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.
All the functionality is moved to Math::swizzle() and the result is
casted to given type only if its header is included. Thus it is possible
to remove include dependency on Color. The original swizzle() is now
just an alias marked as deprecated and will be removed in future
release.
Operators that are part of Vector are operating only with the same type
as Vector itself, operators for multiplying/dividing integral vectors
with floating-point numbers and vectors are now out-of-class and enabled
only for integer vectors. It allows better control (e.g. multiplying
integer and floating-point vector will _always_ result in floating-point
one). Thoroughly tested integer/FP operations and also reworked and
tested operator and funciton reimplementations in subclasses, both for
value correctness and result type correctness.
Also fixed unary RectangularMatrix::operator-() and Vector::operator-()
documentation (was stating that the operation is done in-place, which is
impossible.
* Merged constExpressions() into other test cases, simplified the test
a lot and removing duplicate code.
* Fixed Vector3::xy(), Vector3::xy() and Vector3::xyz() constexpr
overloads, they now return copy instead of reinterpret_cast
reference. The copy is const to make constexpr operations working
even on returned subclass, e.g.:
constexpr Vector4 a;
constexpr Float b = a.xyz().y();
Also updated all dependent classes to follow the change, such as Color
and Rectangle. Backwards compatibility for GCC 4.6 (with lack of support
for delegating constructors) will be done as non-constexpr constructor
using operator=().
Overall architecture is simplififed with this change and also it's not
needed to use reinterpret_cast in matrix internals anymore, thus there
is no need for operator() and [][] works now always as expected without
any risk of GCC misoptimizations.
On the other side, constructing matrix from list of elements is not
possible anymore. You have to specify the elements as list of
column vectors, which might be less convenient to write, but it helps to
distinguish what is column and what is row:
Matrix<2, int> a(1, 2, // before
3, 4);
Matrix<2, int> a(Vector<2, int>(1, 2), // now
Vector<2, int>(3, 4));
For some matrix specializations (i.e. Matrix3 and Matrix4) it is
possible to use list-initialization instead of explicit type
specification:
Matrix<3, int>({1, 2, 3},
{4, 5, 6},
{7, 8, 9});
I didn't yet figure out how to properly implement the general
(constexpr) constructor to also take lists, so it's a bit ugly for now.
Matrix operations are now done column-wise, which should help with
future SIMD implementations, documentation is also updated accordingly.
I also removed forgotten remains of matrix/matrix operator*=(), which
can be confusing, as the multiplication is not commutative. Why it is
not present is explained in d9c900f076.
* Added math equations to Quaternion, Vector and Matrix method
documentation.
* Removed confusing Quat*=Quat operator overload, as it isn't exactly
clear from which side the non-commutative multiplication is done:
Quaternion a;
a *= b; // eh?
a = a*b; // okay!
For similar reason this operator wasn't present in RectangularMatrix
either.
* Unified documentation of expected vector/quaternion normalization
state. Now it is not "assumed" but "expected", because failing to do
so results in assertion failure.
It prevents unwanted implicit conversions from e.g. nullptr to Camera,
Vector2 to Physics::Point etc. By making all the constructors explicit
it is easier to routinely add the keyword to all new classes instead of
thinking about cases when to add and when not to.
Currently, when accidentaly creating specialized Vector from smaller
number of components than required, the error message isn't really
helpful, as it stops on static assert on wrong number of arguments
passed to RectangularMatrix:
Vector3(0, 1); // static assert: wrong number of arguments passed to
// RectangularMatrix<1, 2> -- wtf?!
Now the first argument is Vector2/Vector3 instead of Vector<2>/Vector<3>
and the error message now properly states that no matching constructor
was found.
Vector4 doesn't set W component to one by default anymore, this is now
handled by Point*D itself. This finally allows creating of 2D primitives
and 2D position vectors without messing explicitly with Z = 1.
All classes which should use Point instead of Vector were updated to use
Point instead.
Vladimír Vondruš