👐All-in-one natural hand controller, pointer, and gaze interaction library for A-Frame
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README.md

Super Hands

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Effortlessly add natural, intuitive interactions with tracked controller, touch, or mouse input in A-Frame.

Demo Gif

Super Hans Can't Make a Fist

Introduction

The goal of super-hands is to make it easy to handle user input in Web VR by providing a high-level API that is consistent across all devices. Instead of dealing directly with controller button events, raycasters, and collision detection components, you setup your scene and components instead to respond to 'gestures' like hovering and grabbing.

The currently implemented gestures are:

  • Hover: Holding a controller in the collision space of an entity or pointing at an entity with a cursor or laser pointer
  • Grab: Pressing a button while hovering an entity, potentially also moving it
  • Stretch: Grabbing an entity with two hands and resizing
  • Drag-drop: Activating one entity and then gesturing to another entity to interact with it

How to use super-hands

The family of components in this library fall into two categories:

Core: The super-hands component itself does the work of gathering events from user input devices and collision detection components to interpret them into gestures that it communicates out to the targeted entities via custom events. This component is placed on the same entities as your tracked controllers and/or your cursor raycaster.

Reaction Components: The super-hands core component alone only communicates user intent via gesture events to the entities users want to interact with; reaction components enable the interactivity on those entities. This package includes components for common reactions, hoverable, clickable, grabbable, stretchable, draggable, and droppable, and it is also designed to be easily extended with your own custom reaction components.

Getting started

Browser

Install and use by directly by including the browser files:

<head>
  <title>Most Basic Super-Hands Example</title>
  <script src="https://aframe.io/releases/0.8.2/aframe.min.js"></script>
  <script src="https://cdn.rawgit.com/donmccurdy/aframe-extras/v4.1.2/dist/aframe-extras.min.js"></script>
  <script src="https://unpkg.com/super-hands@3.0.0/dist/super-hands.min.js"></script>
</head>

<body>
  <a-scene>
    <a-assets></a-assets>
    <a-entity>
      <a-camera></a-camera>
      <a-entity sphere-collider="objects: a-box" super-hands hand-controls="left"></a-entity>
      <a-entity sphere-collider="objects: a-box" super-hands hand-controls="right"></a-entity>
    </a-entity>
    <!-- hover & drag-drop won't have any obvious effect without some additional event handlers or components. See the examples page for more -->
    <a-box hoverable grabbable stretchable draggable dropppable color="blue" position="0 0 -1"></a-box>
  </a-scene>
</body>

npm

Install via npm:

npm install super-hands

Then require and use.

require('aframe');
require('super-hands');

Readme contents:

Examples

The examples page showcases a variety of configurations and use cases for super-hands.

Example Scene Description Target VR Devices MoCap preview
Hand controllers with physics Grab, stretch, and drag-drop cubes with simulated physical behavior in roomscale VR Vive, Rift, Windows MR Yes
Gaze and laser pointer controls without physics Showcase fallback controls used for simpler VR devices and fallback interactivity without physics simulation Desktop, mobile, cardboard, Gear VR, Daydream, Vive, Rift, Windows MR Yes
Custom button mapping Configuring schema properties to change button functions Vive, Rift, Windows MR No

News

v3.0.0

  • The 'Less is More' update. This package has scope has been narrowed to keep it maintainable, increase the frequency of updates, and allow for focus on implementing new gestures instead of peripheral components.
    • progressive-controls and a-locomotor removed from this repo. I understand progressive-controls was fairly popular, but is has a compatibility issue with the latest A-Frame which was holding up releases for the entire package. I intend to refactor it and release it in another library, but you can still use the last version by including its source file in your project.
  • Smarter raycasting support: chooses nearest intersected entity first, reordering stack as distances change (* if the raycaster in use updates intersection objects' distances)
  • Improved nested entity handling: only one component can react to each gesture event.
  • Improved stretching of complex physics bodies: all shapes, child entity shapes, and offsets are updated
  • Added support for 'worker' and other aframe-physics-system drivers in grabbable
  • v2.x deprecations removed: drag-droppable component and super-hands.colliderState property.

Previous news

Known Issues

  • Two-handed physics grabs don't feel great
    • Help wanted with configuring ideal constraints for this situation
  • too much recursion errors when using two raycasting controllers: When using raycasters, always set their objects property to prevent the raycasters from colliding with each other's lines.

Compatibility

With progressive-controls, super-hands can provide interactive controls for any device: desktop, mobile ("magic window"), cardboard viewer + button, Daydream, GearVR, Vive, and Rift + Touch.

super-hands dependency version compatibility:

super-hands Version A-Frame Version aframe-extras Version aframe-physics-system Version
^v3.0.0 >=v0.8.2 ^v4.1.2 ^v3.1.2
^v2.0.0 v0.6.x ^v3.11.4 ^v2.0.0

Core Component

super-hands component

The super-hands component is the core of the library. It communicates gesture events to entities based on user-input and entity collisions. The component is generally placed on the controller entities (or the camera for gaze interaction) and depends on a collision detection component (e.g. raycaster, aframe-extras sphere-collider, of aframe-physics-extras physics-collider) which needs to be placed on the same entity or a child entity of super-hands.

Component Schema

Property Description Default Value
colliderEvent Event that your chosen collider emits when identifying a new collision 'hit'
colliderEventProperty Name of property in event detail object which contains the collided entity 'el'
colliderEndEvent Event that your chosen collider emits when a collision ends 'hitEnd'
colliderEndEventProperty Name of property in event detail object which contains the un-collided entity 'el'
grabStartButtons Array of button event types that can initiate grab Button press, touch start, and mouse down events
grabEndButtons Array of button event types that can terminate grab Button release, touch end, and mouse up events
stretchStartButtons Array of button event types that can initiate stretch Button press, touch start, and mouse down events
stretchEndButtons Array of button event types that can terminate stretch Button release, touch end, and mouse up events
dragDropStartButtons Array of button event types that can initiate dragging/hovering Button press, touch start, and mouse down events
dragDropEndButtons Array of button event types that can execute drag-drop Button release, touch end, and mouse up events

Collider-related property defaults are set to work with sphere-collider. Default button events include specific events for vive-controls, hand-controls, oculus-touch-controls, daydream-controls, gearvr-controls, windows-motion-controls, oculus-go-controls, mouse, and touch.

Gesture Events

Events will be emitted by the entity being interacted with. The entity that super-hands is attached to is sent in the event detail as the property hand.

Type Description Target detail object
hover-start Collided with entity collided entity hand: super-hands entity
hover-end No longer collided with entity collided entity hand: super-hands entity
grab-start Button pressed while collided with entity and hand is empty collided entity hand: super-hands entity
grab-end Button released after grab-start collided entity hand: super-hands entity
stretch-start Both controllers have button pressed while collided with entity collided entity hand: super-hands entity, secondHand: second controller entity
stretch-end Release of button after stretch-start collided entity hand: super-hands entity
drag-start Drag-drop button pressed while collided with entity and hand is empty collided entity hand: super-hands entity
drag-end Drag-drop button released while dragging an entity dragged entity hand: super-hands entity
dragover-start Collision with entity while dragging another entity collided entity & held entity hand: super-hands entity, hovered: collided entity, carried: held entity
dragover-end No longer collided with entity from dragover-start collided entity & held entity hand: super-hands entity, hovered: collided entity, carried: held entity
drag-drop Button released while holding an entity and collided with another collided entity & held entity hand: super-hands entity, dropped: carried entity, on (carried entity only): receiving entity

Notes:

  • References to buttons being "released" and "pressed" are dependent on the schema settings.
  • Only one entity at a time will be targeted for each event type, even if multiple overlapping collision zones exist. super-hands tracks a LIFO stack of collided entities and a nearest-first queue of raycasted Entities to determine which will be affected.
  • drag-drop: For the receiving entity, on entry in the detail is null. If needed, use event.target instead.
  • For events triggered by buttons, the triggering button event is passed along in detail.buttonEvent
  • When entities are nested, gesture events will bubble to the closest parent with a related reaction component. This makes it easy to make specific hotspots on larger objects by making the child collidable but placing the reaction component on the parent (e.g., a door with the handle as a collidable child and a grabable parent door so the whole door moves only when the handle is grabbed). To prevent a gesture from bubbling, trap it on the child by giving it reaction components or listening-for and cancelling the gesture events (see Gesture acceptance and rejection)

Global Event Handler Integration

In addition to the A-Frame style gesture events, super-hands also causes standard HTML events analogous to VR interactions to be emitted by the target entities. This allows the use of these common Global Event Handler properties on entities to add reaction directly in the HTML. View the related example to see this in use.

entity HTML attribute conditions event.relatedTarget
onmouseover hovering in an entity's collision zone super-hands entity
onmouseout leaving an entity's collision zone super-hands entity
onmousedown grab started while collided with entity super-hands entity
onmouseup grab ended while collided with entity controller entity
onclick grab started and then ended while collided with entity controller entity
ondragstart drag-drop started while collided with entity controller entity
ondragend drag-drop started while collided with entity controller entity
ondragenter hovering in an entity's collision zone while drag-dropping another entity the other entity*
ondragleave leaving an entity's collision zone while drag-dropping another entity the other entity*
ondrop drag-drop ended while holding an entity over a target the other entity*

The event passed to the handler will be a MouseEvent. At present the only property implemented is relatedTarget, which is set as listed in the table. Drag-dropping events will be dispatched on both the entity being dragged and the drop target, and the relatedTarget property for each will point to the other entity in the interaction.

Reaction Components

Add these components to entities in your scene to make them react to super-hands gestures.

hoverable component

Used to indicate when the controller is within range to interact with an entity by adding the 'hovered' state.

States

Name Description
hovered Added to entity while it is collided with the controller

grabbable component

Makes and entity move along with the controller's movement and rotation while it is grabbed. grabbable works with up-close grabbing (6DOF controllers like Vive and Oculus Touch with hand-controls and sphere-collider) and with pointing at a distance (3DOF controllers like GearVR and Daydream with laser-controls).

This works best with aframe-physics-system to manage grabbed entity movement including position and rotation, but it will fallback to manual position updates if physics is not available or is disabled with usePhysics = never.

Allows for multiple hands to register a grab on an entity. In a non-physics setup, this has no effect other than allowing smooth passing of entities between hands. With physics enabled, additional grabbing hands register their own physics constraints to allow for two-handed wielding of entities. Limit or disable this by setting the maxGrabbers schema property.

Component Schema

Property Description Default Value
startButtons Which button events to accept to start grab []
endButtons Which button events to accept to end grab []
usePhysics Whether to use physics system constraints to handle movement, 'ifavailable', 'only', or 'never' 'ifavailable'
maxGrabbers Limit number of hands that can grab entity simultaneously NaN (no limit)
invert Reverse direction of entity movement compared to grabbing hand false
suppressY Allow movement only in the horizontal plane false

The default for startButtons and endButtons is to accept any button recognized by super-hands grabStartButtons and grabDropEndButtons.

States

Name Description
grabbed Added to entity while it is being carried

clickable component

An alternative version of grabbable that registers that a button was pressed, but does not move the entity. Do not use clickable and grabbable on the same entity (just use grabbable and watch the "grabbed" state instead of "clicked")

Component Schema

Property Description Default Value
startButtons Which button events to accept to start grab []
endButtons Which button events to accept to end grab []

The default for startButtons and endButtons is to accept any button recognized by super-hands grabStartButtons and grabDropEndButtons.

States

Name Description
clicked Added to entity while a button is held down

stretchable component

Makes and entity rescale while grabbed by both controllers as they are moved closer together or further apart.

Component Schema

Property Description Default Value
startButtons Which button events to accept to start stretch []
endButtons Which button events to accept to end stretch []
usePhysics Whether to update physics body shapes with scale changes, 'ifavailable' or 'never' 'ifavailable'
invert Reverse the direction of scaling in relation to controller movement false
phyicsUpdateRate Milliseconds between each update to the physics bodies of a stretched entity 100

The default for startButtons and endButtons is to accept any button recognized by super-hands stretchStartButtons and stretchEndButtons.

There is no CANNON API method for updating physics body scale, but stretchable will manually rescale shapes and offsets for stretched entity body and all descendent entity bodies. This update is throttled and will occur no more than once every physicsUpdateRate milliseconds to improve performance. Set this to a smaller number to increase the physics simulation fidelity. Currently rescalable shapes are: box and sphere. At present, this rescaling is only possible on when using the 'local' physics driver. If using another driver, setting usePhysics: never will avoid errors but also cause loss of sync between stretched entities' appearance and behavior.

States

Name Description
stretched Added to entity while it is grabbed with two hands

draggable component

draggable makes an entity able to participate in a drag and drop gesture with a droppable entity. This does not move an entity (also add grabbable for that functionality), but instead tracks whether a gesture has been made that involves pressing a button down with the controller pointed at this entity, and then moving the controller to point at another entity with the droppable component before releasing.

For interactivity, use the global event handler integration, the event-set from kframe with the drag-drop event, or create your own component.

Component Schema

Property Description Default Value
startButtons Which button events to accept to start drag []
endButtons Which button events to accept to end drag []

The default for startButtons and endButtons is to accept any button recognized by super-hands dragDropStartButtons and dragDropEndButtons.

States

Name Description
dragged Added to entity from button press until button release

droppable component

The droppable component sets an entity up as a target to respond to dragged entities. Optionally, it can be configured to accept only specific entities and to emit custom events on acceptance or rejection.

Combining the accepts and acceptEvent property of droppable with event-set from kframe, you can create rich interactivity without any additional JavaScript or custom components.

Component Schema

Property Description Default Value
accepts CSS query string to specify which entities to respond to '' (accept all entities)
autoUpdate Should it watch for newly added entities that match accepts? May impact performance. true
acceptEvent String. Name of custom event to emit upon successful drag-drop interaction '' (don't emit event)
rejectEvent String. Name of custom event to emit upon rejecting attempted drag-drop that contained an entity not included in accepts '' (don't emit event)

Accept and reject events will contain the dragged entity that was accepted/rejected in the el property of detail.

States

Name Description
dragover Added to the entity while a controller is holding an acceptable draggable entity in the collision space of the droppable entity

Customizing interactivity

Gesture and Response Concept

Separation of Gesture and Response API

Separating the reaction to be the responsibility of the entity affected allows for extensibility. In response to a grab, you may want some entities to lock to the controller and move, others to rotate around a fixed point, and others still to spawn a new entity but remain unchanged. With this API schema, these options can be handled by adding or creating different reaction components to the entities in your scene, and super-hands can work with all of them.

Interactivity

There are two pathways to adding additional interactivity.

  1. A-Frame style: Each component's API documentation describes the A-Frame custom events and states it uses. These can be used on conjunction with other community A-Frame components or by creating custom components for your project that register event listeners and react accordingly.
  2. HTML style: The super-hands component also integrates with the Global Event Handlers Web API to trigger standard mouse events analogous to the VR interactions that can easily be handled through properties like onclick.

Gesture acceptance and rejection

Entities which are the target of gestures communicate back to super-hands that they have accepted the attempted interaction by 'cancelling' the gesture event (i.e. calling .preventDefault() on the event). This allows super-hands to penetrate overlapping and nested entities in order to find the desired target and for reaction components to be discriminating about their conditions for interaction (e.g., droppable). All of the provided reaction components handle this signaling automatically, but, if you create your own reaction components, it is important to cancel the events when responding to a gesture so that super-hands knows the gesture has been accepted and stops searching for a viable target.