Applies an image file as a textured shader to a surface to visualize UVs.
It has options to override the embedded UV tile image file as well as the ability to selectively toggle diffuse and reflection elements and/or specify a reflection map.
You can also specify the UV attribute to use, apply scaling to the textures, and toggle the use of lighting for the geometry.
OpenGL customization in Houdini is pretty slim so there isn't a whole lot of things that you can do with this sort of shader.
https://www.dropbox.com/s/b7eov9m9i5ne9ut/UVVisualize_SOP_Animatrix.otl?dl=1