Re: [PyOpenGL-Users] Using PyopenGL with GLArea

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fantastic thanks for spending the time on that Matti, it works perfectly on
my system I will play around and adapt it to my own program and try out
your suggestions and see what i come up with :)

On Sat, Mar 11, 2017 at 5:15 PM Matti Kariluoma <mat...@gm...>
wrote:

> I forked your gist:
> https://gist.github.com/matti-kariluoma/7786a620abe87deb54c6012b07ded884
>
> I added error-checking to work around the errors I encountered, and placed
> a print-statement to show how to check which PyOpenGL Platform is loaded at
> runtime.
>
> When I tried to run either gist on my Nvidia+Debian laptop (pyopengl
> 3.0.2), the program crashed immediately with an error similar to:
> http://askubuntu.com/questions/175744/x-error-of-failed-request-badrequest-invalid-request-code-or-no-such-operation
> When I tried to run your gist on my Intel+Ubuntu 16.10 machine, your gist
> gives the errors you described. After making my changes, my gist displayed
> a red triangle with platforms "linux2" and "posix".
>
> ==
>
>
> > I just dont 100% get why i need to prefix I would not want to tell a
> user they need todo that
>
> PYOPENGL_PLATFORM allows one codebase to support osx, windows, and various
> linux flavors. A platform is selected at runtime to simplify the
> distribution of PyOpenGL. Some platforms implement things differently-
> there will always be bugs or missing functionality when running on
> different platforms. Avoid the use of `from X import *' to make your code
> more likely to run on a different platform. Instead of:
>   from OpenGL.GLUT import *
>   glutInit([])
> ...try:
>   from OpenGL import GLUT as glut
>   glut.glutInit([])
> ... you'd be surprised how much this helps platform portability.
>
> Each of the platforms has various dependencies that are not installed when
> you get pyopengl from source or pip, however the system package manager
> (apt) will download the dependencies automatically (e.g. freeglut3, etc.)
> for your system's recommended platform. Some of the "optional" platforms
> (osmesa, egl) do not have packages in apt, so you'll need to install the
> dependencies yourself. This becomes very complicated when you use external
> PPAs, or build your own drivers and libraries!
>
> Hint: Use strace to see which drivers/libraries are being used by your
> process, to ensure you are using the drivers/libraries you intend:
>   $ strace python glutexample.py 2>&1 | grep open
> ==
>
>
> >is there a way i can detect the profiles and select the best on startup ?
>
> You can choose between PyOpenGL platforms at runtime by setting
> `os.environ' in your code:
>   import os
>   os.environ['PYOPENGL_PLATFORM'] = 'posix'
>   import OpenGL
>
> ...you /should/ be able to use the `reload' function (
> http://stackoverflow.com/questions/437589/how-do-i-unload-reload-a-python-module)
> to choose a different platform at runtime:
>   import os
>   os.environ['PYOPENGL_PLATFORM'] = 'posix'
>   import OpenGL
>   # check if we have the features we want, if not...
>   if reload_opengl_platform:
>     os.environ['PYOPENGL_PLATFORM'] = 'osmesa'
>     reload(OpenGL)
>
> I did not test the`reload' code above, your results may vary.
>
>
> On 3/9/17 1:57 PM, Oliver Marks wrote:
>
> I am not sure if this is an issue now there are a few things I have
> noticed it occurs when using osmesa on x11 and wayland.
>
> I can now run it on both with x11 it just works in wayland if i prefix
> PYOPENGL_PLATFORM = "EGL" then it works.
>
> I am using ubuntu 16.10 and python-gobject 3.22.0-1 from the repository.
>
>
> PYOPENGL_PLATFORM = "EGL"
>
> I have a gi gtkglarea example on stack overflow
> http://stackoverflow.com/questions/42185728/why-is-glgenvertexarrays-undefined-in-pyopengl-when-using-gtkglarea
> .
>
>
> Tried to use Glut which i have never used before but that seems to be a
> world of pain and brings up new errors :/
>
> - using EGL NotImplementedError: Platform does not define a GLUT font
> retrieval function
> - using osmesa gives me TypeError: unhashable type contextdata.py", line
> 106, in getValue
> - using glx gives me glGenVertexArrays(1) this function takes at least 2
> arguments (1 given)
>
> This is where i got to with the code but it could be completely wrong as
> you don't seem to manage context in the same way but i did not find many
> glut examples most see to use pygame.
>
> https://gist.github.com/olymk2/b156f7490e3f5662e2fa0cf42b8c7c63
>
>
> Anyway my code kind of works I just dont 100% get why i need to prefix I
> would not want to tell a user they need todo that, so is there a way i can
> detect the profiles and select the best on startup
>
>
>
>
>
>
>
>
> On Wed, Mar 8, 2017 at 3:25 PM Matti Kariluoma <mat...@gm...>
> wrote:
>
> I will take a look on Saturday.
>
> 1) In the meantime, could you create a minimal example that demonstrates
> the problem?
>
> Its always very interesting to see simple-looking code that works on some
> platforms but doesn't work on others; we just had an example of such two
> weeks ago from another user.
>
> Ideally your minimal example would not involve the use of the `gi' module,
> or at the very least, include instructions to bring a fresh installation up
> with that package installed, i.e. "sudo apt-get install ..."
>
> 2) Does your problem require `gi' for this error to show?
>
> 3) Is the error reproducible under GLUT or GLFW?
>
> 4) If (2), what steps are needed to install `gi', and what version of `gi'?
> On 3/5/17 12:49 PM, Oly wrote:
>
> Just another thing of note,
>
> using PYOPENGL_PLATFORM = "osmesa" with x11 causes the same issue, so it
> would appear related to the mesa drivers.
>
> What other options can that take, can i enforce nvidia or intel instead of
> osmesa ?
>
> perhaps wayland is defaulting to mesa and x11 is using something else.
>
> feels like i am getting nearer to a solution, or at least a work around.
>
>
>
> On Sun, 5 Mar 2017 at 17:29 Oly <ol...@gm...> wrote:
>
> Also because it maybe useful, i have this being reported by gtk / opengl.
>
>
> Intel_Open_Source_Technology_Center_4.5_(Core_Profile)_Mesa_17.0.0_-_padoka_PPA_Mesa_DRI_Intel(R)_Kabylake_GT2__4.50
> OpenGL Version 4.5_(Core_Profile)_Mesa_17.0.0_-_padoka_PPA
> OpenGL Renderer Mesa_DRI_Intel(R)_Kabylake_GT2_
> Shader Language version 4.50
>
> so it looks like things should be new enough to support that feature under
> wayland.
>
>
> On Sun, 5 Mar 2017 at 17:28 Oly <ol...@gm...> wrote:
>
> Thanks for the offer not sure how i missed your reply.
>
> Anyway i made some progress, yes my issue is with linux and gtk
> specifically I have also found out it has something todo with wayland.
>
> Running the example i can get it to work with my intel and nvidia graphics
> (optimus card) on x11 but if i am using wayland then i get the error above.
>
> Not sure why wayland would effect what available to me anyone seen
> anything similar ?
>
> Seems it i graphics card related.
>
> I did not know about this trick PYOPENGL_PLATFORM="osmesa" so thats useful
> to know but it does not help unfortunately.
>
>
> On Sun, 12 Feb 2017 at 20:20 Matti Kariluoma <mat...@gm...>
> wrote:
>
> I tried to have a look at your code, but I don't have the `gi' package
> on my machine, and `pip install gi' can't find it either.
>
> 1) Would you accept help in the form of a program that starts with
> `from OpenGL import GLUT' , or does your problem require gi?
>
> As for the error you posted, looking at https://mesamatrix.net/ I see
> that glGenVertexArrays is a part of OpenGL 3.0, extension
> GL_ARB_vertex_array_object which seems to have broad support.
>
> 2) Maybe your graphics device (or its driver) is ancient?
>
> Since your gist seems to indicate you are using GTK, I assume you are
> running this under Linux. You may want to look into running PyOpenGL
> under mesa, using one of their software renderers if for whatever
> reason you don't have OpenGL3.0 support.
>
> Using the mesa CPU renderer under Linux:
>
> http://www.mattikariluoma.com/blog/Headless%20Rendered%20OpenGL%20Scenes.html
>
> >From: Oliver Marks <oly@di...> <oly@di...> - 2017-02-11 22:40:09
> >
> >Thought i would have a stab at trying to make this work, I cant find any
> >existing working examples.
> >
> >I have linked a gist if any one want to try.
> >
> >currently I am getting this error.
> >
> >OpenGL.error.NullFunctionError: Attempt to call an undefined function
> >glGenVertexArrays, check for bool(glGenVertexArrays) before calling
> >
> >Which to me sounds like its not available to the context, GLArea is
> >supplying the context so i am unsure why this would be ?
> >
> >Any ideas or can anyone give me some pointers ?
> >
> >https://gist.github.com/olymk2/5b3e49ac83130e580bd9983f2e5d49c3
> >
>
>
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