Makes some cases less consistent (and some convenience shortcuts
impossible), but goes well with the attitude "don't use pointer when it
can't be null".
Until now, all calls to e.g. `Object::translate()` were virtual, which
is _very_ bad for performance. The virtual call is only needed when
setting the transformation via some interface, e.g.
`AbstractTranslationRotation3D`, as the caller doesn't know which
transformation implementation is used.
Now all public-facing transformation methods are inline non-virtual
functions, which are in most cases calling directly the transformation
implementation. In `Abstract*` transformation interfaces these functions
call private virtual `do*()` implementations, which are (re)implemented
in subclasses, but aren't used anywhere except when transforming
directly through the `Abstract*` interfaces. This should have good
impact on performance when doing many transformations in every frame
(although I can't verify it anywhere, as I don't have any significantly
large animated demo). Except of course when doing it through the virtual
interfaces.
As the public-facing transformation methods are now non-virtual, there
are now no "covariant return" issues and they can now return proper
`Object<*Transformation*>` type instead of just `*Transformation*`,
which makes full non-WTF method chaining possible:
Object2D* obj2;
obj2->translate({0.5f, -1.0f}) // Transformation method
->setParentKeepTransformation(obj1); // Object method
Or even this:
Object2D* obj = (new Object2D)->rotate(-15.0_degf);
Vladimír Vondruš