Errors with GroundPrimitives and PolygonGeometry

CesiumJS
1

I am using a PolygonGeometry and trying to create GroundPrimitives with it. Currently I get the follwoing error if I try and add it to scene.primitives “DeveloperError: Not all of the geometry instances have GroundPrimitive support” The docs here https://cesium.com/docs/cesiumjs-ref-doc/GroundPrimitive.html state that GroundPrimitives should work with PolygonGeometries.
The code looks like this:

let polygon = new Cesium.PolygonGeometry({
    polygonHierarchy: new Cesium.PolygonHierarchy(
        Cesium.Cartesian3.fromDegreesArray(bounds)),
});
let instance = new Cesium.GeometryInstance({
    geometry: Cesium.PolygonGeometry.createGeometry(polygon),
    id: cell,
    attributes: {
        color: new Cesium.Color(rgb[0], rgb[1], rgb[2], 0.5),
    },
})

scene.primitives.add(new Cesium.GroundPrimitive({
    geometryInstances: instance,
}));

Is this a bug or is this not supported?

2

Hi,

for lines you can use GroundPolylinePrimitive and GroundPolylineGeometry,

see https://cesium.com/docs/cesiumjs-ref-doc/GroundPolylinePrimitive.html

3

Unfortunately I was trying to color regions with this so lines aren’t really what I’m going for.

4

It looks like you just need to pass the polygon directly without calling createGeometry. Full example:

var viewer = new Cesium.Viewer("cesiumContainer");
var scene = viewer.scene;

var polygon = new Cesium.PolygonGeometry({
  polygonHierarchy : new Cesium.PolygonHierarchy(
    Cesium.Cartesian3.fromDegreesArray([
      -115.0,
      37.0,
      -115.0,
      32.0,
      -107.0,
      33.0,
      -102.0,
      31.0,
      -102.0,
      35.0,
    ])
  )
});

var instance = new Cesium.GeometryInstance({
  geometry : polygon,
  attributes : {
    color : new Cesium.ColorGeometryInstanceAttribute(0.0, 1.0, 1.0, 0.5)
  }
});
scene.primitives.add(new Cesium.GroundPrimitive({
  geometryInstances : instance,
  appearance : new Cesium.PerInstanceColorAppearance()
}));