kc3-lang/SDL

2021-01-22T19:40:26

Implement keyboard grab support for Windows This is implemented via a low-level keyboard hook. Unfortunately, this is rather invasive, but it's how Microsoft recommends that it be done [0]. We want to do as little as possible in the hook, so we only intercept a few crucial modifier keys there, while leaving other keys to the normal event processing flow. We will only install this hook if SDL_HINT_GRAB_KEYBOARD=1, which is not the default. This will reduce any compatibility concerns to just the SDL applications that explicitly ask for this behavior. We also remove the hook when the grab is terminated to ensure that we're not unnecessarily staying involved in key event processing when it's not required anymore. [0]: https://docs.microsoft.com/en-us/windows/win32/dxtecharts/disabling-shortcut-keys-in-games