[Mesa-dev] vbo code and flush explicit mapping

[Jose Fonseca]

----- Original Message -----
> On Mon, Apr 29, 2013 at 2:52 PM, Dave Airlie <airlied at gmail.com> wrote:
> > I've been playing with a gallium driver, and started looking at some
> > wierd gears behaviour,
> >
> > The vbo code maps the buffer with GL_MAP_FLUSH_EXPLICIT_BIT which to
> > me requires that at some point
> > we call ctx->Driver.FlushMappedBufferRange. Now the code attempts to
> > call it in vbo_exec_vtx_unmap
> > but from what I can see the length is always 0 in there and so we
> > never get called.
> >
> > GLsizeiptr length = (exec->vtx.buffer_ptr - exec->vtx.buffer_map) *
> > sizeof(float);
> >
> > but I can not see buffer_ptr != buffer_map when we hit this code, I'm
> > a bit lost at this point, maybe someone else might know more.
> 
> Okay maybe I'm missing something, I'm just tracing gears with softpipe
> and realised the map/unmap
> pairs occur due to the Material calls but they don't actually seem to
> modify the VBOs.

That's weird.

I thought that material changes would just translate to constant buffer updates.

It looks like we replace the glBegin .. glEnd with VBOs, but we still translate Material calls literally.

Now that no Mesa driver handles fixed function directly, we could probably simplify some of these things.


Jose