Ok, I think I'm asking the wrong question. I can set the window size correctly with that call, but it basically scales the same viewport up or down to fit the window size. If I have a bigger window size, I want a bigger viewport as well- is this possible? For example, setting the window size at 320x240 works - but when I set the window to 640x480 instead, I want to see twice as many tiles not the same tiles at twice the size.