DOCS: How to use processors (#2171)

Co-authored-by: lilisha-unity <[email protected]>
Co-authored-by: João Freire <[email protected]>

Author: 3 people

Packages/com.unity.inputsystem/Documentation~/ActionBindings.md

@@ -48,7 +48,7 @@ Each Binding has the following properties:
 |[`action`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_action)|The name or ID of the Action that the Binding should trigger. Note that this can be null or empty (for instance, for  [composites](#composite-bindings)). Not case-sensitive.<br><br>Example: `"fire"`|
 |[`groups`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_groups)|A semicolon-separated list of Binding groups that the Binding belongs to. Can be null or empty. Binding groups can be anything, but are mostly used for [Control Schemes](#control-schemes). Not case-sensitive.<br><br>Example: `"Keyboard&Mouse;Gamepad"`|
 |[`interactions`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_interactions)|A semicolon-separated list of [Interactions](Interactions.md) to apply to input on this Binding. Note that Unity appends Interactions applied to the [Action](Actions.md) itself (if any) to this list. Not case-sensitive.<br><br>Example: `"slowTap;hold(duration=0.75)"`|
-|[`processors`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_processors)|A semicolon-separated list of [Processors](Processors.md) to apply to input on this Binding. Note that Unity appends Processors applied to the [Action](Actions.md) itself (if any) to this list. Not case-sensitive.<br><br>Processors on Bindings apply in addition to Processors on Controls that are providing values. For example, if you put a `stickDeadzone` Processor on a Binding and then bind it to `<Gamepad>/leftStick`, you get deadzones applied twice: once from the deadzone Processor sitting on the `leftStick` Control, and once from the Binding.<br><br>Example: `"invert;axisDeadzone(min=0.1,max=0.95)"`|
+|[`processors`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_processors)|A semicolon-separated list of [Processors](UsingProcessors.md) to apply to input on this Binding. Note that Unity appends Processors applied to the [Action](Actions.md) itself (if any) to this list. Not case-sensitive.<br><br>Processors on Bindings apply in addition to Processors on Controls that are providing values. For example, if you put a `stickDeadzone` Processor on a Binding and then bind it to `<Gamepad>/leftStick`, you get deadzones applied twice: once from the deadzone Processor sitting on the `leftStick` Control, and once from the Binding.<br><br>Example: `"invert;axisDeadzone(min=0.1,max=0.95)"`|
 |[`id`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_id)|Unique ID of the Binding. You can use it to identify the Binding when storing Binding overrides in user settings, for example.|
 |[`name`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_name)|Optional name of the Binding. Identifies part names inside [Composites](#composite-bindings).<br><br>Example: `"Positive"`|
 |[`isComposite`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_isComposite)|Whether the Binding acts as a [Composite](#composite-bindings).|
@@ -87,7 +87,7 @@ myAction.AddCompositeBinding("Axis")
     .With("Negative", "<Gamepad>/leftShoulder");
 ```
 
-Composites can have parameters, just like [Interactions](Interactions.md) and [Processors](Processors.md).
+Composites can have parameters, just like [Interactions](Interactions.md) and [Processors](UsingProcessors.md).
 
 ```CSharp
 myAction.AddCompositeBinding("Axis(whichSideWins=1)");
@@ -466,10 +466,11 @@ You can override aspects of any Binding at run-time non-destructively. Specific
 |Property|Override|Description|
 |--------|--------|-----------|
 |[`path`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_path)|[`overridePath`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_overridePath)|Replaces the [Control path](./Controls.md#control-paths) that determines which Control(s) are referenced in the binding. If [`overridePath`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_overridePath) is set to an empty string, the binding is effectively disabled.<br><br>Example: `"<Gamepad>/leftStick"`|
-|[`processors`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_processors)|[`overrideProcessors`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_overrideProcessors)|Replaces the [processors](./Processors.md) applied to the binding.<br><br>Example: `"invert,normalize(min=0,max=10)"`|
+|[`processors`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_processors)|[`overrideProcessors`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_overrideProcessors)|Replaces the [processors](./UsingProcessors.md) applied to the binding.<br><br>Example: `"invert,normalize(min=0,max=10)"`|
 |[`interactions`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_interactions)|[`overrideInteractions`](../api/UnityEngine.InputSystem.InputBinding.html#UnityEngine_InputSystem_InputBinding_overrideInteractions)|Replaces the [interactions](./Interactions.md) applied to the binding.<br><br>Example: `"tap(duration=0.5)"`|
 
->NOTE: The `override` property values will not be saved along with the Actions (for example, when calling [`InputActionAsset.ToJson()`](../api/UnityEngine.InputSystem.InputActionAsset.html#UnityEngine_InputSystem_InputActionAsset_ToJson)). See [Saving and loading rebinds](#saving-and-loading-rebinds) for details about how to persist user rebinds.
+> [!NOTE]
+> The `override` property values are not saved with the Actions, for example, when calling [`InputActionAsset.ToJson()`](../api/UnityEngine.InputSystem.InputActionAsset.html#UnityEngine_InputSystem_InputActionAsset_ToJson)). Refer to [Saving and loading rebinds](#saving-and-loading-rebinds) for details about how to persist user rebinds.
 
 To set the various `override` properties, you can use the [`ApplyBindingOverride`](../api/UnityEngine.InputSystem.InputActionRebindingExtensions.html#UnityEngine_InputSystem_InputActionRebindingExtensions_ApplyBindingOverride_UnityEngine_InputSystem_InputAction_UnityEngine_InputSystem_InputBinding_) APIs.
 
@@ -527,7 +528,7 @@ playerInput.actions["move"]
 
 ### Setting parameters
 
-A Binding may, either through itself or through its associated Action, lead to [processor](Processors.md), [interaction](Interactions.md), and/or [composite](#composite-bindings) objects being created. These objects can have parameters you can configure through in the [Binding properties view](ActionsEditor.md#bindings) of the Action editor or through the API. This configuration will give parameters their default value.
+A Binding may, either through itself or through its associated Action, lead to [processor](UsingProcessors.md), [interaction](Interactions.md), and/or [composite](#composite-bindings) objects being created. These objects can have parameters you can configure through in the [Binding properties view](ActionsEditor.md#bindings) of the Action editor or through the API. This configuration will give parameters their default value.
 
 ```CSharp
 // Create an action with a "Hold" interaction on it.

Packages/com.unity.inputsystem/Documentation~/Architecture.md

@@ -31,4 +31,4 @@ The high-level Input System code interprets the data in a Device's state buffers
 
 Based on the information in the layouts, the Input System then creates [Control](Controls.md) representations for each of the Device's controls, which let you read the state of each individual Control in a Device.
 
-As part of the high-level system, you can also build another abstraction layer to map Input Controls to your application mechanics. Use [Actions](Actions.md) to [bind](ActionBindings.md) one or more Controls to an input in your application. The Input System then monitors these Controls for state changes, and notifies your game logic using [callbacks](RespondingToActions.md#responding-to-actions-using-callbacks). You can also specify more complex behaviors for your Actions using [Processors](Processors.md) (which perform processing on the input data before sending it to you) and [Interactions](Interactions.md) (which let you specify patterns of input on a Control to listen to, such as multi-taps).
+As part of the high-level system, you can also build another abstraction layer to map Input Controls to your application mechanics. Use [Actions](Actions.md) to [bind](ActionBindings.md) one or more Controls to an input in your application. The Input System then monitors these Controls for state changes, and notifies your game logic using [callbacks](RespondingToActions.md#responding-to-actions-using-callbacks). You can also specify more complex behaviors for your Actions using [Processors](UsingProcessors.md) (which perform processing on the input data before sending it to you) and [Interactions](Interactions.md) (which let you specify patterns of input on a Control to listen to, such as multi-taps).

Packages/com.unity.inputsystem/Documentation~/Controls.md

@@ -121,7 +121,7 @@ Gamepad.current.leftStick.x.ReadValue();
 
 Each type of Control has a specific type of values that it returns, regardless of how many different types of formats it supports for its state. You can access this value type through the [`InputControl.valueType`](../api/UnityEngine.InputSystem.InputControl.html#UnityEngine_InputSystem_InputControl_valueType) property.
 
-Reading a value from a Control might apply one or more value Processors. See documentation on [Processors](Processors.md) for more information.
+Reading a value from a Control might apply one or more value Processors. See documentation on [Processors](UsingProcessors.md) for more information.
 
 [//]: # (#### Default State - TODO)
 
@@ -243,7 +243,7 @@ Use [`InputControl<T>.value`](../api/UnityEngine.InputSystem.InputControl-1.html
 
 ### Control Value Caching
 
-When the `'USE_READ_VALUE_CACHING'` internal feature flag is set, the Input System will switch to an optimized path for reading control values. This path efficiently marks controls as 'stale' when they have been actuated. Subsequent calls to [`InputControl<T>.ReadValue`](../api/UnityEngine.InputSystem.InputControl-1.html#UnityEngine_InputSystem_InputControl_1_ReadValue) will only apply control processing when there have been changes to that control or in case of control processing. Control processing in this case can mean any hard-coded processing that might exist on the control, such as with [`AxisControl`](../api/UnityEngine.InputSystem.Controls.AxisControl.html) which has built-in inversion, normalisation, scaling etc, or any processors that have been applied to the controls' [processor stack](Processors.md#processors-on-controls).
+When the `'USE_READ_VALUE_CACHING'` internal feature flag is set, the Input System will switch to an optimized path for reading control values. This path efficiently marks controls as 'stale' when they have been actuated. Subsequent calls to [`InputControl<T>.ReadValue`](../api/UnityEngine.InputSystem.InputControl-1.html#UnityEngine_InputSystem_InputControl_1_ReadValue) will only apply control processing when there have been changes to that control or in case of control processing. Control processing in this case can mean any hard-coded processing that might exist on the control, such as with [`AxisControl`](../api/UnityEngine.InputSystem.Controls.AxisControl.html) which has built-in inversion, normalisation, scaling etc, or any processors that have been applied to the controls' [processor stack](HowToApplyProcessors.md#processors-on-controls).
 > Note: Performance improvements **are currently not guaranteed** for all use cases. Even though this performance path marks controls as "stale" in an efficient way, it still has an overhead which can degrade performance in some cases.
 
 A positive performance impact has been seen when:

Packages/com.unity.inputsystem/Documentation~/Gamepad.md

@@ -67,7 +67,7 @@ Gamepad.current["Triangle"]
 
 Deadzones prevent accidental input due to slight variations in where gamepad sticks come to rest at their centre point. They allow a certain small inner area where the input is considered to be zero even if it is slightly off from the zero position.
 
-To add a deadzone to gamepad stick, put a [stick deadzone Processor](Processors.md#stick-deadzone) on the sticks, like this:
+To add a deadzone to gamepad stick, put a [stick deadzone Processor](ProcessorTypes.md#stick-deadzone) on the sticks, like this:
 
 ```JSON
      {

Packages/com.unity.inputsystem/Documentation~/HowToApplyProcessors.md

@@ -0,0 +1,84 @@
+---
+uid: input-system-processors
+---
+# Apply Processors
+
+The following are the three different ways of applying Processors to input events. For more information on the general usage of Processors, refer to [Using Processors](UsingProcessors.md).
+
+* [Processors on Bindings](#processors-on-bindings)
+* [Processors on Actions](#processors-on-actions)
+* [Processors on Controls](#processors-on-controls)
+
+## Processors on Bindings
+
+When you create Bindings for your [actions](Actions.md), you can choose to add Processors to the Bindings. These process the values from the controls they bind to, before the system applies them to the Action value. For instance, you might want to invert the `Vector2` values from the controls along the Y-axis before passing these values to the Action that drives the input logic for your application. To do this, you can add an [Invert Vector2](ProcessorTypes.md#invert-vector-2) Processor to your Binding.
+
+If you're using Actions defined in the [Input Actions Editor](ActionsEditor.md), or in an [Action Asset](ActionAssets.md), you can add any Processor to your Bindings in the Input Action editor:
+
+1. Select the Binding you want to add Processors to so that the Binding Properties panel shows up on the right side.
+2. Select the **Add (+)** icon on the __Processors__ foldout to open a list of all available Processors that match your control type.
+3. Choose a Processor type to add a Processor instance of that type. The Processor now appears under the __Processors__ foldout.
+4. (Optional) If the Processor has any parameters, you can edit them in the __Processors__ foldout.
+
+![Binding Processors](Images/BindingProcessors.png)
+
+To remove a Processor, click the Remove (-) icon next to it. You can also use the up and down arrows to change the order of Processors. This affects the order in which the system processes values.
+
+If you create your Bindings in code, you can add Processors like this:
+
+```CSharp
+var action = new InputAction();
+action.AddBinding("<Gamepad>/leftStick")
+    .WithProcessor("invertVector2(invertX=false)");
+```
+
+## Processors on Actions
+
+Processors on Actions work in the same way as Processors on Bindings, but they affect all controls bound to an Action, rather than just the controls from a specific Binding. If there are Processors on both the Binding and the Action, the system processes the ones from the Binding first.
+
+You can add and edit Processors on Actions in the [Input Actions Editor](ActionsEditor.md), or in an  [Action Asset](ActionAssets.md) the [same way](#processors-on-bindings) as you would for Bindings: select an Action to edit, then add one or more Processors in the right window pane.
+
+If you create your Actions in code, you can add Processors like this:
+
+```CSharp
+var action = new InputAction(processors: "invertVector2(invertX=false)");
+```
+
+## Processors on Controls
+
+You can have any number of Processors directly on an [`InputControl`](../api/UnityEngine.InputSystem.InputControl.html), which then process the values read from the Control. Whenever you call [`ReadValue`](../api/UnityEngine.InputSystem.InputControl-1.html#UnityEngine_InputSystem_InputControl_1_ReadValue) on a Control, all Processors on that Control process the value before it gets returned to you. You can use [`ReadUnprocessedValue`](../api/UnityEngine.InputSystem.InputControl-1.html#UnityEngine_InputSystem_InputControl_1_ReadUnprocessedValue) on a Control to bypass the Processors.
+
+The Input System adds Processors to a Control during device creation, if they're specified in the Control's [layout](Layouts.md). You can't add Processors to existing Controls after they've been created, so you can only add Processors to Controls when you're [creating custom devices](Devices.md#creating-custom-devices). The devices that the Input System supports out of the box already have some useful Processors added on their Controls. For instance, sticks on gamepads have a [Stick Deadzone](ProcessorTypes.md#stick-deadzone) Processor.
+
+If you're using a layout generated by the Input System from a [state struct](Devices.md#step-1-the-state-struct) using [`InputControlAttributes`](../api/UnityEngine.InputSystem.Layouts.InputControlAttribute.html), you can specify the Processors you want to use via the [`processors`](../api/UnityEngine.InputSystem.Layouts.InputControlAttribute.html#UnityEngine_InputSystem_Layouts_InputControlAttribute_processors) property of the attribute, like this:
+
+```CSharp
+public struct MyDeviceState : IInputStateTypeInfo
+{
+    public FourCC format => return new FourCC('M', 'Y', 'D', 'V');
+
+    // Add an axis deadzone to the Control to ignore values
+    // smaller then 0.2, as our Control does not have a stable
+    // resting position.
+    [InputControl(layout = "Axis", processors = "AxisDeadzone(min=0.2)")]
+    public short axis;
+}
+```
+
+If you [create a layout from JSON](Layouts.md#layout-from-json), you can specify Processors on your Controls like this:
+
+```CSharp
+{
+    "name" : "MyDevice",
+    "extend" : "Gamepad", // Or some other thing
+    "controls" : [
+        {
+            "name" : "axis",
+            "layout" : "Axis",
+            "offset" : 4,
+            "format" : "FLT",
+            "processors" : "AxisDeadzone(min=0.2)"
+        }
+    ]
+}
+```