[PyOpenGL-Users] glMapBuffer with GL_WRITE_ONLY

[Colin C. <cjc...@gm...>]

Hi everyone,

I've managed to get VBOs working in my PyOpenGL application, but I've  
hit a wall trying to update the data in them.  My VBOs contain  
position and texcoord data only (not interleaved).  Every few frames I  
need to change some of the texcoord data.  I know this is done with  
glMapBuffer, but I can't wrap my head around the python bindings for  
this function.  glMapBuffer returns a ctypes.c_void_p.  I'm very  
comfortable with C, but not with ctypes.  I want to treat this  
c_void_p like a python list of floats, and use slicing to change the  
values at particular locations.  Is this possible?  I'm also very  
worried about performance; I don't want any of the texcoord buffer to  
be copied back into main memory.  I've spent a lot of time hunting  
around with Google, but I'm still lost.  Any help is greatly  
appreciated.

Colin