Draw edges of a polygon with OpenGL shaders

Question

I was wondering if it was possible to draw the edges of a rendered polygon with a specific color using a fragment shader, as in this example picture:

Or should I just render those separately?

Answer 1

See work related on this page: http://web.archive.org/web/20120527185124/http://cgg-journal.com/2008-2/06/index.html

A vertex shader should render polygons where the distance to each edge is colored.

The difference between coloring each "cell" is explained in much detail.