[PATCH v9 6/8] winex11.drv: Implement native mouse-movement raw-input using RawMotion.

[Rémi Bernon]

On 7/31/19 12:41 AM, Derek Lesho wrote:
>> AFAIU the existing RawMotion event handler was sending INPUT messages to
>> the server for the sole purpose of emulating and sending raw input
>> messages.
> 
> It was my impression that MotionNotify events are ignored when the the
> cursor is clipped, due to some bug or problem it.  I went searching to
> see whether the case, and I found this:
> https://github.com/wine-mirror/wine/commit/0e2b4f99a9f5d97f8da0189037b7516cf1585d45#diff-c78b8a343abe990b307f178fe51c8931R332
> 
> This commit came around the time they were adding raw-input, and it
> seems to indicate that there is a problem w/ MotionNotify on a clipped
> cursor, but the ignore case isn't there anymore so maybe things have
> changed.  Some other reasons I'm skeptical that the RawMotion code
> currently in place is only for rawinput events are that
> 
> 1) The input is also sent as WM_MOUSEMOVE by the server, as there was
> no previous infrastructure to send raw-input separately and

This commit is about warping the cursor, then ignoring the MotionNotify 
event induced by the warp itself.

I can see that the a pre-existing ignore case for MotionNotify events 
while clipping is active, comes from 
https://github.com/wine-mirror/wine/commit/8e9b4e0a5c6bee5f72ca2314db26233638f0e1d2 
and 
https://github.com/wine-mirror/wine/commit/da9922b40da5bc581815a4357340f3f128e8c5cb, 
then reverted in 
https://github.com/wine-mirror/wine/commit/9716d1c8619e5fe68d1ad3ab9a18b106499b3fac.

About these commits, I believe that while xinput2 events are received, 
and because they were translated as both raw input messages and normal 
input messages, it was maybe redundant to listen to MotionNotify as 
well. Also, the oldest commit makes me think that there could be some 
back-and-forth movement issues if MotionNotify events are processed 
while RawMotion events were delayed.

Now regarding the interactions between MotionNotify and RawMotion events 
while clipping the cursor, AFAICS MotionNotify events are still received 
when the cursor moves but is blocked by the X11 confine window, with its 
current position in x,y fields.

This means that regardless if the cursor is clipped or not, both 
MotionNotify and RawMotion events will currently get translated to raw 
and normal input messages, the raw message position being compared to 
the current position and converted to relative position, and the normal 
input message position being clamped with the clipping window and not 
sent if it is the same as the last known position (see 
queue_hardware_message in server/queue.c and 
https://github.com/wine-mirror/wine/commit/3909f51122ffc0f6150fa9758ba47c70dcf6b00e).

So with the current code:

* If the cursor moved (inside a clipping window), you get a normal input 
message from either MotionNotify or RawMotion (which ever came first), 
then two raw input message, one with the corresponding relative 
movement, and another with 0x0 relative movement. The second normal 
input message is discarded because the cursor didn't move.

* If the cursor is clipped and blocked by confine window, Wine receives 
(order may vary as well):

   * a MotionNotify event with identical position, which is translated 
to raw input message with 0x0 relative movement, but does not get 
translated to normal input message because the cursor didn't move.

   * a RawMotion event with some relative movement, which is translated 
to the corresponding raw input message with relative movement, and is 
added to current position, then clamped, and then ignored w.r.t. normal 
input message because the clamped position is the same as the last.

Currently if the clipping window is disabled, then no RawMotion events 
are received anyway.

> 
> 2) When somebody tested warframe with my patch before I re-added
> mouse-movements, they had issues that were fixed by rebasing
> mouse-movements on my commit, and warframe does not use raw-input for
> the mouse.

There could be some subtleties I may be overlooking, I will do some 
tests. Thanks for mentioning it.
-- 
Rémi Bernon <rbernon at codeweavers.com>