Rémi Bernon : winebus.sys: Revert direction rotation for UDEV lnxev devices.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: cbd324124ce2a5ddb241f0ff920660aa55b0b5c4
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=cbd324124ce2a5ddb241f0ff920660aa55b0b5c4

Author: Rémi Bernon <rbernon at codeweavers.com>
Date:   Thu Dec  9 14:44:15 2021 +0100

winebus.sys: Revert direction rotation for UDEV lnxev devices.

This partially reverts b431dceeca9aa0d4229c3597b833bcaf04de7110, which
followed some misleading SDL comment, as well as the original dinput
evdev backend code, and resulted in inverted directions instead.

On the Linux drivers side, both in the PID driver or the I-Force driver,
the evdev direction is simply rescaled and passed to the device. It is
then very likely that we should pass through the PID reports direction.

In some other drivers, the sine of the angle is used to modulate the
force magnitude, although that doesn't really tell anything about the
orientation of the direction itself.

The SDL comment is incorrect, and its code isn't actually doing any kind
of conversion other than the rescaling. We now do the same here, and end
up with identical values being sent to evdev, whether we use it directly
or through the SDL library.

It's also been confirmed with hidraw PID capable devices, that with this
change, the direction values in the hardware PID reports are consistent
between the three backends (SDL, evdev, and hidraw).

If some devices are expecting inverted directions then it probably is
something that will need to be solved on the Linux driver level.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=51922
Signed-off-by: Rémi Bernon <rbernon at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 dlls/winebus.sys/bus_udev.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/dlls/winebus.sys/bus_udev.c b/dlls/winebus.sys/bus_udev.c
index dec8435555c..2269f5b904e 100644
--- a/dlls/winebus.sys/bus_udev.c
+++ b/dlls/winebus.sys/bus_udev.c
@@ -1046,14 +1046,9 @@ static NTSTATUS lnxev_device_physical_effect_update(struct unix_device *iface, B
     effect.trigger.button = params->trigger_button;
     effect.trigger.interval = params->trigger_repeat_interval;
 
-    /* Linux FF only supports polar direction, and uses an inverted convention compared
-     * to SDL or dinput (see SDL src/haptic/linux/SDL_syshaptic.c), where the force pulls
-     * into the specified direction, instead of coming from it.
-     *
-     * The first direction we get from PID is in polar coordinate space, so we need to
-     * add 180° to make it match Linux coordinates. */
-    effect.direction = (params->direction[0] + 18000) % 36000;
-    effect.direction = effect.direction * 0x800 / 1125;
+    /* Linux FF only supports polar direction, and the first direction we get from PID
+     * is in polar coordinate space already. */
+    effect.direction = params->direction[0] * 0x800 / 1125;
 
     switch (params->effect_type)
     {