How can I disable gnome window manager keyboard shortcuts for my linux game?

Question

I am porting a game to linux. It is a complex game and has lots of keyboard and mouse shortcuts for finer control. One of the shortcuts utilises alt and right mouse click, which conflicts with some window manager functionality - namely a context menu appears on some machines. I have tried disabling this at runtime by collecting the output of "gsettings get org.gnome.desktop.wm.preferences mouse-button-modifier" and altering it if a conflict is detected, but this is very hacky and only works in a few cases. Does anybody know if there is a better, more reliable way of doing this - preferably a way of disabling all the shortcuts when my game window is active.

Answer 1

You can use some X Server code to grab the keyboard and lock it to the apps window. Which will then prevent anything else from intercepting the keyboard. See for example: https://tronche.com/gui/x/xlib/input/XGrabKeyboard.html

The disadvantage of taking a heavy handed approach like this is it breaks things like being able to Alt+Tab out of your full-screen window.

LWN has an article about all the tricks Valve went through to get Steam to work in Linux ( http://lwn.net/Articles/611969/ ) Valve went as far as to use LD_PRELOAD in places. They had to implement a special overlay to allow stuff like alt-tab to work. You could maybe look in the source code for Steam client to see how they did it.