Intermediate C++ Game Programming Tutorial 18

Another two-parter here, and we got the real stuff now. Virtual functions allow you to unlock the true potential of inheritance in C++. You need to know this shit.

Topics Covered

Part 1

• How to create a virtual function
• Using the override keyword
• Creating a pure virtual function
• Using a container of pointers to manage a heterogeneous collection of objects
• virtual destructors

Part 2

• Using inheritance and composition together
• Basic idea of a polymorphic state machine and its application to entity behavior

Video Timestamp Index

Tutorial 18.1

• Create free function that calls SpecialMove() on the instances of derived classes 0:23

Tutorial 18.2

• WORK-IN-PROGRESS

Source Code

Inheritance Github Repository

Errata

• Forgot the virtual destructor for class Weapon! (this one hurts)
• In the children, the function signatures should be: int CalculateDamage( const Attributes& attr,Dice& d ) const override
• Though not technically an error, it might have been a better decision to make Weapon::GetName() and Weapon::GetRank() (pure) virtual functions (this would reduce the amount of per-instance data to just the vtable ptr)

See also

• Next in series (Tutorial 19)
• Intermediate C++ Game Programming Series