1. A concise explanation of the problem you're experiencing.
Polygon material uses images, but the image is reversed.
cesium 1.47,Polygon material uses pictures, and pictures are normal，but in cesium1.48 cesium1.49 cesium1.50 Polygon material uses images, but the image is reversed
2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.
var addPolygon = viewer.entities.add({
polygon: {
hierarchy: polygonPositionsC,
height: 0.5,
perPositionHeight: true，
material: "./img/camera/44.png"
}
});
3. Context. Why do you need to do this? We might know a better way to accomplish your goal.
4. The Cesium version you're using, your operating system and browser.
Chrome cesium 1.47 1.48 1.49 1.50