Annotation
An Annotation is a labeled Pin that's attached to the surface of a Mesh.
Overview
Position
An Annotation is positioned within one of the triangles of its Mesh's Geometry. Wherever that triangle goes within the 3D view, the Annotation will automatically follow. An Annotation 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 Annotation dynamically calculates its Cartesian coordinates, which it provides in each xeogl coordinate space:
- localPos - 3D position local to the coordinate space of the Geometry,
- worldPos - 3D World-space position,
- viewPos - 3D View-space position, and
- canvasPos - 2D Canvas-space position.
An Annotation automatically recalculates these coordinates whenever its Mesh is replaced or transformed, the Geometry is replaced or modified, or the Camera is moved.
Appearance
As shown in the screen shot above, an Annotation is rendered as a dot with a label attached to it, using HTML elements.
- glyph specifies a character to appear in the dot,
- title and desc specify a title and description to appear in the label, and
- pinShown and labelShown specify whether the pin and label are shown.
Use the stylesheet in annotation-style.css to set the default appearance for Annotations. Use that stylesheet as a guide for your own custom styles.
Visibility
- occludable specifies whether the Annotation becomes invisible whenever its occluded by other objects in the 3D view, and
- visible indicates if the Annotations is currently visible.
Vantage points
Each Annotation may be configured with a vantage point from which to view it, given as eye, look and up properties. To focus attention on an Annotation, you could set the Camera's Lookat to that vantage point, or even fly to the vantage point using a CameraFlightAnimation (which we'll demonstrate in the usage example below).
Interaction
An Annotation fires a "pinClicked" event whenever you click its dot. In the usage example, we make that event show the Annotation's label and set the Camera to the vantage point.
Examples
Usage
In the example below, we use a GLTFModel to load a glTF model of a reciprocating saw. Once the GLTFModel has loaded, we'll then create Annotations on three of its Meshes. Finally, we wire a callback to the "pinClicked" event from each Annotation, so that when you click its Pin, its label is shown and the Camera is positioned at its vantage point.
<script src="../build/xeogl.js"></script>
<script src="js/annotations/pin.js"></script>
<script src="js/annotations/annotation.js"></script>
<link href="js/annotations/annotation-style.css" rel="stylesheet"/>
<script>
var model = new xeogl.GLTFModel({
src: "models/gltf/ReciprocatingSaw/PBR-SpecGloss/Reciprocating_Saw.gltf",
transform: new xeogl.Rotate({
xyz: [1, 0, 0],
angle: 90
})
});
model.on("loaded", function () {
// Position the camera to look at the model
var camera = model.scene.camera;
camera.eye = [-110.89, -44.85, 276.65];
camera.look = [-110.89, -44.85, -0.46];
camera.up = [0, 1, 0];
camera.zoom(20);
// Create three annotations on meshes
// within the model
var a1 = new xeogl.Annotation({
mesh: model.meshes[156], // Red handle
primIndex: 125,
bary: [0.3, 0.3, 0.3],
occludable: true,
glyph: "1",
title: "Handle",
desc: "This is the handle. It allows us to grab onto the saw so we can hold it and make things with it.",
eye: [-355.481, -0.871, 116.711],
look: [-227.456, -57.628, 5.428],
up: [0.239, 0.948, -0.208],
pinShown: true,
labelShown: false
});
var a2 = new xeogl.Annotation({
mesh: model.meshes[156], // Red handle and cover
primIndex: 10260,
bary: [0.333, 0.333, 0.333],
occludable: true,
glyph: "2",
title: "Handle and cover",
desc: "This is the handle and cover. It provides something grab the saw with, and covers the things inside.",
eye: [-123.206, -4.094, 169.849],
look: [-161.838, -37.875, 37.313],
up: [-0.066, 0.971, -0.228],
pinShown: true,
labelShown: false
});
var a3 = new xeogl.Annotation({
mesh: modelentities[796], // Barrel
primIndex: 3783,
bary: [0.3, 0.3, 0.3],
occludable: true,
glyph: "3",
title: "Barrel",
desc: "This is the barrel",
eye: [80.0345, 38.255, 60.457],
look: [35.023, -0.166, 8.679],
up: [-0.320, 0.872, -0.368],
pinShown: true,
labelShown: false
});
// When each annotation's pin is clicked, we'll show the
// annotation's label and fly the camera to the
// annotation's vantage point
var cameraFlight = new xeogl.CameraFlightAnimation();
var lastAnnotation;
function pinClicked(annotation) {
if (lastAnnotation) {
annotation.labelShown = false;
}
annotation.labelShown = true;
cameraFlight.flyTo(annotation);
lastAnnotation = annotation;
}
a1.on("pinClicked", pinClicked);
a2.on("pinClicked", pinClicked);
a3.on("pinClicked", pinClicked);
// If desired, we can also dynamically track the Cartesian coordinates
// of each annotation in Local and World coordinate spaces
a1.on("localPos", function(localPos) {
console.log("Local pos changed: " + JSON.stringify(localPos, null, "\t"));
});
a1.on("worldPos", function(worldPos) {
console.log("World pos changed: " + JSON.stringify(worldPos, null, "\t"));
});
});
</script>Constructor
Annotation
-
[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]String:Object optionalOptional map of user-defined metadata to attach to the Annotation.
-
[mesh]Number | String | Mesh optionalID or instance of the Mesh the Annotation is attached to.
-
[bary=[0.3,0.3,0.3]Float32Array optionalBarycentric coordinates of the Annotation within its triangle.
-
[primIndex=0]Number optional -
[offset=0.2]Number optionalHow far the Annotation is lifted out of its triangle, along the surface normal vector. This is used when occlusion culling, to ensure that the Annotation is not lost inside the surface it's attached to.
-
[occludable=true]Boolean optionalIndicates whether occlusion testing is performed for the Annotation, where it will be flagged invisible whenever it's hidden by something else in the 3D camera.
-
[glyph=""]String optionalShort piece of text to show inside the pin for the Annotation. Automatically truncated to 2 characters.
-
[title=""]String optionalTitle text for the Annotation's label. Automatically truncated to 64 characters.
-
[desc=""]String optionalDescription text for the Annotation's label. Automatically truncated to 1025 characters.
-
[eye=[0,0,-10]Float32Array optionalPosition of the eye when looking at the Annotation.
-
[look=[0,0,0]Float32Array optionalPosition of the look when looking at the Annotation.
-
[up=[0,1,0]Float32Array optionalDirection of the "up" vector when looking at the Annotation.
-
[pinShown=true]Boolean optionalSpecifies whether a UI element is shown at the Annotation's pin position (typically a circle).
-
[labelShown=true]Boolean optionalSpecifies whether the Annotation's label is shown.
-
Index
Properties
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
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]
desc
String
Description text for the Annotation's label.
Automatically truncated to 1025 characters.
Fires a desc event on change.
Default: ""
destroyed
Boolean
True as soon as this Component has been destroyed
eye
Float32Array
Position of the eye when looking at the Annotation.
Fires a eye event on change.
Default: [0,0,10]
glyph
String
Short piece of text to show inside the pin for the Annotation.
Usually this would be a single number or letter.
Automatically truncated to 2 characters.
Fires a glyph event on change.
Default: ""
labelShown
Boolean
Specifies whether the label is shown for the Annotation.
Fires a labelShown event on change.
Default: true
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]
look
Float32Array
Point-of-interest when looking at the Annotation.
Fires a look event on change.
Default: [0,0,0]
mesh
Number | String | xeogl.Mesh
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
pinShown
Boolean
Specifies whether a UI element is shown at the Annotation's pin position (typically a circle).
Fires a pinShown event on change.
Default: true
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
title
String
Title text for the Annotation's label.
Automatically truncated to 64 characters.
Fires a title event on change.
Default: ""
type
String
final
JavaScript class name for this Component.
For example: "xeogl.AmbientLight", "xeogl.ColorTarget", "xeogl.Lights" etc.
up
Float32Array
"Up" vector when looking at the Annotation.
Fires a up event on change.
Default: [0,1,0]
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:
-
valueObjectFloat32Array The property's new value
desc
Fired whenever this Annotation's desc property changes.
Event Payload:
-
valueNumberThe property's new value
destroyed
Fired when this Component is destroyed.
eye
Fired whenever this Annotation's eye property changes.
Event Payload:
-
valueNumberThe property's new value
glyph
Fired whenever this Annotation's glyph property changes.
Event Payload:
-
valueNumberThe property's new value
labelShown
Fired whenever this Annotation's labelShown property changes.
Event Payload:
-
valueNumberThe property's new value
localPos
Fired whenever this Pin's localPos property changes.
look
Fired whenever this Annotation's look property changes.
Event Payload:
-
valueNumberThe property's new value
mesh
Fired whenever this Pin's mesh property changes.
Event Payload:
-
valueObjectThe property's new value
occludable
Fired whenever this Pin's occludable property changes.
Event Payload:
-
valueObjectFloat32Array The property's new value
offset
Fired whenever this Pin's offset property changes.
Event Payload:
-
valueObjectNumber The property's new value
pinClicked
Fired whenever the mouse is clicked on this Annotation's Annotation/pin:property.
pinShown
Fired whenever this Annotation's pinShown property changes.
Event Payload:
-
valueNumberThe property's new value
primIndex
Fired whenever this Pin's primIndex property changes.
Event Payload:
-
valueObjectNumber The property's new value
title
Fired whenever this Annotation's title property changes.
Event Payload:
-
valueNumberThe property's new value
up
Fired whenever this Annotation's up property changes.
Event Payload:
-
valueNumberThe property's new value
visible
Fired whenever this Pin's visible property changes.
Event Payload:
-
valueObjectFloat32Array The property's new value
worldNormal
Fired whenever this Pin's worldNormal property changes.
worldPos
Fired whenever this Pin's worldPos property changes.