Re: [PyOpenGL-Users] Difficulty with the shaders tutorial

[Derakon <de...@gm...>]

On further investigation, those functions weren't available because I
didn't have an OpenGL context yet. My bad. Moving the set-up to later
on in the program (the first paint call) instead gives these errors:

RuntimeError: ('Shader compile failure (0): 0(3) : error C7533: global
variable gl_ModelViewProjectionMatrix is deprecated after version
120\n0(3) : error C7533: global variable gl_Vertex is deprecated after
version 120\n', ['#version 330\n            void main() {\n
    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n
  }'], GL_VERTEX_SHADER)

Feel free to correct me, but it looks like this means that the
tutorial is using deprecated concepts? GL_VERSION is 3.3.0 and
GL_SHADER_VERSION is "3.30 NVIDIA via Cg compiler", for what it's
worth.

-Chris

On Thu, Feb 16, 2012 at 10:05 AM, Derakon <de...@gm...> wrote:
> I'm trying to figure out OpenGL 3. Well, really I'm trying to figure
> out fragment shaders so I can do a false-color filter for my
> monochrome camera displays, but the fragment shader tutorial is also
> an OpenGL 3 tutorial, so it's off the deep end I go. I took a look at
> the shaders tutorial:
> http://pyopengl.sourceforge.net/context/tutorials/shader_1.xhtml
>
> The first problem I run into is literally a context problem: I have no
> idea what the high-level structure of the tutorial is because it's
> broken up into chunks of a few lines at a time separated by
> explanatory text. That'd be fine if the script were repeated without
> those interruptions at some point, or if the chunks of program were
> bigger, but as it stands the code part of the tutorial is very hard to
> read.
>
> The second problem I have is also a context problem: OpenGLContext
> doesn't exist for me. I have a standard Windows Python 2.7 / PyOpenGL
> / numpy install. Fortunately I have some prior experience with OpenGL
> and guess that I can work around this by using WX rendering contexts
> instead. So I adapt the tutorial script to this standalone program:
> http://pastebin.com/KWwi1Ahi
>
> However, when I run this, I get the following error when the first
> call to shaders.compileShader is made:
> OpenGL.error.NullFunctionError: Attempt to call an undefined alternate
> function (glCreateShader, glCreateShaderObjectARB), check for
> bool(glCreateShader) before calling
>
> Amusingly, calling glGetBoolean(glCreateShader) throws *another* error:
> KeyError: ('Unknown specifier
> <OpenGL.platform.baseplatform.glCreateShader object at
> 0x00000000031360F0>', 'Failure in cConverter
> <OpenGL.converters.SizedOutput object at 0x0000000002E27748>',
> (<OpenGL.platform.baseplatform.glCreateShader object at
> 0x00000000031360F0>,), 1, <OpenGL.wrapper.glGetIntegerv object at
> 0x000000000305D4C8>)
>
> -Chris