Re: [Mesa3d-dev] [PATCH] st/mesa: do not advertise S3TC if the external lib is not available

[Marek O. <ma...@gm...>]

OK thanks, I pushed what you suggested.

-Marek

On Sat, Feb 27, 2010 at 9:44 PM, José Fonseca <jfo...@vm...> wrote:

> On Sat, 2010-02-27 at 09:15 -0800, Marek Olšák wrote:
> > Hi,
> >
> > S3TC shouldn't be advertised without the external lib and the attached
> > patch fixes that. Please review.
>
> Hi Marek,
>
> Actually it is a bit more subtle.
>
> S3TC can and should be advertised if the pipe driver supports ST3C
> decompression and *compression*.
>
> No real hardware has circuitry for S3TC compression, granted. But the
> vwmare svga gallium driver does it, by deferring everything to the host.
>
> It was the best solution we found to supporting S3TC without having to
> rely on closed source or questionable bits in the guest.
>
> So the right fix should be:
>
> screen->is_format_supported(screen, PIPE_FORMAT_DXT5_RGBA,
>                                    PIPE_TEXTURE_2D,
>                                    PIPE_TEXTURE_USAGE_SAMPLER, 0) &&
> (ctx->Mesa_DXTn || screen->is_format_supported(screen,
> PIPE_FORMAT_DXT5_RGBA, PIPE_TEXTURE_2D, PIPE_TEXTURE_USAGE_RENDERTARGET,
> 0)
>
> Jose
>
>