Question

The following event can possibly get called hundreds of times a frame.

public bool OnCollision(Body body1, Body body2) {  if(body2.Tag is Dog)       ((Dog)body2.Tag).Bark(); } 

I understand that using ‘is’ causes a cast to be made and then when i want to do something with it, cast it a second time. Is there a more efficient way to check the type? I made a console app trying ‘if(body2.Tag.GetType() == typeOf(Dog))’ but it appears to be even slower than using ‘is’.

Thanks.

Answer 1

 if(body2.Tag is Dog) 

is actually compiled as

Dog Temp = body2.Tag as Dog; if (temp != null) 

In your code, you’re then doing the cast again. Better would be:

Dog dog = body2.Tag as Dog; if (dog != null) {     dog.Bark(); }