Hi
I am trying to get component start location like this
#include "Components/PrimitiveComponent.h"
#include "Components/SceneComponent.h"
FVector Start = GetComponentLocation(); //error undeclared identifier
why I get this error ?
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I don’t do unreal much, but the error message “undeclared identifier” indicates that the compiler does not recognize the symbol “GetComponentLocation()” as a valid function or member of the current scope.
To use the “GetComponentLocation()” function, you need to call it on an instance of a component, such as a primitive component or a scene component, which has this function as a member.
In your code, you are trying to call “GetComponentLocation()” directly without specifying which component it belongs to. To fix the error, you need to first declare and initialize an instance of the component that you want to retrieve the location from, and then call the function on that instance, like this:
`
#include “Components/PrimitiveComponent.h”
#include “Components/SceneComponent.h”
UPrimitiveComponent* MyComponent = nullptr; // declare and initialize an instance of the component
FVector Start = MyComponent->GetComponentLocation(); // call the function on the instance
`
Make sure that you have a valid reference to the component you want to get the location from, or you may get a runtime error.
Hopefully this works
Edit: my code formatting is acting weird, I’m trying to fix it currently
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Thanks but I am calling this from the player class .cpp, I tried your code and it compile but no reference to the player so it crash. In this lesson called “Blueprint Callable” instructor called GetComponentLocation directly from inside the player class .cpp so why it does not work with me ?
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I see, thank you for providing more context. In that case, it sounds like the “undeclared identifier” error you are seeing is because the “GetComponentLocation()” function is not a member of the player class.
The reason why the instructor was able to call “GetComponentLocation()” directly from inside the player class .cpp file may be because they were using a different version of Unreal Engine, or they had set up their project differently.
In any case, if you want to get the location of a component attached to the player, you can use the “GetComponentsByClass” function to retrieve all components of a certain type, and then use the “GetComponentLocation” function on the component you are interested in.
Here’s an example of how you could get the location of the player’s root component (assuming it’s a scene component) using this method:
`
#include “Components/SceneComponent.h”
TArray<USceneComponent*> Components;
GetComponents(Components);
if (Components.Num() > 0)
{
FVector Start = Components[0]->GetComponentLocation();
}
`
This code retrieves all the components attached to the player that are of type “USceneComponent”, and then uses the “GetComponentLocation” function on the first component in the array. You may need to modify the code to fit your specific use case.
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Thanks, how to check component name inside components ?
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To check the name of a component, you can use the “GetName()” function which returns the name of the component as a string. Here’s an example of how you can check the name of a component in Unreal Engine:
`
#include “Components/SceneComponent.h”
USceneComponent* MyComponent = nullptr; // initialize an instance of the component
if (MyComponent)
{
FString ComponentName = MyComponent->GetName(); // get the name of the component
if (ComponentName == "MyComponentName") // check if the name matches
{
// do something
}
}
`
In this code, we first initialize an instance of the component that we want to check the name of. Then, we use the “GetName()” function to retrieve the name of the component as a FString. We can then compare the name to a string literal or another string variable to check if it matches.
Note that the “GetName()” function returns the display name of the component, which may not be the same as the actual class name of the component. If you need to check the class of a component, you can use the “GetClass()” function instead.
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Thanks I will test these and update later.
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