Thread: Windows game loop

A simple game loop might look like this:

Code:

while(!exit)
{
   showIntro()
   while(game)
   {
   }
}

Writing a game loop in using the Windows API doesn't seem so straight forward. What is one method?

I usually do this. It puts messages as first priority so they won't stack up.

Code:

msg Message;
bool GameIsOn = true;

while(GameIsOn)
{
   if(PeekMessage(&Message, NULL, 0, 0))
   {
      TranslateMessage(&Message);
      DispatchMessage(&Message);
   }
   else
   {
      //Update/Render/Whatever
      //To quit, set GameIsOn to false
   }
}

Note the use of PeekMessage() rather than GetMessage().

PeekMessage() will return if there is not a message, allowing the game to continue. This however maens that there will be no point where the game is doing nothing ie100% CPU use

GetMessage() will not return until there is a message for the app. This means the app can sit dormant until it is needed. It will not be able to do background processing unless the app generates a timer msg (very inaccurate)



To be 100% accurate should use the new message loop (which handles the -1 error return)

Code:

while( (bRet = GetMessage( &msg, NULL, 0, 0 )) != 0)
{ 
    if (bRet == -1)
    {
        // handle the error and possibly exit
    }
    else
    {
        TranslateMessage(&msg); 
        DispatchMessage(&msg); 
    }
}

But in a game loop you DO want to make calculations periodically wether a message has been sent or not. Using GetMessage, as you said, will halt execution until another message is sent.