FrameRateMonitor

new Cesium.FrameRateMonitor(options)

Monitors the frame rate (frames per second) in a Scene and raises an event if the frame rate is lower than a threshold. Later, if the frame rate returns to the required level, a separate event is raised. To avoid creating multiple FrameRateMonitors for a single Scene, use FrameRateMonitor.fromScene instead of constructing an instance explicitly.
Name Type Description
options Object optional Object with the following properties:
Name Type Default Description
scene Scene The Scene instance for which to monitor performance.
samplingWindow Number 5.0 optional The length of the sliding window over which to compute the average frame rate, in seconds.
quietPeriod Number 2.0 optional The length of time to wait at startup and each time the page becomes visible (i.e. when the user switches back to the tab) before starting to measure performance, in seconds.
warmupPeriod Number 5.0 optional The length of the warmup period, in seconds. During the warmup period, a separate (usually lower) frame rate is required.
minimumFrameRateDuringWarmup Number 4 optional The minimum frames-per-second that are required for acceptable performance during the warmup period. If the frame rate averages less than this during any samplingWindow during the warmupPeriod, the lowFrameRate event will be raised and the page will redirect to the redirectOnLowFrameRateUrl, if any.
minimumFrameRateAfterWarmup Number 8 optional The minimum frames-per-second that are required for acceptable performance after the end of the warmup period. If the frame rate averages less than this during any samplingWindow after the warmupPeriod, the lowFrameRate event will be raised and the page will redirect to the redirectOnLowFrameRateUrl, if any.

Members

staticCesium.FrameRateMonitor.defaultSettings : Object

The default frame rate monitoring settings. These settings are used when FrameRateMonitor.fromScene needs to create a new frame rate monitor, and for any settings that are not passed to the FrameRateMonitor constructor.

lastFramesPerSecond : Number

Gets the most recently computed average frames-per-second over the last samplingWindow. This property may be undefined if the frame rate has not been computed.

lowFrameRate : Event

Gets the event that is raised when a low frame rate is detected. The function will be passed the Scene instance as its first parameter and the average number of frames per second over the sampling window as its second parameter.

minimumFrameRateAfterWarmup : Number

Gets or sets the minimum frames-per-second that are required for acceptable performance after the end of the warmup period. If the frame rate averages less than this during any samplingWindow after the warmupPeriod, the lowFrameRate event will be raised and the page will redirect to the redirectOnLowFrameRateUrl, if any.

minimumFrameRateDuringWarmup : Number

Gets or sets the minimum frames-per-second that are required for acceptable performance during the warmup period. If the frame rate averages less than this during any samplingWindow during the warmupPeriod, the lowFrameRate event will be raised and the page will redirect to the redirectOnLowFrameRateUrl, if any.

nominalFrameRate : Event

Gets the event that is raised when the frame rate returns to a normal level after having been low. The function will be passed the Scene instance as its first parameter and the average number of frames per second over the sampling window as its second parameter.

quietPeriod : Number

Gets or sets the length of time to wait at startup and each time the page becomes visible (i.e. when the user switches back to the tab) before starting to measure performance, in seconds.

samplingWindow : Number

Gets or sets the length of the sliding window over which to compute the average frame rate, in seconds.

scene : Scene

Gets the Scene instance for which to monitor performance.

warmupPeriod : Number

Gets or sets the length of the warmup period, in seconds. During the warmup period, a separate (usually lower) frame rate is required.

Methods

staticCesium.FrameRateMonitor.fromScene(scene) → FrameRateMonitor

Gets the FrameRateMonitor for a given scene. If the scene does not yet have a FrameRateMonitor, one is created with the FrameRateMonitor.defaultSettings.
Name Type Description
scene Scene The scene for which to get the FrameRateMonitor.
Returns:
The scene's FrameRateMonitor.

destroy() → undefined

Unsubscribes this instance from all events it is listening to. Once an object is destroyed, it should not be used; calling any function other than isDestroyed will result in a DeveloperError exception. Therefore, assign the return value (undefined) to the object as done in the example.
Returns:
Throws:
  • DeveloperError : This object was destroyed, i.e., destroy() was called.
See:

isDestroyed() → Boolean

Returns true if this object was destroyed; otherwise, false.

If this object was destroyed, it should not be used; calling any function other than isDestroyed will result in a DeveloperError exception.
Returns:
True if this object was destroyed; otherwise, false.
See:

pause()

Pauses monitoring of the frame rate. To resume monitoring, FrameRateMonitor#unpause must be called once for each time this function is called.

unpause()

Resumes monitoring of the frame rate. If FrameRateMonitor#pause was called multiple times, this function must be called the same number of times in order to actually resume monitoring.