UInputBehavior

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An InputBehavior implements a state machine for a user interaction. The InputRouter maintains a set of active Behaviors, and when new input events occur, it calls WantsCapture() to check if the Behavior would like to begin capturing the applicable input event stream (eg for a mouse, one or both VR controllers, etc). If the Behavior acquires capture, UpdateCapture() is called until the Behavior indicates that it wants to release the device, or until the InputRouter force-terminates the capture via ForceEndCapture().

For example, something like ButtonSetClickBehavior might work as follows:

• in WantsCapture(), if left mouse is pressed and a button is under cursor, return Begin, otherwise Ignore
• in BeginCapture(), save identifier for button that is under cursor
• in UpdateCapture()
• if left mouse is down, return Continue
• if left mouse is released:
• if saved button is still under cursor, call button.Clicked()
• return End

Written sufficiently generically, the above Behavior doesn't need to know about buttons, it just needs to know how to hit-test the clickable object(s). Similarly separate Behaviors can be written for mouse, VR, touch, gamepad, etc.

Implementing interactions in this way allows the input handling to be separated from functionality.

Syntax

UCLASS (Transient, MinimalAPI)  
class UInputBehavior : public UObject  
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UCLASS (Transient, MinimalAPI) class UInputBehavior : public UObject

Inheritance Hierarchy

• UObjectBase → UObjectBaseUtility → UObject → UInputBehavior

Derived Classes

UInputBehavior derived class hierarchy

• UAnyButtonInputBehavior
• UKeyAsModifierInputBehavior
• UKeyInputBehavior
• UMouseHoverBehavior
• USingleKeyCaptureBehavior
• UTwoAxisPropertyEditInputBehavior

Constructors

Functions

Public