NEW: Expose displayIndex for multi-display support (#1623)

* Add support for distinguishing pointer events from multiple displays

Tests should cover every new code path.

* remove virtual keyword and add missing layout entry

* fix array out of bounds exception due to EraseAtWithCapacity mutating count

* update precompiled layout for FastTouchscreen

* remove uneeded displayIndex setter

* remove platform specific defines

* more cleanup on TouchSimulatorArray handling

* improve displayIndex property inline doc

* set displayIndex outside of getIndex function

* Fixed formatting violations in UITests.cs

* Updating tests for multi-display input changes

* formatting

* Fixing multi-input test

* Ignore 3 failing tvos tests. Seem related to ISX-448

* remove unwanted changes to DefaultInputActions

* fix changelog conflict and moved to Added section

Co-authored-by: Eric Fulton <eric.fulton@unity3d.com>
Co-authored-by: James McGill <james.mcgill@unity3d.com>
Co-authored-by: James McGill <jamesmcgill@users.noreply.github.com>

Author: 3 people

Assets/Tests/InputSystem/Plugins/UITests.cs

@@ -17,6 +17,7 @@ however, it has to be formatted properly to pass verification tests.
 - Added the ability to change the origin positioning and movement behaviour of the OnScreenStick (`OnScreenStick.cs`) via the new `behaviour` property. This currently supports three modes of operation, two of which are new in addition to the previous behaviour. Based on the user contribution from [eblabs](https://github.com/eblabs) in [#658](https://github.com/Unity-Technologies/InputSystem/pull/658).
 - Significantly optimized cost of `InputAction.ReadValue` and `InputControl.ReadValue` calls by introducing caching behaviour to input controls. Input controls now keep track of whether their underlying state has been changed and only read the value from the underlying state and apply processors when absolutely necessary. Optimization is opt-in for now, please call `InputSystem.settings.SetInternalFeatureFlag("USE_READ_VALUE_CACHING", true);` in your project to enable it. If there are issues try enabling `InputSystem.settings.SetInternalFeatureFlag("PARANOID_READ_VALUE_CACHING_CHECKS", true);` and check in the console if there are any errors regarding caching.
 - Added a note in the [supported devices page](Documentation~/SupportedDevices.md) about DualSense support for Android devices.
+- Exposed `displayIndex` property for `Pointer`, `Touchscreen`, `TouchControl`, `TouchState`, `Mouse`, `MouseState` which enables look up of the logical screen associated with a pointer event via (display documentation)[https://docs.unity3d.com/ScriptReference/Display.html]
 
 ### Fixed
 - Fixed composite bindings incorrectly getting a control scheme assigned when pasting into input asset editor with a control scheme selected.

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -35,6 +35,12 @@ public class TouchControl : InputControl<TouchState>
         /// <seealso cref="phase"/>
         public TouchPressControl press { get; set; }
 
+        /// <summary>
+        /// Gets the index of the display that was touched.
+        /// <see href="https://docs.unity3d.com/ScriptReference/Display.html"/>
+        /// </summary>
+        public IntegerControl displayIndex { get; set; }
+
         /// <summary>
         /// The ID of the touch contact as reported by the underlying system.
         /// </summary>
@@ -202,6 +208,7 @@ public TouchControl()
         protected override void FinishSetup()
         {
             press = GetChildControl<TouchPressControl>("press");
+            displayIndex = GetChildControl<IntegerControl>("displayIndex");
             touchId = GetChildControl<IntegerControl>("touchId");
             position = GetChildControl<Vector2Control>("position");
             delta = GetChildControl<DeltaControl>("delta");

Packages/com.unity.inputsystem/InputSystem/Controls/TouchControl.cs

@@ -79,17 +79,19 @@ public struct MouseState : IInputStateTypeInfo
         [InputControl(name = "pointerId", layout = "Digital", format = "BIT", sizeInBits = 1, offset = InputStateBlock.AutomaticOffset)] // Will stay at 0.
         public ushort buttons;
 
-        // Not currently used, but still needed in this struct for padding,
-        // as il2cpp does not implement FieldOffset.
+        /// <summary>
+        /// The index of the display that was moused.
+        /// </summary>
+        [InputControl(name = "displayIndex", layout = "Integer", displayName = "Display Index")]
         [FieldOffset(26)]
-        ushort displayIndex;
+        public ushort displayIndex;
 
         /// <summary>
         /// Number of clicks performed in succession.
         /// </summary>
         /// <value>Successive click count.</value>
         /// <seealso cref="Mouse.clickCount"/>
-        [InputControl(layout = "Integer", displayName = "Click Count", synthetic = true)]
+        [InputControl(name = "clickCount", layout = "Integer", displayName = "Click Count", synthetic = true)]
         [FieldOffset(28)]
         public ushort clickCount;
 
@@ -286,6 +288,7 @@ protected override void FinishSetup()
             rightButton = GetChildControl<ButtonControl>("rightButton");
             forwardButton = GetChildControl<ButtonControl>("forwardButton");
             backButton = GetChildControl<ButtonControl>("backButton");
+            displayIndex = GetChildControl<IntegerControl>("displayIndex");
             clickCount = GetChildControl<IntegerControl>("clickCount");
             base.FinishSetup();
         }

Packages/com.unity.inputsystem/InputSystem/Devices/Mouse.cs

@@ -60,6 +60,9 @@ internal struct PointerState : IInputStateTypeInfo
         [InputControl(name = "press", displayName = "Press", layout = "Button", format = "BIT", bit = 0)]
         public ushort buttons;
 
+        [InputControl(name = "displayIndex", layout = "Integer", displayName = "Display Index")]
+        public ushort displayIndex;
+
         public FourCC format => kFormat;
     }
 }
@@ -180,6 +183,13 @@ public class Pointer : InputDevice, IInputStateCallbackReceiver
         /// </remarks>
         public ButtonControl press { get; protected set; }
 
+        /// <summary>
+        /// The index of the display the Pointer is currently on. This is useful for multiple screen setups.
+        /// This may not be supported on all platforms. When unsupported, this will always produce the index of the primary display i.e. zero.
+        /// <see href="https://docs.unity3d.com/ScriptReference/Display.html"/>
+        /// </summary>
+        public IntegerControl displayIndex { get; protected set; }
+
         /// <summary>
         /// The pointer that was added or used last by the user or <c>null</c> if there is no pointer
         /// device connected to the system.
@@ -210,6 +220,7 @@ protected override void FinishSetup()
             radius = GetChildControl<Vector2Control>("radius");
             pressure = GetChildControl<AxisControl>("pressure");
             press = GetChildControl<ButtonControl>("press");
+            displayIndex = GetChildControl<IntegerControl>("displayIndex");
 
             base.FinishSetup();
         }