cesium-examples/map/3d/static/Cesium/Apps/Sandcastle/gallery/Star Burst.html

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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no">
<meta name="description" content="Star burst overlapping billboards.">
<meta name="cesium-sandcastle-labels" content="Showcases">
<title>Cesium Demo</title>
<script type="text/javascript" src="../Sandcastle-header.js"></script>
<script type="text/javascript" src="../../../ThirdParty/requirejs-2.1.20/require.js"></script>
<script type="text/javascript">
require.config({
baseUrl : '../../../Source',
waitSeconds : 60
});
</script>
</head>
<body class="sandcastle-loading" data-sandcastle-bucket="bucket-requirejs.html">
<style>
@import url(../templates/bucket.css);
</style>
<div id="cesiumContainer" class="fullSize"></div>
<div id="loadingOverlay"><h1>Loading...</h1></div>
<div id="toolbar">
<div id="zoomButtons"></div>
</div>
<script id="cesium_sandcastle_script">
function startup(Cesium) {
'use strict';
//Sandcastle_Begin
var viewer = new Cesium.Viewer('cesiumContainer', {
selectionIndicator : false
});
// Add labels clustered at the same location
var numBillboards = 30;
for (var i = 0; i < numBillboards; ++i) {
var position = Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883);
viewer.entities.add({
position : position,
billboard : {
image : '../images/facility.gif',
scale : 2.5
},
label : {
text : 'Label' + i,
show : false
}
});
}
var scene = viewer.scene;
var camera = scene.camera;
var handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
handler.setInputAction(function(movement) {
// Star burst on left mouse click.
starBurst(movement.position);
}, Cesium.ScreenSpaceEventType.LEFT_CLICK);
handler.setInputAction(function(movement) {
// Remove the star burst when the mouse exits the circle or show the label of the billboard the mouse is hovering over.
updateStarBurst(movement.endPosition);
}, Cesium.ScreenSpaceEventType.MOUSE_MOVE);
camera.moveStart.addEventListener(function() {
// Reset the star burst on camera move because the lines from the center
// because the line end points rely on the screen space positions of the billboards.
undoStarBurst();
});
// State saved across mouse click and move events
var starBurstState = {
enabled : false,
pickedEntities : undefined,
billboardEyeOffsets : undefined,
labelEyeOffsets : undefined,
linePrimitive : undefined,
radius : undefined,
center : undefined,
pixelPadding : 10.0,
angleStart : 0.0,
angleEnd : Cesium.Math.PI,
maxDimension : undefined
};
function offsetBillboard(entity, entityPosition, angle, magnitude, lines, billboardEyeOffsets, labelEyeOffsets) {
var x = magnitude * Math.cos(angle);
var y = magnitude * Math.sin(angle);
var offset = new Cesium.Cartesian2(x, y);
var drawingBufferWidth = scene.drawingBufferWidth;
var drawingBufferHeight = scene.drawingBufferHeight;
var diff = Cesium.Cartesian3.subtract(entityPosition, camera.positionWC, new Cesium.Cartesian3());
var distance = Cesium.Cartesian3.dot(camera.directionWC, diff);
var dimensions = camera.frustum.getPixelDimensions(drawingBufferWidth, drawingBufferHeight, distance, new Cesium.Cartesian2());
Cesium.Cartesian2.multiplyByScalar(offset, Cesium.Cartesian2.maximumComponent(dimensions), offset);
var labelOffset;
var billboardOffset = entity.billboard.eyeOffset;
var eyeOffset = new Cesium.Cartesian3(offset.x, offset.y, 0.0);
entity.billboard.eyeOffset = eyeOffset;
if (Cesium.defined(entity.label)) {
labelOffset = entity.label.eyeOffset;
entity.label.eyeOffset = new Cesium.Cartesian3(offset.x, offset.y, -10.0);
}
var endPoint = Cesium.Matrix4.multiplyByPoint(camera.viewMatrix, entityPosition, new Cesium.Cartesian3());
Cesium.Cartesian3.add(eyeOffset, endPoint, endPoint);
Cesium.Matrix4.multiplyByPoint(camera.inverseViewMatrix, endPoint, endPoint);
lines.push(endPoint);
billboardEyeOffsets.push(billboardOffset);
labelEyeOffsets.push(labelOffset);
}
function starBurst(mousePosition) {
if (Cesium.defined(starBurstState.pickedEntities)) {
return;
}
var pickedObjects = scene.drillPick(mousePosition);
if (!Cesium.defined(pickedObjects) || pickedObjects.length < 2) {
return;
}
var billboardEntities = [];
var length = pickedObjects.length;
var i;
for (i = 0; i < length; ++i) {
var pickedObject = pickedObjects[i];
if (pickedObject.primitive instanceof Cesium.Billboard) {
billboardEntities.push(pickedObject);
}
}
if (billboardEntities.length === 0) {
return;
}
var pickedEntities = starBurstState.pickedEntities = [];
var billboardEyeOffsets = starBurstState.billboardEyeOffsets = [];
var labelEyeOffsets = starBurstState.labelEyeOffsets = [];
var lines = [];
starBurstState.maxDimension = Number.NEGATIVE_INFINITY;
var angleStart = starBurstState.angleStart;
var angleEnd = starBurstState.angleEnd;
var angle = angleStart;
var angleIncrease;
var magnitude;
var magIncrease;
var maxDimension;
// Drill pick gets all of the entities under the mouse pointer.
// Find the billboards and set their pixel offsets in a circle pattern.
length = billboardEntities.length;
i = 0;
while (i < length) {
var object = billboardEntities[i];
if (pickedEntities.length === 0) {
starBurstState.center = Cesium.Cartesian3.clone(object.primitive.position);
}
if (!Cesium.defined(angleIncrease)) {
var width = object.primitive.width;
var height = object.primitive.height;
maxDimension = Math.max(width, height) * object.primitive.scale + starBurstState.pixelPadding;
magnitude = maxDimension + maxDimension * 0.5;
magIncrease = magnitude;
angleIncrease = maxDimension / magnitude;
}
offsetBillboard(object.id, object.primitive.position, angle, magnitude, lines, billboardEyeOffsets, labelEyeOffsets);
pickedEntities.push(object);
var reflectedAngle = angleEnd - angle;
if (i + 1 < length && reflectedAngle - angleIncrease * 0.5 > angle + angleIncrease * 0.5) {
object = billboardEntities[++i];
offsetBillboard(object.id, object.primitive.position, reflectedAngle, magnitude, lines, billboardEyeOffsets, labelEyeOffsets);
pickedEntities.push(object);
}
angle += angleIncrease;
if (reflectedAngle - angleIncrease * 0.5 < angle + angleIncrease * 0.5) {
magnitude += magIncrease;
angle = angleStart;
angleIncrease = maxDimension / magnitude;
}
++i;
}
// Add lines from the pick center out to the translated billboard.
var instances = [];
length = lines.length;
for (i = 0; i < length; ++i) {
var pickedEntity = pickedEntities[i];
starBurstState.maxDimension = Math.max(pickedEntity.primitive.width, pickedEntity.primitive.height, starBurstState.maxDimension);
instances.push(new Cesium.GeometryInstance({
geometry : new Cesium.SimplePolylineGeometry({
positions : [starBurstState.center, lines[i]],
arcType : Cesium.ArcType.NONE,
granularity : Cesium.Math.PI_OVER_FOUR
}),
attributes : {
color : Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.WHITE)
}
}));
}
starBurstState.linePrimitive = scene.primitives.add(new Cesium.Primitive({
geometryInstances : instances,
appearance : new Cesium.PerInstanceColorAppearance({
flat : true,
translucent : false
}),
asynchronous : false
}));
viewer.selectedEntity = undefined;
starBurstState.radius = magnitude + magIncrease;
}
function updateStarBurst(mousePosition) {
if (!Cesium.defined(starBurstState.pickedEntities)) {
return;
}
if (!starBurstState.enabled) {
// For some reason we get a mousemove event on click, so
// do not show a label on the first event.
starBurstState.enabled = true;
return;
}
// Remove the star burst if the mouse exits the screen space circle.
// If the mouse is inside the circle, show the label of the billboard the mouse is hovering over.
var screenPosition = Cesium.SceneTransforms.wgs84ToWindowCoordinates(scene, starBurstState.center);
var fromCenter = Cesium.Cartesian2.subtract(mousePosition, screenPosition, new Cesium.Cartesian2());
var radius = starBurstState.radius;
if (Cesium.Cartesian2.magnitudeSquared(fromCenter) > radius * radius || fromCenter.y > 3.0 * (starBurstState.maxDimension + starBurstState.pixelPadding)) {
undoStarBurst();
} else {
showLabels(mousePosition);
}
}
function undoStarBurst() {
var pickedEntities = starBurstState.pickedEntities;
if (!Cesium.defined(pickedEntities)) {
return;
}
var billboardEyeOffsets = starBurstState.billboardEyeOffsets;
var labelEyeOffsets = starBurstState.labelEyeOffsets;
// Reset billboard and label pixel offsets.
// Hide overlapping labels.
for (var i = 0; i < pickedEntities.length; ++i) {
var entity = pickedEntities[i].id;
entity.billboard.eyeOffset = billboardEyeOffsets[i];
if (Cesium.defined(entity.label)) {
entity.label.eyeOffset = labelEyeOffsets[i];
entity.label.show = false;
}
}
// Remove lines from the scene.
// Free resources and reset state.
scene.primitives.remove(starBurstState.linePrimitive);
starBurstState.linePrimitive = undefined;
starBurstState.pickedEntities = undefined;
starBurstState.billboardEyeOffsets = undefined;
starBurstState.labelEyeOffsets = undefined;
starBurstState.radius = undefined;
starBurstState.enabled = false;
}
var currentObject;
function showLabels(mousePosition) {
var pickedObjects = scene.drillPick(mousePosition);
var pickedObject;
if (Cesium.defined(pickedObjects)) {
var length = pickedObjects.length;
for (var i = 0; i < length; ++i) {
if (pickedObjects[i].primitive instanceof Cesium.Billboard) {
pickedObject = pickedObjects[i];
break;
}
}
}
if (pickedObject !== currentObject) {
if (Cesium.defined(pickedObject) && Cesium.defined(pickedObject.id.label)) {
if (Cesium.defined(currentObject)) {
currentObject.id.label.show = false;
}
currentObject = pickedObject;
pickedObject.id.label.show = true;
} else if (Cesium.defined(currentObject)) {
currentObject.id.label.show = false;
currentObject = undefined;
}
}
}
//Sandcastle_End
Sandcastle.finishedLoading();
}
if (typeof Cesium !== 'undefined') {
startup(Cesium);
} else if (typeof require === 'function') {
require(['Cesium'], startup);
}
</script>
</body>
</html>