[Bug 42863] Multiple games require sample_c_lz for cube/array textures ( Winexy, Witcher 3, Flame in the Flood)

https://bugs.winehq.org/show_bug.cgi?id=42863

--- Comment #10 from Matteo Bruni  ---
(In reply to Guillaume Charifi from comment #9)
> It's probably just plain wrong, but can't it be simulated by
> dot(textureGather(sampler, pos, refZ), vec4(0.25)) ?

Well, that's certainly incorrect in general. Weighting the four samples
appropriately would be okay for the linear interpolation magnification case.
That still leaves out the other cases though.

Another workaround could be to use an ad-hoc sampler or texture view overriding
the texture levels / LOD to just enable level 0. It doesn't sound too appealing
though, it would probably require some quite invasive and ugly changes to
wined3d and the additional sampler / texture view would have to be used only
for sample_c_lz i.e. we would waste a texture unit if the texture is also
sampled without _lz in the same shaders. Not sure there are other realistic
options though.

I don't know if Józef has already given some thought about a sensible fix.