It would be great to have this issue debated and fixed. I have the impression 
that using the Cairo backend suffers from the same problem. 

Alexandre

> Le 22-11-2013 à 14:57, Ronie Salgado <[email protected]> a écrit :
> 
> Hello,
> 
> I want to know about the Pharo graphic system architecture, I whould like to 
> know if there's some documentation explaining his inner works.
> 
> For NBOpenGL and Roassal 3D in particular, I'm having some flickering, which 
> I think is related to the way that the OpenGL framebuffer is transferred into 
> a pharo window.
> 
> In NBOpenGL, rendering is done in a offscreen FBO, whose content is 
> transferred into main memory y blitted into a pharo window. The pharo window 
> of course must be blitted or renderer into the screen, which means anothere 
> transfer into the GPU. In other words, we are a GPU->CPU->GPU memory 
> roundtrip.
> 
> The consequences of this are the lost of performance, the lost of 
> double-buffering and which is more important, the lost v-sync. The lack of 
> v-sync is seen in the way of tearing, which is more appreciated when moving 
> on the X-axis in a 3d view, such as in the Roassal3D example in 
> R3Example>>city.
> 
> I have heard that in pharo 3, all of the graphics are being moving into 
> Athens, a new graphics, for which I donr't know where's the documentation. I 
> believe that athens is a vector graphics API, which several backends as 
> cairo, which also has an opengl backend. I would like to share that OpenGL 
> context to avoid that round-trip if possible, or use a native window for the 
> OpenGL stuff, but to that I need to know how pharo graphics are done.
> 
> Greetings,
> Ronie Salgado

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