[PD-dev] [GEM] rendering context (gem2pdp)

Tom Schouten doelie at zzz.kotnet.org
Wed Mar 5 06:43:37 CET 2003


hi all

i was wondering if it is possible (and how) to change the rendering context 
in gem, with respect to interfacing it to pdp (or something else) without gem 
using it's own display window. 

what i am interested in is having gem render to an offscreen area (pbuffer) 
and output this as a pdp packet.

it is possible to use pbuffers and disable the window context entirely, but 
it seems it requires rather a large cut in gem. maybe i'm not seeing this 
correctly but i think it would involve something like this:


* GemWinCreateXWin needs to be replaced by something that constructs a 
pbuffer instead of a window.

* the place where the buffers are swapped: glutSwapBuffers() in GemMan.cpp 
a glReadPixels should be inserted that converts the data in the pbuffer to a 
pdp packet.

* the glXMakeCurrent(constInfo.dpy, constInfo.win, constInfo.context) in 
GemMan.cpp should be replaced by a glXMakeContextCurrent(dpy, pbuffer, 
pbuffer, context_pbuffer) call.


anyone any thoughts on this?

tom




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