Polygon outline geometry not clipping to terrain in columbus view.

1. A concise explanation of the problem you're experiencing.

Polygon outline geometry not clipping to terrain

2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.

this._outlinePolygon = new Cesium.Primitive({
                    geometryInstances: new Cesium.GeometryInstance({
                        geometry: Cesium.PolygonOutlineGeometry.fromPositions({
            positions: this.getPositions()
                        attributes: {
                            color: Cesium.ColorGeometryInstanceAttribute.fromColor(this.strokeColor)
                    appearance: new Cesium.PerInstanceColorAppearance({
                        flat: true,
                        renderState: {
                            depthTest: {
                                enabled: true
                            lineWidth: Math.min(this.strokeWidth || 1.0, maximumAliasedLineWidth)

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.



Does it work in 2D and 3D modes?

Can you provide a complete Sandcastle example I can run? That’ll help me identify if it’s a bug. You can go to Sandcastle (https://cesiumjs.org/Cesium/Build/Apps/Sandcastle/) click “share” and then paste the link here.