mirror of
https://github.com/jiawanlong/Cesium-Examples.git
synced 2025-07-04 15:17:36 +00:00
217 lines
7.7 KiB
HTML
217 lines
7.7 KiB
HTML
<!--********************************************************************
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* by jiawanlong
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*********************************************************************-->
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<!DOCTYPE html>
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<html>
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<head>
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<meta charset="UTF-8" />
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<link rel="stylesheet" href="./../../libs/cesium/Cesium1.98/Widgets/widgets.css" />
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<script type="text/javascript" src="./../../libs/cesium/Cesium1.98/Cesium.js"></script>
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<script src="https://unpkg.com/axios/dist/axios.min.js"></script>
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<script src="./turf.min.js"></script>
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</head>
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<body style="
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margin: 0;
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overflow: hidden;
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">
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<div id="map" style="margin: 0 auto; width: 100%; height: 100vh"></div>
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<script type="text/javascript">
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Cesium.Ion.defaultAccessToken =
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"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJqdGkiOiIyMjBhMzcxMC0wNjBiLTRmYjItYjY1MC0wMzAwMzMyMGUyMmEiLCJpZCI6MzAzNzc3LCJpYXQiOjE3NDc2Mzk0NTV9.E_90aKtVdzRGlU2z48VwJ4mWvl-uuDkfQBCOO6zbzn4";
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const viewer = new Cesium.Viewer("map", {});
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viewer.scene.debugShowFramesPerSecond = true;
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viewer.scene.globe.depthTestAgainstTerrain = true;
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viewer.terrainProvider = new Cesium.CesiumTerrainProvider({
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url: 'http://data.mars3d.cn/terrain'
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});
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var polygonPos;
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var slopes;
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const delta = 0.002;
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var width;
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var height;
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function addSlopeCanvas(extent) {
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polygonPos = turf.getCoord(extent);
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const rectangle = Cesium.Rectangle.fromDegrees(...polygonPos);
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const positions = [];
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width = Math.ceil((polygonPos[2] - polygonPos[0]) / delta);
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height = Math.ceil((polygonPos[3] - polygonPos[1]) / delta);
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radio = width / height;
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const ddx =
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Cesium.Cartesian3.distance(
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Cesium.Cartesian3.fromDegrees(polygonPos[0], polygonPos[1]),
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Cesium.Cartesian3.fromDegrees(polygonPos[2], polygonPos[1])
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) / width;
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const ddy =
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Cesium.Cartesian3.distance(
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Cesium.Cartesian3.fromDegrees(polygonPos[0], polygonPos[1]),
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Cesium.Cartesian3.fromDegrees(polygonPos[0], polygonPos[3])
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) / height;
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for (let y = 0; y < height; y++) {
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for (let x = 0; x < width; x++) {
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const longitude = Cesium.Math.toDegrees(
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Cesium.Math.lerp(rectangle.west, rectangle.east, x / (width - 1))
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);
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const latitude = Cesium.Math.toDegrees(
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Cesium.Math.lerp(rectangle.north, rectangle.south, y / (height - 1))
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);
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positions.push(
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Cesium.Cartographic.fromDegrees(longitude - delta / 2, latitude)
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);
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positions.push(
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Cesium.Cartographic.fromDegrees(
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longitude - delta / 2,
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latitude - delta / 2
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)
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);
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positions.push(
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Cesium.Cartographic.fromDegrees(longitude, latitude + delta / 2)
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);
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positions.push(
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Cesium.Cartographic.fromDegrees(
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longitude - delta / 2,
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latitude + delta / 2
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)
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);
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positions.push(
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Cesium.Cartographic.fromDegrees(longitude + delta / 2, latitude)
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);
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positions.push(
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Cesium.Cartographic.fromDegrees(
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longitude + delta / 2,
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latitude + delta / 2
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)
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);
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positions.push(
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Cesium.Cartographic.fromDegrees(longitude, latitude - delta / 2)
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);
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positions.push(
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Cesium.Cartographic.fromDegrees(
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longitude + delta / 2,
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latitude - delta / 2
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)
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);
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positions.push(Cesium.Cartographic.fromDegrees(longitude, latitude)); // mid
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}
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}
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slopes = [];
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Cesium.sampleTerrainMostDetailed(viewer.terrainProvider, positions).then(
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(updatedPositions) => {
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for (let i = 0; i < updatedPositions.length; i += 9) {
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let center = updatedPositions[i + 8];
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const westHeight = updatedPositions[i + 0].height;
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let maxHeight = westHeight;
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let maxIndex = i + 0;
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const westSouthHeight = updatedPositions[i + 1].height;
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if (westSouthHeight > maxHeight) {
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maxHeight = westSouthHeight;
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maxIndex = i + 1;
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}
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const northHeight = updatedPositions[i + 2].height;
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if (northHeight > maxHeight) {
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maxHeight = northHeight;
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maxIndex = i + 2;
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}
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const westNorthHeight = updatedPositions[i + 3].height;
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if (westNorthHeight > maxHeight) {
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maxHeight = northHeight;
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maxIndex = i + 3;
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}
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const eastHeight = updatedPositions[i + 4].height;
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if (eastHeight > maxHeight) {
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maxHeight = eastHeight;
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maxIndex = i + 4;
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}
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const eastNorthHeight = updatedPositions[i + 5].height;
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if (eastNorthHeight > maxHeight) {
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maxHeight = eastNorthHeight;
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maxIndex = i + 5;
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}
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const southHeight = updatedPositions[i + 6].height;
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if (southHeight > maxHeight) {
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maxHeight = southHeight;
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maxIndex = i + 6;
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}
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const eastSouthHeight = updatedPositions[i + 7].height;
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if (eastSouthHeight > maxHeight) {
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maxHeight = eastSouthHeight;
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maxIndex = i + 7;
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}
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const fx =
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(westSouthHeight +
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2 * southHeight +
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eastSouthHeight -
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(westNorthHeight + 2 * northHeight + eastNorthHeight)) /
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(8 * ddx);
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const fy =
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(eastNorthHeight +
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2 * eastHeight +
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eastSouthHeight -
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(westNorthHeight + 2 * westHeight + westSouthHeight)) /
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(8 * ddy);
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const slope = Math.atan(Math.sqrt(fx ** 2 + fy ** 2));
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slopes.push(slope);
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}
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createMaterial();
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}
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);
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}
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function createMaterial() {
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const canvas = toCanvas();
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const positions = [
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Cesium.Cartesian3.fromDegrees(polygonPos[0], polygonPos[1]),
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Cesium.Cartesian3.fromDegrees(polygonPos[0], polygonPos[3]),
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Cesium.Cartesian3.fromDegrees(polygonPos[2], polygonPos[3]),
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Cesium.Cartesian3.fromDegrees(polygonPos[2], polygonPos[1]),
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];
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const polygon = viewer.entities.add({
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polygon: {
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hierarchy: new Cesium.PolygonHierarchy(positions),
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material: new Cesium.ImageMaterialProperty({
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image: canvas,
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}),
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classificationType: Cesium.ClassificationType.BOTH,
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},
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});
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}
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function toCanvas() {
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const w = width;
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const h = height;
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const canvas = document.createElement("canvas");
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canvas.height = h;
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canvas.width = w;
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const ctx = canvas.getContext("2d");
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const bitmap = new Uint8ClampedArray(w * h * 4); // 各像素点rgba
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console.log(slopes);
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for (let y = 0; y < h; y++) {
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for (let x = 0; x < w; x++) {
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const slope = slopes[y * w + x];
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const hue = (1 - slope / (Math.PI / 2)) / 2;
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const color = Cesium.Color.fromHsl(hue, 1, 0.6).withAlpha(0.7);
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const bitmapIndex = (y * w + x) * 4;
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bitmap[bitmapIndex + 0] = color.red * 255;
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bitmap[bitmapIndex + 1] = color.green * 255;
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bitmap[bitmapIndex + 2] = color.blue * 255;
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bitmap[bitmapIndex + 3] = color.alpha * 255;
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}
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}
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const imageData = new ImageData(bitmap, w, h);
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ctx.putImageData(imageData, 0, 0);
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return canvas;
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}
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addSlopeCanvas([78.64, 33.72, 78.79, 34.02]);
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viewer.camera.setView({
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destination: Cesium.Cartesian3.fromDegrees(78.7, 33.85, 30000),
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});
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</script>
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</body>
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</html> |