实际需求

这个需求来源于之前的一个项目，当时用了一个第三方插件，里边有一些绘制线段的代码，c++层用的是drawdebugline，当时看底层，觉得应该没问题，不应该在release上跑不起来，由于种种原因，没有时间去搞这块，后来丢给其他同事，也解决了，但是没有按照我的思路来。

最近在玩各种ai工具，觉得有点意思，就去解决点实际问题，就拿当时的问题练练手。

1.头文件

#pragma once#include "Kismet/BlueprintFunctionLibrary.h"
#include "RuntimeLineDrawer.generated.h"UCLASS()
class YOURMODULE_API URuntimeLineDrawer : public UBlueprintFunctionLibrary
{GENERATED_BODY()public:/** 在运行时（含Shipping）绘制一条线 */UFUNCTION(BlueprintCallable, Category="RuntimeDraw")static void DrawLineRuntime(UObject* WorldContextObject,FVector Start,FVector End,FLinearColor Color = FLinearColor::Red,float Thickness = 2.f,float LifeTime = 0.f,bool bDepthTest = true);
};

2.源文件

#include "RuntimeLineDrawer.h"
#include "Engine/World.h"
#include "Engine/Engine.h"
#include "Components/LineBatchComponent.h"
#include "Engine/EngineTypes.h" // SDPG_World, SDPG_Foregroundvoid URuntimeLineDrawer::DrawLineRuntime(UObject* WorldContextObject,FVector Start,FVector End,FLinearColor Color,float Thickness,float LifeTime,bool bDepthTest
)
{if (!WorldContextObject) return;UWorld* World = WorldContextObject->GetWorld();if (!World) return;// 确保世界里有一个持久的 LineBatcher（发布版也可用）ULineBatchComponent* LineBatcher = World->PersistentLineBatcher;if (!LineBatcher){LineBatcher = NewObject<ULineBatchComponent>(World);LineBatcher->RegisterComponentWithWorld(World);World->PersistentLineBatcher = LineBatcher;}// 构建一条线（FBatchedLine）// DepthPriority: 0=SDPG_World, 1=SDPG_Foregroundconst uint8 DepthPriority = bDepthTest ? (uint8)SDPG_World : (uint8)SDPG_Foreground;TArray<FBatchedLine> Lines;Lines.Emplace(Start, End, Color, Thickness, LifeTime, DepthPriority);LineBatcher->DrawLines(Lines);LineBatcher->MarkRenderStateDirty(); // 提示渲染更新
}

3.用法

URuntimeLineDrawer::DrawLineRuntime(this, FVector(0,0,100), FVector(100,0,100),FLinearColor::Green, 3.f, /*LifeTime*/2.f, /*bDepthTest*/true);

小结

这只是个例子，完整的代码托管在完整代码，可以看下目录结构，如下：

YourProject/
└─ Plugins/└─ RuntimeLineDraw/├─ RuntimeLineDraw.uplugin└─ Source/└─ RuntimeLineDraw/├─ RuntimeLineDraw.Build.cs├─ Public/│  └─ RuntimeLineDrawer.h└─ Private/├─ RuntimeLineDrawer.cpp└─ RuntimeLineDrawModule.cpp

有兴趣可以去看看我这是以插件的形式给出的，具体，可以参考上图放到你自己的项目工程中。