Posted by gouessej on Sep 23, 2021; 10:49am
URL: https://forum.jogamp.org/Using-glPrimitiveRestartIndex-to-declare-multiple-geometries-in-the-same-VBO-tp4041307p4041311.html

I have never used this feature but I think that you have to pass a real index. You pass 4 vertices and you indicate that the 5th vertex is the primitive restart vertex by passing its index to glPrimitiveRestartIndex. Maybe I'm wrong.