Fences don't show up

[Ryanf55]

If you enable a fence on mavproxy map, it should mirror in mavcesium. It's not - the fence protocol has changed to mission items and we're probably looking for the wrong data in mavcesium.

[Ryanf55]

Made some progress decoding fences. Due to the changes in fences in MAVProxy, there's now inclusion/exclusion vertex and circles. These aren't handled. We can support any number of them.

• 5001: https://mavlink.io/en/messages/common.html#MAV_CMD_NAV_FENCE_POLYGON_VERTEX_INCLUSION
• 5002: https://mavlink.io/en/messages/common.html#MAV_CMD_NAV_FENCE_POLYGON_VERTEX_EXCLUSION
• 5003: https://mavlink.io/en/messages/common.html#MAV_CMD_NAV_FENCE_CIRCLE_INCLUSION
  • Sandcastle Example
• 5004: https://mavlink.io/en/messages/common.html#MAV_CMD_NAV_FENCE_CIRCLE_EXCLUSION

Polygon Inclusion

• param1 is equal to the number of polygon points(4)

The existing feature to set up the fence walls with a certain height does not appear to work, I filed a question upstream here:
https://community.cesium.com/t/how-to-sample-single-point-terrain-value-with-sampleterrainmostdetailed/36616

It seems mavlink expects mavcesium to close the polygons (on a 4-sided fence, the mavlink mission has 3 fence items).

I don't know how to tell two adjacent fence objects apart yet. Maybe the param1 value?

Circle Inclusion

Because param1 is the radius, this is easy, that can be treated on its own and renderd as a GroundPrimitive CircleGeometry

Geometry and ID

I think it's best to treat the geofence as an immutable geometry object. Maybe geometry can be combined?
https://cesium.com/learn/cesiumjs/ref-doc/CircleGeometry.html#.createGeometry

Let's color inclusions and exclusions differently. Also, if they are enabled or disabled, could be nice to see.