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@@ -589,3 +589,340 @@ enum class EMassProcessingPhase : uint8
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采用信号的订阅处理系统来协调 Entity 之间的通信，需要继承 `UMassSignalProcessorBase` 来处理特定信号，这个信号的注册需要依赖 `UMassSignalSubsystem`
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具体信号传递的案例可以查看 `UMassStateTreeProcessor` 类，该类并没有重写 `Execute` 函数，而是重写了 `SignalEntities` 函数，因为 `UMassSignalProcessorBase` 基类中处理了本帧收到的信号，并将影响到的 Entity 都通过调用 `SignalEntities` 传递给子类
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+
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+## 自己看代码
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+
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+以 `MassZombies` 项目为例
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+
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+> https://github.com/stopthem/MassZombies
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+
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+### 配置 AMassSpawner
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+
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+
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+
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+在场景中配置 `AMassSpawner` 用于生成对象
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+
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+通过 `EntityTypes` 来配置
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+
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+```cpp
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+
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+/**
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+ * Describes an entity type to spawn.
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+ */
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+USTRUCT(BlueprintType)
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+struct FMassSpawnedEntityType
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+{
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+ GENERATED_BODY()
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+
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+ UPROPERTY(BlueprintReadWrite, EditAnywhere, Category = "Mass|Spawn")
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+ TSoftObjectPtr<UMassEntityConfigAsset> EntityConfig;
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+
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+ UPROPERTY(BlueprintReadWrite, EditAnywhere, Category = "Mass|Spawn", meta = (ClampMin = 0.0f, UIMin = 0.0f))
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+ float Proportion = 1.0f;
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+};
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+```
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+
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+`FMassSpawnedEntityType` 用于配置一个 `Entity`
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+
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+`Proportion` 用于表示一个比例，比如一次性可能需要生成多种类型的 `Entity`，每个类型的 `Entity` 占的比例是多少？这个数量是 `Proportion` 来控制的
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+
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+> 将 `EntityTypes` 所有 `Entity` 的 `Proportion` 求和并归一化，进而得到每个 `Entity` 的比例
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+
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+`EntityConfig` 是一个 `UMassEntityConfigAsset`，是一个 `UDataAsset`，用于配置每个 `Entity` 包含的 `FMassFragment`
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+
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+> `FMassFragment` 前面解释过，用于表示 `ECS` 中的一个 `Component`，用于存储纯数据
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+
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+不过 `EntityConfig` 并没有直接配置 `FMassFragment` 而是通过 `UMassEntityTraitBase` 进行配置
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+
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+以 `UMassLookAtTargetTrait` 为例，通过重写 `BuildTemplate` 将所需的 `FMassFragment` 和 `FMassTag` 添加到 `BuildContext` 中
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+
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+```cpp
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+UCLASS(meta=(DisplayName="Look At Target"))
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+class UMassLookAtTargetTrait : public UMassEntityTraitBase
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+{
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+ GENERATED_BODY()
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+
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+protected:
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+
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+ virtual void BuildTemplate(FMassEntityTemplateBuildContext& BuildContext, const UWorld& World) const override
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+ {
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+ BuildContext.AddTag<FMassLookAtTargetTag>();
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+ BuildContext.AddFragment<FTransformFragment>();
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+ }
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+};
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+```
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+
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+
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+
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+在遍历完所有配置的 `Traits` 之后，会将该 `UDataAsset` 的 `GUID` 和 配置的 Traits 信息注册到 `UMassSpawnerSubsystem` 中，并构建出 `FMassEntityTemplate`
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+
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+```cpp
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+UMassSpawnerSubsystem* SpawnerSystem = UWorld::GetSubsystem<UMassSpawnerSubsystem>(&World);
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+
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+// 获取 UDataAsset 文件的 GUID 和 TemplateData
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+
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+return TemplateRegistry.FindOrAddTemplate(TemplateID, MoveTemp(TemplateData)).Get();
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+```
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+
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+> `FMassEntityConfig::GetOrCreateEntityTemplate` 函数源码
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+
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+如果该 `GUID` 在 `UMassSpawnerSubsystem` 中保存过，则从缓存中直接得到包含 `Data` 和 `GUID` 的 `FMassEntityTemplate`
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+
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+那么什么是 `FMassEntityTemplate` ？
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+
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+核心作用是将实体配置数据 (`FMassEntityTemplateData`) 与运行时实体类型 (`FMassArchetypeHandle`) 进行绑定，创建不可变的、可直接用于生成实体的模板
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+
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+```cpp
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+struct MASSSPAWNER_API FMassEntityTemplate final : public TSharedFromThis<FMassEntityTemplate>
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+{
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+private:
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+ FMassEntityTemplateData TemplateData;
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+ FMassArchetypeHandle Archetype;
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+ FMassEntityTemplateID TemplateID;
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+}
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+```
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+
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+在构造 `FMassEntityTemplate` 对象的时候，会通过传入 `TemplateID` 和 `TemplateData` 计算得到 `Archetype`
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+
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+```cpp
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+const FMassArchetypeHandle ArchetypeHandle = EntityManager.CreateArchetype(GetCompositionDescriptor(), FName(GetTemplateName()));
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+SetArchetype(ArchetypeHandle);
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+```
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+
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+> `Archetype` 可以理解为原型，`Entity` 的数据构成具体包括哪些 `FMassFragment` 类型，通过 `Archetype` 可以知道一个 `Entity` 所需的内存大小是多少，进而计算得到一个 `Chunk` (内存块) 可以存储多少个 `Entity` 的数据
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+
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+### UMassProcessor
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+
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+`ECS` 是由 `Entity` + `Component` + `System` 组成
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+
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+- `Entity` 表示一个实体
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+- `Component` 用于存储实体的数据，通常一个 `Entity` 对应多个 `Component`
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+- `System` 用于处理数据
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+
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+对应 `MassAI` 来说
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+
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+`FMassArchetypeData` 可以表示 `Entity` 中具有哪些 `Component`，并且存储这些 `Component` 的内容到 `Chunk` 中
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+
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+> 通常来说，一个 `Chunk` 的大小是 128KB
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+
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+```cpp
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+namespace UE::Mass
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+{
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+ constexpr int32 ChunkSize = 128*1024;
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+}
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+```
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+
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+`FMassFragment` 则表示一个 `Component`，用于存储一个纯信息
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+
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+那么 `System` 是什么？
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+
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+在 `MassAI` 中，使用 `UMassProcessor` 来处理数据
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+
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+> `Processor` 加工; 数据处理器
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+
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+```cpp
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+UCLASS(abstract, EditInlineNew, CollapseCategories, config = Mass, defaultconfig, ConfigDoNotCheckDefaults)
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+class MASSENTITY_API UMassProcessor : public UObject
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+{
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+// 常用函数
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+public:
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+ virtual void Initialize(UObject& Owner) {}
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+ virtual void PostInitProperties() override;
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+
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+ virtual void DebugOutputDescription(FOutputDevice& Ar, int32 Indent = 0) const;
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+ virtual FString GetProcessorName() const { return GetName(); }
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+ virtual void ExportRequirements(FMassExecutionRequirements& OutRequirements) const;
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+ virtual void Execute(FMassEntityManager& EntityManager, FMassExecutionContext& Context);
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+ virtual void ConfigureQueries() override;
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+
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+// 常用属性
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+private:
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+ UPROPERTY(EditAnywhere, Category = "Pipeline", meta = (Bitmask, BitmaskEnum = "/Script/MassEntity.EProcessorExecutionFlags"), config)
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+ int32 ExecutionFlags;
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+
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+ UPROPERTY(EditDefaultsOnly, Category = Processor, config)
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+ EMassProcessingPhase ProcessingPhase = EMassProcessingPhase::PrePhysics;
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+
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+ UPROPERTY(EditDefaultsOnly, Category = Processor, config)
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+ FMassProcessorExecutionOrder ExecutionOrder;
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+
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+ TArray<FMassEntityQuery*> OwnedQueries;
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+}
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+```
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+
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+| 属性 | 作用 | 使用示例 |
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+| --- | --- | --- |
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+| ExecutionFlags | 控制 Processor 执行环境，Server、Client、Standalone | ExecutionFlags((int32)(EProcessorExecutionFlags::Server | EProcessorExecutionFlags::Standalone)) |
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+| ProcessingPhase | 定义 Processor 的执行阶段 | EMassProcessingPhase::PrePhysics |
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+| ExecutionOrder | 精细控制同阶段内的执行顺序 | |
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+| OwnedQueries | 存储 RegisterQuery | |
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+
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+`ProcessingPhase` 的值，有以下几种类型
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+
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+> 这个按需修改，通常来说都是 `PrePhysics`
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+
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+```cpp
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+UENUM()
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+enum class EMassProcessingPhase : uint8
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+{
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+ PrePhysics,
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+ StartPhysics,
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+ DuringPhysics,
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+ EndPhysics,
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+ PostPhysics,
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+ FrameEnd,
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+ MAX,
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+};
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+```
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+
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+`ExecutionOrder` 的值有以下几种
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+
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+```cpp
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+namespace UE::Mass::ProcessorGroupNames
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+{
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+ const FName UpdateWorldFromMass = FName(TEXT("UpdateWorldFromMass"));
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+ const FName SyncWorldToMass = FName(TEXT("SyncWorldToMass"));
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+ const FName Behavior = FName(TEXT("Behavior"));
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+ const FName Tasks = FName(TEXT("Tasks"));
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+ const FName Avoidance = FName(TEXT("Avoidance"));
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+ const FName Movement = FName(TEXT("Movement"));
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+}
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+```
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+
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+#### 构造函数
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+
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+以 `UMoveToPlayerProcessor` 为例
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+
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+设置 自动注册 （`bAutoRegisterWithProcessingPhases`）
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+
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+设定执行顺序在 `Avodiance` 和 `Movement` 之前
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+
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+```cpp
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+UMoveToPlayerProcessor::UMoveToPlayerProcessor()
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+{
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+ // Automatically create a instance
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+ bAutoRegisterWithProcessingPhases = true;
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+
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+ // Execute before avoidance and movement because its best that we set our goal before
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+ ExecutionOrder.ExecuteBefore.Add(UE::Mass::ProcessorGroupNames::Avoidance);
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+ ExecutionOrder.ExecuteBefore.Add(UE::Mass::ProcessorGroupNames::Movement);
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+}
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+```
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+
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+除了 `ExecuteBefore` 之外，还有几个
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+
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+```cpp
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+
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+USTRUCT()
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+struct FMassProcessorExecutionOrder
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+{
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+ GENERATED_BODY()
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+
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+ /** Determines which processing group this processor will be placed in. Leaving it empty ("None") means "top-most group for my ProcessingPhase" */
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+ UPROPERTY(EditAnywhere, Category = Processor, config)
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+ FName ExecuteInGroup = FName();
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+
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+ UPROPERTY(EditAnywhere, Category = Processor, config)
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+ TArray<FName> ExecuteBefore;
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+
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+ UPROPERTY(EditAnywhere, Category = Processor, config)
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+ TArray<FName> ExecuteAfter;
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+};
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+```
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+
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+`ExecutionOrder` 的作用主要是为了排序，给各个 Processor 指定执行顺序
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+
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+#### ConfigureQueries
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+
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+以 `UMassLookAtProcessor::ConfigureQueries` 为例
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+
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+```cpp
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+void UMassLookAtProcessor::ConfigureQueries()
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+{
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+ EntityQuery_Conditional.AddRequirement<FMassLookAtFragment>(EMassFragmentAccess::ReadWrite);
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+ EntityQuery_Conditional.AddRequirement<FTransformFragment>(EMassFragmentAccess::ReadOnly);
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+ EntityQuery_Conditional.AddRequirement<FMassMoveTargetFragment>(EMassFragmentAccess::ReadOnly);
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+ EntityQuery_Conditional.AddRequirement<FMassZoneGraphLaneLocationFragment>(EMassFragmentAccess::ReadOnly, EMassFragmentPresence::Optional);
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+ EntityQuery_Conditional.AddRequirement<FMassLookAtTrajectoryFragment>(EMassFragmentAccess::ReadWrite, EMassFragmentPresence::Optional);
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+ EntityQuery_Conditional.AddRequirement<FMassZoneGraphShortPathFragment>(EMassFragmentAccess::ReadOnly, EMassFragmentPresence::Optional);
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+ EntityQuery_Conditional.AddTagRequirement<FMassMediumLODTag>(EMassFragmentPresence::None);
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+ EntityQuery_Conditional.AddTagRequirement<FMassLowLODTag>(EMassFragmentPresence::None);
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+ EntityQuery_Conditional.AddTagRequirement<FMassOffLODTag>(EMassFragmentPresence::None);
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+ EntityQuery_Conditional.AddChunkRequirement<FMassVisualizationChunkFragment>(EMassFragmentAccess::ReadOnly);
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+ EntityQuery_Conditional.SetChunkFilter(&FMassVisualizationChunkFragment::AreAnyEntitiesVisibleInChunk);
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+ EntityQuery_Conditional.AddSubsystemRequirement<UMassNavigationSubsystem>(EMassFragmentAccess::ReadOnly);
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+ EntityQuery_Conditional.AddSubsystemRequirement<UZoneGraphSubsystem>(EMassFragmentAccess::ReadOnly);
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+}
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+```
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+
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+`FMassEntityQuery` 主要用于高效检索和处理满足特定条件的实体集合。通过声明式查询语法，实现了对海量实体的高性能筛选和处理，是 Mass 框架实现高效数据处理的关键机制
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+
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+> `MassEntityQuery` 的类型是 `FMassEntityQuery`
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+
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+对 `FMassEntityQuery` 的使用，常见于下面这些
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+
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+| 常用接口 | 作用 |
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+| --- | --- |
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+| AddRequirement | 设定 `Processor` 对指定类型的 `FMassFragment` 的读写权限 |
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+| AddTagRequirement | 设置查找的 FMassFragment 必须包含某些 Tag，根据参数配置进行筛选 |
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+| AddChunkRequirement | 设置对 FMassChunkFragment 的读写权限 |
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+| SetChunkFilter | 添加 Chunk 的过滤器 |
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+| AddConstSharedRequirement | 设定对 FMassSharedFragment 的过滤 |
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+| AddSharedRequirement | |
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+| AddSubsystemRequirement | 设置对 Subsystem 的读写权限 |
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+| RegisterWithProcessor | 注册这个 FMassEntityQuery |
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+
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+通过前面这些对 `Requirement` 的设定，通过 ForEach 操作可以在 `MassEntityManager` 中获取符合条件的 `MassEntity` 并对其进行相应的操作
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+
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+至于查询条件枚举，内容如下
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+
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+```cpp
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+UENUM()
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+enum class EMassFragmentPresence : uint8
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+{
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+ /** All of the required fragments must be present */
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+ All,
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+ /** One of the required fragments must be present */
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+ Any,
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+ /** None of the required fragments can be present */
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+ None,
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+ /** If fragment is present we'll use it, but it missing stop processing of a given archetype */
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+ Optional,
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+ MAX
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+};
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+```
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+
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+| 枚举类型 | 作用
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+| --- | --- |
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+| All | 必须存在 |
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+| Any | 至少存在一个 |
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+| None | 禁止存在 |
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+| Optional | 可选存在，存在时会被使用，不存在不影响匹配 |
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+
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+#### Execute
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+
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+```cpp
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+const UMassNavigationSubsystem& MassNavSystem = Context.GetSubsystemChecked<UMassNavigationSubsystem>();
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+const UZoneGraphSubsystem& ZoneGraphSubsystem = Context.GetSubsystemChecked<UZoneGraphSubsystem>();
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+
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+const int32 NumEntities = Context.GetNumEntities();
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+const TArrayView<FMassLookAtFragment> LookAtList = Context.GetMutableFragmentView<FMassLookAtFragment>();
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+const TConstArrayView<FTransformFragment> TransformList = Context.GetFragmentView<FTransformFragment>();
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+const TConstArrayView<FMassMoveTargetFragment> MoveTargetList = Context.GetFragmentView<FMassMoveTargetFragment>();
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+const TConstArrayView<FMassZoneGraphLaneLocationFragment> ZoneGraphLocationList = Context.GetFragmentView<FMassZoneGraphLaneLocationFragment>();
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+const TConstArrayView<FMassZoneGraphShortPathFragment> ShortPathList = Context.GetFragmentView<FMassZoneGraphShortPathFragment>();
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+const TArrayView<FMassLookAtTrajectoryFragment> LookAtTrajectoryList = Context.GetMutableFragmentView<FMassLookAtTrajectoryFragment>();
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+```
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+
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+通过 `Context` 参数，可以通过不同的接口，获取不同的内容
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+
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+- 因为 `FMassLookAtFragment` 的读写权限是 `ReadWrite`，使用 `GetMutableFragmentView` 获取
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+
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+- 因为 `FTransformFragment` 的读写权限是 `ReadOnly`，使用 `GetFragmentView` 获取
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+
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+- 因为 `UZoneGraphSubsystem` 的读写权限是 `ReadOnly`，使用 `GetSubsystemChecked` 获取
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+
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+- 如果 `Subsystem` 的读写权限是 `ReadWrite`，使用 `GetMutableSubsystem` 获取
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+
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+- 如果想要获取 `Chunk` 也可以通过 `GetChunkFragmentPtr` 和 `GetChunkFragment` 两个接口
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+
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