Highlight polygons of a mesh

I’m doing a terrain editor, my terrain is just a mesh constructed procedurally with triangles, and I would like to highlight some triangles, in bright green or something, to have some kind of selection and operate on it. What’s the better approach for this in c++?

You can duplicate (or instance, if it’s within a single Geom or GeomNode) the geometry into the scene graph, with a new state to make it render in the effect you like. This is, for instance, how the ‘h’ key works to highlight geometry in pview. (Press ‘h’, then the down/left/right arrows, to walk the scene graph in pview and see the highlight.)