scheduling

Method Overview

Method Details

addFrameTask(phases){FrameTaskHandle}static

Registers a frame task. An animation frame is composed of different phases to let various actors execute code before, after, or during the rendering of MapView or SceneView.

Parameter

phases PhaseCallbacks The callbacks for each phase of the frame.

Returns

Type	Description
FrameTaskHandle	A handle to remove, pause, or resume the frame task.

Example

// Animate the scene view camera heading in every frame
let handle = scheduling.addFrameTask({
  update: function() {
    let camera = view.camera.clone();
    camera.heading += 0.2;
    view.camera = camera;
  }
});

// Remove frame task as soon as the user starts navigating in the view
reactiveUtils.whenOnce(() => view.navigating, () => handle.remove());

schedule(callback){Object}static

Schedules the execution of a callback function at the next web browser tick. Unlike addFrameTask, a scheduled callback will only run once. Scheduling a task for the next execution tick can be useful when you want to throttle/accumulate functionality over a single javascript execution context.

Parameter

callback Function The function to call at the next tick.

Returns

Type	Description
Object	Returns an scheduling handler with a remove() method that can be called to prevent the callback to be called at the next tick. Property Type Description remove Function When called, removes the callback from the callbacks queue.

Example

// Use scheduling.schedule to log an error message at most once per tick
let logErrorHandle;

function logError(error) {
  if (!logErrorHandle) {
    logErrorHandle = scheduling.schedule(function() {
      console.error(error);
      logErrorHandle = null;
    });
  }
});

Type Definitions

FrameTaskHandle Object

An object to remove or pause a frame task registered with addFrameTask().

Properties

pause Function Pause the execution the frame task at every frame.

resume Function Resumes the execution the frame task.

remove Function Removes the frame task.

PhaseCallback(event)

A function called at a specific phase of the animation frame.

Parameter

event PhaseEvent optional An object with timing information.

PhaseCallbacks Object

A set of callbacks that will be called at specific phases of the animation frame.

Properties

prepare PhaseCallback optional A callback called before rendering.

render PhaseCallback optional A callback to execute rendering logic.

update PhaseCallback optional A callback to execute state update logic.

PhaseEvent Object

An object with timing information.

Properties

time Number The absolute time at the start of the current animation frame.

deltaTime Number The elapsed time since the last animation frame.

elapsedFrameTime Number The amount of time spent within the current animation frame. This can be used for budgeting (e.g. some tasks may already have run).