koobas.hobune.stream
Upcast vs GetComponent
Has anyone any idea of what might be more optimized. Consider this example.
public abstract class BaseMono: MonoBehaviour {
}
And classes which inherit from this base class.
public class A: BaseMono{
}
public class B: BaseMono{
}
Inside BaseMono i have a method which finds type inheriting this. Which of these methods would execute this resolve faster.
TellMe1() Uses getcomponent
TellMe2() Uses upcast
TellMe3() Uses is keyword, but returns only logical yes or not, instead of possible valid instance.
Upcast and is are quite instant, but i am not sure how heavy is getcomponent behind the scenes. Unity development enviroment kinda suggest me to use getcomponent, because of mono being the root of this chain, but it feels like it isnt the fastest. is keyword sure is the most readable though.
public abstract class BaseMobo: MonoBehaviour {
public void TellMe1(){
if(gameObject.GetComponent<A>() != null) {print("A is parent"); return;}
if(gameObject.GetComponent<B>() != null) {print("B is parent"); return;}
}
public void TellMe2(){
if( ((A)this) != null) {print("A is parent"); return;}
if( ((B)this) != null) {print("B is parent"); return;}
}
//Is not the same, but useful
public void TellMe3(){
if( this is A) {print("A is parent"); return;}
if( this is B) {print("B is parent"); return;}
}
}
$$anonymous$$eep in $$anonymous$$d upcasting goes up the inheritance chain. At the top of the chain is the type "object" at the bottom is your concrete type. Upcasting is always safe (treating a concrete class as a base class). Downcasting on the other hand can fail (casting a base class reference to a more concrete class)
The normal cast will throw an invalid casting exception if the type can't be casted into the specifid type.
The as-cast will return null is the cast is not possible.
So only use a "normal" case when you are sure that the cast is possible. It's common to pair the "is" operator with a normal downcast or to use an as downcast with a null check.
ps: all your examples are lacking curly brackets for your if statements. Without brackets an if only affects the next statement that directly follows the if. So your "return" statements are outside the if and will execute unconditionally.
You should avoid placing the statement in the same line as the if. In some cases it makes sense but usually it's better to place it in the next line, indented.
So your if in line 15 would look like this:
if( this is A)
print("A is parent");
return;
while you want
if( this is A) {
print("A is parent");
return;
}
Yeah, downcasts should be treated more carefully. You are flooding this with answers, im blushing. Thank you for your time bunny, have a good day. Upvoted everything i can ;)
The best and safest way is using either an "is" check in combination with a down cast or an "as" cast. GetComponent makes no sense as you get in trouble if there are multiple instances of a component on the same gameobject.
So either use:
if (this is A)
{
A a = (A)this; // here the down cast is safe since we know it's an "A"
// A specific stuff
}
else if (this is B)
{
B b = (B)this; // here the down cast is safe since we know it's an "A"
// B specific stuff
}
Or use
A a = this as A;
if (a != null)
{
// A specific stuff
}
B b = this as B;
if (b != null)
{
// B specific stuff
}
I have single instance per gameobject root, which is validated in Reset(). But it still logially makes sense to not use getcomponent, which am happy about. $$anonymous$$y thoughts exactly, thanks!
