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Index › Programming Questions & Help › OpenGL and 3D Libraries › GLGraphics Threaded Class- No OpenGL context
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GLGraphics Threaded Class- No OpenGL context (Read 1323 times)
Johnny Ow
GLGraphics Threaded Class- No OpenGL context
Apr 23rd, 2009, 11:28pm  
I implemented a class that implements Runnable.  When I try to run a GLSL filter in this thread via GLTextureFilter.apply(), I get this error:

Code:
Exception in thread "Thread-6" javax.media.opengl.GLException: No OpenGL context current on this thread
	at javax.media.opengl.glu.GLU.getCurrentGL(GLU.java:234)
	at javax.media.opengl.glu.GLU.gluOrtho2D(GLU.java:1184)
	at codeanticode.glgraphics.GLState.setOrthographicView(GLState.java:66)
	at codeanticode.glgraphics.GLTextureFilter.setGLConf(GLTextureFilter.java:488)
	at codeanticode.glgraphics.GLTextureFilter.apply(GLTextureFilter.java:202)
	at codeanticode.glgraphics.GLTextureFilter.apply(GLTextureFilter.java:141)

I think it's because this thread doesn't know anything about the OpenGL canvas I created in the main processing thread via size().  Is there a way to create a second canvas or share the main thread's canvas?
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JohnG
Re: GLGraphics Threaded Class- No OpenGL context
Reply #1 - Apr 24th, 2009, 2:04am  
I believe that OpenGL isn't thread-safe, that is it doesn't work across threads properly.

It may be possible to create a completely separate GLContext for your thread, but then I think you'd have problems getting any data from it to your main context to actually show anything you've drawn to it.
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Johnny Ow
Re: GLGraphics Threaded Class- No OpenGL context
Reply #2 - Apr 24th, 2009, 6:29am  
In this case, I do not need to draw anything in my work thread--I just want to run a shader that does some GPGPU calculations.  The results will be transferred/stored in an array.
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