Raspberry Pi: Keyboard recognized in Menu but not in Game

[Gemba]

Describe the bug
On a Raspberry Pi the binary can be started and shows up the menu. In the menu navigation works with keyboard controls but after starting a new game the keyboard events are no longer recognized.

Allegro Lib
Tested with 4.4.3.1 (bundled with this repo) as well as with 4.4.2.1 from Raspi OS Buster.

To Reproduce
Steps to reproduce the behavior:

1. Build this repo on Raspberry Pi
2. Start headoverheels, navigate to new game
3. Let game start
4. Notice that no keyboard presses are recognized

Expected behavior
Keyboard should be usable in game.

Testsystem

• OS: Raspi OS Buster (Debian 10)
• Generic wired USB keyboard attached
• Reproducable on Raspberry Pi 3 or Raspberry Pi 4

Additional context

• Running from a full desktop on the Pi (lxde) or with a minimal xinit session does not make a difference
• Also posted some additional info on the RetroPie forum: https://retropie.org.uk/forum/topic/33861/head-over-heels-from-2003-would-it-work-on-retropie/13?_=1678903291603
• However: On a Desktop X11 System (Debian 11, x64, Bullseye with allegro lib from repo 4.4.3.1 or bundled with this repo) the game is fully playable.

PS: Thanks for reviving this classic game and gem.

[Gemba]

Do you have hints/ideas how to track this down? Maybe it is also related to the allegro lib itself.

[Gemba]

FWIW. As a workaround the allegro 5 build can be used. However, this limits the usage to the Raspberry Pi 4, as the Raspberry Pi 3 and the Head-over-Heels allegro5 binaries are not performing well together.

cf. https://gist.github.com/Gemba/f2c541f6e027d7278e948f80e311e318#file-headoverheels-sh-L46

[dougmencken]

Such “the keyboard works in menus but not in the game” I am sometimes suffering (but sometimes not, it looks really random) when I run the game thru gdb (the debugger)

[dougmencken]

@Gemba I’m sure you’d like the 6dd444c patch

[dougmencken]

as for the issue with keyboard, that’s what I’ve got

keys are handled in two distinct threads, those which control the game and those which control the characters

so anything that treats threads unequally may broke the key handling

the good news are that since C++11 there’s std::thread
https://en.cppreference.com/w/cpp/thread/thread

does anyone want to try porting thread handling to std::thread, maybe?