A function for doubling the screen itself instead of doubling a duplicate of it [...]
Dependet on which Version you use:
- SDL2 : SDL_SetWindowSize or in Fullscreen SDL_SetWindowDisplayMode
- SDL1.2 : SDL_SetVideoMode
The difference between them is that the first one really change the resoultion and the second on just set a new video mode to the resolution you want IT doesn't scale anything what on the screen is from what i know.