cameraviewport()

Use something similar to the example code below to find the available video modes for a users system. Once you have a list of valid modes, either pick one, or let the user decide which mode to use via an options menu. Other commands you may wish to check out are GfxModeExists (width,height,depth) and Windowed3D()

; CountGFXModes()/GfxModeWidth/GfxModeHeight/GfxModeDepth example 

intModes=CountGfxModes() 

Print "There are " + intModes + "graphic modes available:" 

; Display all modes including width, height, and color depth 
For t = 1 To intModes 
Print "Mode " + t + ": 
Print "Width=" + GfxModeWidth(t) 
Print "Height=" + GfxModeHeight(t) 
Print "Height=" + GfxModeDepth(t) 
Next