VisiblityAnalysis

Example:

// 1. 给定观察点与目标点进行通视分析
var visiblity = new Cesium.VisiblityAnalysis({ scene: scene });
scene.visualAnalysisManager.add(visiblity);
visiblity.viewPosition = new Cesium.Cartesian3(6378138.905101178, 22.20128910645181, 16.69161471354458);
visiblity.targetPosition = new Cesium.Cartesian3(6378158.153515804, 47.68794749465568, 34.93181937554349);

// 2. 监听鼠标事件进行通视分析
var visiblityAction = true;
var visiblitying = false;
var handler = new Cesium.ScreenSpaceEventHandler(viewer.scene.canvas);
// 左键开始
handler.setInputAction(function (movement) {
    if (visiblity !== undefined) {
        if (visiblityAction) {
            var cartesian = viewer.scene.pickPosition(movement.position);
            var cartographic = Cesium.Cartographic.fromCartesian(cartesian);
            cartographic.height += 1.0; //避免埋入模型中
            cartesian = Cesium.Cartographic.toCartesian(cartographic);
            if (cartesian !== undefined && !visiblitying) {
                visiblity.viewPosition = cartesian;
            } else {
                visiblity.targetPosition = cartesian;
                visiblityAction = false;
            }
            visiblitying = true;
        }
        console.log(visiblity.viewPosition);
    }
}, Cesium.ScreenSpaceEventType.LEFT_CLICK);
//鼠标右键结束
handler.setInputAction(function (movement) {
    if (visiblitying) {
        var cartesian = viewer.scene.pickPosition(movement.position);
        if (cartesian !== undefined) {
            visiblity.targetPosition = cartesian;
        }
        visiblityAction = false;
        visiblitying = false;
    }
}, Cesium.ScreenSpaceEventType.RIGHT_CLICK);
handler.setInputAction(function (movement) {
    if (visiblitying) {
        var cartesian = viewer.scene.pickPosition(movement.endPosition);
        if (cartesian) {
            visiblity.targetPosition = cartesian;
        }
    }
}, Cesium.ScreenSpaceEventType.MOUSE_MOVE);

// 3. 创建环形通视分析
var drawElement = new Cesium.DrawElement(viewer);
drawElement.startDrawingCircle({
    color: new Cesium.Color(0.2, 0.4, 0.3, 1.0),
    callback: function (result) {
        drawElement.stopDrawing();
        visiblity.lookAroundAnalysis({
            viewPosition: result.center,
            radius: result.radius,
            percentCallback: function (percent) {
                console.log(percent);
            }
        });
    }
});

// 4. 移除通视分析
scene.visualAnalysisManager.remove(visiblity);
visiblity.destroy();