Fixes LIT (https://bugs.dolphin-emu.org/issues/13635). The text does not include normals, but has lighting enabled. With the previous default of (0, 0, 0), lighting was always black (as dot(X, (0, 0, 0)) is always 0). It seems like the normal from the map in the background (0, 0, 1) is re-used.
LIT also has the vertex color enabled while vertex color is not specified, the same as SMS's debug cubes; the default MissingColorValue GameINI value of solid white seems to work correctly in this case.
This adjusts the NaN replacement logic introduced in #9928 to work around the HLSL compiler optimizing away calls to isnan, which caused that functionality to not work with ubershaders on D3D11 and D3D12 (it did work with specialized shaders, despite a warning being logged for both; that warning is also now gone). Note that the `D3DCOMPILE_IEEE_STRICTNESS` flag did not solve this issue, despite the warning suggesting that it might.
Suggested by @kayru and @jamiehayes.
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
debaf63fe8 moved the "Sonic epsilon hack"
to vertex shaders. However, it was only done for targets with depth
clamping. If this is not available, for example the target is OpenGL ES,
the Sonic problem appears (https://bugs.dolphin-emu.org/issues/11897).
A version of the "Sonic epsilon hack" is added for targets without
depth clamping.
Cel-damage depends on lighting being calculated for the first channel
even though there is no color in the vertex format (defaults to the
material color). If lighting for the channel is not enabled, the vertex
will use the default color as before.
The default value of the color is determined by the number of elements in
the vertex format. This fixes the grey cubes in Super Mario Sunshine.
If the color channel count is zero, we set the color to black before the
end of the vertex shader. It's possible that this would be undefined
behavior on hardware if a vertex color index that was greater than the
channel count was used within TEV.
Now that we've converted all of the shader generators over to using fmt,
we can drop the old Write() member function and perform a rename
operation on the WriteFmt() to turn it into the new Write() function.
All changes within this are the removal of a <cstdarg> header, since the
previous printf-based Write() required it, and renaming. No functional
changes are made at all.
