Primitive exception for empty rectangle

[pjcozzi]

Run the following in Sandcastle:

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

var instance = new Cesium.GeometryInstance({
    geometry : new Cesium.RectangleOutlineGeometry({
        rectangle : Cesium.Rectangle.fromDegrees(-100.0, 30.0, -100.0, 30.0)
    }),
    attributes : {
        color : Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.WHITE)
    }
});
scene.primitives.add(new Cesium.Primitive({
    geometryInstances : instance,
    appearance : new Cesium.PerInstanceColorAppearance({
        flat : true,
        renderState : {
            lineWidth : Math.min(2.0, scene.maximumAliasedLineWidth)
        }
    })
}));

Note that the rectangle's west === east and south === north.

This is not an exceptional case. We should just render nothing. I suspect there is a similar issue in RectangleGeometry and probably most geometries.

@bagnell can you have a look after we finish billboards/labels on terrain?

[TomPed]

If you change this:

rectangle : Cesium.Rectangle.fromDegrees(-100.0, 30.0, -100.0, 30.0)

to this:

rectangle : Cesium.Rectangle.fromDegrees()

I believe that you get the same error. So should we also not allow the parameters to be optional? Or should I just add and if check: if ((north === south) || (east === west)) and handle this case separately?

[pjcozzi]

Leave Rectangle.fromDegrees as is, and do the check in RectangleOutlineGeometry and OutlineGeometry (and most likely through the pipeline into Primitive, which should now not assume the input geometry has any vertices.

We should check the other geometries too, e.g., if all sides of a box have length zero, etc.

[TomPed]

Gotcha, thanks.

[hpinkos]

Fixed in #3599