ItemSpawner.h

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// Copyright Blue Isle Studios Inc 2018. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "ItemSpawner.generated.h"
 
#define CLAIMED_SPAWN "ClaimedSpawn"
#define ITEM_SPAWN "ItemSpawn"
 
class USceneComponent;
 
USTRUCT(Blueprintable)
struct FSpawnableItem
{
    GENERATED_USTRUCT_BODY()
 
    /* Which Item to spawn */
    UPROPERTY(EditInstanceOnly, BlueprintReadWrite)
    TSubclassOf<class AActor> SpawnableItem = nullptr;
    /* Limit spawning to spawnpoints containing this tag. If empty, it will spawn at any spawn point. */
    UPROPERTY(EditInstanceOnly, BlueprintReadWrite)
    FName Tag = NAME_None;
    /* The chance of this item spawning is SpawnWeight / AllSpawnWeights. If you have 3 Items with 100 weight, your chance to spawn would be 100/300 or 1 in 3. */
    UPROPERTY(EditInstanceOnly, BlueprintReadWrite, meta = (ClampMin = "0.001", ClampMax = "1000.0", UIMin = "0.001", UIMax = "1000.0"))
    float SpawnWeight = 100.0f;
    /* What is the minimum and maximum number of items of this type that should be spawned? The SpawnMinMax of the group will supersede individual items should they conflict.
    @ Example: 5 items all want to spawn at least 2 times but the spawn maximum of the group is 6. Only 6 items will be spawned. */
    UPROPERTY(EditInstanceOnly, BlueprintReadWrite)
    FVector2D SpawnMinMax = FVector2D(1.0f, 2.0f);
 
    uint32 SpawnedCount = 0;
};
 
USTRUCT(Blueprintable)
struct FSpawnGroup
{
    GENERATED_USTRUCT_BODY()
 
    FName GroupName = FName("New SpawnGroup");
    /* List of actors used to spawn items at. Any actor components with the Tag "ItemSpawn" will also be considered as a viable spawn location.*/
    UPROPERTY(EditInstanceOnly, BlueprintReadWrite)
    TArray<AActor*> Spawnpoints;
    /* Which items can be spawned at SpawnPoints list? */
    UPROPERTY(EditInstanceOnly, BlueprintReadWrite)
    TArray<FSpawnableItem> SpawnableItems;
    /* What is the minimum and maximum number of items that should be spawned? This value will supersede any per item min/max settings.
    @ Example: 5 SpawnableItems all want to spawn at least 2 times but the spawn maximum of the group is 6. Only 6 items will be spawned. */
    UPROPERTY(EditInstanceOnly, BlueprintReadWrite)
    FVector2D SpawnMinMax = FVector2D(5.0f, 10.0f);
    /* Each time an item randomly spawns, it's chance to spawn again will be multiplied by this value in order to lower its chance of dropping another time.*/
    UPROPERTY(EditInstanceOnly, BlueprintReadWrite, meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
    float DuplicatesPenalty = 0.5f;
};
 
UCLASS()
class PROJECTX_API AItemSpawner : public AActor
{
    GENERATED_BODY()
    
public: 
    UPROPERTY(EditInstanceOnly, BlueprintReadWrite, Category = ItemSpawner)
    TMap<FName, FSpawnGroup> SpawnGroups;
 
    AItemSpawner();
 
protected:
    virtual void BeginPlay() override;
 
private:
    UWorld* World = nullptr;
 
    void BuildSpawnList(const FSpawnGroup& SpawnGroup, TArray<USceneComponent*>& SpawnLocations);
    void SpawnItems(FSpawnGroup& SpawnGroup, const TArray<USceneComponent*>& SpawnLocations);
    void SpawnItem(FSpawnableItem& Item, TArray<USceneComponent*>& SpawnLocations);
    void BuildFilteredSpawnList(const FSpawnableItem& SpawnableItem, TArray<USceneComponent*>& FilteredSpawnList, const TArray<USceneComponent*>& SpawnLocations);
    void ClampSpawnAmountsToGroup(FSpawnGroup& SpawnGroup, float& SpawnWeightTotal, uint32& TotalItemSpawnMinimums, uint32& TotalItemSpawnMaximums);
    void Cleanup(TArray<USceneComponent*>& SpawnLocations);
 
    USceneComponent* GetUnusedSpawnPoint(const TArray<USceneComponent*>& SpawnLocations) const;
 
    bool IsSpawnableItemValid(FSpawnableItem& SpawnableItem, const FSpawnGroup& SpawnGroup, const TArray<USceneComponent*>& SpawnLocations);
    bool IsSpawnGroupValid(FSpawnGroup& SpawnGroup, const TArray<USceneComponent*>& SpawnLocations);
 
    FORCEINLINE const uint32 GetSpawnGroupMinimumSpawns(const FSpawnGroup& SpawnGroup) const { return (uint32)SpawnGroup.SpawnMinMax.X; }
    FORCEINLINE const uint32 GetSpawnGroupMaximumSpawns(const FSpawnGroup& SpawnGroup) const { return (uint32)SpawnGroup.SpawnMinMax.Y; }
    FORCEINLINE const uint32 GetItemMinimumSpawns(const FSpawnableItem& SpawnableItem) const { return (uint32)SpawnableItem.SpawnMinMax.X; }
    FORCEINLINE const uint32 GetItemMaximumSpawns(const FSpawnableItem& SpawnableItem) const { return (uint32)SpawnableItem.SpawnMinMax.Y; }
 
};