Billboard&Cesium.BillboardCollection
面朝屏幕的图片
http://localhost:8080/Apps/Sandcastle/index.html?src=development%2FBillboards.html&label=Development
image.png
//链式返回，new Cesium.BillboardCollection() 生成一个对象，这个对象是另一个scene.primitives.add的参数
//position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883)
//position 空间直角坐标系，由经纬度坐标转换而来；这里的经纬度省略了Z的参数
// 可以增加一句 var height = Cesium.defaultValue(444444);
// position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883,height )
function addBillboard() {
Sandcastle.declare(addBillboard);
//链式返回，new Cesium.BillboardCollection() 生成一个对象，这个对象是另一个scene.primitives.add的参数
var billboards = scene.primitives.add(new Cesium.BillboardCollection());
billboards.add({
image : '../images/Cesium_Logo_overlay.png',
position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883)
});
}
sizeInMeters : true, //图像的尺寸被指定成图像实际的尺寸，不随地图的缩放而变换大小
function sizeBillboardInMeters() {
Sandcastle.declare(sizeBillboardInMeters);
var center = Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883);
var heading = Cesium.Math.toRadians(50.0);
var pitch = Cesium.Math.toRadians(-20.0);
var range = 100.0;
viewer.camera.lookAt(center, new Cesium.HeadingPitchRange(heading, pitch, range));
var billboards = scene.primitives.add(new Cesium.BillboardCollection());
billboards.add({
image : '../images/Cesium_Logo_overlay.png',
sizeInMeters : true, //图像的尺寸被指定成图像实际的尺寸
position : center
});
}
一次创建多个
function addMultipleBillboards() {
Sandcastle.declare(addMultipleBillboards);
var logoUrl = '../images/Cesium_Logo_overlay.png';
var facilityUrl = '../images/facility.gif';
var billboards = scene.primitives.add(new Cesium.BillboardCollection());
billboards.add({
image : logoUrl,
position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883)
});
billboards.add({
image : facilityUrl,
position : Cesium.Cartesian3.fromDegrees(-80.50, 35.14)
});
billboards.add({
image : facilityUrl,
position : Cesium.Cartesian3.fromDegrees(-80.12, 25.46)
});
}
//scaleByDistance 设置屏幕像素缩放比，150米的时候放大一倍，150000米的时候，缩放到0.5
//Cesium.NearFarScalar四个值，最近的距离，最远的距离，缩放比例范围
function scaleByDistance() {
Sandcastle.declare(scaleByDistance);
var billboards = scene.primitives.add(new Cesium.BillboardCollection());
billboards.add({
image : '../images/facility.gif',
position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883),
scaleByDistance : new Cesium.NearFarScalar(1.5e2, 2.0, 1.5e7, 0.5)
});
}
translucencyByDistance 改动透明度，地球缩放到很小时，透明度增大
function fadeByDistance() {
Sandcastle.declare(fadeByDistance);
var billboards = scene.primitives.add(new Cesium.BillboardCollection());
billboards.add({
image : '../images/Cesium_Logo_overlay.png',
position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883),
translucencyByDistance : new Cesium.NearFarScalar(1.5e2, 1.0, 1.5e7, 0.2)
});
}
pixelOffset : new Cesium.Cartesian2(0.0, -facilityHeight), //在原位置上偏移，防止叠在一起看不到了
pixelOffsetScaleByDistance : new Cesium.NearFarScalar(1.0e3, 1.0, 1.5e6, 0.0), //随着距离改变偏移量
translucencyByDistance : new Cesium.NearFarScalar(1.0e3, 1.0, 1.5e6, 0.1)//随着距离改变透明度
function offsetByDistance() {
Sandcastle.declare(offsetByDistance);
Cesium.when.all([
Cesium.Resource.createIfNeeded('../images/Cesium_Logo_overlay.png').fetchImage(),
Cesium.Resource.createIfNeeded('../images/facility.gif').fetchImage()
],
function(images) {
var billboards = scene.primitives.add(new Cesium.BillboardCollection());
// As viewer zooms closer to facility billboard,
// increase pixelOffset on CesiumLogo billboard to this height
var facilityHeight = images[1].height;
// colocated billboards, separate as viewer gets closer
billboards.add({
image : images[1],
position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883),
horizontalOrigin : Cesium.HorizontalOrigin.CENTER,
verticalOrigin : Cesium.VerticalOrigin.BOTTOM
});
billboards.add({
image : images[0],
position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883),
horizontalOrigin : Cesium.HorizontalOrigin.CENTER,
verticalOrigin : Cesium.VerticalOrigin.BOTTOM,
pixelOffset : new Cesium.Cartesian2(0.0, -facilityHeight), //在原位置上偏移，防止叠在一起看不到了
pixelOffsetScaleByDistance : new Cesium.NearFarScalar(1.0e3, 1.0, 1.5e6, 0.0), //随着距离改变偏移量
translucencyByDistance : new Cesium.NearFarScalar(1.0e3, 1.0, 1.5e6, 0.1)//随着距离改变透明度
});
});
}
添加点的公告牌
image.png
function addPointBillboards() {
Sandcastle.declare(addPointBillboards);
// A white circle is drawn into a 2D canvas. The canvas is used as
// a texture for billboards, each of which applies a different color
// and scale to change the point's appearance.
//
// The 2D canvas can draw much more than circles. See:
// https://developer.mozilla.org/en/Canvas_tutorial
var canvas = document.createElement('canvas');
canvas.width = 16;
canvas.height = 16;
var context2D = canvas.getContext('2d');
context2D.beginPath();
context2D.arc(8, 8, 8, 0, Cesium.Math.TWO_PI, true);
context2D.closePath();
context2D.fillStyle = 'rgb(255, 255, 255)';
context2D.fill();
var billboards = scene.primitives.add(new Cesium.BillboardCollection());
billboards.add({
imageId : 'custom canvas point',
image : canvas,
position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883),
color : Cesium.Color.RED,
scale : 0.5
});
billboards.add({
imageId : 'custom canvas point',
image : canvas,
position : Cesium.Cartesian3.fromDegrees(-80.50, 35.14),
color : Cesium.Color.BLUE
});
billboards.add({
imageId : 'custom canvas point',
image : canvas,
position : Cesium.Cartesian3.fromDegrees(-80.12, 25.46),
color : Cesium.Color.LIME,
scale : 2
});
}
增加marker的公告牌
image.png
function addMarkerBillboards() {
Sandcastle.declare(addMarkerBillboards);
var billboards = scene.primitives.add(new Cesium.BillboardCollection());
// Add several billboards based on the above image in the atlas.
billboards.add({
image : '../images/whiteShapes.png',
imageSubRegion : new Cesium.BoundingRectangle(49, 43, 18, 18),
position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883),
color : Cesium.Color.LIME
});
billboards.add({
image : '../images/whiteShapes.png',
imageSubRegion : new Cesium.BoundingRectangle(61, 23, 18, 18),
position : Cesium.Cartesian3.fromDegrees(-84.0, 39.0),
color : new Cesium.Color(0, 0.5, 1.0, 1.0)
});
billboards.add({
image : '../images/whiteShapes.png',
imageSubRegion : new Cesium.BoundingRectangle(67, 80, 14, 14),
position : Cesium.Cartesian3.fromDegrees(-70.0, 41.0),
color : new Cesium.Color(0.5, 0.9, 1.0, 1.0)
});
billboards.add({
image : '../images/whiteShapes.png',
imageSubRegion : new Cesium.BoundingRectangle(27, 103, 22, 22),
position : Cesium.Cartesian3.fromDegrees(-73.0, 37.0),
color : Cesium.Color.RED
});
billboards.add({
image : '../images/whiteShapes.png',
imageSubRegion : new Cesium.BoundingRectangle(105, 105, 18, 18),
position : Cesium.Cartesian3.fromDegrees(-79.0, 35.0),
color : Cesium.Color.YELLOW
});
}
在框架体系中增加广告牌，平移旋转缩放，全部围绕着billboards.modelMatrix
平移到某一点后，旋转X轴转到朝东，Y转到朝北，z轴转到正上方。
billboards.modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(center);
function inReferenceFrame() {
Sandcastle.declare(inReferenceFrame);
var billboards = scene.primitives.add(new Cesium.BillboardCollection());
var center = Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883);
billboards.modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(center);
var facilityUrl = '../images/facility.gif';
// center
billboards.add({
image : facilityUrl,
position : new Cesium.Cartesian3(0.0, 0.0, 0.0)
});
// east
billboards.add({
image : facilityUrl,
position : new Cesium.Cartesian3(1000000.0, 0.0, 0.0)
});
// north
billboards.add({
image : facilityUrl,
position : new Cesium.Cartesian3(0.0, 1000000.0, 0.0)
});
// up
billboards.add({
image : facilityUrl,
position : new Cesium.Cartesian3(0.0, 0.0, 1000000.0)
});
}
特点：
始终面朝屏幕，即使旋转也面朝屏幕
注意创建的集群对象 Cesium.BillboardCollection
为什么不能创建单个Billboard？Entity来解决此问题
Label&Cesium.LabelCollection
面朝屏幕的文字
http://localhost:8080/Apps/Sandcastle/index.html?src=development%2FLabels.html&label=Development
特点：
始终朝向屏幕
注意创建的是集群对象 Cesium.LabelCollection()
Label对象只能用在LabelCollection当中
PointPrimitive&Cesium.PointPrimitiveCollection
http://localhost:8080/Apps/Sandcastle/index.html?src=development%2FPointPrimitives.html&label=Development