Is it possible to Outline a view port in threejs?

Question

I've created a scene with two cameras and one renderer. each camera is looking at the scene from a different angle and I have the first camera rendering on the entire screen then the second camera I have rendering in a small view port laying on top of the first render. I was wondering if there is a way to have that second view port outlined so that each look separate

Answer 1

Yes, you can outline an inset viewport by rendering a solid-colored rectangle slightly larger than the inset prior to rendering the inset.

// border
renderer.setScissorTest( true );
renderer.setScissor( x, y, width, height );
renderer.setClearColor( 0xffffff, 1 ); // border color
renderer.clearColor(); // clear color buffer

Then, render the inset. Just make sure the inset background is opaque.

three.js r.86