C++ To Blueprints Random Loot Drop

#pragma once

#include "CoreMinimal.h"
#include "Kismet/BlueprintFunctionLibrary.h"
#include "Runtime/Engine/Classes/GameFramework/Actor.h"
#include "Kismet/KismetMathLibrary.h"
#include "LootBox.generated.h"


// Custom struct that ties an object class to an integer to determine drop rate

USTRUCT(BlueprintType)
struct FLoot_Box
{
    GENERATED_USTRUCT_BODY()

public:

    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Nebula Structs")
        TSubclassOf <AActor> Item_Class;
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Nebula Structs", meta = (ClampMin = "0", ClampMax = "100", UIMin = "0", UIMax = "100"))
        int32 Drop_Rate;

};

UCLASS()
class CODE_TEST_API ULootBox : public UBlueprintFunctionLibrary
{
    GENERATED_BODY()

public:

    /* Input "Loot Box" struct array and their respective "drop rate" ( 50 = 50% chance of being selected),
    output will be the randomly selected class. The boolean output is for error handling to ensure the total "drop rate" = 100
    Node will not function unless the total is exactly 100, negative values will be treated as their positive counterparts */

    UFUNCTION(BlueprintCallable, meta = (Category = "Nebula Nodes", Keywords = "Loot, Drop, Random, Loot Box, Chance"))
        static void Random_Drop_Rate(TArray <FLoot_Box> Loot_Classes, TSubclassOf <AActor> &Drop_Item, bool &Drop_Rate_Equal_100);

};


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// Fill out your copyright notice in the Description page of Project Settings.

#include "LootBox.h"

void ULootBox::Random_Drop_Rate(TArray <FLoot_Box> Loot_Classes, TSubclassOf <AActor> &Drop_Item, bool &Drop_Rate_Equal_100)
{
    // Declare temporary integer array for storing all "Drop Rates"

    TArray <int32> DropRateArray;
    int32 EqualTo100 = 0;

    // Add input array drop rates to temporary array while summing the values to create a range "max" for each Loot Item

    for (int x = 0; x < Loot_Classes.Num(); ++x)
    {
        if (x == 0)
        {
            DropRateArray.Add(FMath::Abs(Loot_Classes[x].Drop_Rate));
        }
        else
        {
            DropRateArray.Add(FMath::Abs(Loot_Classes[x].Drop_Rate) + (DropRateArray[x-1]));
        }
    }

    // Ensure all "Drop Rates" sum to EXACTLY 100

    if (DropRateArray.Last() == 100)
    {
        // Generate a random number

        int32 DropIndex = UKismetMathLibrary::RandomIntegerInRange(1, 100);

        // Start with the lowest range "max value" and keep moving up until random int <= max of range

        for (int x = 0; x < DropRateArray.Num(); ++x)
        {
            if (DropIndex <= DropRateArray[x])
            {
                Drop_Item = Loot_Classes[x].Item_Class;
                break;
            }
            else
                ;
        }
        Drop_Rate_Equal_100 = true;
    }

    // If drop rates do NOT sum to exactly 100 return a false boolean and a null drop item

    else
    {
        Drop_Item = nullptr;
        Drop_Rate_Equal_100 = false;
    }
}