pyopengl-users

[PyOpenGL-Users] Vertex Buffer Objects

[J. A. <ja...@ca...>]

I've been fiddling around trying to get the Nehe example code for lesson 45 
working with PyOpenGl 3.xxx, however I can't seem to work out how to get it 
to work - I keep getting memory read errors.

Has anybody managed to get VBOs working? Any pointers? Example code?

Thanks,

Jeremy Appleyard

[PyOpenGL-Users] Vertex Buffer Objects

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

I need some advice with creating VBOs in PyOpenGL.  I was writing a demo 
app to use a template for a student assignment and ironically I can not 
seem to create one myself.  I've included some excerpts from the demo 
application and the top of the call stack from the crash log.  I am 
working under the assumption that I just do not know how to pass memory 
address properly in python.  Any advice would  be appreciated.

Test System is a MacBook Pro ATI graphics card.

VertexBuffer = GL.GLuint(0)   
IndexBuffer  = GL.GLuint(0)

def initBuffer
    global VertexBuffer,IndexBuffer
    VertexBuffer = glGenBuffersARB(1)   
    IndexBuffer = glGenBuffersARB(1)

def DrawGLScene():
    """
    Main drawing function
    """

    # Clear The Screen And The Depth Buffer
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    glLoadIdentity()                 # Reset The View
    glTranslatef( 0.0, 0.0, -25.0)   # Move out a bit to see everything.
 
    global VertexBuffer,IndexData
    glColor3f(1,1,1)
    glDisable(GL_TEXTURE_2D)
    glDisable(GL_LIGHTING)
    glColor3f(1,1,1)
    glBegin(GL_QUADS)   # Create a White Polygon
    glVertex3d(-25,-10,-25);
    glVertex3d( 25,-10,-25);
    glVertex3d( 25,-10, 25);
    glVertex3d(-25,-10, 25);
    glEnd()
    glColor3f(1,0,0)
    indexData=array([0,1,2,3], dtype=int)#Load The VBO With the same 
polygon just a little higher
    vertexCoordData=array([-25, -8, -25, 
                      25, -8, -25,
                      25, -8,  25,
                     -25, -8,  25],dtype=float)
   
   
    glEnableClientState(GL_VERTEX_ARRAY)
    glBindBufferARB(GL_ARRAY_BUFFER_ARB, VertexBuffer);
    glBufferDataARB(GL_ARRAY_BUFFER_ARB, vertexCoordData, 
GL_STREAM_DRAW);        
    glVertexPointer(3,GL_FLOAT,0,None);
   
   
    glEnableClientState(GL_VERTEX_ARRAY)
    glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER, IndexBuffer);
    glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER, indexData, 
GL_STREAM_DRAW);        
    glIndexPointer(GL_INT,0,None);
   
    glDrawElements( GL_QUADS,12, GL_UNSIGNED_INT,indexData);
    glDisableClientState(GL_VERTEX_ARRAY);
   
    glEnable(GL_TEXTURE_2D)
    glEnable(GL_LIGHTING)
    
    # since this is double buffered, swap the buffers to display what 
just got
    # drawn.
    glutSwapBuffers()              


Crash Log
Thread 0 Crashed:
0   libSystem.B.dylib                 0xffff07c2 __memcpy + 34
1   ...pple.ATIRadeonX1000GLDriver    0x131d7ee1 gldAllocVertexBuffer + 
27809
2   GLEngine                          0x130b54ee 
gleDrawArraysOrElements_VBO_Exec + 1950
3   libGL.dylib                       0x93302aa4 glDrawElements + 52
4   _ctypes.so                        0x00abb41d .LCFI1 + 23 (darwin.S:84)
5   _ctypes.so                        0x00abb3be ffi_call + 98 
(ffi_darwin.c:265)
6   _ctypes.so                        0x00ab5e98 _CallProc + 355 
(callproc.c:679)
......

[PyOpenGL-Users] IDLE, threads and pyopengl

[JoN <jo...@we...>]

Under Linux.

Ok this is really strictly a python question, but its in an opengl context
(sic), so I thought I'd start here.  I'll find some python lists to ask as well.

I have an environment under design that drives pyopengl but there is a lot of
threaded stuff going on using python threads.  Part of it is a 3d editor (yes
yes I know there are good ones already, its just the data model this one uses is
for solid rendering and i need some custom code).

Now ideally whilst building the editor I'd be able to run IDLE in one X window
and have the GL output in another X window (albeit via MESA, but thats good
enough for debugging).

Question is, can I safely launch threads from inside IDLE?

That's it, that's my Q!

Jon






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Re: [PyOpenGL-Users] IDLE, threads and pyopengl

[JoN <jo...@we...>]

And then he realizes he's asked the completely wrong question.

What I meant to ask was:

Can IDLE - or any python command interpreter for that matter? - be run itself as
a pythread ?

I have a threaded environment.  It would be really nice if I could pretend to be
just another thread and do my locking and unlocking etc as that thread, in the
course of development.

(Of course not all modules in python are pythread-safe, but I've factored that
in as the threaded environment I'm using makes almost no standard module calls,
and the rest I can deal with case-by-case).

Jon


Quoting JoN <jo...@we...>:

> 
> Under Linux.
> 
> Ok this is really strictly a python question, but its in an opengl context
> (sic), so I thought I'd start here.  I'll find some python lists to ask as
> well.
> 
> I have an environment under design that drives pyopengl but there is a lot
> of
> threaded stuff going on using python threads.  Part of it is a 3d editor
> (yes
> yes I know there are good ones already, its just the data model this one uses
> is
> for solid rendering and i need some custom code).
> 
> Now ideally whilst building the editor I'd be able to run IDLE in one X
> window
> and have the GL output in another X window (albeit via MESA, but thats good
> enough for debugging).
> 
> Question is, can I safely launch threads from inside IDLE?
> 
> That's it, that's my Q!
> 
> Jon
> 
> 
> 
> 
> 
> 
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Re: [PyOpenGL-Users] IDLE, threads and pyopengl

[JoN <jo...@we...>]

Actually the 'cmd' module seems to fit the bill.
Anybody had experience running it as a thread?

http://docs.python.org/lib/module-cmd.html

Jon


Quoting JoN <jo...@we...>:

> 
> And then he realizes he's asked the completely wrong question.
> 
> What I meant to ask was:
> 
> Can IDLE - or any python command interpreter for that matter? - be run itself
> as
> a pythread ?
> 
> I have a threaded environment.  It would be really nice if I could pretend to
> be
> just another thread and do my locking and unlocking etc as that thread, in
> the
> course of development.
> 
> (Of course not all modules in python are pythread-safe, but I've factored
> that
> in as the threaded environment I'm using makes almost no standard module
> calls,
> and the rest I can deal with case-by-case).
> 
> Jon
> 
> 
> Quoting JoN <jo...@we...>:
> 
> > 
> > Under Linux.
> > 
> > Ok this is really strictly a python question, but its in an opengl context
> > (sic), so I thought I'd start here.  I'll find some python lists to ask as
> > well.
> > 
> > I have an environment under design that drives pyopengl but there is a lot
> > of
> > threaded stuff going on using python threads.  Part of it is a 3d editor
> > (yes
> > yes I know there are good ones already, its just the data model this one
> uses
> > is
> > for solid rendering and i need some custom code).
> > 
> > Now ideally whilst building the editor I'd be able to run IDLE in one X
> > window
> > and have the GL output in another X window (albeit via MESA, but thats
> good
> > enough for debugging).
> > 
> > Question is, can I safely launch threads from inside IDLE?
> > 
> > That's it, that's my Q!
> > 
> > Jon
> > 
> > 
> > 
> > 
> > 
> > 
> > --------------------------------------------------------------------
> > Come and visit Web Prophets Website at http://www.webprophets.net.au
> > 
> > 
> > -------------------------------------------------------------------------
> > Take Surveys. Earn Cash. Influence the Future of IT
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> your
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> > 
> 
> 
> 
> 
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Re: [PyOpenGL-Users] IDLE, threads and pyopengl

[Mike C. F. <mcf...@vr...>]

JoN wrote:
> And then he realizes he's asked the completely wrong question.
>
> What I meant to ask was:
>
> Can IDLE - or any python command interpreter for that matter? - be run itself as
> a pythread ?
>   
There have been systems that used Idle connected up to a GUI with 
PyOpenGL running in it.  I seem to recall systems with IPython and a Tk 
OpenGL GUI as well.  I haven't done it myself, nor do I know if they 
actually used threads.  Normally what happens is that you need to 
arrange to have two event loops running.  Some GUIs (wxPython, for 
instance) can handle that using threads as long as you make sure that 
your first import of wxPython is in the secondary thread (IIRC).  
Running an interpreter thread using cmd should allow you to run that in 
a background thread and let the GUI use the main thread AFAICS.

I code my own systems using something like the wxPython shell widget 
hooked up to a wxPython GUI, so the system all runs in the same thread, 
but that has its own challenges when you want a user to code (e.g. they 
want to time.sleep() in a script).

HTH,
Mike

-- 
________________________________________________
  Mike C. Fletcher
  Designer, VR Plumber, Coder
  http://www.vrplumber.com
  http://blog.vrplumber.com

[PyOpenGL-Users] Low traffic on this list?

[JoN <jo...@we...>]

By the way, has the traffic on this list dropped dramatically or are my mail
filter rules up the duff?

I seem to only have 21 messages stored since 12 feb 2007.

Jon


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Re: [PyOpenGL-Users] IDLE, threads and pyopengl

[Shane H. <sha...@ie...>]

ipython is certainly doing this.  I saw the demo at PyCon, and have  
been using it to great effect in debugging and interacting with my wx  
app.

 > ipython -wthread

Works for wxPython guis.  --help gives more options and a bit more  
insight into it.  I'd have a look at what they did to see if it will  
work for you as is, or for your own cmd-based interactive app.

-Shane

On Mar 12, 2007, at 10:37 PM, Mike C. Fletcher wrote:

> JoN wrote:
>> And then he realizes he's asked the completely wrong question.
>>
>> What I meant to ask was:
>>
>> Can IDLE - or any python command interpreter for that matter? - be  
>> run itself as
>> a pythread ?
>>
> There have been systems that used Idle connected up to a GUI with
> PyOpenGL running in it.  I seem to recall systems with IPython and  
> a Tk
> OpenGL GUI as well.  I haven't done it myself, nor do I know if they
> actually used threads.  Normally what happens is that you need to
> arrange to have two event loops running.  Some GUIs (wxPython, for
> instance) can handle that using threads as long as you make sure that
> your first import of wxPython is in the secondary thread (IIRC).
> Running an interpreter thread using cmd should allow you to run  
> that in
> a background thread and let the GUI use the main thread AFAICS.
>
> I code my own systems using something like the wxPython shell widget
> hooked up to a wxPython GUI, so the system all runs in the same  
> thread,
> but that has its own challenges when you want a user to code (e.g.  
> they
> want to time.sleep() in a script).
>
> HTH,
> Mike

Re: [PyOpenGL-Users] IDLE, threads and pyopengl

[JoN <jo...@we...>]

Much thanks Mike and Shane, I'll look into these.

Cheers
Jon



Quoting Shane Holloway <sha...@ie...>:

> ipython is certainly doing this.  I saw the demo at PyCon, and have  
> been using it to great effect in debugging and interacting with my wx  
> app.
> 
>  > ipython -wthread
> 
> Works for wxPython guis.  --help gives more options and a bit more  
> insight into it.  I'd have a look at what they did to see if it will  
> work for you as is, or for your own cmd-based interactive app.
> 
> -Shane
> 
> On Mar 12, 2007, at 10:37 PM, Mike C. Fletcher wrote:
> 
> > JoN wrote:
> >> And then he realizes he's asked the completely wrong question.
> >>
> >> What I meant to ask was:
> >>
> >> Can IDLE - or any python command interpreter for that matter? - be  
> >> run itself as
> >> a pythread ?
> >>
> > There have been systems that used Idle connected up to a GUI with
> > PyOpenGL running in it.  I seem to recall systems with IPython and  
> > a Tk
> > OpenGL GUI as well.  I haven't done it myself, nor do I know if they
> > actually used threads.  Normally what happens is that you need to
> > arrange to have two event loops running.  Some GUIs (wxPython, for
> > instance) can handle that using threads as long as you make sure that
> > your first import of wxPython is in the secondary thread (IIRC).
> > Running an interpreter thread using cmd should allow you to run  
> > that in
> > a background thread and let the GUI use the main thread AFAICS.
> >
> > I code my own systems using something like the wxPython shell widget
> > hooked up to a wxPython GUI, so the system all runs in the same  
> > thread,
> > but that has its own challenges when you want a user to code (e.g.  
> > they
> > want to time.sleep() in a script).
> >
> > HTH,
> > Mike
> 
> 
> -------------------------------------------------------------------------
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