How can I resize the game?

[V-Man]

Open your AssaultCube config folder. Open init.cfg for editing.
Change the line that starts "fullscreen" to

[SELECT ALL] Code:

fullscreen 0

In-game, once you've closed the error notification dialog, type

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/fullscreen 1; screenres 1024 768; resetgl

(if your laptop monitor is 1024x768.)

You may wish to bind all of that to a key in autoexec.cfg so you can just press it and be on your way. For example,

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bind BACKQUOTE [fullscreen 1; screenres 1024 768; resetgl]

To keep the settings in place (i.e., so that you don't have to keep editing init.cfg each time you play), open autoexec.cfg for editing. Add this at the bottom:

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add2alias onQuit [fullscreen 0; scr_w 800; scr_h 600]

HTH