Drawing a "multi" geometry shape in osgEarth

[Warren-Whitfield]

Hi All
I am relatively new to osgEarth. I want to draw an outline (or filled) polygon type shape consisting of lines and arcs. What is the best way to do this please?

[gwaldron]

You are looking for Annotations.

Look at the example earth file annotation.earth in the tests folder. The "Draped Polygon" annotation should do what you want.

If you need to do it in code, take a look at the osgearth_annotation.cpp example app; lots of examples in there.

[Warren-Whitfield]

Cool thanks Glenn that works ok. (I needed to do it in code by the way)

But, I don't have these functions as used in the osgearth_annotation.cpp example line 366 onwards.
// highlight annotation upon hover by default:
DecorationInstaller highlightInstaller("hover", new HighlightDecoration());

I'm using vcpkg and did a complete search of file contents in the folder and I definitely don't have these.

Any thoughts?

Additionally, so currently I have an outline of two lines and two arcs representing a range/azimuth selection sector. The primitives are in essence all seperate entities. So how would I fill this area? In reality, I guess I want this to be some sort of polygon or enclosed area. (

[gwaldron]

Exactly, you are going to have to make a polygonal feature if you want to fill it.

There is no such class DecorationInstaller, are you using an old version of osgEarth?

[Warren-Whitfield]

Ok, I'll try that, thanks

That extract was from the osgearth_annotation.cpp example?

[gwaldron]

What version of osgEarth are you using? 3.5 is the latest.

[Warren-Whitfield]

The version from vcpkg is as follows:-
osgearth:x64-linux 3.4#1

[gwaldron]

I had to go all the way back to Version 2.7 to find a reference to DecorationInstaller.

https://github.com/gwaldron/osgearth/blob/osgearth-2.7/src/applications/osgearth_annotation/osgearth_annotation.cpp#L492

That is 9 years ago :)

[Warren-Whitfield]

Sh!t, my apologies, its just what came up when I first searched osgEarth examples and I've never bothered to check the version. Sorry about that!

So re my previous query, how do I get that sector into a polygon to be able to fill it? It consists of 2 LineStrings and 2 CircleNodes.

[gwaldron]

:)
There's no function in osgEarth to union geometries or nodes like that, so you're going to have to make a FeatureNode or LocalGeometryNode with your custom geometry. Good luck!

[Warren-Whitfield]

So, I've decided to just create my own arc's using a series of line segments. That seemed the simplest solution to me to get everything into a polygon so that it can be filled if required.