C++ allows creating arrays with initializer lists shorter than array
length, but for vectors and matrices it will be error prone and hard to
debug. Removed deleted constructor, as it is now catched with
static_assert as well. Also this was possible before (and wasn't catched
with the deleted constructor), now isn't:
Matrix<2, int> a(1, 2);
Each function which returned e.g. Vector<size, T> was in subclasses
overloaded with function returning e.g. Vector3<T>, so the user is able
to use subclass-specific functions. It was nightmare to maintain and it
cluttered the documentation a lot.
Long-standing TODO. It is better to have size first, because it is more
significant than type (e.g. because there are Vector4<T> specializations
and not VectorT<4> specializations). It is also IMHO easier for user to
distinguish/read the type than before:
Vector<float, 4> -> Vector4<float> // before
Vector<4, float> -> Vector4<float> // now
Because no operator= which took the class itself as argument (parent
class only), the compiler generated default assignment and assignment
move constructors, e.g.
Vector3<T>& operator=(const Vector3<T>&);
Vector3<T>& operator=(Vector3&&);
Resulting in conflicts when using assignment uniform initialization,
i.e. it wasn't possible to do things like this, but that's now fixed:
Vector3<int> vec;
vec = {0, 1, 2};
Other functions left untouched (they are still taking e.g. Vector<T,
3> instead of Vector3<T>), because it saves one useless dummy
constructor call (which would be visible in profiler, but without
having any performance impacts altogether).
Before it was one constructor using bool parameter, which is massive
antipattern:
Matrix4 m(false); // Huh? No Matrix4 then or what?
Iẗ́'s now separated into two distinct constructors, of them one can be
already declared as constexpr (hooray). The usage is as follows:
Matrix4 a; // Default (identity matrix)
Matrix4 b(Matrix4::Identity); // Explicitly identity matrix
Matrix4 c(Matrix4::Zero); // Zero-filled matrix
Also deleted constructor from one parameter, so following mistakes
now cannot compile:
Matrix4 d(true); // Both would set element at [0][0] to 1,
Matrix4 e(Matrix3::Zero); // and other to 0
Removed functions at(), set() and add(), everything (and more) can be
now done using operator[]. Accessing matrix elements is now done through
column vectors, e.g.:
Matrix4 a;
a.at(row, col); // before
a[col][row]; // now
Note that because operator[] on Matrix returns column vector (there is
nothing like row vector), the parameter "order" is now swapped.
Types saved inside Matrix and Vector will be at most time smaller than
or the same size as references to them, so no move semantic and
forwarding is necessary.
It should improve performance, because what can be computed at compile
time is now computed at compile time. In addition these things have been
changed or improved:
* Removed constructors from T*, as they cannot be AFAIK written using
constexpr functions only and they only do unnecessary data copying
most of the time. The functionality is now provided using static
functions Matrix*::from() and Vector*::from() which returns either
const or non-const reference to original data, so no copy is
performed. These functions also have explicit warning about unsafe
operations.
* Defaulted copy constructors and assignment operators, using
"default initialization" for arrays instead of memsetting it with
zeros. It should behave the same and this way we don't need any
memcpy(), memset() etc. from <cstring>, which is good.
Multiplication, division, addition and substraction is now done
primarily in assigning operators, as they do the computations in-place,
so they are more memory efficient than implementing them using e.g.
`*this = *this+other;`.
Updated unit test only for matrix multiplication, as vector unit tests
test arithmetic asssign operators too.
Mainly to be consistent with Matrix::transposed() function name,
furthermore calling
Matrix::inverse()
could look like the original matrix is being inversed, while calling
Matrix::inversed()
implies that the function doesn't change the original matrix, but
returns the result instead.
Vladimír Vondruš