I'm mad at my dad
Why are you mad at your dad.
He won't let me go outside
Your parents want what is best for you and you need to take that into consideration. If you dad does not want you to go outside you should trust that it is for a good reason and obey him or you could be punished.
I'm an adult, my dad has no right to make me stay at home.
If you can't respect him and you are an adult you need to move out. It isn't his responsibility to take care of you when you are capable.