pyopengl-users

[PyOpenGL-Users] Shader doesn't compile with Python 3

[Matt W. <li...@mi...>]

Hi all,

I'm really enjoying using PyOpenGL. I've just switched over to using
Python3 but I've hit a problem with compiling my shaders. As an example,
consider this code:

---------- test.py

from OpenGL.GL import shaders, GL_VERTEX_SHADER

import pygame
screen = pygame.display.set_mode((800, 800), pygame.OPENGL)

VERTEX_SHADER = shaders.compileShader("""
    #version 130

    void main()
    {
    }
    """, GL_VERTEX_SHADER)

----------

I'm running all this on Linux (openSUSE 12.3) with the following
configuration:

GL_RENDERER: GeForce GTX 560 Ti/PCIe/SSE2
GL_VERSION: 4.3.0 NVIDIA 313.30
GL_SHADING_LANGUAGE_VERSION: 4.30 NVIDIA via Cg compiler

If I run this code with 'python test.py' then it runs fine (briefly flashes
a window without complaint). However, when running under Python 3 with
'python3 test.py' it gives the following error:

----------

Traceback (most recent call last):
  File "./test.py", line 14, in <module>
    """, GL_VERTEX_SHADER)
  File
"/home/matt/.local/lib/python3.3/site-packages/OpenGL/GL/shaders.py", line
233, in compileShader
    shaderType,
RuntimeError: ('Shader compile failure (0):\n0(1) : error C0130: invalid
character literal\n0(1) : error C0000: syntax error, unexpected special
error tag, expecting "::" at token "<error>"\n0(1) : error C0130: invalid
character literal\n', [b'\n\t#version 130\n\t\n\tvoid
main()\n\t{\n\t}\n\t'], GL_VERTEX_SHADER)

----------

Given that the first error is 'invalid character literal', I'm assuming
that this is an encoding problem. It looks like (as far as I can tell)
PyOpenGL is sending an ASCII-encoded byte string but maybe that's not what
is expected?

Is anyone else seeing this problem or can reproduce this? Or does anyone
have an idea of the reason it's happening or a fix for it?

Regards,
Matt Williams

Re: [PyOpenGL-Users] Shader doesn't compile with Python 3

[Ian M. <ia...@ge...>]

Pass it binary strings.

Re: [PyOpenGL-Users] Shader doesn't compile with Python 3

[Matt W. <li...@mi...>]

On 14 April 2013 16:05, Ian Mallett <ia...@ge...> wrote:
> Pass it binary strings.

If I do that with:

VERTEX_SHADER = shaders.compileShader(b"""
    #version 130

    void main()
    {
    }
    """, GL_VERTEX_SHADER)

then it still works correctly on Python 2.7 but with Python 3.3 it errors with:

RuntimeError: ('Shader compile failure (0):\n0(1) : error C0125:
integer constant overflow\n0(1) : error C0000: syntax error,
unexpected unsigned integer constant at token "<uint-const>"\n', [10,
9, 35, 118, 101, 114, 115, 105, 111, 110, 32, 49, 51, 48, 10, 9, 10,
9, 118, 111, 105, 100, 32, 109, 97, 105, 110, 40, 41, 10, 9, 123, 10,
9, 125, 10, 9], GL_VERTEX_SHADER)

So it looks to be passing a list of integers referring to the correct
ASCII characters.

The Python source file itself is utf-8 encoded but since I'm only
using the ASCII range of characters, it's the same as if it were ASCII
encoded.

I have the same problem if I do:

VERTEX_SHADER = shaders.compileShader("""
    #version 130

    void main()
    {
    }
    """.encode('ascii'), GL_VERTEX_SHADER)

with an identical error.

Regards,
Matt Williams

Re: [PyOpenGL-Users] Shader doesn't compile with Python 3

[Chris B. - N. F. <chr...@no...>]

I'm not using py3, but maybe you need to encode the string into a
bytes object ASCII.

-Chris
On Apr 14, 2013, at 1:44 PM, Matt Williams <li...@mi...> wrote:

> On 14 April 2013 16:05, Ian Mallett <ia...@ge...> wrote:
>> Pass it binary strings.
>
> If I do that with:
>
> VERTEX_SHADER = shaders.compileShader(b"""
>    #version 130
>
>    void main()
>    {
>    }
>    """, GL_VERTEX_SHADER)
>
> then it still works correctly on Python 2.7 but with Python 3.3 it errors with:
>
> RuntimeError: ('Shader compile failure (0):\n0(1) : error C0125:
> integer constant overflow\n0(1) : error C0000: syntax error,
> unexpected unsigned integer constant at token "<uint-const>"\n', [10,
> 9, 35, 118, 101, 114, 115, 105, 111, 110, 32, 49, 51, 48, 10, 9, 10,
> 9, 118, 111, 105, 100, 32, 109, 97, 105, 110, 40, 41, 10, 9, 123, 10,
> 9, 125, 10, 9], GL_VERTEX_SHADER)
>
> So it looks to be passing a list of integers referring to the correct
> ASCII characters.
>
> The Python source file itself is utf-8 encoded but since I'm only
> using the ASCII range of characters, it's the same as if it were ASCII
> encoded.
>
> I have the same problem if I do:
>
> VERTEX_SHADER = shaders.compileShader("""
>    #version 130
>
>    void main()
>    {
>    }
>    """.encode('ascii'), GL_VERTEX_SHADER)
>
> with an identical error.
>
> Regards,
> Matt Williams
>
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Re: [PyOpenGL-Users] Shader doesn't compile with Python 3

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

On 13-04-14 04:43 PM, Matt Williams wrote:
> On 14 April 2013 16:05, Ian Mallett <ia...@ge...> wrote:
>> Pass it binary strings.
> If I do that with:
>
> VERTEX_SHADER = shaders.compileShader(b"""
>      #version 130
>
>      void main()
>      {
>      }
>      """, GL_VERTEX_SHADER)
>
> then it still works correctly on Python 2.7 but with Python 3.3 it errors with:
The above code (with or without the b) works with Python 2.7, 3.2 and 
3.3 on Ubuntu 64-bit with fglrx drivers when using bzr head. bzr head 
*also* for the first time, can run test_core.py on all of those 
platforms (when numpy and pygame are installed), however, I don't see 
anything in the changes I made which should have caused the error you saw.

If you can test on bzr head, that would let me know whether we're 
looking at something already fixed, or a continuing bug.

HTH,
Mike

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

Re: [PyOpenGL-Users] Shader doesn't compile with Python 3

[Matt W. <li...@mi...>]

On 16 April 2013 03:43, Mike C. Fletcher <mcf...@vr...> wrote:
> The above code (with or without the b) works with Python 2.7, 3.2 and
> 3.3 on Ubuntu 64-bit with fglrx drivers when using bzr head. bzr head
> *also* for the first time, can run test_core.py on all of those
> platforms (when numpy and pygame are installed), however, I don't see
> anything in the changes I made which should have caused the error you saw.
>
> If you can test on bzr head, that would let me know whether we're
> looking at something already fixed, or a continuing bug.

I've just tested it with bzr head and it seems the issue is resolved
there. It appears to compile the shaders without problem.

I also ran test_core.py and it ran fine without any apparent failures.

I am noticing a new and different problem (something ctypes-related I
think) but I'll investigate that a little first and post on the list
if I can't resolve it.

cheers,
Matt Williams

Re: [PyOpenGL-Users] Shader doesn't compile with Python 3

[Gabriele L. <gab...@gm...>]

I'm having the same problem in python 3 (not being able to compile the 
shaders because it gets an invalid literal). Did you find any actual 
workaround for that?

Re: [PyOpenGL-Users] Shader doesn't compile with Python 3

[Chris B. - N. F. <chr...@no...>]

On Tue, May 28, 2013 at 10:53 PM, Gabriele Lanaro
<gab...@gm...> wrote:
> I'm having the same problem in python 3 (not being able to compile the
> shaders because it gets an invalid literal). Did you find any actual
> workaround for that?

IIUC shaders have to be written in ASCII, perhaps with Py3, you are
passing unicode in -- ty encoding it to ascii and passing the bytes
object instead.

Or maybe I totally mis-understand the issue!

-Chris



-- 

Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R            (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chr...@no...

Re: [PyOpenGL-Users] Shader doesn't compile with Python 3

[Gabriele L. <gab...@gm...>]

@Chris yes, that's basically the issue. The function glShaderSource in py3
wants an 'str' object instead of a 'bytes' one. If you pass a 'bytes' you
have to convert it to 'str'. And in the non-bzr version there is probably
some code that doesn't correctly handles bytes strings.

I was able to solve the problem by backporting the function compileshader.
In this way it works with both py2 and py3:

def compileShader( source, shaderType ):

    """Compile shader source of given type
        source -- GLSL source-code for the shader
    shaderType -- GLenum GL_VERTEX_SHADER, GL_FRAGMENT_SHADER, etc,
        returns GLuint compiled shader reference
    raises RuntimeError when a compilation failure occurs
    """
    if isinstance(source, str):

        source = [source]
    elif isinstance(source, bytes):

        source = [source.decode('utf-8')]

    shader = glCreateShader(shaderType)
    glShaderSource(shader, source)
    glCompileShader(shader)
    result = glGetShaderiv(shader, GL_COMPILE_STATUS)

    if not(result):
        # TODO: this will be wrong if the user has
        # disabled traditional unpacking array support.
        raise RuntimeError(
            """Shader compile failure (%s): %s"""%(
                result,
                glGetShaderInfoLog( shader ),
            ),
            source,
            shaderType,
        )
    return shader




On Wed, May 29, 2013 at 9:23 AM, Chris Barker - NOAA Federal <
chr...@no...> wrote:

> On Tue, May 28, 2013 at 10:53 PM, Gabriele Lanaro
> <gab...@gm...> wrote:
> > I'm having the same problem in python 3 (not being able to compile the
> > shaders because it gets an invalid literal). Did you find any actual
> > workaround for that?
>
> IIUC shaders have to be written in ASCII, perhaps with Py3, you are
> passing unicode in -- ty encoding it to ascii and passing the bytes
> object instead.
>
> Or maybe I totally mis-understand the issue!
>
> -Chris
>
>
>
> --
>
> Christopher Barker, Ph.D.
> Oceanographer
>
> Emergency Response Division
> NOAA/NOS/OR&R            (206) 526-6959   voice
> 7600 Sand Point Way NE   (206) 526-6329   fax
> Seattle, WA  98115       (206) 526-6317   main reception
>
> Chr...@no...
>

Re: [PyOpenGL-Users] Shader doesn't compile with Python 3

[Matt W. <li...@mi...>]

On 29 May 2013 06:53, Gabriele Lanaro <gab...@gm...> wrote:
> I'm having the same problem in python 3 (not being able to compile the
> shaders because it gets an invalid literal). Did you find any actual
> workaround for that?

The only solution I found was to update to the latest version in bzr.
Have you tried that?

I agree that it's not an ideal solution but it worked for me.

Matt

Re: [PyOpenGL-Users] Shader doesn't compile with Python 3

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

On 13-05-29 12:23 PM, Matt Williams wrote:
> On 29 May 2013 06:53, Gabriele Lanaro <gab...@gm...> wrote:
>> I'm having the same problem in python 3 (not being able to compile the
>> shaders because it gets an invalid literal). Did you find any actual
>> workaround for that?
> The only solution I found was to update to the latest version in bzr.
> Have you tried that?
>
> I agree that it's not an ideal solution but it worked for me.
I've released a 3.1.0a1 on PyPi (hidden, so they are not automatically 
installed when users ask to install PyOpenGL).  You should be able to 
pull the equivalent of bzr head with:

     pip install "PyOpenGL==3.1.0a1" "PyOpenGL-accelerate==3.1.0a1"

with the caveat that those are source-code only releases at the moment, 
so your target platform will need a Python-module compilation 
environment available.  The tarballs include the still-in-process egl 
and es[1,2,3] packages, those are *not* ready for *any* use.

HTH,
Mike

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