Questioning the depth_clamp_test in d3d8:visual

[Joerg-Cyril.Hoehle at t-systems.com]

Hi,

Trying to understand bugs #10636 and #19773 , I glanced at the
d3d8 visual.ok directx test results.  It appears that the green
colour on test.winehq does not mean much.

 - All (any exception?) WTB machines skip the tests because
   d3d8 is not installed.
 - Same for Francois Gouget's virtual machines.
That alone explains green colour.

 - Wylda's *real* machine #1 (NVidia gfx) produces 5 errors:
visual.c:1411: Test failed: color 0x00ffffff.
visual.c:1413: Test failed: color 0x00ffffff.
visual.c:1415: Test failed: color 0x00ffffff.
 - "geniuh"'s (NVidia) machine as well.
 - Saulius' (NVidia) XP and w7 machines shows only these 3 errors.

 - Wylda's Intel-based machine #2 passes the tests.  Hurray!
 - One unknown win7 machine with Intel gfx also passes them.
 - Aurimas' machine produces one different error (also Intel gfx).

BTW, Wylda recently mentioned that the d3d tests produce
vastly different graphics on his 2 machines.

My conclusion: the tests only prove that Wine wants to mimic Intel graphics,
but they do not account for the variety of observed test results.
Danger: one may draw false conclusions from the ok() and
wrongly generalize supposed behaviour of the tested functions.

Looking at Wine test data (from 1.3.12), it appears that Wine
implements exactly the opposite behaviour: the NVidia (+ 1 ATI) machines
pass the tests, e.g. behave like Intel on native, while the Intel gfx one
(eeepc) produces the 3 errors known from native NVidia!

This smells wrong...

Regards,
 Jörg Höhle