Re: [PyOpenGL-Users] [Fwd: Re: Vertex Buffer Objects]

[Steven W. <st...@li...>]

Mike C. Fletcher wrote:
> Steven White wrote:
>> After dinner I was able to sit down with some help and remove several 
>> questionable lines of code that had slowly found there way in to the 
>> code as I was stripping down the application during debugging to find 
>> the error.  Unifying the type to GL.GLuint seems to have fixed the 
>> system crash problem, but the VBO will still does not post to the 
>> display.  By removing the index buffer and only using the index data 
>> during the glDrawArrays  call I was able to get what looked like a 
>> bow tie artifact on the screen on my friends fedora 5 machine, but 
>> both of my personal machines render only the clear color.  
> I've attached a version that (with current BZR head of PyOpenGL) 
> renders two squares.  You can comment out the second call to 
> glDrawElements if you want to run it on an older PyOpenGL.  I'm just 
> using the OpenGL.arrays.vbo.VBO implementation, I know, lazy, but oh 
> well.  If you want you can just trace through and see what OpenGL 
> calls are running with the VBO bind/unbind calls.  This version will 
> work with either core or ARB versions of vertex buffer objects.
>
> BTW, if you could just attach runnable files when sending a support 
> request it would help me.  Having to strip off the line numbers uses 
> up time that could be spent on development.
>> I have stripped my application to an exit command and a single 
>> polygon render and attached copied it at the bottom of this message.  
>> I am hopping in the morning someone with more experience in pyOpenGL 
>> can inform me on what may be causing the issue.  As a side note I am 
>> having a rather hard time debugging the application because non of my 
>> profilers seem to be able to intercept the opengl calls.  Does anyone 
>> have a solution for the OpenGL side of an pyOpenGL application like 
>> you would in C.
> You can use the built-in pdb module to debug Python code.  Just do:
>
>    import pdb; pdb.set_trace()
>
> before the call you want to trace into and you can step down to the 
> call that's going into the GL.  Since that call is normally to the 
> system GL directly it's somewhat difficult to trace it below that (you 
> can go into ctypes, but that's seldom useful), since ctypes has 
> stabilized I haven't had to go below that level.
>
> HTH,
> Mike
>
Thanks for the help.  I wasn't sure if the mailing list would allow 
attachments, I will make sure to do so in the future

Steven A White