Fastest Type Comparison?

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)bo         


        

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();
}