Useful for squeezing out last bits of performance, e.g. in this case:
Vector3 a;
a[0] = something++;
a[1] = something++;
a[2] = something++;
In the code all elements are first zeroed out and then overwritten
later, thus it might be good to avoid the zero-initialization:
Vector3 a{Math::NoInit};
a[0] = something++;
a[1] = something++;
a[2] = something++;
This will of course be more useful in far larger data types and arrays
of these.
Some classes are by default constructed zero-filled while other are set
to identity and the only way to to check this is to look into the
documentation. This changes the default constructor of all classes to
take an optional "tag" which acts as documentation about how the type is
constructed. Note that this result in no behavioral changes, just
ability to be more explicit when writing the code. Example:
// These two are equivalent
Quaternion q1;
Quaternion q2{Math::IdentityInit};
// These two are equivalent
Vector4 vec1;
Vector4 vec2{Math::ZeroInit};
Matrix4 a{Math::IdentityInit, 2}; // 2 on diagonal
Matrix4 b{Math::ZeroInit}; // all zero
This functionality was already present in some ugly form in Matrix,
Matrix3 and Matrix4 classes. It was long and ugly to write, so it is
now generalized into the new Math::IdentityInit and Math::ZeroInit tags,
the original Matrix::IdentityType, Matrix::Identity, Matrix::ZeroType
and Matrix::Zero are deprecated and will be removed in the future
release.
Math::Matrix<7, Int> m{Math::Matrix<7, Int>::Identity}; // before
Math::Matrix<7, Int> m{Math::IdentityInit}; // now
It is often annoying to write e.g. this, especially in generic code:
T dot = Math::Vector<size, T>::dot(a, b);
When this is more than enough and the compiler can infer the rest from
the context:
T dot = Math::dot(a, b);
There are more downsides and confusing cases (you can call
Math::Vector<3, T>::dot(), Math::Vector3<T>::dot() and Color3::dot() and
it is still the same function), so I made these as free functions in
Math namespace. You can now also abuse ADL for the calls, but I would
advise against that for better readability:
T d = dot(a, b); // dot?! what on earth is dot? and what is a?
The only downside found when porting is that you need to specify the
type somehow when having both parameters as initializer lists:
T d = dot({2.0f, -1.5f}, {1.0f, 2.5f}); // error
T d = dot(Complex{2.0f, -1.5f}, {1.0f, 2.5f}); // okay
But that's probably reasonable (and it's also highly corner case,
the functions were used this way only in tests).
The original static member functions are of course still present, but
marked as deprecated and will be removed at some point in future.
The only places where they aren't absolute are:
- when header is included from corresponding source file
- when including headers which are not part of final installation (e.g.
test-specific configuration, headers from Implementation/)
Everything what was in src/ is now in src/Corrade, everything from
src/Plugins is now in src/MagnumPlugins, everything from external/ is in
src/MagnumExternal. Added new CMakeLists.txt file and updated the other
ones for the moves, no other change was made. If MAGNUM_BUILD_DEPRECATED
is set, everything compiles and installs like previously except for the
plugins, which are now in MagnumPlugins and not in Magnum/Plugins.
Besides all the good things it is now possible to do even more insane
and useless constexpr-fu:
constexpr auto a = Math::Matrix3x3<Int>::fromDiagonal({1, 3, 2});
/* 7 0
0 7 */
constexpr Math::Matrix<a.diagonal()[2], Int> c(7);
We would need to duplicate all the functionality found in Vector, which
I don't think is needed at all. If anyone needs to do this, it is
possible to "linearize" the matrix into long vector and do the
operations on it.
Also updated subclass operator implementation, added tests for it, both
for proper returned value and proper result type.
Needed to adjust the test cases slightly, because they were firing the
assert even if they shouldn't and the "expect fail" case wasn't working
at all. I now badly need proper floating-point equality comparison.
It seems that with Clang you cannot split declaration and definition of
`constexpr` function. These should be as short as possible anyway, thus
it is non-issue.
Also fixed unary RectangularMatrix::operator-() and Vector::operator-()
documentation (was stating that the operation is done in-place, which is
impossible.
As there is no Magnum::TypeTraits struct anymore, there is no need to
have redundant name in it. Hopefully Doxygen will handle the difference
between this and Corrade's TypeTraits.h properly.
* Merged constExpressions() into other test cases, reducing duplicates
and simplifying the checks.
* Fixed old-and-forgotten operator[] overload in Matrix subclasses, it
was reinterpret_cast on T* array, it is now sufficient to do only
static_cast. Constexpr operator[] overload returns const copy to make
constexpr operations working even on returned value, e.g.:
constexpr Matrix4 a;
constexpr Vector3 b = a[2].xyz();
Vladimír Vondruš