API Docs for: 0.7.0

Component

Defined in: src/component.js:1
Module: xeogl

The Component class is the base class for all xeogl components.

Usage

Component IDs

Every Component has an ID that's unique within the parent Scene. xeogl generates the IDs automatically by default, however you can also specify them yourself. In the example below, we're creating a scene comprised of Scene, Material, Geometry and Entity components, while letting xeogl generate its own ID for the Geometry:

// The Scene is a Component too
var scene = new xeogl.Scene({
   id: "myScene"
});

var material = new xeogl.PhongMaterial(scene, {
   id: "myMaterial"
});

var geometry = new xeogl.Geometry(scene, {
   id: "myGeometry"
});

// Let xeogl automatically generate the ID for our Entity
var entity = new xeogl.Entity(scene, {
   material: material,
   geometry: geometry
});

We can then find those components like this:

// Find the Scene
var theScene = xeogl.scenes["myScene"];

// Find the Material
var theMaterial = theScene.components["myMaterial"];

// Find all PhongMaterials in the Scene
var phongMaterials = theScene.types["xeogl.PhongMaterial"];

// Find our Material within the PhongMaterials
var theMaterial = phongMaterials["myMaterial"];

Component inheritance

TODO

All xeogl components extend the Component base type. Each component

For example, if this component is a Rotate, which extends Transform, which in turn extends Component, then this property will have the value:

["xeogl.Component", "xeogl.Transform"]

TODO

// Evaluates true:
var isComponent = theMaterial.isType("xeogl.Component");

// Evaluates true:
var isMaterial = theMaterial.isType("xeogl.Material");

// Evaluates true:
var isPhongMaterial = theMaterial.isType("xeogl.PhongMaterial");

// Evaluates false:
var isMetallicMaterial = theMaterial.isType("xeogl.MetallicMaterial");

Note that the chain is ordered downwards in the hierarchy, ie. from super-class down towards sub-class.

Metadata

You can set optional metadata on your Components, which can be anything you like. These are intended to help manage your components within your application code or content pipeline. You could use metadata to attach authoring or version information, like this:

// Scene with authoring metadata
var scene = new xeogl.Scene({
   id: "myScene",
   meta: {
       title: "My bodacious 3D scene",
       author: "@xeographics",
       date: "February 30 2018"
   }
});

// Material with descriptive metadata
var material = new xeogl.PhongMaterial(scene, {
   id: "myMaterial",
   diffuse: [1, 0, 0],
   meta: {
       description: "Bright red color with no textures",
       version: "0.1",
       foo: "bar"
   }
});

Logging

Components have methods to log ID-prefixed messages to the JavaScript console:

material.log("Everything is fine, situation normal.");
material.warn("Wait, whats that red light?");
material.error("Aw, snap!");

The logged messages will look like this in the console:

[LOG]   myMaterial: Everything is fine, situation normal.
[WARN]  myMaterial: Wait, whats that red light..
[ERROR] myMaterial: Aw, snap!

Destruction

Get notification of destruction directly on the Components:

material.on("destroyed", function() {
   this.log("Component was destroyed: " + this.id);
});

Or get notification of destruction of any Component within its Scene, indiscriminately:

scene.on("componentDestroyed", function(component) {
   this.log("Component was destroyed: " + component.id);
});

Then destroy a component like this:

material.destroy();

Creating custom Components

Subclassing a Component to create a new xeogl.ColoredTorus type:

xeogl.ColoredTorus = xeogl.Component.extend({

    type: "xeogl.ColoredTorus",

    _init: function (cfg) { // Constructor

        this._torus = new xeogl.Entity({
            geometry: new xeogl.TorusGeometry({radius: 2, tube: .6}),
            material: new xeogl.MetallicMaterial({
                baseColor: [1.0, 0.5, 0.5],
                roughness: 0.4,
                metallic: 0.1
            })
        });

        this.color = cfg.color;
    },

    _props: {

        // The color of this ColoredTorus.
        color: {
            set: function (color) {
                this._torus.material.baseColor = color;
            },
            get: function () {
                return this._torus.material.baseColor;
            }
        }
    },

    _destroy: function () {
        this._torus.geometry.destroy();
        this._torus.material.destroy();
        this._torus.destroy();
    }
});

Examples

Constructor

Component

(
  • [scene]
  • [cfg]
)

Defined in src/component.js:1

Parameters:

  • [scene] Scene optional

    Parent Scene - creates this Component within the default Scene when omitted.

  • [cfg] optional

    DepthBuf configuration

    • [id] String optional

      Optional ID, unique among all components in the parent Scene, generated automatically when omitted.

    • [meta] String:Object optional

      Optional map of user-defined metadata to attach to this Component.

    • [isDefault] Boolean optional

      Set true when this is one of xeogl's default components.

Methods

create

(
  • [cfg]
)

Convenience method for creating a Component within this Component's Scene.

The method is given a component configuration, like so:

var material = myComponent.create({
     type: "xeogl.PhongMaterial",
     diffuse: [1,0,0],
     specular: [1,1,0]
}, "myMaterial");

Parameters:

  • [cfg] optional

    Configuration for the component instance.

Returns:

:

destroy

()

Destroys this component.

Fires a destroyed event on this Component.

Automatically disassociates this component from other components, causing them to fall back on any defaults that this component overrode on them.

TODO: describe effect with respect to #create

error

(
  • message
)

Logs an error for this component to the JavaScript console.

The console message will have this format: [ERROR] [<component type> =<component id>: <message>

Also fires the message as an error event on the parent Scene.

Parameters:

  • message String

    The message to log

fire

(
  • event
  • value
  • [forget=false]
)

Fires an event on this component.

Notifies existing subscribers to the event, optionally retains the event to give to any subsequent notifications on the event as they are made.

Parameters:

  • event String

    The event type name

  • value Object

    The event parameters

  • [forget=false] Boolean optional

    When true, does not retain for subsequent subscribers

hasSubs

(
  • event
)
Boolean

Returns true if there are any subscribers to the given event on this component.

Parameters:

  • event String

    The event

Returns:

Boolean:

True if there are any subscribers to the given event on this component.

isType

(
  • type
)
Boolean

Tests if this component is of the given type, or is a subclass of the given type.

The type may be given as either a string or a component constructor.

This method works by walking up the inheritance type chain, which this component provides in property superTypes, returning true as soon as one of the type strings in the chain matches the given type, of false if none match.

Examples:

var myRotate = new xeogl.Rotate({ ... });

myRotate.isType(xeogl.Component); // Returns true for all xeogl components
myRotate.isType("xeogl.Component"); // Returns true for all xeogl components
myRotate.isType(xeogl.Rotate); // Returns true
myRotate.isType(xeogl.Transform); // Returns true
myRotate.isType("xeogl.Transform"); // Returns true
myRotate.isType(xeogl.Entity); // Returns false, because xeogl.Rotate does not (even indirectly) extend xeogl.Entity

Parameters:

  • type String | Function

    Component type to compare with, eg "xeogl.PhongMaterial", or a xeogl component constructor.

Returns:

Boolean:

True if this component is of given type or is subclass of the given type.

log

(
  • message
)

Logs a console debugging message for this component.

The console message will have this format: [LOG] [<component type> <component id>: <message>

Also fires the message as a log event on the parent Scene.

Parameters:

  • message String

    The message to log

off

(
  • handle
)

Cancels an event subscription that was previously made with on or once.

Parameters:

  • handle String

    Publication handle

on

(
  • event
  • callback
  • [scope=this]
)
String

Subscribes to an event on this component.

The callback is be called with this component as scope.

Parameters:

  • event String

    The event

  • callback Function

    Called fired on the event

  • [scope=this] Object optional

    Scope for the callback

Returns:

String:

Handle to the subscription, which may be used to unsubscribe with {@link #off}.

once

(
  • event
  • callback
  • [scope=this]
)

Subscribes to the next occurrence of the given event, then un-subscribes as soon as the event is handled.

This is equivalent to calling on, and then calling off inside the callback function.

Parameters:

  • event String

    Data event to listen to

  • callback Function(data)

    Called when fresh data is available at the event

  • [scope=this] Object optional

    Scope for the callback

warn

(
  • message
)

Logs a warning for this component to the JavaScript console.

The console message will have this format: [WARN] [<component type> =<component id>: <message>

Also fires the message as a warn event on the parent Scene.

Parameters:

  • message String

    The message to log

Properties

destroyed

Boolean

True as soon as this Component has been destroyed

id

String final

Unique ID for this Component within its parent Scene.

isDefault

Boolean

Indicates whether this is one of the Scene's built-in Components.

metadata

Object

Arbitrary, user-defined metadata on this component.

scene

Scene final

The parent Scene that contains this Component.

superTypes

Array of String final

An array of strings that indicates the chain of super-types within this component's inheritance hierarchy.

For example, if this component is a Rotate, which extends Transform, which in turn extends Component, then this property will have the value:

["xeogl.Component", "xeogl.Transform"]
                    

Note that the chain is ordered downwards in the hierarchy, ie. from super-class down towards sub-class.

type

String final

JavaScript class name for this Component.

For example: "xeogl.AmbientLight", "xeogl.ColorTarget", "xeogl.Lights" etc.

Events

destroyed

Fired when this Component is destroyed.