On Don, 2013-03-14 at 23:35 +0100, Martin Andersson wrote:
> On Thu, Mar 14, 2013 at 7:45 PM, Marek Olšák <mar...@gmail.com> wrote:
> >
> > + /* See if the texture format already matches the format and type,
> > + * in which case the memcpy-based fast path will likely be used and
> > + * we don't have to blit. */
> > + if (_mesa_format_matches_format_and_type(rb->Format, format,
> > + type, pack->SwapBytes)) {
> > + goto fallback;
> > + }
>
> On my system (Intel core i7 and AMD 6950) the memcpy fast-path takes
> around 210 milliseconds and the blit path takes around 9 milliseconds, for a
> 1920x1200 image. So it is much faster, at least on my system, to use the
> blit path even when the mesa format matches format and type.
>
> To test this I forced the use of the memcpy fast-path (the mesa format was
> MESA_FORMAT_XRGB8888, the format was GL_BGRA and the type was
> GL_UNSIGNED_BYTE). I visually inspected the resulting image and I could
> not see anything wrong with it.
>
> But perhaps forcing the use of the memcpy fast-path invalidates the results.
> Or there might be some other issues that I am missing, but I just wanted to
> say that on my system it is better to remove this check.
If the read buffer is in VRAM, reading from it with the CPU directly
will be very slow.
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Debian, X and DRI developer
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev
