Posted by MarcoNL on Oct 21, 2021; 8:39am
URL: https://forum.jogamp.org/Incorrect-context-on-GLCanvas-drawable-tp4041391p4041395.html

Hi Julien,

thanks a lot for your reply!

As far as I can see from vtkJoglCanvasComponent.java source code (https://github.com/Kitware/VTK/blob/master/Wrapping/Java/vtk/rendering/jogl/vtkJoglCanvasComponent.java), the GLCanvas is indeed initialized like this:

GLCanvas glCanvas = new GLCanvas(new GLCapabilities(GLProfile.getMaximum(true)));

In fact, when the GLCanvas-based VTK component is initially used in my application, it ALWAYS works fine. Once the GLCanvas-based panel is displayed for the first time in my application, GLEventListener.init() is called inside vtkAbstractJoglComponent.java (see https://github.com/Kitware/VTK/blob/master/Wrapping/Java/vtk/rendering/jogl/vtkAbstractJoglComponent.java). At this point, the "GLContext ctx" variable defined inside the GLEventListener.init() always corresponds with an OpenGL 4.6 context, as logged by a "ctx.toString()" call. So far, so good.

However, when a "full screen mode" function is invoked in my application, sometimes my application crashes. Here is what this "full screen mode" function does:

1) Remove the GLCanvas-based component from its container
    --> GLEventListener.dispose() is called inside vtkAbstractJoglComponent.java --> see https://github.com/Kitware/VTK/blob/master/Wrapping/Java/vtk/rendering/jogl/vtkAbstractJoglComponent.java)

2) Create a new JFrame

3) Add the existing GLCanvas-based component (i.e., the same GLCanvas which was created at point 1 above, hence apparently using the same GLCapabilities) to this newly-created JFrame
    --> GLEventListener.init() is invoked again inside vtkAbstractJoglComponent.java
However, this time, if I invoke "ctx.toString()" inside the init() callback, **SOMETIMES** I get an OpenGL 1.1 context, and when this happens, my application crashes, because VTK crashes, due to insufficient OpenGL context.

Do you have an explanation as to why the second GLEventListener.init() made on the same GLCanvas instance (following to removal of the panel from its container + add of the panel to new JFrame) **SOMETIMES** returns an OpenGL 1.1 context?

I was suspecting some threading issue, but I've verified and I am sure that all init() and all dispose() calls are always done on the same thread, which is the EDT (SwingUtilities.isEventDispatcherThread() always returns 'true' in these callbacks).

Any hint would be greatly appreciated.
Thanks in advance for your feedback.

Best regards,

Marco Sambin