cesium 3dtiles模型单体化点击高亮效果

前言

cesium 官网的api文档介绍地址cesium官网api，里面详细的介绍 cesium 各个类的介绍，还有就是在线例子：cesium 官网在线例子，这个也是学习 cesium 的好素材。

cesium官网在线例子

https://sandcastle.cesium.com/?src=3D+Tiles+Feature+Picking.html

大概思路如下：

• 加载3dtiles模型

var tileset = new Cesium.Cesium3DTileset({
url: Cesium.IonResource.fromAssetId(75343),
});
viewer.scene.primitives.add(tileset);

• 创建html元素，鼠标移动以及点击模型高亮作用

// HTML overlay for showing feature name on mouseover
var nameOverlay = document.createElement("div");
viewer.container.appendChild(nameOverlay);
nameOverlay.className = "backdrop";
nameOverlay.style.display = "none";
nameOverlay.style.position = "absolute";
nameOverlay.style.bottom = "0";
nameOverlay.style.left = "0";
nameOverlay.style["pointer-events"] = "none";
nameOverlay.style.padding = "4px";
nameOverlay.style.backgroundColor = "black";

• 设置选中要素的样式以及创建选中模型

// Information about the currently selected feature
var selected = {
feature: undefined,
originalColor: new Cesium.Color(),
};

// An entity object which will hold info about the currently selected feature for infobox display
var selectedEntity = new Cesium.Entity();

• 鼠标响应事件交互

// 获取默认的左键单击处理程序，用于在左键单击时未拾取要素
var clickHandler = viewer.screenSpaceEventHandler.getInputAction(
Cesium.ScreenSpaceEventType.LEFT_CLICK
);

// 如果支持剪影，则鼠标上方的剪影功能为蓝色，鼠标单击的剪影功能为绿色
// 如果不支持轮廓，请将特征颜色更改为鼠标悬停时为黄色，单击鼠标时为绿色
if (
Cesium.PostProcessStageLibrary.isSilhouetteSupported(viewer.scene)
) {
// 支持轮廓
var silhouetteBlue = Cesium.PostProcessStageLibrary.createEdgeDetectionStage();
silhouetteBlue.uniforms.color = Cesium.Color.BLUE;//蓝色
silhouetteBlue.uniforms.length = 0.01;
silhouetteBlue.selected = [];

var silhouetteGreen = Cesium.PostProcessStageLibrary.createEdgeDetectionStage();
silhouetteGreen.uniforms.color = Cesium.Color.LIME;
silhouetteGreen.uniforms.length = 0.01;
silhouetteGreen.selected = [];

viewer.scene.postProcessStages.add(
Cesium.PostProcessStageLibrary.createSilhouetteStage([
silhouetteBlue,
silhouetteGreen,
])
);

// 在悬停时勾勒出蓝色的轮廓
viewer.screenSpaceEventHandler.setInputAction(function onMouseMove(
movement
) {
// 如果先前高亮显示了某个要素，请撤消该高亮显示
silhouetteBlue.selected = [];

//点击新要素
var pickedFeature = viewer.scene.pick(movement.endPosition);
if (!Cesium.defined(pickedFeature)) {
nameOverlay.style.display = "none";
return;
}

//要素被点击，显示它的覆盖内容
nameOverlay.style.display = "block";
nameOverlay.style.bottom =
viewer.canvas.clientHeight - movement.endPosition.y + "px";
nameOverlay.style.left = movement.endPosition.x + "px";
var name = pickedFeature.getProperty("BIN");
nameOverlay.textContent = name;

// 突出显示尚未选定的功能
if (pickedFeature !== selected.feature) {
silhouetteBlue.selected = [pickedFeature];
}
},
Cesium.ScreenSpaceEventType.MOUSE_MOVE);

// 在信息框中显示选定内容和元数据
viewer.screenSpaceEventHandler.setInputAction(function onLeftClick(
movement
) {
// 如果先前选择了某个特征，请撤消高亮显示
silhouetteGreen.selected = [];

// 点击新要素
var pickedFeature = viewer.scene.pick(movement.position);
if (!Cesium.defined(pickedFeature)) {
clickHandler(movement);
return;
}

// Select the feature if it's not already selected
if (silhouetteGreen.selected[0] === pickedFeature) {
return;
}

// 保存选定要素的原始颜色
var highlightedFeature = silhouetteBlue.selected[0];
if (pickedFeature === highlightedFeature) {
silhouetteBlue.selected = [];
}

// 高亮新选择要素
silhouetteGreen.selected = [pickedFeature];

// 设置要素信息框描述
var featureName = pickedFeature.getProperty("name");
selectedEntity.name = featureName;
selectedEntity.description =
'Loading <div class="cesium-infoBox-loading"></div>';
viewer.selectedEntity = selectedEntity;
selectedEntity.description =
'<table class="cesium-infoBox-defaultTable"><tbody>' +
"<tr><th>BIN</th><td>" +
pickedFeature.getProperty("BIN") +
"</td></tr>" +
"<tr><th>DOITT ID</th><td>" +
pickedFeature.getProperty("DOITT_ID") +
"</td></tr>" +
"<tr><th>SOURCE ID</th><td>" +
pickedFeature.getProperty("SOURCE_ID") +
"</td></tr>" +
"</tbody></table>";
},
Cesium.ScreenSpaceEventType.LEFT_CLICK);
} else {
// 不支持轮廓。相反，更改特征颜色
// 有关当前突出显示的功能的信息
var highlighted = {
feature: undefined,
originalColor: new Cesium.Color(),
};

// 鼠标移动显示黄色
viewer.screenSpaceEventHandler.setInputAction(function onMouseMove(
movement
) {
// 如果先前高亮显示了某个要素，请撤消该高亮显示
if (Cesium.defined(highlighted.feature)) {
highlighted.feature.color = highlighted.originalColor;
highlighted.feature = undefined;
}
// 点击新要素
var pickedFeature = viewer.scene.pick(movement.endPosition);
if (!Cesium.defined(pickedFeature)) {
nameOverlay.style.display = "none";
return;
}
// 要素被点击，显示它的覆盖内容
nameOverlay.style.display = "block";
nameOverlay.style.bottom =
viewer.canvas.clientHeight - movement.endPosition.y + "px";
nameOverlay.style.left = movement.endPosition.x + "px";
var name = pickedFeature.getProperty("name");
if (!Cesium.defined(name)) {
name = pickedFeature.getProperty("id");
}
nameOverlay.textContent = name;
// Highlight the feature if it's not already selected.
if (pickedFeature !== selected.feature) {
highlighted.feature = pickedFeature;
Cesium.Color.clone(
pickedFeature.color,
highlighted.originalColor
);
pickedFeature.color = Cesium.Color.YELLOW;
}
},
Cesium.ScreenSpaceEventType.MOUSE_MOVE);

//为所选内容上色并在信息框中显示元数据
viewer.screenSpaceEventHandler.setInputAction(function onLeftClick(
movement
) {
// 如果先前选择了某个特征，请撤消高亮显示
if (Cesium.defined(selected.feature)) {
selected.feature.color = selected.originalColor;
selected.feature = undefined;
}
// 点击新要素
var pickedFeature = viewer.scene.pick(movement.position);
if (!Cesium.defined(pickedFeature)) {
clickHandler(movement);
return;
}
// Select the feature if it's not already selected
if (selected.feature === pickedFeature) {
return;
}
selected.feature = pickedFeature;
// Save the selected feature's original color
if (pickedFeature === highlighted.feature) {
Cesium.Color.clone(
highlighted.originalColor,
selected.originalColor
);
highlighted.feature = undefined;
} else {
Cesium.Color.clone(pickedFeature.color, selected.originalColor);
}
// Highlight newly selected feature
pickedFeature.color = Cesium.Color.LIME;
// Set feature infobox description
var featureName = pickedFeature.getProperty("name");
selectedEntity.name = featureName;
selectedEntity.description =
'Loading <div class="cesium-infoBox-loading"></div>';
viewer.selectedEntity = selectedEntity;
selectedEntity.description =
'<table class="cesium-infoBox-defaultTable"><tbody>' +
"<tr><th>BIN</th><td>" +
pickedFeature.getProperty("BIN") +
"</td></tr>" +
"<tr><th>DOITT ID</th><td>" +
pickedFeature.getProperty("DOITT_ID") +
"</td></tr>" +
"<tr><th>SOURCE ID</th><td>" +
pickedFeature.getProperty("SOURCE_ID") +
"</td></tr>" +
"<tr><th>Longitude</th><td>" +
pickedFeature.getProperty("longitude") +
"</td></tr>" +
"<tr><th>Latitude</th><td>" +
pickedFeature.getProperty("latitude") +
"</td></tr>" +
"<tr><th>Height</th><td>" +
pickedFeature.getProperty("height") +
"</td></tr>" +
"<tr><th>Terrain Height (Ellipsoid)</th><td>" +
pickedFeature.getProperty("TerrainHeight") +
"</td></tr>" +
"</tbody></table>";
},
Cesium.ScreenSpaceEventType.LEFT_CLICK);

其他小专栏例子：3dtiles单体化

https://xiaozhuanlan.com/topic/3241096587
具体看上述链接文章，里面有详细的介绍

本篇文章效果例子：结合geoserver实现3dtiles倾斜模型单体化点击高亮

实现思路如下：鼠标点击倾斜模型，获取对应的点击坐标点；然后根据pick获取到的坐标点，结合geoserver发布的wfs服务，进行空间查询，匹配对应的geojson数据；最后根据获取到的geojson数据源来绘制显示高亮效果，并且弹出对应气泡窗口。

效果图：

• 监听鼠标点击事件：

this.handler.setInputAction(function (evt) { //单机开始绘制
var picks = viewer.scene.drillPick(evt.position);
viewer.scene.render();
var cartesian;
var isOn3dtiles = false;
for (var i = 0; i < picks.length; i++) {
if ((picks[i] && picks[i].primitive) || picks[i] instanceof Cesium.Cesium3DTileFeature) { //模型上拾取
isOn3dtiles = true;
}
}
if (isOn3dtiles) {
cartesian = viewer.scene.pickPosition(evt.position);
var lnglat = cUtil.cartesianToLnglat(cartesian);//坐标转换
that.queryWFSData([lnglat]);
} else {
console.warn("请到模型上拾取！");
return;
}
}, Cesium.ScreenSpaceEventType.LEFT_CLICK);

• geoserver空间查询，具体的wfs服务空间查询参数那些可以参照这篇文章，cesium结合geoserver实现地图空间查询(附源码下载)：

queryWFSData: function (lnglats) {
if (!lnglats || lnglats.length < 1) return;
var that = this;
queryWFSData({
typeName: typeName,
propertyName: propertyName,
url: mapUrl,
queryData: {
type: '1',
coors: lnglats
},
success: function (data) {
if (!data.features || data.features.length == 0) {
console.warn("未查询到相关数据！");
return;
}
that.loadGeojson(data);//查询结果高亮绘制显示
}
})
}

• 高亮绘制显示：

loadGeojson: function (data) {
if (!data) return;
var that = this;
Cesium.GeoJsonDataSource.load(data, {
stroke: Cesium.Color.HOTPINK,
fill: Cesium.Color.YELLOW.withAlpha(.8),
clampToGround: true,
strokeWidth: 3
}).then(function (dataSource) {
that.quyerDataSourceArr.push(dataSource);
viewer.dataSources.add(dataSource);
var entities = dataSource.entities.values;
that.bindPopup(entities);
viewer.flyTo(entities, {
offset: new Cesium.HeadingPitchRange(0, Cesium.Math.toRadians(-90.0), 100)
});
});
}

• 气泡窗口显示：

bindPopup: function (entities) {
if (!entities || entities.length < 1) return;
var that = this;
entities.forEach(function (ent) {
ent.attr = "loadgeojson";
var properties = ent._properties;
var contentStr = "";
for (var i in properties) {
var name = ppObj[i];
var value = properties[i]._value;
if (name && value) {
contentStr +=
`
<tr>
<td>${name}</td>
<td>${value}</td>
</tr>
`;
}
}
var content =
`
<table style='width:200px;'>
${contentStr}
</table>
`;
//绑定弹窗
var hierarchy = ent.polygon.hierarchy._value.positions;
var center = cUtil.getCenterByPositions(hierarchy);
var lnglat = cUtil.cartesianToLnglat(center);
var tileH = viewer.scene.sampleHeight(Cesium.Cartographic.fromDegrees(lnglat[0], lnglat[1]));
var popupCartesian = Cesium.Cartesian3.fromDegrees(lnglat[0], lnglat[1], tileH);
var popup = new MovePrompt(viewer, {
type: 2,
content: content,
popupCartesian: popupCartesian,
offset: {
y: -30
}
})
that.popupArr.push(popup);
ent.popup = popup;
});
}

更多精彩文章，见下面的cesium小专栏：

GIS之家/Cesium专题 － 小专栏​xiaozhuanlan.com