No touch events on Surface devices

[Herb]

On a MS Surface 3, all touch events come in as mouse events:

- sf::EventType::MouseButtonPressed
- sf::EventType::MouseButtonReleased  <-- rarely receive this one
- sf::EventType::MouseMoved

This would be okay if the Released messages were reliable, but rarely receive them.

Also tried using sf::Touch::isDown() but it never returns true.  It's like SFML is completely unable to hook the touchscreen at all on these Surface devices.

I searched the forum before posting this.  Does anyone know of a reliable workaround?

Thanks.

[Mario]

If possible, try using a debug build and step through related window messages. Don't think any of us has a Surface 3 for testing (unless anyone is up for buying me one… ).

[Herb]

Hi Mario,

Yes, I did step through with a debugger, and set breakpoints.  That is how I verified that only mouse events are coming in.  Besides events, the sf::Touch class is not returning any activity at all.  Am I missing an SFML setup or initialization call for touchscreen?

Thanks.

[Laurent]

Touch events are not implemented in the Windows back-end. So unless the OS correctly maps them to mouse events, you won't get anything.

[Herb]

Thanks for the reply, Laurent.  *Please* add that to the documentation.  I spent about 16 hours on this unnecessarily.

[Mario]

Argh, right, now I remember that pull request still isn't merged!

You can check out SFML's branch "feature/windows_touch", which includes touch support for Windows – although it's untested on actual devices.

You can find the details in this pull request.

If you want to give it a spin, leave your feedback in the PR.

Just keep in mind this branch implements the touch events but not the functions to check directly (i.e. sf::Touch*()).