search

jkuhlmann / gainput

Cross-platform C++ input library supporting gamepads, keyboard, mouse, touch
http://gainput.johanneskuhlmann.de/
MIT License
858 stars 103 forks source link

Receiving both WM_LBUTTONDOWN and WM_LBUTTONUP in same frame #36

Open GameOverture opened 7 years ago

GameOverture commented 7 years ago

If these two messages occur and are processed in the same frame (via InputManager::HandleMessage()), by the time InputManager::Update() is invoked it will essentially think nothing happened as the boolean has been flipped back already.

Under normal circumstances a "down" and "up" message for either mouse or keyboard usually doesn't get processed in the same frame. At least can't make it happen without the use of breakpoints in code.

However I have an ELO touchscreen hooked into a Windows 7 embedded image, which is responsible for sending these mouse events, to emulate mouse stuff for programs that don't understand touch. When I tap the screen the WM_LBUTTONDOWN and WM_LBUTTONUP get sent essentially at the same time (in order), and cause the input to be ignored as explained above.

I should be able to hack my way around this problem, but I figured I'd mention it here.

jkuhlmann commented 7 years ago

Thanks for the heads-up. You're right this is a problem if you check the state of an input device (or via InputMap). This should, however, not be a problem if you use an input listener (be it InputListener or MappendInputListener).

Does that help? Can you confirm that this works?

GameOverture commented 7 years ago

When looking through your library I did notice InputDeltaState being coupled with listeners, and they might be able to solve this problem. My code that utilizes and wraps around gainput is meant to be a generic, reusable library so I don't want to have to enforce using listeners (yet).

I managed to fix the issue on my end, and I sent a pull request with those changes. Feel free to use or ignore the pull request. It's not a lot of code, but I may have not accounted for all the different features and platforms you support.