Re: [PyOpenGL-Users] Opengl Constant problem

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

On 13-01-18 07:32 PM, Wojciech Daniło wrote:
> Hi! I'm new to OpenGL and PyOpenGL, but Im trying to create a project 
> to my colledge and I'm facing a big problem. I was trying to resolve 
> it but without luck :(
>
> I'm trying to execute the python example (volume rendering in 
> pyopengl) from http://www.siafoo.net/snippet/310, which uses the code 
> from http://www.siafoo.net/snippet/142 and in that code the author 
> uses PyOpenGL constant GL_STATIC_DRAW_ARB.
>
> Unfortunatelly my Python (2.7) with PyOpengl 3.0.2-r1000 complains, 
> that this variable is not defined (gentoo linux, x86 64).
>
> It is used though in some examples like: 
> http://www.songho.ca/opengl/gl_vbo.html.
>
> So the api has changed? Or maybe the example is wrong?
The namespace was cleaned up, so that you only get the ARB constants if 
you explicitly import them, but your snippets are actually using *core* 
entry points, so you may as well use the core constant:

GL_STATIC_DRAW

if you really want to use the ARB version:

from OpenGL.GL.ARB.vertex_buffer_object import *

but there's no reason to do that unless you want to use glBufferDataARB too.

> How can I use glBufferData from OpenGl and what to pass as fourth 
> argument to make it working?
>
> In the example there was glBufferData(GL_ARRAY_BUFFER, data[i], 
> GL_STATIC_DRAW_ARB), where data is numpy array containing volume 
> representation of an object.

Just drop the _ARB. There is also an OpenGL.arrays.vbo.VBO helper class 
that can be used, should you want to avoid some of the lower-level details.

Hope that helps,
Mike

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