Actually, it is possible to disable the GLSL vertical flip performed in GLJPanel by using the property jogl.gljpanel.noglsl. However, it affects all instances, there is no clean way of disabling it only for one instance of this class.
This possibility would be useful in a software using both plain GLJPanel instances in good conditions with this flip enabled and some GLJPanel instances built by some scenegraph APIs with which this feature can cause some conflicts with their build-in shaders, especially in JMonkeyEngine 3 and in JogAmp's Ardor3D Continuation. This flip has some limitations:
I suggest to add a flag "glslFlipEnabled" into GLJPanel set to the same value than USE_GLSL_TEXTURE_RASTERIZER by default. It could be used here:
This flag can be implemented in the same way than skipGLOrientationVerticalFlip but the documentation should mention that modifying it after the initialization makes no sense and has no effect.