aframe-typescript-redux

0.0.16 • Public • Published

A-Frame + Redux

At Olio Apps, we are applying tools and practices from our experience creating React and React Native applications to engineering VR software for the web.

Redux Connected Aframe Component Example

We will be discussing the complete example below. You can also play with a live example in action at https://codesandbox.io/s/o71qm45xy.

Foo

To summarize, we will be doing the following:

  1. adding aframe-typescript-redux to an a-frame project
  2. defining a Redux Store
  3. instantiating ReduxConnectedSystem and connecting it to this redux store
  4. creating an AFrame entity that is redux-connected
  5. defining my-component and adding listeners for redux store changes
  6. defining an onClick function in order to dispatch a redux action

1. Add Aframe-Typescript-Redux to your project

To connect your aframe component to redux, the following packages are required: a-frame, aframe-typescript-redux, and redux. In this example, we use the cdns for each and include the scripts in the head of our html file .

<html>
    <head>
        <!-- a-frame -->
        <script src="https://aframe.io/releases/0.8.0/aframe.min.js"></script>
        
        <!--  aframe-typescript-redux -->
        <script type="text/javascript" src="https://cdn.rawgit.com/olioapps/aframe-typescript-redux/48b60dde/dist-umd/index.js"></script>
        
        <!--  redux -->
        <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/redux/4.0.0/redux.js">

2. Define a Redux Store

Defining a simple redux store involves at least 3 main pieces:

  • the shape of the store,
  • the root reducer,
  • any action(s) for altering the store.

After these three pieces are in place, the store itself can be created.

// define shape of store
const initialState = {
    count: 1
}

// define actions
const doAdd = () => ({ type: "DO_ADD" })

// define root reducer
const reducer = (state = initialState, action) => {
    switch (action.type) {
        case "DO_ADD":
            return { count: state.count + 1 }
        default:
            return state
    }
}

// finally, create the store with the root reducer
const store = Redux.createStore(reducer)

In the example above, dispatching the doAdd action will increment the store's count it holds by one:

console.log(store.getState()) // { count: 1 }

store.dispatch(doAdd()) // dispatch doAdd to the store

console.log(store.getState()) // { count: 2 }

See Redux documentation for more details.

3. Instantiate ReduxConnectedSystem and Connect It To The Redux Store

// create a new instance of AframeRedux.ReduxConnectedSystem,
// pass in the just created store, then register it
const system = new AframeRedux.ReduxConnectedSystem(store).register()

Instantiating a ReduxConnectedSystem and supplying your redux store will cause store changes to be forwarded to entities bound to the redux-connected component.

4. Create a redux-connected AFrame Entity

Below is the html to create an aframe a-text entity which is given a component my-component, and is also redux connected via redux-connected:

<a-text my-component redux-connected="count: count"
    color="black"
    position="0 2 -5">
</a-text>

Defining redux-connected="count: count" causes the entity to be notified of changes to the count property in the store, via an event of the name count.

5. Define my-component and add listeners for store changes

The component my-component is defined as follows:

AFRAME.registerComponent("my-component", {
    init: function() {
        this.el.addEventListener("count", function(event) {
            const score = event.detail.newState
            this.setAttribute("value", score)
        })
    }
})

In the init function, AFRAME creates an instance of my-component and attaches it to the entity. At this point we can attach a listener to the element (this.el) to listen for events called count, which will be forwarded by ReduxConnectedSystem to the event handler whenever the count property in state changes.

Alternatively, the watched redux store property could have been specified using the watchedKeys property on the entity component:

<a-text my-component redux-connected="watchedKeys: count"
...

When watchedKeys is used, the event listened to by the target component (my-component in these examples) is assumed to have the same name as the watched redux property. Multiple redux store keys/events can be specified, eg. watchedKeys: prop1,prop2,prop3.

6. Define onClick to dispatch actions

The button click handler dispatches doAdd to the store when it is clicked, causing the store to change state, and in turn ReduxConnectedSystem notifies any entities listening to changes to the count property.

// define click handler
const onClick = () => {
    store.dispatch(doAdd())
}

We defined a simple button outside of the scene to hold the click handler. When the button is clicked, the a-text entity within the scene increments itself.

// create an html button holding the new onClick function
<a onclick="javascript:onClick()" id="clickMe" href="#">Click Me</a>

Contact

We are interested in hearing your questions and feedback.

Email: vr@olioapps.com

Additional Reading

License

This program is free software and is distributed under an MIT License.

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npm i aframe-typescript-redux

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  • rachoac