Composite Bindings

You might want to have several controls act in unison to mimic a different type of control. The most common example of this is using the W, A, S, and D keys on the keyboard to form a 2D vector control equivalent to mouse deltas or gamepad sticks. Another example is to use two keys to form a 1D axis equivalent to a mouse scroll axis.

This is difficult to implement with normal bindings. You can bind a ButtonControl to an action expecting a Vector2, but doing so results in an exception at runtime when the Input System tries to read a Vector2 from a control that can deliver only a float.

Composite bindings (that is, bindings that are made up of other bindings) solve this problem. Composites themselves don't bind directly to controls; instead, they source values from other bindings that do, and then synthesize input on the fly from those values.

To create a composite binding, select the appropriate composite type for your action while adding a binding in the actions editor. The types of composite bindings available are as follows:

Types of composite bindings

The Add binding (+) menu contains the following options.

Value	Description
Add Binding	Adds a simple binding and is not a composite
Add Positive/Negative Binding	Adds a 1D axis composite binding made of two button sub-bindings, one that pulls a 1D axis in its negative direction, and another that pulls it in its positive direction. It is implemented in the AxisComposite class. The output is a float. If Controls from both the positive and the negative side are actuated, then the resulting value of the axis Composite depends on the Which side wins binding property.
Add Up/Down/Left/Right Composite	Adds a 2D axis composite binding that represents a 4-way button control like the D-pad on gamepads. Each button sub-binding represents a cardinal direction, is most useful for representing up-down-left-right controls, such as WASD keyboard input. It is implemented in the Vector2Composite class. The output is a Vector2. This composite's mode property allows you to choose whether the inputs should be treated as digital or analog controls.
Add Up/Down/Left/Right/Forward/Backward Composite	Adds a 3D composite binding that represents a 6-way button where two combinations each control one axis of a 3D vector. Implemented in the Vector3Composite class. The output is a Vector3. This composite's mode property allows you to choose whether the inputs should be treated as digital or analog controls.
Add Binding With One Modifier	Adds a composite with two sub-bindings, named Binding and Modifier, which requires the user to hold down the modifier button in addition to another control from which the actual value of the binding is determined. This can be used, for example, for bindings such as "SHIFT+1". Implemented in the OneModifierComposite class. The buttons can be on any Device, and can be toggle buttons or full-range buttons such as gamepad triggers. The output is a value of the same type as the control bound to the sub-binding named Binding.
Add Binding With Two Modifiers	Adds a composite with three sub-bindings, named Binding, Modifier 1 and Modifier 2, which requires the user to hold down two modifier buttons in addition to another control from which the actual value of the binding is determined. This can be used, for example, for bindings such as "SHIFT+CTRL+1". Implemented in the TwoModifiersComposite class. The buttons can be on any Device, and can be toggle buttons or full-range buttons such as gamepad triggers. The output is a value of the same type as the control bound to the sub-binding named Binding.

Note

You can also create custom composite bindings from code