API Docs for: 0.7.0

CameraFollowAnimation

Extends Component
Module: animation
Parent Module: xeogl

A CameraFollowAnimation makes the Scene's Camera dynamically follow a target component in order to keep it entirely in camera.

Overview

  • A target can be an instance or ID of any Component subtype that provides a World-space AABB.
  • Can be configured to either fly or jump to each updated position of the target.
  • Can be configured to automatically adjust the distance between the Camera's Lookat's eye and look to keep the target fitted to the view volume.

Examples

Usage

In the example below, we'll use a CameraFollowAnimation to automatically follow an Entity. Our CameraFollowAnimation's fit property is set true, which causes it to automatically keep the Entity fitted to the view volume. Although we can orbit the Entity using the CameraControl, we you can't control the distance of the Camera from the Entity because our CameraFollowAnimation automatically controls that distance in order to do the automatic fitting.

// Create a red torus Entity with a Translate modelling transform
// that allows it to move around in World-space
var entity = new xeogl.Entity({
    geometry: new xeogl.TorusGeometry(),
    material: new xeogl.PhongMaterial({
         diffuse: [1, 0.3, 0.3]
    }),
    transform: new xeogl.Translate({
        xyz: [0,0,0]
    })
});

// Create a CameraFollowAnimation that makes the Scene's Camera's Lookat follow the Entity while keeping it
// fitted to the view volume. The CameraFollowAnimation will jump to each new location, and since an update will occur on every frame,
// the effect will be as if we're smoothly flying after the Entity. If the updates occur sporadically,
// then we would probably instead configure it to fly to each update, to keep the animation smooth.
var cameraFollowAnimation = new xeogl.CameraFollowAnimation({
    target: entity,
    fit: true,   // Fit target to view volume
    fitFOV: 35,  // Target will occupy 35 degrees of the field-of-view
    fly: false // Jump to each updated boundary extents
});

// Create a SplineCurve along which we'll animate our Entity
var curve = new xeogl.SplineCurve({
    points: [
        [-10, 0, 0],
        [-5, 15, 0],
        [20, 15, 0],
        [10, 0, 0]
    ]
});

// Bind the Entity Translate to a point on the SplineCurve
curve.on("point", function(point) {
    entity.transform.xyz = point;
});

// Animate the point along the SplineCurve using the Scene clock
curve.scene.on("tick", function(e) {
    curve.t = (e.time - e.startTime) * 0.01;
});

// Allow user control of the Camera with mouse and keyboard
// (zooming will be overridden by the auto-fitting configured on our CameraFollowAnimation)
new xeogl.CameraControl();

Constructor

CameraFollowAnimation

(
  • [scene]
  • [cfg]
)

Parameters:

  • [scene] Scene optional

    Parent Scene - creates this CameraFollowAnimation within xeogl's default Xeogl/scene:property by default.

  • [cfg] optional

    Configs

    • [id] String optional

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

    • [meta] optional

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

    • [target] Number | String | Camera optional

      ID or instance of a Component to follow. Must be within the same Scene as this CameraFollowAnimation. Defaults to the parent Scene.

    • [fly] Boolean optional

      Indicates whether this CameraFollowAnimation will either fly or jump to each updated position of the target target.

    • [fit] Boolean optional

      When true, will ensure that this CameraFollowAnimation automatically adjusts the distance between the Camera's Lookat's eye and look to keep the target Boundary3D fitted to the view volume.

    • [fitFOV=45] Number optional

      How much of field-of-view, in degrees, that a target target should fill the canvas when fitting to camera.

    • [trail] Boolean optional

      When true, will cause this CameraFollowAnimation to point the camera in the direction that it is travelling.

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

fit

Boolean

When true, will ensure that this CameraFollowAnimation always adjusts the distance between the camera's eye and look positions so as to ensure that the target is always filling the view volume.

When false, the eye will remain at its current distance from the look position.

Default: true

fitFOV

Number

When fit is set, to fit the target target in view, this property indicates how much of the total field-of-view, in degrees, that the target should fill.

Default: 45

fly

Boolean

Indicates whether this CameraFollowAnimation will either fly or jump to each updated position of the target.

Leave this false if the target updates continuously, otherwise leave it true if you want the camera to fly smoothly to each updated target extents for a less disorientating experience.

Default: false

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.

target

Component

The World-space Boundary3D followed by this CameraFollowAnimation.

Must be within the same Scene as this CameraFollowAnimation. Defaults to the parent Scene when set to a null or undefined value.

trail

Boolean

When true, will cause this CameraFollowAnimation to point the Camera in the direction that it is travelling.

Default: false

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.

target

Fired whenever this CameraFollowAnimation's target property changes.

Event Payload:

  • value Object

    The property's new value