九、RPGItem.h/cpp & PrimaryDataAsset

PrimaryDataAsset

请先阅读，官方文档：资源管理

/**
 * A DataAsset that implements GetPrimaryAssetId and has asset bundle support, which makes it something that can be manually loaded/unloaded from the AssetManager
 * Making blueprint subclasses of this is useful because you can make blueprint-only primary asset types
 * Blueprint subclasses will end up with a PrimaryAssetType equal to the name of the first native class found going up the hierarchy, or the top level blueprint class that directly subclasses this
 * IE, if you have PrimaryDataAsset -> ParentNativeClass -> ChildNativeClass -> BlueprintAsset the type will be ChildNativeClass
 * Whereas if you have PrimaryDataAsset -> ParentBlueprintClass -> ChildBlueprintClass the type will be ParentBlueprintClass
 * To override this behavior, override GetPrimaryAssetId in your native class
 */

PrimaryDataAsset为我们默认实现了继承自UObject的GetPrimaryAssetId()方法，并提供了asset bundle支持。

---

RPGItem.h/cpp

主要包含Item各种属性：

• ItemType ： 用于Primary Asset 资源管理
• ItemName: 玩家看到的道具名
• ItemDiscription: 道具说明文字
• ItemIcon： 道具图标
• Price: 道具价格
• MaxCount: 道具在背包中的最大值（本游戏中，1代表不可消耗：如武器、技能，<=0代表无穷，如药水）
• MaxLevel：道具的最大等级
• GrantedAbility：使用道具将会获得的技能
• AbilityLevel：技能等级

注意：当我们用蓝图拓展这个类时，只能修改属性，不能拓展方法。

头文件：

// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.

#pragma once

#include "ActionRPG.h"
#include "Engine/DataAsset.h"
#include "Styling/SlateBrush.h"
#include "RPGAssetManager.h"
#include "RPGItem.generated.h"

class URPGGameplayAbility;

/** Base class for all items, do not blueprint directly */
UCLASS(Abstract, BlueprintType)
class ACTIONRPG_API URPGItem : public UPrimaryDataAsset
{
    GENERATED_BODY()

public:
    /** Constructor */
    URPGItem()
        : Price(0)
        , MaxCount(1)
        , MaxLevel(1)
        , AbilityLevel(1)
    {}

    /** Type of this item, set in native parent class */
    UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = Item)
    FPrimaryAssetType ItemType;

    /** User-visible short name */
    UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Item)
    FText ItemName;

    /** User-visible long description */
    UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Item)
    FText ItemDescription;

    /** Icon to display */
    UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Item)
    FSlateBrush ItemIcon;

    /** Price in game */
    UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Item)
    int32 Price;

    /** Maximum number of instances that can be in inventory at once, <= 0 means infinite */
    UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Max)
    int32 MaxCount;

    /** Returns if the item is consumable (MaxCount <= 0)*/
    UFUNCTION(BlueprintCallable, BlueprintPure, Category = Max)
    bool IsConsumable() const;

    /** Maximum level this item can be, <= 0 means infinite */
    UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Max)
    int32 MaxLevel;

    /** Ability to grant if this item is slotted */
    UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Abilities)
    TSubclassOf GrantedAbility;

    /** Ability level this item grants. <= 0 means the character level */
    UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Abilities)
    int32 AbilityLevel;

    /** Returns the logical name, equivalent to the primary asset id */
    UFUNCTION(BlueprintCallable, Category = Item)
    FString GetIdentifierString() const;

    /** Overridden to use saved type */
    virtual FPrimaryAssetId GetPrimaryAssetId() const override;
};

源文件：

// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.

#include "Items/RPGItem.h"

bool URPGItem::IsConsumable() const
{
    if (MaxCount <= 0)
    {
        return true;
    }
    return false;
}

FString URPGItem::GetIdentifierString() const
{
    return GetPrimaryAssetId().ToString();
}

FPrimaryAssetId URPGItem::GetPrimaryAssetId() const
{
    // This is a DataAsset and not a blueprint so we can just use the raw FName
    // For blueprints you need to handle stripping the _C suffix
    return FPrimaryAssetId(ItemType, GetFName());
}

其他继承自URPGItem的类有URPGPotionItem,URPGSkillItem,URPGTokenItem,URPGWeaponItem。这些子类主要是在构造函数中改变ItemType的值。武器还添加了一个TSubclassOf来指明武器对应的actor。

---

例子

生命恢复药

斧子