FIX: Suppress touch simulation while the Device Simulator is open [UUM-153420]

[jfreire-unity]

Description

Backport of trunk PR unity/unity#123402.

Problem

A single mouse click in the Device Simulator produces two active touches when "Simulate Touch Input From Mouse or Pen" is enabled in the Input Debugger. EnhancedTouch.Touch.activeTouches reports two entries with different touch IDs, in different coordinate spaces, both at finger index 0:

[0] {id=1 finger=0 phase=Began position=(1754.00, 858.00) ...}
[1] {id=4 finger=0 phase=Began position=(490.40, 202.40) ...}

Fixes UUM-151404 which was reported through LinkedIn, and we could not exactly reproduce what the user mention in the specific versions. 1.19 actually didn't reproduce this bug because it was obfuscated by another bug fixed in 1.20.

Cause

Two Touchscreen devices are live at once and each produces a touch per click:

• "Device Simulator Touchscreen", added by InputSystemPlugin, fed from DeviceSimulator.touchScreenInput.
  • For Input System, UITK callbacks are used to be converted into touchscreen events in the queue.
• "Simulated Touchscreen", added by TouchSimulation, fed from Mouse/Pen events.

Nothing has ever prevented these two from coexisting, so they are in fact producing separate events.

Solution

Pragmatic fix: TouchSimulation now skips event processing while a Device Simulator view is open, so the Device Simulator's touchscreen is the only source of "simulated touches". The Input Debugger's toggle is shown as unavailable while a simulator is open, since it would otherwise appear to work while having no effect.

This means Device Simulator in fact takes over "Touch Simulation".

Testing status & QA

Test suite was run locally on 6000.0 at least.

Overall Product Risks

• Complexity: 1
• Halo Effect: 1

Comments to reviewers

Code is the same as the trunk PR.

Checklist

Before review:

• Changelog entry added.
  • Explains the change in Changed, Fixed, Added sections.
  • For API change contains an example snippet and/or migration example.
  • JIRA ticket linked, example (case %%). If it is a private issue, just add the case ID without a link.
  • Jira port for the next release set as "Resolved".
• Tests added/changed, if applicable.
  • Functional tests Area_CanDoX, Area_CanDoX_EvenIfYIsTheCase, Area_WhenIDoX_AndYHappens_ThisIsTheResult.
  • Performance tests.
  • Integration tests.
• Docs for new/changed API's.
  • Xmldoc cross references are set correctly.
  • Added explanation how the API works.
  • Usage code examples added.
  • The manual is updated, if needed.

During merge:

• Commit message for squash-merge is prefixed with one of the list:
  • NEW: ___.
  • FIX: ___.
  • DOCS: ___.
  • CHANGE: ___.
  • RELEASE: 1.1.0-preview.3.

[u-pr]

💡 Harness Review

The touch-suppression implementation is coherent, but the added fixture lifecycle does not preserve pre-existing simulator state across test runs.

_{Reviewed commit f88f5e9}

_{🤖 Helpful? 👍/👎}

[jfreire-unity]

💡 Harness Review

The touch-suppression implementation is coherent, but the added fixture lifecycle does not preserve pre-existing simulator state across test runs.

Reviewed commit f88f5e9

🤖 Helpful? 👍/👎

Looks worse than it sounds, it's a small corner case improvement for testing and is not a blocker.

[Pauliusd01]

Did a quick recheck on 6000.0.74f1, lgtm

[ekcoh]

Approving but the P1 findings sounds/looks real to me, I would suggest fixing that separately across versions then.

[codecov-github-com]

Codecov Report

Attention: Patch coverage is 90.78947% with 7 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...InputSystem/Editor/Debugger/InputDebuggerWindow.cs	0.00%	4 Missing ⚠️
...m/Runtime/Plugins/EnhancedTouch/TouchSimulation.cs	92.00%	2 Missing ⚠️
...System/Editor/DeviceSimulator/InputSystemPlugin.cs	66.66%	1 Missing ⚠️

@@           Coverage Diff            @@
##           develop    #2484   +/-   ##
========================================
  Coverage    78.95%   78.96%           
========================================
  Files          767      767           
  Lines       140914   140989   +75     
========================================
+ Hits        111262   111333   +71     
- Misses       29652    29656    +4     

Flag	Coverage Δ
inputsystem_MacOS_6000.0	5.30% <0.00%> (-0.01%)	⬇️
inputsystem_MacOS_6000.0_project	77.50% <90.78%> (+0.01%)	⬆️
inputsystem_MacOS_6000.3	5.30% <0.00%> (-0.01%)	⬇️
inputsystem_MacOS_6000.3_project	77.50% <90.78%> (+0.01%)	⬆️
inputsystem_MacOS_6000.6	5.29% <0.00%> (-0.01%)	⬇️
inputsystem_MacOS_6000.6_project	77.56% <90.78%> (+0.01%)	⬆️
inputsystem_Ubuntu_6000.0	5.30% <0.00%> (-0.01%)	⬇️
inputsystem_Ubuntu_6000.0_project	77.41% <90.78%> (+0.01%)	⬆️
inputsystem_Ubuntu_6000.3	5.30% <0.00%> (-0.01%)	⬇️
inputsystem_Ubuntu_6000.3_project	77.41% <90.78%> (+0.01%)	⬆️
inputsystem_Ubuntu_6000.6	5.29% <0.00%> (-0.01%)	⬇️
inputsystem_Ubuntu_6000.6_project	77.47% <90.78%> (+0.01%)	⬆️
inputsystem_Windows_6000.0	5.30% <0.00%> (-0.01%)	⬇️
inputsystem_Windows_6000.0_project	77.63% <90.78%> (+0.01%)	⬆️
inputsystem_Windows_6000.3	5.30% <0.00%> (-0.01%)	⬇️
inputsystem_Windows_6000.3_project	77.62% <90.78%> (+0.01%)	⬆️
inputsystem_Windows_6000.6	5.29% <0.00%> (-0.01%)	⬇️
inputsystem_Windows_6000.6_project	77.69% <90.78%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
.../Tests/InputSystem/Plugins/DeviceSimulatorTests.cs	100.00% <100.00%> (ø)
...System/Editor/DeviceSimulator/InputSystemPlugin.cs	74.00% <66.66%> (-0.23%)	⬇️
...m/Runtime/Plugins/EnhancedTouch/TouchSimulation.cs	91.07% <92.00%> (+0.61%)	⬆️
...InputSystem/Editor/Debugger/InputDebuggerWindow.cs	2.38% <0.00%> (-0.01%)	⬇️

... and 1 file with indirect coverage changes

ℹ️ Need help interpreting these results?

[jfreire-unity]

I'm forcing landing this. The failure that currently exists is also on develop and i'm trying to fix it with https://github.cds.internal.unity3d.com/unity/pets.pvp-catalog/pull/306