Posted by gouessej on Jul 02, 2015; 8:48am
URL: https://forum.jogamp.org/Possible-to-use-vertex-shader-without-vbo-tp4034532p4034796.html

You can call it in the display() method of your GLEventListener or directly in drawTerrain() if it is called directly or indirectly in display() which seems to be the case (difficult to think about that based on a tiny snippet). If you don't call it, it won't draw anything.