jPCT's coordinate system
A few words on jPCT's coordinate system, because it causes some confusion from time to time. In "normal" GL-like coordinate system, positive x goes to the right, y goes up and z comes out of the screen. In jPCT, this is rotated 180° around x, so that x still goes to the right, but z goes INTO the screen and y goes DOWN. If you want/have to use third party code that uses a different system, some conversion is needed, which should be pretty simple to do.