要看资源大小可以用Asset Size Mapper来查看。直接点右键就可以看到了。

Features¶

常见技术参数:

API 一般有DX 11/12, OGL,OGLES,vulkan.
Texture Resolution 材质解析度
Quadcore-Multithread 多核心多线程
Tesselation 曲面线分
Deferred shading 延迟渲染
Live Create 编辑器动态创建
Full-Dynamic Realtime shading 全动态实时阴影
Direct illumination (直接光照)
indirect illumination
Global illumination
Local illumination 局光映射
Photon mapping 光子映射贴图
Raytracing 光线追踪
Radiosity 实时辐射照明，计算发光用
bouncing light
sub-surface scatterring
Translucency shader
Normal map
parallax occlusion 视差映射贴图
Displacement map 硬件位移置换图
megatexture 顶点贴图
Multi-sample 多重采样
Alphato coverage
shadow map
instancing 点缓存系统
Gizmo particle 容积粒子
Volume Shader
Vertex Animation
Character dynmaics

4.12 现在支持 VR editor,以及sequencer用法。sequencer用法，保存不是静态二维数据，而一个三维场景。

如何制作一个夜晚明月的场景¶

https://www.youtube.com/watch?v=0YpZlUzkQVk

CalcAABB¶

> VehicleAdvanced_C-Win64-Debug.exe!UPhysicsAsset::CalcAABB(const USkinnedMeshComponent * MeshComp, const FTransform & LocalToWorld) Line 120 C++: VehicleAdvanced_C-Win64-Debug.exe!USkinnedMeshComponent::CalcMeshBound(const FVector & RootOffset, bool UsePhysicsAsset, const FTransform & LocalToWorld) Line 731 C++ VehicleAdvanced_C-Win64-Debug.exe!USkeletalMeshComponent::CalcBounds(const FTransform & LocalToWorld) Line 1394 C++ VehicleAdvanced_C-Win64-Debug.exe!USceneComponent::UpdateBounds() Line 913 C++ VehicleAdvanced_C-Win64-Debug.exe!USkeletalMeshComponent::PostBlendPhysics() Line 438 C++ VehicleAdvanced_C-Win64-Debug.exe!USkeletalMeshComponent::PostAnimEvaluation(FAnimationEvaluationContext & EvaluationContext) Line 1337 C++ VehicleAdvanced_C-Win64-Debug.exe!USkeletalMeshComponent::RefreshBoneTransforms(FActorComponentTickFunction * TickFunction) Line 1262 C++ VehicleAdvanced_C-Win64-Debug.exe!USkeletalMeshComponent::InitAnim(bool bForceReinit) Line 370 C++ VehicleAdvanced_C-Win64-Debug.exe!USkeletalMeshComponent::OnRegister() Line 309 C++ VehicleAdvanced_C-Win64-Debug.exe!UActorComponent::ExecuteRegisterEvents() Line 1094 C++ VehicleAdvanced_C-Win64-Debug.exe!UActorComponent::RegisterComponentWithWorld(UWorld * InWorld) Line 871 C++ VehicleAdvanced_C-Win64-Debug.exe!AActor::IncrementalRegisterComponents(int NumComponentsToRegister) Line 3828 C++ VehicleAdvanced_C-Win64-Debug.exe!ULevel::IncrementalUpdateComponents(int NumComponentsToUpdate, bool bRerunConstructionScripts) Line 806 C++ VehicleAdvanced_C-Win64-Debug.exe!ULevel::UpdateLevelComponents(bool bRerunConstructionScripts) Line 739 C++ VehicleAdvanced_C-Win64-Debug.exe!UWorld::UpdateWorldComponents(bool bRerunConstructionScripts, bool bCurrentLevelOnly) Line 1328 C++ VehicleAdvanced_C-Win64-Debug.exe!UWorld::InitializeActorsForPlay(const FURL & InURL, bool bResetTime) Line 3048 C++ VehicleAdvanced_C-Win64-Debug.exe!UEngine::LoadMap(FWorldContext & WorldContext, FURL URL, UPendingNetGame * Pending, FString & Error) Line 9809 C++ VehicleAdvanced_C-Win64-Debug.exe!UEngine::Browse(FWorldContext & WorldContext, FURL URL, FString & Error) Line 8945 C++ VehicleAdvanced_C-Win64-Debug.exe!UGameInstance::StartGameInstance() Line 339 C++ VehicleAdvanced_C-Win64-Debug.exe!UGameEngine::Init(IEngineLoop * InEngineLoop) Line 529 C++ VehicleAdvanced_C-Win64-Debug.exe!FEngineLoop::Init() Line 2185 C++ VehicleAdvanced_C-Win64-Debug.exe!EngineInit() Line 41 C++ VehicleAdvanced_C-Win64-Debug.exe!GuardedMain(const wchar_t * CmdLine, HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, int nCmdShow) Line 136 C++ VehicleAdvanced_C-Win64-Debug.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 189 C++ [External Code]

Physical Simulation¶

Unreal的物理引擎用的是nvidia的Physix,并且各种动画的连接，也就是Joint,不过在Unreal中叫Physical Contraint. Unreal只是做了一个转接，把这些都交给了物理引擎。但是为了减少计算量，没有用原来那个mesh网格来做仿真的计算，如果直接那些mesh网格，就成有限元分析了。运算量是巨量。重新用一些简单长方体，球体，圆柱体来进行近似计算了。

一般Physical 都是建立在skeletal mesh 上的。

Precomputed¶

在设置属性的，可用通过PrecomputedVisualVolumes来设置哪些东东是可以提前计算好的，也就是放在cooking阶段就计算的。同时也可以通过:command:start initviews 来查看。

当然也可以通过 start openglrhi 来查看。

Editor技巧¶

keyboardshortcut设置在https://docs.unrealengine.com/latest/INT/Engine/UI/KeyBindings/index.html，并且应该可以不同theme,例如使用3Dmax的习惯，或者blender的习惯。 blueeditor的一张表在https://cdn2.unrealengine.com/blog/BlueprintCheatSheet-1989117414.pdf https://docs.unrealengine.com/latest/INT/Engine/Blueprints/UserGuide/CheatSheet/index.html 关键是Ctrl+F 的搜索功能。

plugin¶

用法 #. put into /<Engine>/Plgins/Runtime or <YourProjects>/Plugins/ #. build #. Run editor #. check it in puglin list

当你真正使用时,也还会有各种各样的问题,例如生成生成以及reference的更新等等. https://forums.unrealengine.com/showthread.php?49057-UE-4-Python-Tools-from-Tragnarion

当你有各种各样的需求时,看看https://wiki.unrealengine.com/Category:Plug-ins 有没有现成插件可以用的. 或者论坛里看看,有什么合适的例如下面,有人做一个blueprint 共享库. https://forums.unrealengine.com/showthread.php?3851-%2839%29-Rama-s-Extra-Blueprint-Nodes-for-You-as-a-Plugin-No-C-Required

BLUI 插件 https://forums.unrealengine.com/showthread.php?58192-PLUGIN-BLUI-Open-Source-HTML5-JS-CSS-HUD-UI-Release-1-0! 以及各种常用尺寸，一般情况是1 unreal unit = 1cm,以及X,Y,Z等等的尺寸。 https://wiki.unrealengine.com/User_Submitted_Art_Specifications

TextureMoviePlugin https://github.com/Ehamloptiran/TextureMoviePlugin 实现就如http://www.jianshu.com/p/291ff6ddc164,用于VR 非常方便

当然你如果添加自己的脚本,可以考参scriptplugin,它已经生成公共的接口,让你很方便嵌入任何脚本语言.例如 Lua. https://forums.unrealengine.com/showthread.php?3958-Scripting-Language-extensions-via-plugins

https://github.com/enlight/klawr,用C#来做gameplay logic scripts.

一个更强的组件,那是runtime mesh generate,当然这个性能可能是问题,但是这个就为内容的动态演化提供了可能,尤其在虚拟现实中真实会更强. https://forums.unrealengine.com/showthread.php?113432-Runtime-Mesh-Component-Rendering-high-performance-runtime-generated-meshes!

AI in Game¶

Unreal 中一个专门的AI插件SkookumScript. 可以直接操作人物. https://forums.unrealengine.com/showthread.php?25379-SkookumScript-Plug-in

其中一个重要的項目那就是nvmesh的生成,如果是自己做游戏,可以用recastvaigation来做. https://github.com/gwli/recastnavigation 或者使用这些工具来生成,例如Kynapse | Autodesk Gameware

导航网格的生成主要用是计算几何以及A*算法.

AI 的sourcecode 在c:UE4_12EngineSourceRuntimeAIModulePrivateNavigationPathFollowingComponent.cpp

在项目中有四处,AI System,Collision,Navigation Mesh,Navigation System. navmesh要动态生成要在这里配置,默认是静态生成的.

> [0x55449F4C] UPathFollowingComponent::UPathFollowingComponent(UPathFollowingComponent * this, const FObjectInitializer & ObjectInitializer) Line 36 C++: [0x55545E64] UPathFollowingComponent::__DefaultConstructor(const FObjectInitializer & X) Line 115 C++ [0x555310E0] InternalConstructor<UPathFollowingComponent>(const FObjectInitializer & X) Line 2543 C++ [0x53B2E72C] UClass::CreateDefaultObject(UClass * this) Line 3340 C++ [0x53698658] UClass::GetDefaultObject(UClass * this, bool bCreateIfNeeded) Line 2196 C++ [0x53C54338] UObjectLoadAllCompiledInDefaultProperties() Line 728 C++ [0x53C53CC0] ProcessNewlyLoadedUObjects() Line 818 C++ [0x53687E40] FEngineLoop::PreInit(FEngineLoop * this, const TCHAR * CmdLine) Line 1498 C++ [0x53681C20] FEngineLoop::PreInit(FEngineLoop * this, int32 ArgC, TCHAR ** ArgV, const TCHAR * AdditionalCommandline) Line 694 C++ [0x53681188] AndroidMain(android_app * state) Line 286 C++ [0x53683CCC] android_main(android_app * state) Line 453 C++ [0x536BF0DC] android_app_entry(void * param) Line 233 C++ [0x4070DC28] libc.so!__pthread_start(void*)() C++ [0x406E8294] libc.so!__start_thread() C++ ??() C++

跳起的处理 > [0x55A554E4] UCharacterMovementComponent::SetMovementMode(UCharacterMovementComponent * this, EMovementMode NewMovementMode, uint8 NewCustomMode) Line 804 C++

[0x55A68BA0] UCharacterMovementComponent::SetPostLandedPhysics(UCharacterMovementComponent * this, const FHitResult & Hit) Line 4777 C++ [0x55A68970] UCharacterMovementComponent::ProcessLanded(UCharacterMovementComponent * this, const FHitResult & Hit, float remainingTime, int32 Iterations) Line 4750 C++ [0x55A6243C] UCharacterMovementComponent::PhysFalling(UCharacterMovementComponent * this, float deltaTime, int32 Iterations) Line 3595 C++ [0x55A5CB5C] UCharacterMovementComponent::StartNewPhysics(UCharacterMovementComponent * this, float deltaTime, int32 Iterations) Line 2355 C++ [0x55A5AD24] UCharacterMovementComponent::PerformMovement(UCharacterMovementComponent * this, float DeltaSeconds) Line 1931 C++ [0x55A56BC8] UCharacterMovementComponent::TickComponent(UCharacterMovementComponent * this, float DeltaTime, ELevelTick TickType, FActorComponentTickFunction * ThisTickFunction) Line 1076 C++ [0x55A24E80] FActorComponentTickFunction::ExecuteTick(float, ELevelTick, ENamedThreads::Type, TRefCountPtr<FGraphEvent> const&)::$_12::operator()(float) const(const class {...} * this, float DilatedTime) Line 700 C++ [0x55A14B6C] FActorComponentTickFunction::ExecuteTickHelper<FActorComponentTickFunction::ExecuteTick(float, ELevelTick, ENamedThreads::Type, TRefCountPtr<FGraphEvent> const&)::$_12>(UActorComponent*, bool, float, ELevelTick, FActorComponentTickFunction::ExecuteTick(float, ELevelTick, ENamedThreads::Type, TRefCountPtr<FGraphEvent> const&)::$_12 const&)(UActorComponent * Target, bool bTickInEditor, float DeltaTime, ELevelTick TickType, const class {...} & ExecuteTickFunc) Line 2888 C++ [0x55A14A24] FActorComponentTickFunction::ExecuteTick(FActorComponentTickFunction * this, float DeltaTime, ELevelTick TickType, ENamedThreads::Type CurrentThread, const FGraphEventRef & MyCompletionGraphEvent) Line 698 C++ [0x564C0984] FTickFunctionTask::DoTask(FTickFunctionTask * this, ENamedThreads::Type CurrentThread, const FGraphEventRef & MyCompletionGraphEvent) Line 261 C++ [0x564C05CC] TGraphTask<FTickFunctionTask>::ExecuteTask(TGraphTask<FTickFunctionTask> * this, TArray<FBaseGraphTask*, FDefaultAllocator> & NewTasks, ENamedThreads::Type CurrentThread) Line 999 C++ [0x53718A70] FBaseGraphTask::Execute(FBaseGraphTask * this, TArray<FBaseGraphTask*, FDefaultAllocator> & NewTasks, ENamedThreads::Type CurrentThread) Line 472 C++ [0x53719CA4] FNamedTaskThread::ProcessTasksNamedThread(FNamedTaskThread * this, int32 QueueIndex, bool bAllowStall) Line 930 C++ [0x53718DF0] FNamedTaskThread::ProcessTasksUntilQuit(FNamedTaskThread * this, int32 QueueIndex) Line 677 C++ [0x53716FB8] FTaskGraphImplementation::ProcessThreadUntilRequestReturn(FTaskGraphImplementation * this, ENamedThreads::Type CurrentThread) Line 1725 C++ [0x53717394] FTaskGraphImplementation::WaitUntilTasksComplete(FTaskGraphImplementation * this, const FGraphEventArray & Tasks, ENamedThreads::Type CurrentThreadIfKnown) Line 1774 C++ [0x564BBB94] FTickTaskSequencer::ReleaseTickGroup(FTickTaskSequencer * this, ETickingGroup WorldTickGroup, bool bBlockTillComplete) Line 529 C++ [0x564B5750] FTickTaskManager::RunTickGroup(FTickTaskManager * this, ETickingGroup Group, bool bBlockTillComplete) Line 1434 C++ [0x55DEEE5C] UWorld::RunTickGroup(UWorld * this, ETickingGroup Group, bool bBlockTillComplete) Line 703 C++ [0x55DF0184] UWorld::Tick(UWorld * this, ELevelTick TickType, float DeltaSeconds) Line 1197 C++ [0x55C3F9E0] UGameEngine::Tick(UGameEngine * this, float DeltaSeconds, bool bIdleMode) Line 1040 C++ [0x53682E84] FEngineLoop::Tick(FEngineLoop * this) Line 2769 C++ [0x536812F4] AndroidMain(android_app * state) Line 326 C++ [0x53683CCC] android_main(android_app * state) Line 453 C++ [0x536BF0DC] android_app_entry(void * param) Line 233 C++ [0x4070DC28] libc.so!__pthread_start(void*)() C++ [0x406E8294] libc.so!__start_thread() C++ ??() C++

解决碰撞回避两种,一种是Unreal实现简单的办法(bUseRVOAvoidance)void UCharacterMovementComponent::SetAvoidanceEnabled(bool bEnable来使用,那一种Recast的修改来实现的.可以通过继承 UCLASS(BlueprintType) class AIMODULE_API UCrowdFollowingComponent : public UPathFollowingComponent, public ICrowdAgentInterfac 来使用. 具体用法可以参考https://wiki.unrealengine.com/Unreal_Engine_AI_Tutorial_-_2_-_Avoidance

具体动作都是这里进行的¶

void UCharacterMovementComponent::StartNewPhysics(float deltaTime, int32 Iterations) {

if ((deltaTime < MIN_TICK_TIME) || (Iterations >= MaxSimulationIterations) || !HasValidData()) {

return;

}

if (UpdatedComponent->IsSimulatingPhysics()) {

UE_LOG(LogCharacterMovement, Log, TEXT(“UCharacterMovementComponent::StartNewPhysics: UpdateComponent (%s) is simulating physics - aborting.”), *UpdatedComponent->GetPathName()); return;

}

const bool bSavedMovementInProgress = bMovementInProgress; bMovementInProgress = true;

switch ( MovementMode ) { case MOVE_None:

break;

case MOVE_Walking:

PhysWalking(deltaTime, Iterations); break;

case MOVE_NavWalking:

PhysNavWalking(deltaTime, Iterations); break;

case MOVE_Falling:

PhysFalling(deltaTime, Iterations); break;

case MOVE_Flying:

PhysFlying(deltaTime, Iterations); break;

case MOVE_Swimming:

PhysSwimming(deltaTime, Iterations); break;

case MOVE_Custom:

PhysCustom(deltaTime, Iterations); break;

default:

UE_LOG(LogCharacterMovement, Warning, TEXT(“%s has unsupported movement mode %d”), *CharacterOwner->GetName(), int32(MovementMode)); SetMovementMode(MOVE_None); break;

}

bMovementInProgress = bSavedMovementInProgress; if ( bDeferUpdateMoveComponent ) {

SetUpdatedComponent(DeferredUpdatedMoveComponent);

}

} 背后采用的Apex来实现,从void UCharacterMovementComponent::NotifyJumpApex()是可以看到的.

如何建模¶

#.　使用建模仿真软件生成高模.　然后导出. #.　再blender等变成低模,并且模块化.　例如选一模导出一下.　然后删除一些再导出一些组件. #.　再导入Unreal.　进行进一步的开发. 例如https://www.youtube.com/watch?annotation_id=annotation_1089853839&feature=iv&src_vid=bero-JBTAX8&v=Ux_zJ4WJbZg

如何导入真实的地形¶

#.　从http://opentopo.sdsc.edu/datasets 下载数据 #.　利用类似于L3DT的工具生成map #. 导入Unreal, Window>Level>import new map. https://www.youtube.com/watch?v=K41WMgJUFEk