why is it that when i redraw the entire background it does not flicker. but if i draw the entire background first, then just redraw the section of the background that was drawn over, it flickers.
the following code flickers...
Code:
//draws initial background
	DrawIMG(back, 0, 0);		  // if i move this to wher Update_Background() is, it will not flicker
 
	/* Game loop *************/
 
	bool done = false;
	while(!done)
	{
		while ( SDL_PollEvent(&gameloop) )
		{
			if ( gameloop.type == SDL_QUIT ) { done = true; }
			if ( gameloop.type == SDL_KEYDOWN )
			{
				if ( gameloop.key.keysym.sym == SDLK_ESCAPE )
				{
					done = true;
				}
			}
		}
 
		keys = SDL_GetKeyState(NULL);
 
		Update_Background();	 //updates background
 
		Move_Block();		 //moves block
 
		Draw_Block();		 //draws block
 
		SDL_Flip(screen); // flips buffer
 
	}
btw: i have SDL_DOUBLEBUF turned on