API Docs for:

Pin

A Pin is a pinned position on the surface of a Mesh.

Overview

Position

A Pin is positioned within one of the triangles of its Mesh's Geometry. Wherever that triangles goes within the 3D view, the Pin will automatically follow. An Pin specifies its position with two properties:

  • primIndex, which indicates the index of the triangle within the Geometry indices, and
  • bary, the barycentric coordinates of the position within the triangle.

From these, an Pin dynamically calculates its Cartesian coordinates, which it provides in each xeogl coordinate space:

An Pin automatically recalculates these coordinates whenever its Mesh is replaced or transformed, the Geometry is replaced or modified, or the Camera is moved.

Visibility

  • occludable specifies whether the Pin becomes invisible whenever its occluded by other objects in the 3D view, and
  • visible indicates if the Pins is currently visible.

  • To determine if each Pin is occluded, xeogl renders the scene to a hidden framebuffer, along with a colored point for each Pin's position. Then xeogl determines each Pin to be occluded if the pixel at its position does not match the special pin color. The color is configured as some unusual color that is not used elsewhere in the scene.

Example

In the example below we'll create an Mesh with a TorusGeometry, then attach a Pin to it. Then we'll subscribe to changes to the Pin's position and visibility status.

var mesh = new xeogl.Mesh({
   geometry: new xeogl.TorusGeometry(),
   transform: new xeogl.Translate({
       xyz: [0,0,0]
   });
});

var pin = new xeogl.Pin({
   mesh: mesh,
   primIndex: 12,              // Triangle index in Geometry indices array
   bary: [0.11, 0.79, 0.08]    // Barycentric coordinates in the triangle
});

var localPos   = pin.localPos;     // 3D Local-space position
var worldPos   = pin.worldPos;     // 3D World-space position
var viewPos    = pin.viewPos;      // 3D View-space position
var canvasPos  = pin.canvasPos;    // 2D Canvas-space position

// Listen for change of the Pin's Local-space cartesian position,
// which is caused by modification of Pin's Geometry or update to
// the Pin's 'primIndex' or 'bary' properties.
pin.on("localPos", function() {
   //...
});

// Listen for change of the Pin's World-space cartesian position,
// which is caused by update of Pin's Local-space position or by
// animation of the Mesh by its modelling Transform.
pin.on("worldPos", function() {
   //...
});

// Listen for change of Pin visibility. The Pin becomes invisible when it
// falls outside the canvas, or when an object occludes the Pin's position
// in the 3D view.
pin.on("visible", function(visible) { // Pin visibility has changed
   if (visible) {
       this.log("Pin is not occluded and within canvas.");
   } else {
       this.log("Pin is either occluded or is off the canvas.");
   }
});

Constructor

Pin

(
  • [scene]
  • [cfg]
)

Parameters:

  • [scene] Scene optional

    Parent Scene - creates this Pin 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.

    • [meta] String:Object optional

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

    • [mesh] Number | String | Mesh optional

      ID or instance of the Mesh the Pin is attached to.

    • [primIndex=0] Number optional

      Index of the triangle containing the Pin. Within the Mesh's Geometry indices, this is the index of the first vertex for the triangle.

    • [bary=[0.3,0.3,0.3] Float32Array optional

      Barycentric coordinates of the Pin within its triangle.

    • [offset=0.2] Number optional

      How far the Pin is lifted out of its triangle, along the surface normal vector. This is used when occlusion culling, to ensure that the Pin is not lost inside the surface it's attached to.

    • [occludable=false] Boolean optional

      Indicates whether occlusion testing is performed for the Pin, where it will be flagged invisible whenever it's hidden by something else in the 3D view.

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 Component/superTypes:property, 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.Mesh); // Returns false, because xeogl.Rotate does not (even indirectly) extend xeogl.Mesh

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

(
  • subId
)

Cancels an event subscription that was previously made with Component#on() or Component#once().

Parameters:

  • subId String

    Publication subId

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 subIdd.

This is equivalent to calling Component#on(), and then calling Component#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

bary

Float32Array

Barycentric coordinates of this Pin within its triangle.

A value of [0.3, 0.3, 0.3] is the center of the triangle.

Fires a bary event on change.

Default: [0.3,0.3,0.3]

canvasPos

Float32Array final

Canvas-space 2D coordinates of this Pin.

This is read-only and is automatically calculated.

Default: [0,0]

destroyed

Boolean

True as soon as this Component has been destroyed

id

String final

Unique ID for this Component within its parent Scene.

localPos

Float32Array final

Local-space 3D coordinates of this Pin.

This is read-only and is automatically calculated.

Fires a localPos event on change.

Default: [0,0,0]

mesh

Number | String | xeogl.Mesh

The Mesh this Pin is attached to.

You can attach a Pin to a different Mesh at any time.

Note that primIndex should always be within the indices of the Geometry belonging to the Mesh.

Fires an mesh event on change.

metadata

Object

Arbitrary, user-defined metadata on this component.

model

Model final

The Model which contains this Component, if any.

Will be null if this Component is not in a Model.

occludable

Float32Array

Indicates whether occlusion testing is performed for this Pin.

When this is true, then visible will be false whenever the Pin is hidden behind something else in the 3D view.

Set this false if the Pin is to remain visible when hidden behind things while being within the canvas.

Fires a occludable event on change.

Default: false

offset

Number

How far the Pin is lifted out of its triangle, along the surface normal vector.

This is used when occlusion culling, to ensure that the Pin is not lost inside the surface it's attached to.

Fires a offset event on change.

Default: 0.2

primIndex

Number

Index of the triangle containing this pin.

Within the indices of the Geometry attached to the Mesh, this is the index of the first element for that triangle.

Fires a primIndex event on change.

Default: 0

scene

Scene final

The parent Scene that contains this Component.

type

String final

JavaScript class name for this Component.

For example: "xeogl.AmbientLight", "xeogl.MetallicMaterial" etc.

viewPos

Float32Array final

View-space 3D coordinates of this Pin.

This is read-only and is automatically calculated.

Default: [0,0,0]

visible

Boolean final

Indicates if this Pin is currently visible.

This is read-only and is automatically calculated.

The Pin is invisible whenever:

  • canvasPos is currently outside the canvas, or
  • occludable is true and the Pin is currently occluded by something in the 3D view.

Fires a visible event on change.

Default: true

worldNormal

Float32Array final

World-space normal vector of this Pin.

This is read-only and is automatically calculated.

Fires a worldNormal event on change.

Default: [0,0,1]

worldPos

Float32Array final

World-space 3D coordinates of this Pin.

This is read-only and is automatically calculated.

Fires a worldPos event on change.

Default: [0,0,0]

Events

bary

Fired whenever this Pin's bary property changes.

Event Payload:

  • value Object

    Float32Array The property's new value

destroyed

Fired when this Component is destroyed.

localPos

Fired whenever this Pin's localPos property changes.

mesh

Fired whenever this Pin's mesh property changes.

Event Payload:

  • value Object

    The property's new value

occludable

Fired whenever this Pin's occludable property changes.

Event Payload:

  • value Object

    Float32Array The property's new value

offset

Fired whenever this Pin's offset property changes.

Event Payload:

  • value Object

    Number The property's new value

primIndex

Fired whenever this Pin's primIndex property changes.

Event Payload:

  • value Object

    Number The property's new value

visible

Fired whenever this Pin's visible property changes.

Event Payload:

  • value Object

    Float32Array The property's new value

worldNormal

Fired whenever this Pin's worldNormal property changes.

worldPos

Fired whenever this Pin's worldPos property changes.