Wireframe stencil(?) - terrain editing tool radius in UnrealEd

Here’s what I want:

It’s a circular wireframe that lies along the terrain as you move the mouse. I could calculate the line intersections myself and build a mesh on-the-fly, but it would be slow as hell. Is there a way to render this?

If you want OpenGL to do the hard work you could use the GLU nurb surface tesselator to generate to mesh for you.


Seems to me you could establish the mouse position projected down onto the map, and then while rendering the map render a second pass at that part with the same geometry but no depth writing, some z offset, and an additive/blend/whatever texture.

I’ll look into the nurbs thing.

I don’t want a blended texture, I want a wireframe circle.