If I'm making a small library for handling 2D shapes, should polymorphism generally be avoided? I know that it can worsen performance but it's not like polymorphism is never used in game development so I'm unsure of where it actually isn't appropriate.

If we assume we have quite many shapes that all need constant collision detection and similar, how detrimental will polymorphism be to performance? I ask because it's tempting to have an abstract Shape that concrete child classes like Polygon and Circle could inherit from, allowing me to iterate over and handle different kinds of shapes quite smoothly. But will calling purely virtual functions of Shape many many times cause performance hits? I'm not too familiar with exactly how polymorphism can affect performance.