Add Starfish to the toolbox

Description

Add the Starfish as a new tool to the package. It is an interaction technique (more precisely an interactor) that help the user selecting a target by graphically constraining the selector to an implicit surface defined with ray marching. It consists of a set of targets that are selected given certain parameters (proximity to the user, maximum number of target...). This selected targets are then used as tips of branches that are bounded together to form a shape ressembling a starfish defined by an implicit surface.

While holding the button assigned to Starfish, the implicit surface is shown and a displayed selector that follows the true (free) selector is graphically constrained to this implicit surface. Once the displayed selector collides with one of the Starfish target, the user can choose to interact with this target by releasing the button assigned to Starfish. This action triggers a series of events associated to the target and defined by the user.

The Starfish origin always appear in front of the assigned controller with a distance defined by the user.

The tool needs the XRI Interaction Toolkit, as well as the Unity Input System in order to work.

The tool contains materials for the Unity Standard Render Pipeline and the URP.

Testing

The Starfish was tested both with Unity Play Mode and after a build. It is also fully compatible with the Workbench and the Meta Quest 2 and 3. The scenario tested on the Meta Quest was to choose between multiple targets, some of them were not selectable because of the defined Starfish parameters. Each target was triggering a different series of events. The scenario tested on the Workbench was the same.

Here is an example of the Starfish in action :

Starfish Testing