API Docs for: 0.7.0

Transform

Extends Component
Module: transforms
Parent Module: xeogl

A Transform is a modelling, viewing or projection transformation.

Overview

Examples

Usage

In this example we'll create the table shown below, which consists of five Entities that share a BoxGeometry and each connect to a different leaf within a hierarchy of Translate, Rotate and Scale components. Each Entity also has its own PhongMaterial to give it a distinct color.

// Shared Geometry
var boxGeometry = new xeogl.BoxGeometry();

// Position of entire table
var tablePos = new xeogl.Translate({
   xyz: [0, 6, 0]
});

// Orientation of entire table
var tableRotate = new xeogl.Rotate({
   xyz: [1, 1, 1],
   angle: 0,
   parent: tablePos
});

// Red table leg
var tableLeg1 = new xeogl.Entity({
   geometry: boxGeometry,
   transform: new xeogl.Scale({
       xyz: [1, 3, 1],
       parent: new xeogl.Translate({
           xyz: [-4, -6, -4],
           parent: tableRotate
       })
   }),
   material: new xeogl.PhongMaterial({
       diffuse: [1, 0.3, 0.3]
   })
});

// Green table leg
var tableLeg2 = new xeogl.Entity({
   geometry: boxGeometry,
   transform: new xeogl.Scale({
       xyz: [1, 3, 1],
       parent: new xeogl.Translate({
           xyz: [4, -6, -4],
           parent: tableRotate
       })
   }),
   material: new xeogl.PhongMaterial({
       diffuse: [0.3, 1.0, 0.3]
   })
});

// Blue table leg
var tableLeg3 = new xeogl.Entity({
   geometry: boxGeometry,
   transform: new xeogl.Scale({
       xyz: [1, 3, 1],
       parent: new xeogl.Translate({
           xyz: [4, -6, 4],
           parent: tableRotate
       })
   }),
   material: new xeogl.PhongMaterial({
       diffuse: [0.3, 0.3, 1.0]
   })
});

// Yellow table leg
var tableLeg4 = new xeogl.Entity({
   geometry: boxGeometry,
   transform: new xeogl.Scale({
       xyz: [1, 3, 1],
       parent: new xeogl.Translate({
           xyz: [-4, -6, 4],
           parent: tableRotate
       })
   }),
   material: new xeogl.PhongMaterial({
       diffuse: [1.0, 1.0, 0.0]
   })
});

// Purple table top
var tableTop = new xeogl.Entity({
   geometry: boxGeometry,
   transform: new xeogl.Scale({
       xyz: [6, 0.5, 6],
       parent: new xeogl.Translate({
           xyz: [0, -3, 0],
           parent: tableRotate
       })
   }),
   material: new xeogl.PhongMaterial({
       diffuse: [1.0, 0.3, 1.0]
   })
});

// Zoom camera out a bit
// Get the Camera from one of the Entities
tableTop.camera.view.zoom(10);

// Spin the entire table

var angle = 0;

scene.on("tick", function () {
   angle += 0.5;
   tableRotate.angle = angle;
});

Constructor

Transform

(
  • [scene]
  • [cfg]
)

Parameters:

  • [scene] Scene optional

    Parent Scene - creates this Transform in the default Scene when omitted.

  • [cfg] optional

    Configs

    • [id] String optional

      Optional ID, unique among all components in the parent Scene, generated automatically when omitted. You only need to supply an ID if you need to be able to find the Transform by ID within the Scene.

    • [meta] String:Object optional

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

    • [parent] String | Transform optional

      ID or instance of a parent Transform within the same Scene.

    • [postMultiply=true] Boolean optional

      Flag that indicates whether this Transform is post-multiplied (default) or pre-multiplied by its parent Transform.

    • [matrix=[1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]] Float32Array optional

      One-dimensional, sixteen element array of elements for the Transform, an identity matrix by default.

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.

leafMatrix

Float32Array

Returns the product of all matrix's on Transforms on the path via parent up to the root.

The value of this property will have a fresh value after each Transform/updated:property event, which is fired whenever any Transform on the path receives an update for its matrix or matrix property.

Default: [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]

leafNormalMatrix

Float32Array

Returns the product of all Transform/normalMatrix:property's on Transforms on the path via parent up to the root.

The value of this property will have a fresh value after each Transform/updated:property event, which is fired whenever any Transform on the path receives an update for its matrix or matrix property.

Default: [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]

matrix

Float32Array

The Transform's local matrix.

Fires a matrix event on change.

Default: [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]

metadata

Object

Arbitrary, user-defined metadata on this component.

parent

Transform

The parent Transform.

postMultiply

Boolean

Flag that indicates whether this Transform is post-multiplied (default) or pre-multiplied by its parent Transform.

Default: true

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.

matrix

Fired whenever this Transform's matrix property changes.

Event Payload:

  • value Object

    The property's new value

updated

Fired whenever this Transform's leafMatrix property changes.

This event does not carry the updated property value. Instead, subscribers will need to read that property again to get its updated value (which may be lazy-computed then).