Error: %s\n", SDL_GetError() );
}
else
{
//Create window
window = SDL_CreateWindow( "SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN );
if( window == NULL )
{
printf( "Window could not be created! SDL_Error: %s\n", SDL_GetError() );
}
else
{
//Get window surface
screenSurface = SDL_GetWindowSurface( window );
//Fill the surface white
SDL_FillRect( screenSurface, NULL, SDL_MapRGB( screenSurface->format, 0xFF, 0xFF, 0xFF ) );
//Update the surface
SDL_UpdateWindowSurface( window );
cout << " Ok" << endl;
//Wait two seconds
SDL_Delay( 20000 );
}
}
//Destroy window
SDL_DestroyWindow( window );
//Quit SDL subsystems
SDL_Quit();
return 0;
Why could that problem happen?
Thank you in advance

Answer 1

In order for a program written SDL to "respond" to operating system, you should give control back to SDL for it to process system messages and give them back to you as SDL events (mouse events, keyboard events and so on).
To do that, you have to add a loop that uses SDL_PollEvent, that should look something
while(true)
{
SDL_Event e;
while (SDL_PollEvent(&e))
{
// Decide what to do with events here
}
// Put the code that is executed every "frame".
// Under "frame" I mean any logic that is run every time there is no app events to process
}
There are some special events such as SDL_QuiEvent that you would need to handle to have a way to close your application. If you want to handle it, you should modify your code to look something like this:
while(true)
{
SDL_Event e;
while (SDL_PollEvent(&e))
{
if(e.type == SDL_QUIT)
{
break;
}
// Handle events
}
// "Frame" logic
}