context Class
context includes some general functions which allow interaction
with system components.
The Singleton instance of the class will automatically be created on World
startup and can be accessed via AR.context.
context also allows for some custom functionality, for example
onLocationChanged, which will be triggered by the system as soon as the
user's location changes. It enables the developer to find out about the
user's location and thus setup the AR scene to his needs.
AR.context.onLocationChanged = function(latitude, longitude, altitude, accuracy){ //now, add custom functionality to build the AR scene based on the location ... }
Item Index
Properties
- clickBehavior
- hardware.flashlight deprecated
- hardware.flashlightAvailable deprecated
- scene.cullingDistance
- scene.globalScale
- scene.maxScalingDistance
- scene.minScalingDistance
- scene.scalingFactor
- services.camera deprecated
- services.sensors deprecated
- versionNumber
Events
Methods
destroyAll
()
Destroys all objects.
See AR.ARchitectObject.destroy() for effects of this call.
openInBrowser
-
url
-
forceNativeBrowser
Opens the specified url in the native Browser. If forceNativeBrowser is true, the URL will be opened in the native browser (e.g. Safari on iOS), otherwise it will be opened in a new webview.
setCloudRecognitionServerRegion
-
region
-
options
Sets the desired server region to be used. Regions can be chosen among the Americas, China and Europe with Europe being the default behaviour. Invalid input parameters results in Europe silently being chosen.
Parameters:
-
region
Stringinteger value identifying the region {1 : Americas, 2 : China, 3 : Europe} Please refer to the CONST.js file for the definition of the region enumeration.
-
options
Object optionalAdditional Parameters to explicitly specify the cloud recognition server by URL.
Accepted options-properties are
startVideoPlayer
-
uri
Starts the native video player and plays the video at the specified URI. Will close the video player automatically when the video finished.
Parameters:
-
uri
Stringthe uri to the video
Properties
clickBehavior
String
clickBehavior controls what should be considered a click. The following options are available:
- AR.CONST.CLICK_BEHAVIOR.CLICK: the platform considers a click only when the user presses and releases the screen at the same screen region. The click is fired after the user releases the finger from the screen
- AR.CONST.CLICK_BEHAVIOR.TOUCH_DOWN: click fires as soon as the user touches the screen
- AR.CONST.CLICK_BEHAVIOR.TOUCH_UP: click fires as soon as the user puts the finger off the screen, regardless of where the user started the touch on the screen.
Default: AR.CONST.CLICK_BEHAVIOR.CLICK
scene.cullingDistance
Number
The maximum distance at which objects are visible in the scene, in meters. If an object's distance to the user is further than the culling distance, the object will not be visible in the scene. Must be a positive whole number.
Default: 50000
scene.globalScale
Float
The amount of scaling that is applied to all drawables in the scene. Use this value to alter the drawable size on different devices so that the world appears in a common look when running on different devices.
Must be in the range of [-1, MAX_FLOAT].
Setting the global scale to 0 will scale all drawables to a size of 0.
Setting the global scale to -1 indicates that the SDK should calculate the value by itself, so that all drawables are equal in pixel size among different devices.
Automatic Scaling
The reference device is a 4 inch iPhone screen (e.g. iPhone 5). All other devices will adjust their global scale so that drawables will appear in the size as if the world would run on the reference device.
Default: 1.0
scene.maxScalingDistance
Number
The distance, in meters, at which objects will keep their size on the screen even when the user moves further away. If the user is further than maxScalingDistance, the object will not appear any smaller than the size it took on at maxScalingDistance. Must be a positive whole number.
Default: 20000
scene.minScalingDistance
Number
The distance, in meters, at which objects will start to appear smaller on the screen when the user moves further away. If the user is closer than minScalingDistance, the object will not appear any bigger than the size it took on at minScalingDistance. Must be a positive whole number.
Default: 10
scene.scalingFactor
Number
The amount of scaling that is applied between minScalingDistance and maxScalingDistance.
The scalingFactor controls the size the object takes on at maxScalingDistance, in percentage of the size it took on at minScalingDistance.
Must be in the range of [0,1].
Set the scalingFactor to 1 if no scaling should be applied for the objects.
Default: 0.1
versionNumber
String
Returns the Wikitude SDK version number. The string is formatted in a dot notation with a major, minor and bugfix part. E.g. 4.0.0
Events
onLocationChanged
The function will be called as soon as
- the location is fetched the first time, or
- the location of the user changes.
The trigger is null by default, and will thus result in no action executed when the trigger fires. A developer can add custom functionality by assigning a custom function to onLocationChanged.
Event Payload:
onScreenClick
Executed when the user clicks on the screen, no HTML element was hit and either
- no Drawable was hit on the click, or
- Drawables were hit on the click, but even the last Drawable in the click queue returned false in its onClick trigger.
See AR.Drawable.onClick() for details on the click-queue.