Proper return value declaration for a C++ function

[xianthryllis]

Definitely a newbie question here…

I attempted a C++ class for my Actor. Here is the header file:

USTRUCT(BlueprintType)
struct FPointCloudPoint
{
	GENERATED_BODY()

	FVector Vector;
	FColor Color;
};

UCLASS()
class POINTCLOUDPRACTICE_API APointCloudScript : public AActor
{
	GENERATED_BODY()

public:
	APointCloudScript();
protected:
	virtual void BeginPlay() override;
public:
	virtual void Tick(float DeltaTime) override;

	UFUNCTION(BlueprintCallable, Category = "Make Point Cloud")
		TArray<FPointCloudPoint> GeneratePointCloud();
};

And here is the function in source file:

TArray<APointCloudScript::FPointCloudPoint> APointCloudScript::GeneratePointCloud()
{
    TArray<FPointCloudPoint> PointCloudArray;

    const int32 NumPoints = 100;
    FRandomStream RandomStream;

    for (int32 i = 1; i <= NumPoints; i++)
    {
         //The rest of the code here that creates a random vector and color...//

        FPointCloudPoint Point;
        Point.Vector = ResultVector;
        Point.Color = RandomColor;
        //Append to array
          PointCloudArray.Add(Point);
    }

    return PointCloudArray;
}

Basically what I want to happen is for this GeneratePointCloud function to return an array of struct PointCloudPoint. But I am getting an error:

error C2039: ‘FPointCloudPoint’: is not a member of ‘APointCloudScript’

which do not makes sense to my newbie brain. I would appreciate any help!

[F1nansist (Debuild)]

Hi, xianth ryllis

1. U didnt initialized “ResultVector” and “RandomColor” in method in source file. I dont understand how visual studio compiled this (or live coding)
2. Add “UPROPERTY(BlueprintReadWrite)” to each field in your struct (it is necessary if u want to break or to make struct in blueprints)

[xianthryllis]

Hello, thank you for your reply. Here is the copy of the entire method:

// Function to generate a point cloud with random points
TArray<APointCloudScript::FPointCloudPoint> APointCloudScript::GeneratePointCloud()
{
    TArray<FPointCloudPoint> PointCloudArray;

    const int32 NumPoints = 100;
    FRandomStream RandomStream;

    for (int32 i = 1; i <= NumPoints; i++)
    {
        // Step 1: Create a random unit vector
        float RandomX = RandomStream.FRandRange(-1.0f, 1.0f);
        float RandomY = RandomStream.FRandRange(-1.0f, 1.0f);
        float RandomZ = RandomStream.FRandRange(-1.0f, 1.0f);
        FVector RandomVector(RandomX, RandomY, RandomZ);
        RandomVector.Normalize();

        // Step 2: Get a random float to vary the scale of the vector
        float RandomFloat = RandomStream.FRandRange(10.0f, 500.0f);

        // Step 3: Multiply the vector and the float
        FVector ResultVector = RandomVector * RandomFloat;

        // Step 4: Add a random color
        uint8 RandomR = RandomStream.RandRange(0, 255);
        uint8 RandomG = RandomStream.RandRange(0, 255);
        uint8 RandomB = RandomStream.RandRange(0, 255);
        FColor RandomColor(RandomR, RandomG, RandomB, 255);

        // Step 5: Create a PointCloudPoint and append it to the array
        FPointCloudPoint Point;
        Point.Vector = ResultVector;
        Point.Color = RandomColor;
        PointCloudArray.Add(Point);
    }

    return PointCloudArray;
}

I had them declared on these lines:
FVector RandomVector(RandomX, RandomY, RandomZ);
and
FColor RandomColor(RandomR, RandomG, RandomB, 255);

or should I have had also declared them somewhere else in the code?

As for point number 2, it is not necessary because I would be needing to edit them in the blueprints, but I’m going to add UPROPERTY if it’s gonna make the whole thing compile and work

[F1nansist (Debuild)]

Add “UPROPERTY(BlueprintReadWrite)” in struct fileds and check if it will solve the problem

[xianthryllis]

Yes, already did:

I still get the same error:
error C2039: ‘FPointCloudPoint’: is not a member of ‘APointCloudScript’

[F1nansist (Debuild)]

TArray<APointCloudScript::FPointCloudPoint> APointCloudScript::GeneratePointCloud()
Look at this definition. Ur function return array of struct “FPointCloudPoint” and u say that class owns this struct but it is wrong.

“APointCloudScript::FPointCloudPoint” means that ur class owns this struct. Look at header and u will see that struct is independent.

This is what visual studio says. What IDE do you use?

[xianthryllis]

Hello, thank you for replying. I am also using Visual Studio.

So I put my struct under the class APointCloudScript. Here’s how it looks:

header:

source file:

I still get the error: : Error: Unable to find ‘class’, ‘delegate’, ‘enum’, or ‘struct’ with name ‘FPointCloudPoint’

the error is called on the header file on the line:
TArray<APointCloudScript::FPointCloudPoint> APointCloudScript::GeneratePointCloud();

Please let me know if I understood you correctly.

[F1nansist (Debuild)]

I m not sure how legal is to use ustruct in uclass but the next code works

Header:

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "PointCloudScript.generated.h"

USTRUCT(BlueprintType)
struct FPointCloudPoint
{
	GENERATED_BODY()

	UPROPERTY(BlueprintReadWrite)
	FVector Vector;
	UPROPERTY(BlueprintReadWrite)
	FColor Color;
};

UCLASS()
class CASTLEASSAULT_API APointCloudScript : public AActor
{
	GENERATED_BODY()
	
public:	
	UFUNCTION(BlueprintCallable, Category = "Make Point Cloud")
	TArray<FPointCloudPoint> GeneratePointCloud();

};

Source:

#include "PointCloudScript.h"

TArray<FPointCloudPoint> APointCloudScript::GeneratePointCloud()
{
    TArray<FPointCloudPoint> PointCloudArray;

    const int32 NumPoints = 100;
    FRandomStream RandomStream;

    for (int32 i = 1; i <= NumPoints; i++)
    {
        // Step 1: Create a random unit vector
        float RandomX = RandomStream.FRandRange(-1.0f, 1.0f);
        float RandomY = RandomStream.FRandRange(-1.0f, 1.0f);
        float RandomZ = RandomStream.FRandRange(-1.0f, 1.0f);
        FVector RandomVector(RandomX, RandomY, RandomZ);
        RandomVector.Normalize();

        // Step 2: Get a random float to vary the scale of the vector
        float RandomFloat = RandomStream.FRandRange(10.0f, 500.0f);

        // Step 3: Multiply the vector and the float
        FVector ResultVector = RandomVector * RandomFloat;

        // Step 4: Add a random color
        uint8 RandomR = RandomStream.RandRange(0, 255);
        uint8 RandomG = RandomStream.RandRange(0, 255);
        uint8 RandomB = RandomStream.RandRange(0, 255);
        FColor RandomColor(RandomR, RandomG, RandomB, 255);

        // Step 5: Create a PointCloudPoint and append it to the array
        FPointCloudPoint Point;
        Point.Vector = ResultVector;
        Point.Color = RandomColor;
        PointCloudArray.Add(Point);
    }

    return PointCloudArray;
}

[xianthryllis]

Cool! It worked! Thank you sooooo much!