[Mesa-dev] vbo code and flush explicit mapping

[Dave Airlie]

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.

Dave.