Bug report: Brake3 combine not working on 2.19.6 or newer

[Delta]

Another issue that popped up on Discord; a user had issues with T-Link not working on current firmware. I had an opportunity this weekend to narrow it down to a specific functionality.

Issue: Virtual toe brake function is unresponsive.
Observed in: 2.19.6, 2.19.7
Last observed working: 2.18.F
Steps to reproduce:
Have black box configured for T-Rudders - default Blackbox settings (logical 6: physical 4 - 8% A7 BrakeV3, logical 8: physical 4 + 8% A7 BrakeV3) are fine.
Cause a brake input on physical 4 while the pedals are centered, by trim or an axis on a linked device.
Expected behavior: Both brake axes engage
Observed behavior: Both brake axes stay idle
Additional notes:
If logical axis 4 is made visible, it does move.
It the BrakeV3 modifier is removed from the axis, it does move.

[jukelo]

I'm experiencing the same issue, my toe brakes set up using BrakeV3 no longer works on GF4 MCGU + Trudder V plugged into a single BB.

The same profile works fine in 2.18.F, breaks on 2.19.7.

Here's a video of the issue: https://www.youtube.com/watch?v=ab4bUjnVvKA

Physical axis 7 is the T-rudder axis, Physical axis 8 is the MCGU brake lever. Logical 3 and 4 (RotX and RotY) are the virtual toe brakes.

[jukelo]

For testing I created this profile on the Gladiator (cleaner set up than my MCGU + T-Rudder tangle):

The behaviour expected and observed in 2.18.F:
Logical 5 & 6 (X and Y) controlled by the joystick's main axes (roll and pitch, physical 1 and 2).
Logical 3 (RotZ) controlled by the Twist axis (physical 3).
Logical 4 controlled by the mini throttle (physical 4). The mini throttle was calibrated using Acn = on, starting calibration in the 'Up' position since I want full range with Cn = off.

Logical 1 & 2 (RotX and RotY) as virtual toe brakes, controlled by the mini throttle, using BrakeV3 + and - respectively with virtual axis 3 as BrakeV3 input. When twist (RotZ) is turned left or right, RotX or RotY respectively will move towards zero, from the mini throttle's value.

This video shows the expected 2.18.F behaviour:
https://youtu.be/vorO7W6zGzA


2.19.7, behaves as such:

When the mini throttle lever is moved down (towards max value), neither RotX nor RotY increase in value. Moving the twist axis (RotZ) has no effect at this point.
When the roll axis (physical 1) is moved to the left, X moves towards zero.
When the roll axis is moved to the right, both X and logical 1 (RotX) move to the right. If the twist is then moved to the left, RotX will move towards the left.
When the pitch axis (physical 2) is moved forward, Y moves towards zero.
When the pitch axis is moved backwards, both Y and logical 2 (RotY) move to the right. If the twist is then moved to the right, RotY will move towards zero.

Adjusting the bias values for physical axes 1 or 2 moves the starting value for RotX / RotY.

We can conclude that when BrakeV3 is used in 2.19.7, Logical axis 1 and 2 behave as though they had AxID = 1 and 2 regardless of the actual AxID value used.

This video shows the broken behaviour in 2.19.7:
https://youtu.be/HHMKx555FUY

[Delta]

Worth pointing out that this completely breaks the virtual toe brakes feature, as that requires two physicals to source from the same logical. There might be some workarounds that involve modifying trim, particularly in pushbutton-based scenarios like T-Link or SCG/KG12/F14+pedals, but the canonical approach is pretty much broken.

[Delta]

Fixed in 2.19.9 (3) as mentioned in
https://forum.il2sturmovik.ru/topic/970 ... ent-933326
Confirmed on my setup