At first I designed a hugely disrupting change that basically deprecated
everything related to 8-bit linear RGB colors, but then I took a step
back and reconsidered 8-bit linear RGB as a valid use case.
The documentation of Color classes, typedefs and literals was clarified
to mention that these classes should always represent linear RGB and
that 8-bit colors are commonly treated as *not* linear and one should be
aware of it.
There is now a new Color3::fromSrgb() and Color3::toSrgb() that converts
from sRGB representation to a linear RGB usable for calculations and
then back. For four-component colors, there is now
Color4::fromSrgbAlpha() and Color4::toSrgbAlpha(). Similarly to what
OpenGL sRGB behavior is regarding to alpha, the alpha channel is kept
linear, that's why I'm also calling it sRGB + alpha instead of sRGBA.
Besides that, there are four new literals _srgb, _srgba, _srgbf and
_srgbaf that have different semantics to support the sRGB workflow. The
8-bit versions are equivalent to _rgb and _rgba, though they don't
return Color3 but a non-color Vector3 to hint that the result is not a
linear RGB color. Main purpose of these is documentation. The float
versions apply an inverse sRGB curve to the input, returning a linear
RGB color.
Vladimír Vondruš
2b97e53360