This is quite big, so:
* There are new Magnum::PixelFormat and Magnum::CompressedPixelFormat
enums, which contain generic API-independent formats. In particular,
PixelFormat replaces GL::PixelFormat and GL::PixelType with a single
value.
* There's GL::pixelFormat(), GL::pixelType(),
GL::compressedPixelFormat() to convert the generic enums to
GL-specific. The mapping is only in one direction, done with a lookup
table (generic enums are indices to that table).
* GL classes taking the formats directly (such as GL::BufferImage) have
overloads that take both the GL-specific and generic format.
* The generic Image, CompressedImage, ImageView, CompressedImageView,
and Trade::ImageData classes now accept the generic formats
first-class. However, it's also possible to store an
implementation-specific value to cover cases where a generic format
enum doesn't have support for a particular format. This is done by
wrapping the value using pixelFormatWrap() or
compressedPixelFormatWrap(). Particular GPU APIs then assume it's
their implementation-specific value and extract the value back using
pixelFormatUnwrap() or compressedPixelFormatUnwrap(). There's also an
isPixelFormatImplementationSpecific() and
isCompressedPixelFormatImplementationSpecific() that distinguishes
these values.
* Many operations need pixel size and in order to have it even for
implementation-specific formats, a corresponding pixelSize()
overload is found via ADL on construction and the calculated size
stored along the format. Previously the pixel size was only
calculated on demand, but that's not possible now. In case such
overload is not available, it's possible to pass pixel size manually
as well.
* In order to support the GL format+type pair, Image, ImageView and
Trade::ImageData, there's now an additional untyped formatExtra()
field that holds the second value.
* The CompressedPixelStorage class is now unconditionally available on
all targets, including OpenGL ES and WebGL. However, on OpenGL ES the
GL APIs expect that it's all at default values.
I attempted to preserve backwards compatibility as much as possible:
* The PixelFormat and CompressedPixelFormat enum now contains generic
API-independent values. The GL-specific formats are present there,
but marked as deprecated. Use either the generic values or
GL::PixelFormat (togehter with GL::PixelType) and
GL::CompressedPixelFormat instead. There's a lot of ugliness caused
by this, but seems to work well.
* *Image::type() functions are deprecated as they were too
GL-specific. Use formatExtra() and cast it to GL::PixelType instead.
* Image constructors take templated format or format+extra arguments,
so passing GL-specific values to them should still work.
The general part stays in the root namespace, while the GL-specific
stuff goes to the GL namespace. Also all GL-specific documentation was
moved to relevant APIs in the GL namespace. This finally allows me to
build PixelStorage.cpp as part of the root namespace.
The PixelStorage::pixelSize() function and
PixelStorage::dataProperties() taking a pair of GL::PixelFormat /
GL::PixelType enums is deprecated, use GL::pixelSize() and
dataProperties() taking pixel size directly instead. A lot of code is
still using these, including images; the deprecated aliases are inlined
in the header to avoid a compile-time dependency on the GL library.
Proofread everything, make the packages the first choice (and manual
build only as a backup catch-all solution), don't force the users to
CMake but provide useful snippets to show how to use the libs from
CMake.
And removing the bundled std::optional implementation. This finally
makes this library compatible with C++17. Since this would be a huge
backwards-incompatible change that would make everyone angry, the
following had to be done in case both CORRADE_BUILD_DEPRECATED and
MAGNUM_BUILD_DEPRECATED is defined:
* Under C++11 and C++14, Containers::Optional / Containers::NullOpt is
aliased to std::optional / std::nullopt. This is no worse than the
state before, when we also provided these symbols.
* Under C++17, where standard <optional> header is available,
Containers::Optional provides implicit conversion to it. Only one-way
conversion is supported, as there was fortunately no Magnum API that
took std::optional via parameter, and there might be some corner
cases that this doesn't cover. The goal is to have all examples
compiling with the old API, at least.
* There's a new test especially for this, which checks that both the
C++11 and C++17 ways of doing things work as they should.
The typedef and conversion is marked as deprecated, so it will spit out
many warnings to push users to upgrade. I hope I can completely remove
this mess soon :/
In order to have a seamless transition for all the plugins and potential
user code the original constructor was marked as deprecated and there is
a new constructor taking also the colors.
It complains about singatures not matching the implicit and thus not
being defaultable. Works everywhere else, even on GCC 4.7 and 5.0, so I
don't bother.
In particular it is now possible to override the MAGNUM_PLUGINS_DIR
variables and even specify them relative, which will make them relative
to executable location.
It's nice when everything clicks together :)
Vladimír Vondruš