CameraFollowAnimation
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 Lookat/eye:property and Lookat/look:property to keep the target fitted to the view volume.
Examples
- Following an Mesh with the Camera
- Following an Mesh with the Camera, keeping Mesh fitted to view volume
Usage
In the example below, we'll use a CameraFollowAnimation to automatically follow an Mesh. Our CameraFollowAnimation's
fit property is set true, which causes it to automatically
keep the Mesh fitted to the view volume. Although we can orbit the
Mesh using the CameraControl, we you can't control the
distance of the Camera from the Mesh because our CameraFollowAnimation
automatically controls that distance in order to do the automatic fitting.
// Create a red torus Mesh with a Translate modelling transform
// that allows it to move around in World-space
var mesh = new xeogl.Mesh({
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 Mesh 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 Mesh. 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: mesh,
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 Mesh
var curve = new xeogl.SplineCurve({
points: [
[-10, 0, 0],
[-5, 15, 0],
[20, 15, 0],
[10, 0, 0]
]
});
// Bind the Mesh Translate to a point on the SplineCurve
curve.on("point", function(point) {
mesh.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 -
[cfg]optionalConfigs
-
[id]String optionalOptional ID, unique among all components in the parent Scene, generated automatically when omitted.
-
[meta]optionalOptional map of user-defined metadata to attach to this CameraFollowAnimation.
-
[target]Number | String | Camera optional -
[fly]Boolean optionalIndicates whether this CameraFollowAnimation will either fly or jump to each updated position of the target target.
-
[fit]Boolean optionalWhen true, will ensure that this CameraFollowAnimation automatically adjusts the distance between the Camera's Lookat's Lookat/eye:property and Lookat/look:property to keep the target Boundary3D fitted to the view volume.
-
[fitFOV=45]Number optionalHow much of field-of-view, in degrees, that a target target should fill the canvas when fitting to camera.
-
[trail]Boolean optionalWhen true, will cause this CameraFollowAnimation to point the camera in the direction that it is travelling.
-
Index
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]optionalConfiguration 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:
-
messageStringThe 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:
-
eventStringThe event type name
-
valueObjectThe event parameters
-
[forget=false]Boolean optionalWhen true, does not retain for subsequent subscribers
hasSubs
-
event
Returns true if there are any subscribers to the given event on this component.
Parameters:
-
eventStringThe event
Returns:
True if there are any subscribers to the given event on this component.
isType
-
type
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.MeshParameters:
-
typeString | FunctionComponent type to compare with, eg "xeogl.PhongMaterial", or a xeogl component constructor.
Returns:
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>
Parameters:
-
messageStringThe message to log
off
-
subId
Cancels an event subscription that was previously made with Component#on() or Component#once().
Parameters:
-
subIdStringPublication subId
on
-
event -
callback -
[scope=this]
Subscribes to an event on this component.
The callback is be called with this component as scope.
Parameters:
-
eventStringThe event
-
callbackFunctionCalled fired on the event
-
[scope=this]Object optionalScope for the callback
Returns:
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:
-
eventStringData event to listen to
-
callbackFunction(data)Called when fresh data is available at the event
-
[scope=this]Object optionalScope for the callback
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 Lookat/eye:property and Lookat/look:property 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
model
Model
final
The Model which contains this Component, if any.
Will be null if this Component is not in a Model.
target
Component
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.MetallicMaterial" etc.