Re: [PyOpenGL-Users] Missing definitions? GLbyte, GL_R8UI

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

On Mon, Jan 6, 2014 at 1:46 AM, Carl Olsson <car...@gm...> wrote:

> I'm targeting OpenGL 3.3 so I figured the texture_rg stuff would be
> part of the core API.
>
It is, but you don't have an OpenGL 3.3 core context. I'm fairly sure
PyOpenGL sets up an OpenGL 2 context.

I'm working on an 8-bit indexed-colour (palette) image renderer so I
> need unnormalised integer textures to properly store the pixel
> information.
>
> All the other typedefs I've tried work fine (GLfloat, GLint, GLuint,
> etc.) just GLbyte doesn't seem to be defined for some reason."GLbyte =
> ctypes.c_ubyte" does the trick though for numpy data type.
>
I'll assume this is for using VBOs or something. Otherwise, you shouldn't
need these C typenames in Python, IIRC.


> I am basically new to OpenGL (dabled a little over a decade ago on a
> software OpenGL renderer as my video card at the time didn't support
> OpenGL :p), this is partly an exercise to learn the modern shader
> pipeline, so I figured the forward compatibility would prevent
> anything undesirably legacy creeping in.
>
I typically have my students start with OpenGL 2, as the required concepts
are far simpler. Getting triangles on the screen and learning how to
manipulate them at the intuitive level requisite for graphics programming
is hard enough without

setting up GLSL shaders and grokking in fullness the rendering pipeline. As
you're new to OpenGL, that recommendation stands as mine for you as well.
However, if you still want to learn GL 3+ style straight off, I recommend
the Lighthouse 3D tutorials, which are both technically virtuous and
accessible.

Regarding GL_R8UI, as I said, you probably won't need it for a while. Use
GL_RGBA or GL_RGB for loading standard color textures.

Ian