Re: [PyOpenGL-Users] VBO question

[Jason H. <Jas...@vo...>]

Sure thing.  Here is basically everything I changed to get this to work.  I'm not an expert in OGL, so I could be doing some things wrong.


from ctypes import c_void_p
from OpenGL.GL import *
from OpenGL.GL.ARB.vertex_buffer_object import *
import OpenGL.arrays.arraydatatype
import numpy


## Right after OGL is initialized ##
if glInitVertexBufferObjectARB():
        # build meshes
        # compile shaders


## When a mesh is being built ##
ADT = OpenGL.arrays.arraydatatype.ArrayDatatype

# iterate over each face and build up vertices
vertices.append( [ x, y, z, r, g, b, a ] )

# convert vertices to a numpy array

# send vertices to the GPU
vb_name = glGenBuffersARB( 1 )
glBindBufferARB( GL_ARRAY_BUFFER_ARB, vb_name )
glBufferDataARB( GL_ARRAY_BUFFER_ARB, ADT.arrayByteCount( vertices ), ADT.voidDataPointer( vertices ), GL_STATIC_DRAW_ARB )


## In the mesh bind function ##
glBindBufferARB( GL_ARRAY_BUFFER_ARB, vb_name )

# bind vertex
id = getGetAttribLocation( shader, "position" )
glEnableVertexAttribArray( id )
glVertexAttribPointer( id, 3, GL_FLOAT, GL_FALSE, sizeof( vertex ), None )

# bind color
id = getGetAttribLocation( shader, "color" )
glEnableVertexAttribArray( id )
glVertexAttribPointer( id, 4, GL_FLOAT, GL_FALSE, sizeof( vertex ), c_void_p( OFFSET_VERTEX_COLOR ) )


## In my main render loop ##
glUseProgramObjectARB( shader )
mesh.bind( )
glDrawArrays( GL_TRIANGLES, 0, mesh.num_raw_verts )
mesh.unbind( )
glUseProgramObjectARB( shader )


-Jason

-----Original Message-----
From: W.H. Gomersall [mailto:wh...@he...] On Behalf Of Henry Gomersall
Sent: Tuesday, June 21, 2011 3:20 AM
To: Jason Hayes
Cc: pyo...@li...
Subject: RE: [PyOpenGL-Users] VBO question

On Mon, 2011-06-20 at 18:29 -0700, Jason Hayes wrote:
> Thanks for the reply Henry.  After a lot of trial and error, I finally
> figured out what the real problem is.  I'm on OpenGL 3.3 and
> glVertexPointer and the others have been deprecated since 3.0, but
> PyOpenGL tries to maintain backwards compatability I guess.  So I
> figured out the correct method and switched to glVertexAttribPointer
> and wrote a GLSL shader, now everything works great.

For my benefit as much as others, would you share the code snippet that loads the vertex array?

Thanks,

Henry


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