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模型压平功能（可以按照多边形进行不同高度压平）

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jiawanlong 2025-03-21 16:42:39 +08:00
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commit fa6b55da28
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71
examples/cesiumEx/3.1.7、模型压平.html Normal file
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@ -0,0 +1,71 @@
<!--********************************************************************
* by jiawanlong
*********************************************************************-->
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<link rel="stylesheet" href="./../../libs/cesium/Cesium1.98/Widgets/widgets.css">
<script type="text/javascript" src="./../../libs/cesium/Cesium1.98/Cesium.js"></script>
<script src="./flat.js"></script>
</head>
<body style="margin: 0; overflow: hidden; background: #fff; width: 100%; height: 100%; position: absolute; top: 0">
<div id="map" style="margin: 0 auto; width: 100%; height: 100%"></div>
<script type="text/javascript">
Cesium.Ion.defaultAccessToken = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJqdGkiOiI3ZjQ5ZGUzNC1jNWYwLTQ1ZTMtYmNjYS05YTY4ZTVmN2I2MDkiLCJpZCI6MTE3MTM4LCJpYXQiOjE2NzY0NDUyODB9.ZaNSBIfc1sGLhQd_xqhiSsc0yr8oS0wt1hAo9gbke6M'
const viewer = new Cesium.Viewer('map', {});
// 开启帧率
viewer.scene.debugShowFramesPerSecond = true;
const tileset = new Cesium.Cesium3DTileset({
url: "http://mapgl.com/data/model/qx-simiao/tileset.json",
maximumScreenSpaceError: 1,
});
viewer.terrainProvider = new Cesium.CesiumTerrainProvider({
url: 'http://data.mars3d.cn/terrain'
});
tileset.readyPromise
.then(function (tileset) {
viewer.scene.primitives.add(tileset);
viewer.zoomTo(tileset)
var cartographic = Cesium.Cartographic.fromCartesian(tileset.boundingSphere.center);
var surface = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, 0.0);
var offset = Cesium.Cartesian3.fromRadians(cartographic.longitude, cartographic.latitude, 80);
var translation = Cesium.Cartesian3.subtract(offset, surface, new Cesium.Cartesian3());
tileset.modelMatrix = Cesium.Matrix4.fromTranslation(translation.clone());
let arr = [
new Cesium.Cartesian3( -2580727.5168023095, 4650258.972413558, 3508953.4819122115 ),
new Cesium.Cartesian3( -2581252.4920162656, 4650087.404390791, 3508794.900735431 ),
new Cesium.Cartesian3( -2581254.813624642, 4649950.479168881, 3508978.370871617 ),
new Cesium.Cartesian3( -2580723.027766725, 4650025.757869746, 3509279.009217198 ),
]
let flatTool = new Flat(tileset, {
flatHeight: -30
})
flatTool.addRegion({
positions: arr,
id: new Date().getTime()
});
})
.catch(function (error) {
console.log(error);
});
</script>
</body>
</html>

7
examples/cesiumEx/config.js
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@ -548,6 +548,7 @@ var exampleConfig = {
thumbnail: "2.4.6、点击获取子节点.jpg", thumbnail: "2.4.6、点击获取子节点.jpg",
fileName: "2.4.6、点击获取子节点" fileName: "2.4.6、点击获取子节点"
}, },
] ]
}, },
} }
@ -596,6 +597,12 @@ var exampleConfig = {
thumbnail: "3.1.6、点击获取属性.jpg", thumbnail: "3.1.6、点击获取属性.jpg",
fileName: "3.1.6、点击获取属性" fileName: "3.1.6、点击获取属性"
}, },
{
name: "3.1.7、模型压平",
name_en: "3.1.7、模型压平",
thumbnail: "3.1.7、模型压平.jpg",
fileName: "3.1.7、模型压平"
},
] ]
}, },
} }

217
examples/cesiumEx/flat.js Normal file
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/**
* @class
* @description 3dtiles模型压平
*/
class Flat {
/**
*
* @param {Cesium.Cesium3DTileset} tileset 三维模型
* @param {Object} opt
* @param {Number} opt.flatHeight 压平高度
*/
constructor(tileset, opt) {
if (!tileset) return;
this.tileset = tileset;
this.opt = opt || {};
this.flatHeight = this.opt.flatHeight || 0;
this.center = tileset.boundingSphere.center.clone();
this.matrix = Cesium.Transforms.eastNorthUpToFixedFrame(this.center.clone());
this.localMatrix = Cesium.Matrix4.inverse(this.matrix, new Cesium.Matrix4());
// 多面的坐标数组
this.regionList = [];
// 多个面坐标转为局部模型坐标
this.localPositionsArr = [];
}
/**
* 添加压平面
* @param {Object} attr 参数
* @param {Cesium.Cartesian3[]} attr.positions 压平面坐标
* @param {Number} attr.height 压平深度，当前不支持单独设置
* @param {Number} attr.id 唯一标识
*/
addRegion(attr) {
let { positions, height, id } = attr || {};
// this.flatHeight = height;
if (!id) id = (new Date()).getTime() + "" + Number(Math.random() * 1000).toFixed(0);
this.regionList.push(attr);
for (let i = 0; i < this.regionList.length; i++) {
let item = this.regionList[i];
const positions = item.positions;
let localCoor = this.cartesiansToLocal(positions);
this.localPositionsArr.push(localCoor);
}
const funstr = this.getIsinPolygonFun(this.localPositionsArr);
let str = ``;
for (let i = 0; i < this.localPositionsArr.length; i++) {
const coors = this.localPositionsArr[i];
const n = coors.length;
let instr = ``;
coors.forEach((coordinate, index) => {
instr += `points_${n}[${index}] = vec2(${coordinate[0]}, ${coordinate[1]});\n`;
})
str += `
${instr}
if(isPointInPolygon_${n}(position2D)){
vec4 tileset_local_position_transformed = vec4(tileset_local_position.x, tileset_local_position.y, ground_z, 1.0);
vec4 model_local_position_transformed = czm_inverseModel * u_tileset_localToWorldMatrix * tileset_local_position_transformed;
vsOutput.positionMC.xy = model_local_position_transformed.xy;
vsOutput.positionMC.z = model_local_position_transformed.z+ modelMC.z*0.002;
return;
}`;
}
this.updateShader(funstr, str);
}
/**
* 根据id删除压平的面
* @param {String} id 唯一标识
*/
removeRegionById(id) {
if (!id) return;
this.regionList = this.regionList.filter((attr) => {
return attr.id != id;
})
this.localPositionsArr = [];
for (let i = 0; i < this.regionList.length; i++) {
let item = this.regionList[i];
const positions = item.positions;
let localCoor = this.cartesiansToLocal(positions);
this.localPositionsArr.push(localCoor);
}
const funstr = this.getIsinPolygonFun(this.localPositionsArr);
let str = ``;
for (let i = 0; i < this.localPositionsArr.length; i++) {
const coors = this.localPositionsArr[i];
const n = coors.length;
let instr = ``;
coors.forEach((coordinate, index) => {
instr += `points_${n}[${index}] = vec2(${coordinate[0]}, ${coordinate[1]});\n`;
})
str += `
${instr}
if(isPointInPolygon_${n}(position2D)){
vec4 tileset_local_position_transformed = vec4(tileset_local_position.x, tileset_local_position.y, ground_z, 1.0);
vec4 model_local_position_transformed = czm_inverseModel * u_tileset_localToWorldMatrix * tileset_local_position_transformed;
vsOutput.positionMC.xy = model_local_position_transformed.xy;
vsOutput.positionMC.z = model_local_position_transformed.z+ modelMC.z*0.002;
return;
}`;
}
this.updateShader(funstr, str);
}
/**
* 销毁
*/
destroy() {
this.tileset.customShader = undefined;
}
/**
* 根据数组长度，构建 判断点是否在面内 的压平函数
*/
getIsinPolygonFun(polygons) {
let pmap = polygons.map((polygon) => polygon.length);
let uniqueArray = this.getUniqueArray(pmap);
let str = ``;
uniqueArray.forEach(length => {
str += `
vec2 points_${length}[${length}];
bool isPointInPolygon_${length}(vec2 point){
int nCross = 0; // 交点数
const int n = ${length};
for(int i = 0; i < n; i++){
vec2 p1 = points_${length}[i];
vec2 p2 = points_${length}[int(mod(float(i+1),float(n)))];
if(p1[1] == p2[1]){
continue;
}
if(point[1] < min(p1[1], p2[1])){
continue;
}
if(point[1] >= max(p1[1], p2[1])){
continue;
}
float x = p1[0] + ((point[1] - p1[1]) * (p2[0] - p1[0])) / (p2[1] - p1[1]);
if(x > point[0]){
nCross++;
}
}
return int(mod(float(nCross), float(2))) == 1;
}
`
})
return str
}
updateShader(vtx1, vtx2) {
let flatCustomShader = new Cesium.CustomShader({
uniforms: {
u_tileset_localToWorldMatrix: {
type: Cesium.UniformType.MAT4,
value: this.matrix,
},
u_tileset_worldToLocalMatrix: {
type: Cesium.UniformType.MAT4,
value: this.localMatrix,
},
u_flatHeight: {
type: Cesium.UniformType.FLOAT,
value: this.flatHeight,
},
},
vertexShaderText: `
// 所有isPointInPolygon函数
${vtx1}
void vertexMain(VertexInput vsInput, inout czm_modelVertexOutput vsOutput){
vec3 modelMC = vsInput.attributes.positionMC;
vec4 model_local_position = vec4(modelMC.x, modelMC.y, modelMC.z, 1.0);
vec4 tileset_local_position = u_tileset_worldToLocalMatrix * czm_model * model_local_position;
vec2 position2D = vec2(tileset_local_position.x,tileset_local_position.y);
float ground_z = 0.0 + u_flatHeight;
// 多个多边形区域
${vtx2}
}`,
});
this.tileset.customShader = flatCustomShader;
}
// 数组去重，不能处理嵌套的数组
getUniqueArray = (arr) => {
return arr.filter(function (item, index, arr) {
//当前元素，在原始数组中的第一个索引==当前索引值，否则返回当前元素
return arr.indexOf(item, 0) === index;
});
}
// 世界坐标转数组局部坐标
cartesiansToLocal(positions) {
let arr = [];
for (let i = 0; i < positions.length; i++) {
let position = positions[i];
let localp = Cesium.Matrix4.multiplyByPoint(
this.localMatrix,
position.clone(),
new Cesium.Cartesian3()
)
arr.push([localp.x, localp.y]);
}
return arr;
}
}

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