I want to draw a diffuse circle, but the circle is rotated at some position on the earth. What’s the reason?
When the longitude of the coordinates of the ellipse approaches 180, the semiminoraxis attribute of the ellipse will be flipped and jittered when it is dynamically changed？
This is my code
const viewer = new Cesium.Viewer("cesiumContainer");
const image = './circle.png';
const options = {
maxradius: 500000,
minradius: 500,
speed: 100,
position: Cesium.Cartesian3.fromDegrees(179.38038414341867,-48.39592928270119,564559.6260739185),
height: 564559.6260739185,
text: 'alarm'
};
const step = (options.maxradius - options.minradius) / options.speed;
const getRadius = () => {
options.minradius += step;
if (options.minradius > options.maxradius) {
options.minradius = 500;
}
return options.minradius;
};
const getOpacity = () => {
const alpha = 1 - options.minradius / options.maxradius;
return Cesium.Color.WHITE.withAlpha(alpha);
};
const radius = new Cesium.CallbackProperty(getRadius, false);
const color = new Cesium.CallbackProperty(getOpacity, false);
const circle = viewer.entities.add({
position: options.position,
name: 'Dycircle',
label: {
text: options.text,
font: '15px Helvetica',
fillColor: Cesium.Color.LIME
},
ellipse: {
height: options.height,
semiMinorAxis: radius,
semiMajorAxis:500000,
material: new Cesium.ImageMaterialProperty({
image: image,
repeat: new Cesium.Cartesian2(1.0, 1.0),
transparent: true,
color: color
}),
outlineColor: Cesium.Color.RED
}
});
viewer.flyTo(circle);
