It’s very important to display debugging information about your level or models during developing game level. Previously, I used 3ds max to place all objects, including lights and it was not easy task. Tweak lighting in 3ds max, switch to engine, check lighting etc…
Now several debugging modes are supported in Glow engine - wire-frame mode, displaying normals in world space, depth of pixel, lights, physics, AI (triggers), navigation meshes.
All modes can be used same time (except normals, depth and diffuse color), button “layers” should be pressed and mode selected.
Room from “Deadly Light” demo, lighted with 6 lights:

Same room in wire-frame debug mode:

Normals mode:

Lights debugger: