VR4Medical/ICI/Library/PackageCache/com.unity.xr.interaction.toolkit@76258c00be3e/Documentation~/locomotion-providers.md

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xri-locomotion-providers

Locomotion Providers overview

Locomotion Providers implement different types of locomotion.

The toolkit supplies multiple Locomotion Providers, which implement the LocomotionProvider abstract class.

Locomotion Providers contain a reference to the Locomotion Mediator component, which gives the Locomotion Provider access to the XR Body Transformer component. If the Locomotion Mediator is null, the Locomotion Provider will attempt to find one.

Once the Locomotion Provider has calculated the transformation, the provider is ready to begin locomotion.

Use TryPrepareLocomotion to communicate with the Locomotion Mediator and attempt to transition the provider into the LocomotionState.Preparing state. If this succeeds, then the provider can enter the LocomotionState.Moving by waiting for the mediator's next Update in which the provider's canStartMoving is true. This will provide the Locomotion Provider with access to the XR Body Transformer.

Alternatively, use TryStartLocomotionImmediately to attempt to transition the provider into the LocomotionState.Moving state and to gain access to the required XR Body Transformer immediately. Note, TryStartLocomotionImmediately will bypass LocomotionState.Preparing state and the LocomotionProvider.canStartMoving check.

When the Locomotion Provider transitions into the LocomotionState.Moving state, the provider can begin trying to queue the desired transformation with the XR Body Transformer. See the Locomotion overview XR Body Transformer section for a more thorough explanation of the queueing process.

Upon completion of the locomotion, use TryEndLocomotion to have the Locomotion Mediator attempt to transition the Locomotion Provider to the LocomotionState.Ended. The Locomotion Mediator will call LocomotionProvider.OnLocomotionStateChanging if successful.

The LocomotionProvider abstract class also provides public events:

• locomotionStarted is invoked once the provider successfully enters the LocomotionState.Moving state.
• locomotionEnded is invoked once the provider successfully enters the LocomotionState.Ended state and all of the provider's queued transformations have been applied, if any.
• locomotionStateChanged is invoked immediately upon the provider transitioning LocomotionState.
• beforeStepLocomotion is invoked just before the provider's queued transformations are applied.
• afterStepLocomotion is invoked just after the provider's queued transformations are applied.