Will allow for more convenient usage of e.g. ShapeGroup operators:
Physics::ObjectShape3D* shape;
shape->setShape(Physics::Sphere3D({}, 0.75f) ||
Physics::AxisAlignedBox3D({}, {3.0f, 1.5f, 2.0f}));
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.
* In shader uniforms (projectionMatrix makes more sense than projection
alone)
* For underlying types for SceneGraph transformation. It is already
used in Drawable::clean() as transformationMatrix, so why not use it
also in AbstractFeature::clean(). Moreover, clean() could be in
future also done using something else, this helps to distinguish the
type just from parameter name.
* In Physics shapes - applyTransformationMatrix() (as it could be in
future also done using something else).
Vladimír Vondruš