Re: [PyOpenGL-Users] VBO help and performance

[Leo H. <leo...@gm...>]

I don't claim to be a PyOpenGL master so YMMV, but when I did something
similar a few years ago, I had to add a call to tostring() to prepare the
array for PyOpenGL.  I was using Numeric at the time, so the relevant code
fragments were:

        self.vertexPositions = Numeric.zeros((size*3,3),Numeric.Float32)
        self._vertexPositionStr = self.vertexPositions.tostring()
        glEnableClientState(GL_VERTEX_ARRAY)
        glVertexPointer(3,GL_FLOAT,0,self._vertexPositionStr)

I haven't actually used this code much in several years though.

Leo



On Sat, May 1, 2010 at 4:08 PM, Wakefield, Robert
<rjw...@en...>wrote:

> Hello,
>
> I've been using PyOpenGL to try to get faster graphics in pygame, and from
> what I've been able to find online VBOs are the best way to optimize in my
> case (2D sprites and tiled backgrounds).  However, for some reason they and
> the vertex arrays they're based on won't work.  In even the simplest
> example, nothing appears, while the corresponding display list or
> glBegin/End call works without a hitch.  Am I missing something, or could
> this be a technical issue?  Any other ideas as to what's wrong?  The code I
> have in the draw test is listed below (I also tried to generate/bind
> buffers, to no effect, but I think the problem is the array):
>
>    # shows nothing; also didn't work with GL_INT and integer types or
> typing in the '.0' for decimal.
>    vertices = numpy.array([0,0,  0,128,  128,128], dtype=numpy.float32)
>    glEnableClientState(GL_VERTEX_ARRAY)
>    glVertexPointer(2, GL_FLOAT, 0, vertices)
>    glDrawArrays(GL_TRIANGLES, 0, 3)
>    glDisableClientState(GL_VERTEX_ARRAY)
>
>    # this, however, works fine.  The data points and mode (GL_TRIANGLES)
> are both identical
>    glBegin(GL_TRIANGLES)
>    glVertex2f(0.0, 0.0)
>    glVertex2f(0.0, 128.0)
>    glVertex2f(128.0, 128.0)
>    glEnd()
>
>
>
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