viewerPerformanceWatchdogMixin

viewerPerformanceWatchdogMixin是一个Cesium.js的混合对象，用于监测Cesium Viewer的性能表现。

定义

var viewer = new Cesium.Viewer('cesiumContainer');

Cesium.viewerPerformanceWatchdogMixin(viewer);

方法和属性

_cesiumViewerPerformanceWatchdogMixin

用于指定该混合对象是属于Cesium的，避免命名冲突。

performanceWatchdog

Cesium PerformanceWatchdog对象，用于监测Cesium Viewer的性能表现。

属性

lowFrameRateMessage

当Cesium Viewer的帧率低于可接受的范围时，显示在控制台的消息文本。默认值为 The rendering engine is not keeping up with the expected framerate.

goodFrameRateCallback

当Cesium Viewer的帧率恢复到可接受的范围时，所执行的回调函数。该回调被传入当前 Viewer 对象以及实时帧率（以 Hz 为单位）。

function goodFrameRateCallback(viewer, fps) {
    console.log("Viewer's FPS:", fps);
}

lowFrameRateCallback

当Cesium Viewer的帧率低于可接受的范围时，所执行的回调函数。该回调被传入当前 Viewer 对象以及实时帧率（以 Hz 为单位）.

function lowFrameRateCallback(viewer, fps) {
    console.warn("Viewer's FPS is too low:", fps);
}

lowFrameRateTrigger

定义了低帧率下限。如果帧率低于这个下限，它会触发lowFrameRateCallback。默认值是5。

var performanceWatchdog = viewer.performanceWatchdog;
performanceWatchdog.lowFrameRateTrigger = 10;

minimumFrameRateAfterWarmup

定义的performanceWatchdog的足够高的帧率是多少。默认值是20。

samplingWindow

定义从c位置开始之前的帧范围，在该时间范围内，帧率的平均值将被监控。默认值是30.

var performanceWatchdog = viewer.performanceWatchdog;
performanceWatchdog.samplingWindow = 60;

warmupPeriod

以秒为单位定义performanceWatchdog冷启动阶段的持续时间。在此期间, performanceWatchdog将仅仅持续记录帧率。当过去的时间超过这个值后，performanceWatchdog将开始触发goodFrameRateCallback，lowFrameRateCallback将在触发之前立即触发前缀事件。默认值为5.

var performanceWatchdog = viewer.performanceWatchdog;
performanceWatchdog.warmupPeriod = 10;

方法

evenStart

开始统计帧率

var performanceWatchdog = viewer.performanceWatchdog;
performanceWatchdog.evenStart();

eventEnd

结束统计帧率

var performanceWatchdog = viewer.performanceWatchdog;
performanceWatchdog.eventEnd();

update

更新性能监控的触发器。这将更新当前帧率，并根据活动的值调用回调。

var performanceWatchdog = viewer.performanceWatchdog;
performanceWatchdog.update();

destroy

删除已设定的性能监控触发器。

var performanceWatchdog = viewer.performanceWatchdog;
performanceWatchdog.destroy();

示例

var viewer = new Cesium.Viewer('cesiumContainer');

Cesium.viewerPerformanceWatchdogMixin(viewer);
var performanceWatchdog = viewer.performanceWatchdog;

performanceWatchdog.lowFrameRateCallback = function(viewer, fps) {
    console.warn("Viewer's FPS is too low:", fps);
};

performanceWatchdog.goodFrameRateCallback = function(viewer, fps) {
    console.log("Viewer's FPS:", fps);
};

performanceWatchdog.lowFrameRateTrigger = 10;
performanceWatchdog.minimumFrameRateAfterWarmup = 20;
performanceWatchdog.samplingWindow = 60;
performanceWatchdog.warmupPeriod = 10;

performanceWatchdog.watchFrameRate();

参考

cesiumjs