ColinPitrat/caprice32

Wish a headless mode, triggered by command line option

Closed this issue · 3 comments

cpcitor commented

Context

For a number of years I've been using caprice32 for automated tests in cpc-dev-tool-chain. For every test the test bench runs an instance of caprice32 with a command line looks like cap32 $(DSKNAME) -c cap32_fortest.cfg -a 'run"$(PROJNAME)' -a CAP32_WAITBREAKCAP32_SCRNSHOT -a CAP32_EXIT where CAP32_WAITBREAK was implemented in #112.

Situation

It was nice initially that a window appears to monitor the test progress. But:

  1. Sometimes I'm typing something in another window while the tested thing compiles, then the test launches, a window appears and gets keypresses from what I'm typing, which breaks the run"sometest command line and lets the emulator sits idle until I close it, failing the test. A non-regression test should run isolated.
  2. As I add more tests, a number of emulator windows appear then disappear until all tests run, disrupting usability of the desktop while tests run.
  3. Thinking about it, an unattended test suite should not need a graphical display at all.

Wish

I wish a command line argument, like --headless, with the following effect:

  • No window opens.
  • No window -> no interactive event
  • No interactive event -> no desktop or test disruption (obligatory reference)

Turns out this is very easy, ref. Possible to run SDL2 headless? - SDL Development - Simple Directmedia Layer.

Before call to SDL_Init() add SDL_SetHint(SDL_HINT_VIDEODRIVER, "offscreen");

I'm writing code for it and will open a PR.

ColinPitrat commented

Having a command line argument sounds good but IIRC you can already do this with an environment variable (SDL_VIDEO_DRIVER if my memory serves me well)

cpcitor commented

Having a command line argument sounds good but IIRC you can already do this with an environment variable (SDL_VIDEO_DRIVER if my memory serves me well)

Indeed, using SDL_VIDEODRIVER=dummy does the same in practice on my setup (actually render graphics in-memory, allowing screenshots to PNG). Surprisingly, SDL_VIDEODRIVER=offscreen also exists and in practice has the same result.

We can ditch this PR, my tests will simply use SDL_VIDEODRIVER=dummy and SDL_AUDIODRIVER=dummy. I confirmed using strace that the process does not try to reach X or a pulse-compatible sound service.

ColinPitrat commented

Thanks. Don't hesitate should you need any other feature!