Private _availablePrivate _imagesPrivate _managerPrivate _supportedTrue if Image Tracking is available. This information is only available when the XR session has started, and will be true if image tracking is supported and images were provided and they have been processed successfully.
List of XrTrackedImage that contain tracking information.
True if Image Tracking is supported.
Private _onPrivate _onAdd an image for image tracking. A width can also be provided to help the underlying system estimate the appropriate transformation. Modifying the tracked images list is only possible before an AR session is started.
Image that is matching real world image as close as possible. Resolution of images should be at least 300x300. High resolution does NOT improve tracking performance. Color of image is irrelevant, so grayscale images can be used. Images with too many geometric features or repeating patterns will reduce tracking stability.
Width (in meters) of image in the real world. Providing this value as close to the real value will improve tracking quality.
Tracked image object that will contain tracking information. Returns null if image tracking is not supported or if the XR manager is not active.
// image of a book cover that has width of 20cm (0.2m)
app.xr.imageTracking.add(bookCoverImg, 0.2);
Fire an event, all additional arguments are passed on to the event listener.
Name of event to fire.
Optional arg1: anyFirst argument that is passed to the event handler.
Optional arg2: anySecond argument that is passed to the event handler.
Optional arg3: anyThird argument that is passed to the event handler.
Optional arg4: anyFourth argument that is passed to the event handler.
Optional arg5: anyFifth argument that is passed to the event handler.
Optional arg6: anySixth argument that is passed to the event handler.
Optional arg7: anySeventh argument that is passed to the event handler.
Optional arg8: anyEighth argument that is passed to the event handler.
Self for chaining.
obj.fire('test', 'This is the message');
Test if there are any handlers bound to an event name.
The name of the event to test.
True if the object has handlers bound to the specified event name.
obj.on('test', function () { }); // bind an event to 'test'
obj.hasEvent('test'); // returns true
obj.hasEvent('hello'); // returns false
Detach an event handler from an event. If callback is not provided then all callbacks are unbound from the event, if scope is not provided then all events with the callback will be unbound.
Optional name: stringName of the event to unbind.
Optional callback: HandleEventCallbackFunction to be unbound.
Optional scope: objectScope that was used as the this when the event is fired.
Self for chaining.
const handler = function () {
};
obj.on('test', handler);
obj.off(); // Removes all events
obj.off('test'); // Removes all events called 'test'
obj.off('test', handler); // Removes all handler functions, called 'test'
obj.off('test', handler, this); // Removes all handler functions, called 'test' with scope this
Attach an event handler to an event.
Name of the event to bind the callback to.
Function that is called when event is fired. Note the callback is limited to 8 arguments.
Optional scope: object = ...Object to use as 'this' when the event is fired, defaults to current this.
Can be used for removing event in the future.
obj.on('test', function (a, b) {
console.log(a + b);
});
obj.fire('test', 1, 2); // prints 3 to the console
const evt = obj.on('test', function (a, b) {
console.log(a + b);
});
// some time later
evt.off();
Attach an event handler to an event. This handler will be removed after being fired once.
Name of the event to bind the callback to.
Function that is called when event is fired. Note the callback is limited to 8 arguments.
Optional scope: object = ...Object to use as 'this' when the event is fired, defaults to current this.
obj.once('test', function (a, b) {
console.log(a + b);
});
obj.fire('test', 1, 2); // prints 3 to the console
obj.fire('test', 1, 2); // not going to get handled
Remove an image from image tracking.
Tracked image to be removed. Modifying the tracked images list is only possible before an AR session is started.
Static EVENT_Fired when the XR session is started, but image tracking failed to process the provided images. The handler is passed the Error object.
app.xr.imageTracking.on('error', (err) => {
console.error(err.message);
});
Image Tracking provides the ability to track real world images using provided image samples and their estimated sizes. The underlying system will assume that tracked image can move and rotate in the real world and will try to provide transformation estimates and its tracking state.