A bug when rendering primitive with more than one geometry instance

CesiumJS
1

Sandcastle example: Cesium Sandcastle

Browser: Google Chrome 119.0.6045.160

Operating System: Microsoft Windows 10 Professional

Source Code:
const viewer = new Cesium.Viewer(“cesiumContainer”);

const instances = [ ];
const polygonGeometry1 = new Cesium.PolygonGeometry({
polygonHierarchy: new Cesium.PolygonHierarchy([{ “x”: -2400641.090816039, “y”: 5381130.100542436, “z”: 2433328.5092790457 }, { “x”: -2400474.9719961607, “y”: 5381408.726737343, “z”: 2432879.19963749 }, { “x”: -2401689.930302587, “y”: 5380956.179691228, “z”: 2432682.408250566 }, { “x”: -2401636.078986657, “y”: 5380731.1518189395, “z”: 2433229.5619592783 }, { “x”: -2401056.3660955857, “y”: 5380825.658537882, “z”: 2433590.23144021 }])
});
const polygonInstance1 = new Cesium.GeometryInstance({
geometry: polygonGeometry1,
attributes: {
color: Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.AQUA.withAlpha(0.3))
},
});
instances.push(polygonInstance1);
const polygonGeometry2 = new Cesium.PolygonGeometry({
polygonHierarchy: new Cesium.PolygonHierarchy([{ “x”: -2401516.764516469, “y”: 5380675.1539282, “z”: 2433469.5256546633 }, { “x”: -2401099.3682896723, “y”: 5381176.246928616, “z”: 2432777.94279018 }, { “x”: -2401535.3805373986, “y”: 5381232.170150966, “z”: 2432227.516087851 }, { “x”: -2402269.347054639, “y”: 5380837.068363779, “z”: 2432375.8157362673 }, { “x”: -2401942.311879878, “y”: 5380556.648291801, “z”: 2433312.607624896 }])
});
const polygonInstance2 = new Cesium.GeometryInstance({
geometry: polygonGeometry2,
attributes: {
color: Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.YELLOW.withAlpha(0.5))
},
});
instances.push(polygonInstance2);
const polygonGeometry3 = new Cesium.PolygonGeometry({
polygonHierarchy: new Cesium.PolygonHierarchy([{ “x”: -2401267.806317249, “y”: 5380732.599506225, “z”: 2433587.3856536835 }, { “x”: -2401094.7140932013, “y”: 5380973.462258056, “z”: 2433228.0018187007 }, { “x”: -2401456.962450918, “y”: 5380918.131284394, “z”: 2432994.434511724 }, { “x”: -2401926.5443844274, “y”: 5380661.93202834, “z”: 2433096.8101673303 }, { “x”: -2401555.4938714677, “y”: 5380567.300366957, “z”: 2433668.429810298 }])
});
const polygonInstance3 = new Cesium.GeometryInstance({
geometry: polygonGeometry3,
attributes: {
color: Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.RED.withAlpha(0.7))
},
});
instances.push(polygonInstance3);
const polygonGeometry4 = new Cesium.PolygonGeometry({
polygonHierarchy: new Cesium.PolygonHierarchy([{ “x”: -2401456.932098427, “y”: 5380844.045173162, “z”: 2433157.2129374146 }, { “x”: -2401007.840056206, “y”: 5381366.335047787, “z”: 2432449.993122666 }, { “x”: -2401934.5380039974, “y”: 5381010.967925442, “z”: 2432322.116788277 }, { “x”: -2402493.0858713463, “y”: 5380702.537193162, “z”: 2432451.9243560797 }, { “x”: -2401735.4288811344, “y”: 5380742.196945204, “z”: 2433107.8922376856 }])
});
const polygonInstance4 = new Cesium.GeometryInstance({
geometry: polygonGeometry4,
attributes: {
color: Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.GREEN)
},
});
instances.push(polygonInstance4);
viewer.scene.primitives.add(new Cesium.GroundPrimitive({
geometryInstances: instances,
appearance: new Cesium.PerInstanceColorAppearance()
}));

viewer.camera.flyTo({
destination:{x: -2403509.8429785646, y: 5385086.594574532, z: 2430897.2611216223},
orientation : {
heading:6.271242180095195,
pitch:-0.7264978610534887,
roll:0.00003630429651302336
}
});

Overlaps between polygons render incorrectly.

First camera perspective screenshot of incorrect overlaps between polygons：

Snipaste_2023-11-29_15-13-31
Snipaste_2023-11-29_15-13-311519×955 236 KB

Secondly camera perspective screenshot of incorrect overlaps between polygons：

Snipaste_2023-11-29_15-13-54
Snipaste_2023-11-29_15-13-541519×955 250 KB

Screenshot of correct overlaps between polygons:

image
image1680×1010 202 KB

2

If you want to adjust the order: Z-Indexing Geometry.

3

Hi,SAYEOR,thanks for your reply,there is nothing about the overlaps order.I concerned about the shape of the overlap between polygons and polygons is incorrect in different camera perspective.When you are changing the camera orientation or position,you can see the shape of the overlap between polygons and polygons changing at the same time.

4

Hey, it looks like this is another instance of a known bug being tracked in this Github issue: GroundPrimitive Render Error · Issue #11291 · CesiumGS/cesium · GitHub
I will make a note of your report there so we can use it to help determine priority. Feel free to track that issue for updates