Frustum
A Frustum defines a perspective projection as a frustum-shaped view volume for a Camera.
Overview
- A Camera has a Frustum to configure its frustum-based perspective projection mode.
- A Frustum lets us explicitly set the positions of the left, right, top, bottom, near and far planes, which is useful for asymmetrical view volumes, such as those used for stereo viewing.
- A Frustum's near and far properties specify the distances to the WebGL clipping planes.
Examples
Usage
- See Camera
Constructor
Frustum
-
[owner]
-
[cfg]
Parameters:
-
[owner]
Component optionalOwner component. When destroyed, the owner will destroy this component as well. Creates this component within the default Scene when omitted.
-
[cfg]
optionalConfigs
-
[id]
String optionalOptional ID, unique among all components in the parent scene, generated automatically when omitted.
-
[meta]
String:Object optionalOptional map of user-defined metadata to attach to this Frustum.
-
[left=-1]
Number optionalPosition of the Frustum's left plane on the View-space X-axis.
-
[right=1]
Number optionalPosition of the Frustum's right plane on the View-space X-axis.
-
[bottom=-1]
Number optionalPosition of the Frustum's bottom plane on the View-space Y-axis.
-
[top=1]
Number optionalPosition of the Frustum's top plane on the View-space Y-axis.
-
[near=0.1]
Number optionalPosition of the Frustum's near plane on the View-space Z-axis.
-
[far=1000]
Number optionalPosition of the Frustum's far plane on the positive View-space Z-axis.
-
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:
-
message
StringThe 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
StringThe event type name
-
value
ObjectThe 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:
-
event
StringThe 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.Mesh
Parameters:
-
type
String | 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:
-
message
StringThe message to log
off
-
subId
Cancels an event subscription that was previously made with Component#on() or Component#once().
Parameters:
-
subId
StringPublication subId
on
-
event
-
callback
-
[scope=this]
Subscribes to an event on this component.
The callback is be called with this component as scope.
Parameters:
-
event
StringThe event
-
callback
FunctionCalled 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:
-
event
StringData event to listen to
-
callback
Function(data)Called when fresh data is available at the event
-
[scope=this]
Object optionalScope for the callback
Properties
bottom
Number
Position of this Frustum's bottom plane on the View-space Y-axis.
Fires a bottom event on change.
Default: -1.0
destroyed
Boolean
True as soon as this Component has been destroyed
far
Number
Position of this Frustum's far plane on the positive View-space Z-axis.
Fires a far event on change.
Default: 10000.0
left
Number
Position of this Frustum's left plane on the View-space X-axis.
Fires a left event on change.
Default: -1.0
matrix
Float32Array
The Frustum's projection transform matrix.
Fires a Frustum/matrix:event event on change.
Default: [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]
model
Model
final
The Model which contains this Component, if any.
Will be null if this Component is not in a Model.
near
Number
Position of this Frustum's near plane on the positive View-space Z-axis.
Fires a near event on change.
Default: 0.1
right
Number
Position of this Frustum's right plane on the View-space X-axis.
Fires a right event on change.
Default: 1.0
top
Number
Position of this Frustum's top plane on the View-space Y-axis.
Fires a top event on change.
Default: 1.0
type
String
final
JavaScript class name for this Component.
For example: "xeogl.AmbientLight", "xeogl.MetallicMaterial" etc.
Events
bottom
Fired whenever this Frustum's bottom property changes.
Event Payload:
-
value
ObjectThe property's new value
destroyed
Fired when this Component is destroyed.
far
Fired whenever this Frustum's far property changes.
Event Payload:
-
value
ObjectThe property's new value
left
Fired whenever this Frustum's left property changes.
Event Payload:
-
value
ObjectThe property's new value
near
Fired whenever this Frustum's near property changes.
Event Payload:
-
value
ObjectThe property's new value