[PATCH] wined3d: Check GLSL version when using ARB_shader_bit_encoding with uvec4.

[Henri Verbeet]

On Fri, 19 Apr 2019 at 16:38, Paul Gofman <gofmanp at gmail.com> wrote:
> On 4/19/19 14:42, Henri Verbeet wrote:
> > On Fri, 19 Apr 2019 at 15:42, Paul Gofman <gofmanp at gmail.com> wrote:
> > It may be worth trying to make it work with ivec4() instead of
> > uvec4(). Ironlake is perhaps a little special in that it does have
> > true integer support, but not GLSL 1.30.
> >
> Do you think it will be portable when converting special values from
> signed integers? As I read the specs, converting NaN with
> (u)intBitsToFloat() is already undefined, but seems to work. Won't
> representing specials through signed integers be leaving more room for
> different behaviour on various cards, drivers and GLSL versions? I can
> sure make it and test on what I have here, but it seems hard to be sure
> how universally this will work.
>
That and "negative" values are the main issues I'd be potentially
worried about, but at the same time I wouldn't expect drivers/hardware
to go out of their way to distinguish between singned/unsigned here.
We could also potentially switch between uvec4 and ivec4 based on
whether we have GLSL 1.30 or not, but that may not offer any
advantages in practice.