wmurphyrdA-Frame Physics Extras
Add-on components for the
aframe-physics-system
to add additional collision detection and behavior control options.
physics-collider
A collision detection component powered by the physics simulation with low overhead and precise collision zones. This is intended to be placed on tracked controller entities to monitor collisions and report them to a gesture interpretation component such as super-hands.
API
| Property | Description | Default Value |
|---|---|---|
| ignoreSleep | Wake sleeping bodies on collision? | true |
physics-collider can also report collisions with static bodies when
ignoreSleep is true. This can be useful to create collision detection zones
for interactivity with things other than dynamic bodies.
Events
| Type | Description | Detail object |
|---|---|---|
| collisions | Emitted each tick if there are changes to the collision list | els: array of new collisions. cleardEls: array of collisions which have ended. |
collision-filter
Control which physics bodies interact with each other or ignore each other.
This can improve physics system performance by skipping unnecessary
collision checks. It also controls which entities can be interacted with
via physics-collider
API
| Property | Description | Default Value |
|---|---|---|
| group | Collision group this entity belongs to | 'default' |
| collidesWith | Array of collision groups this entity will interact with | 'default' |
| collisionForces | Should other bodies react to collisions with this body? | true |
collisionForces controls whether collisions with this body generate any
forces. Setting this to false allows for collisions to be registered and
tracked without causing any corresponding movement. This is useful for
your controller entities with physics-collider because it is difficult
to pick things up if they are constantly bumped away when your hand gets close.
This can be toggles through events with a controller button press
if you want to be able to bump other
objects sometimes and reach inside to pick them up other times.
There is an example of this on the examples page.
Turning off collisionForces can also be useful
for setting static bodies as collision zones to detect the presence
of other entities without disturbing them.
sleepy
Make entities settle down and be still after physics collisions. Very useful for zero-gravity user interfaces to keep entities from floating away. Also can help performance as sleeping bodies are handled efficiently by the physics simulation.
API
| Property | Description | Default Value |
|---|---|---|
| allowSleep | Enable sleep for this body | true |
| speedLimit | Maximum velocity for sleep to initiate | 0.25 |
| delay | Time interval to check for sleep initiation (seconds) | 0.25 |
| linearDamping | Deceleration of liner forces on the entity (0 to 1) | 0.99 |
| angularDamping | Deceleration of angular forces on the entity (0 to 1) | 0.99 |
| holdState | Entity state in which sleep is suspended | 'grabbed' |
Adding sleepy to any body will activate sleep for the entire physics system
and will affect other bodies because the cannon defaults for all bodies
are to allow sleep with a speed limit of 0.1 and delay of 1 second. You can
add sleepy="allowSleep: false; linearDamping: 0.01; angularDamping: 0.01"
to restore default behavior to an entity if needed.
Sleeping bodies will ignore static bodies
(hence why physics-collider has an ignoreSleep setting) until they
are woken by a dynamic or kinematic body. Sleep will break constraints,
so the holdState property allows you to suspend sleep during interactions
such as grabbing/carrying the entity.
Examples
View the examples page to see aframe-physics-extras in action.
Installation
Browser
Install and use by directly including the browser files:
<!DOCTYPE html>
<html>
<head>
<title>My A-Frame Scene</title>
<script src="https://aframe.io/releases/0.7.0/aframe.min.js"></script>
<script src="//cdn.rawgit.com/donmccurdy/aframe-physics-system/v2.1.0/dist/aframe-physics-system.min.js"></script>
<script src="https://unpkg.com/super-hands@2.0.2/dist/super-hands.min.js"></script>
<script src="https://unpkg.com/aframe-physics-extras@0.1.2/dist/aframe-physics-extras.min.js"></script>
</head>
<body>
<a-scene physics="gravity: 0">
<a-assets>
<a-mixin id="controller"
physics-collider
static-body="shape: sphere; sphereRadius: 0.02"
super-hands="colliderEvent: collisions;
colliderEventProperty: els;
colliderEndEvent: collisions;
colliderEndEventProperty: clearedEls"
collision-filter = "group: hands;
collidesWith: red, blue;
collisionForces: false">
</a-mixin>
<a-mixin id="cube" dynamic-body grabbable
geometry="primitive: box; width: 0.5; height: 0.5; depth: 0.5">
</a-mixin>
</a-assets>
<!-- settings pulled in from controller mixin above -->
<a-entity hand-controls="left" mixin="controller"></a-entity>
<a-entity hand-controls="right" mixin="controller"></a-entity>
<!-- can be picked up because it collides with the hands group and vice versa -->
<a-entity mixin="cube" position="0 1.6 -1" material="color: red" sleepy
collision-filter="group: red; collidesWith: default, hands, blue">
</a-entity>
<!-- even though the controller has blue in its collidesWith list,
since the blue cube doesn't also have hands in its list, you cannot
pick it up, but you can knock it around with the red cube -->
<a-entity mixin="cube" position="0 1 -1" material="color: blue" sleepy
collision-filter="group: blue; collidesWith: default, red">
</a-entity>
<!-- floor entity. 'default' collision group so cubes will bounce off -->
<a-box width="20" depth="20" height="0.1" static-body
collision-filter="collidesWith: red, blue"
material="color: #7BC8A4"></a-box>
</a-scene>
</body>
</html>npm
Install via npm:
npm installThen require and use.
require('aframe');
require('aframe-physics-system')
require('aframe-physics-extras');