Resource

A Resource is a type where its memory is controlled by SDL, usually with functions like SDL_Create*() and SDL_Destroy*().

To represent this type, we first create CRTP base class that contains all the functions, but delegates the actual storage to its base class. There is currently two available base classes, ObjectUnique and ObjectRef, and we use them to typedef an owning and a non owning versions of the resource. For example, for SDL_Surface we have:

• SurfaceBase: struct with all OO-like functions wrapped as member functions;
• Surface: an alias for the SurfaceBase instantiated with ObjectUnique, this is the owning version, so it will destruct the contained surface when it goes out of scope by the good old RAII rules;
  • You can still opt out of this by either calling ObjectUnique::release() or move assigning it to SurfaceRef;
• SurfaceRef: an alias for the SurfaceBase instantiated with ObjectRef, this is the non owning version, so it can be safely used for parameters that do not take ownership, to use like a rudimentary borrowed or week reference, or just to opt out of RAII and managing the lifetime by yourself;
  • You can destroy manually the resource by calling the respective *Destroy method, eg. SurfaceBase::Destroy().