Hello,
That is a good question. I am no expert in that area, and I just fiddled on until it worked.
After a bit of investigating the original code I found out how it worked. What I did was resizing the image in a separate thread. For this I needed a OpenGL context, because gluScaleImage is used by OpenSceneGraph. So in this thread I create a new OpenGL context for the gluScaleImage. So the texture is never uploaded to the graphic card for display in this process. I never really looked at what OpenSceneGraph did I my thread, but it worked.
I now also found out the problem. My image is normally not a power of two. So I would read it in, remember the original size and then rescale the image in another thread and display it using the original size to determine the size of the texturequad to display it on. An image with the power of two dimensions loads up fast enough, with (almost) no stuttering.
Using the the option resizeNPOS=False still gives a delay when uploading the texture to the graphic card. That is what my example program did and what confused me.
So this more or less solves my problem. Except that I now need to make something to automatically scale those images. It would be nice if the scaling could be done when loading the texture, because then the director solution would work. So something like viz.addTexture('test.png', instantScale=True).
Thanx for all the help. Sometimes it is just a matter of asking me the right questions.
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