Posted by Demoscene Passivist on Feb 10, 2012; 1:05pm
URL: https://forum.jogamp.org/SOLVED-Mapping-two-different-types-of-Textures-on-the-same-geometry-tp3731946p3732461.html

As far as I can see u don't unbind the FBO. So thats an explanation why u do not see anything :) If u don't unbind the FBO and rebind the other textures again in the next frame, but using the same texture unit, mapping will fail with multiple textures.

Sounds u have to dive deeper into the "texture unit"/"texture id" stuff. Maybe this thread helps ...