本文目录 27 个章节
Unity-Unreal
# Unity->Unreal
创建时间：2021/12/15 16:27
- Unity->UE 官方
- Glossary
- Projects and Files
- Actor
- Blueprint vs. Prefab
- Component
- Blueprint or C++?
- Transform Components
- Actor
- Gameplay Framework
- Programming
- Event Functions
- Unity功能在Unreal中实现
- Physics: RigidBody vs. Primitive Component
- Input events
- Exception
- Unity->UE经验博客
- Actor Lifecycle
- 销毁对象
- Garbage Collection
- Advanced GC
- 对象查找
- Referencing Assets
- Actor与蓝图的加载、生成
- 资源路径
- Actor Lifecycle
- Unreal vs. Unity
- Ref
可以通过Unity那边的概念、结构、操作方式来理解Unreal。但是又不能完全类比，不能期待一方中的操作方法在另一方里面一定有，如果完全一致的话，两个就变成同一个引擎了。接近本质的点上可以对照去看，比如序列化、反序列化，比如内存管理、资源管理等，是独立于引擎的，都要有的。而上层的、操作习惯上的点就不能一一对照了。
Unity->UE 官方
Glossary
Unity -> Unreal
Prefab -> Blueprint Class Mesh -> Static Mesh Skinned Mesh -> Skeletal Mesh Shader -> Material, Material Editor Material -> Material Instance Material Instance -> ? Sprite -> EditorPaper2D Mecanim -> Persona , Animation Blueprint UI -> UMG (Unreal Motion Graphics)
Raycast -> Line Trace, Shape Trace
Rigid Body -> Collision, Physics
Projects and Files
Content - Assets
Map file - Scene, Map files store data about your Level and the objects in it, as well as lighting data and certain level-specific settings.
Edit->Project Settings->Platforms->Android/... - "player settings" in Unity
Source sub-folder -
Actor
In Unity, GameObject is C# class which you cannot directly extend. In UE4, Actor is a C++ class which you can extend and customize using inheritance.
任意可以被放置到关卡中的游戏物体都是一个 Actor
Actor 可以被认为维系了一些特殊 Object 的容器，这些特殊 Object 被称为组件（Component）
Actor像是Prefab一样，可以在场景中实例化多个，当Actor进行了修改，那么场景中的物体会同样被修改
Blueprint vs. Prefab
UE4中，Unity的Prefab使用Blueprint Class替代。Blueprint Class支持继承，修改公共的Function很方便。
蓝图-Code挂Asset Prefab-Asset挂code
Component
BeginPlay = Initialize Component = Unity Start() Tick Component = Unity Update
Blueprint or C++?
Most projects will use a mix of Blueprints and C++. Many developers prototype game functionality using Blueprints, because it is so easy and fun, and later move some or all of it to C++ for performance and engineering rigor.
Transform Components
Root Component - any subclass of Scene Component
A Scene Component gives the Actor a location, rotation, and scale in the world which is applied hierarchically to all components underneath it.
Actor
Actors are most common class used for gameplay in UE4 and the only type that can be Spawned into the World. So everything you place in your level will be an Actor.
Object is actually the base class of all Unreal classes, including Actor and many others.
Gameplay Framework
https://docs.unrealengine.com/4.27/en-US/InteractiveExperiences/Framework/ customized built-in Actor classes replication and networking features
Programming
Event Functions
Remember, in UE4 it is important to call the parent class' version of method.
A - Actor sub-class U - Object sub-class F - plain data structures or non-UObject classes
Unity功能在Unreal中实现
文档中查阅：https://docs.unrealengine.com/4.27/en-US/Basics/UnrealEngineForUnityDevs/
Instantiating GameObject / Spawning Actor Casting from One Type to Another
Destroying GameObject / Actor Destroying GameObject / Actor (With 1 Second Delay) Disabling GameObjects / Actors
Accessing the GameObject / Actor from a Component Accessing a Component from the GameObject / Actor Finding GameObjects / Actors Adding tags to GameObjects / Actors Adding tags to MonoBehaviours / ActorComponents Comparing tags on GameObjects / Actors and MonoBehaviours / ActorComponents
Physics: RigidBody vs. Primitive Component
Layers vs Channels RayCast vs RayTrace Triggers
Kinematic Rigidbodies
Input events
Engine-Input
Exception
check() - You can pass in an error message. ensure() - log an error with a full call stack
Unity->UE经验博客
Actor Lifecycle
https://docs.unrealengine.com/4.27/en-US/ProgrammingAndScripting/ProgrammingWithCPP/UnrealArchitecture/Actors/ActorLifecycle/ Destroy EndPlay OnDestroy - 不要用这个，要用EndPlay
销毁对象
public class AGenericClass<T> where T : IComparable<T> { }
Garbage Collection
Advanced GC
Clustering -: builds clusters of objects that are all destroyed together
Cluster Merging - For example, a particle system asset may reference a material asset, but if cluster merging is turned off, the material and the particle system will remain in separate clusters for garbage collection purposes. With cluster merging turned on, the particle asset cluster will be merged with the material cluster due to the particle system referencing the material.
对象查找
public class AGenericClass<T> where T : IComparable<T> { }
Referencing Assets
Direct Property Reference Construction Time Reference Indirect Property Reference
Actor与蓝图的加载、生成
public class AGenericClass<T> where T : IComparable<T> { }
资源路径
目前UE4采用每个资源一个包，以前UE3和UE2时代，一个包中可以有多个资源对象，因此现在包名和资源名都是一样的，除非有手动重命名过。
public class AGenericClass<T> where T : IComparable<T> { }