一.创造一个USTRUCT
1.首先需要创建一个，None。
#include "LineDataStruct.generated.h"FTPAData里加入GENERATED_USTRUCT_BODY();
//Topic=DDS_TPA_Data, 预测航迹线，单次事件
USTRUCT()
struct FTPAData
{GENERATED_USTRUCT_BODY();int16 header; // 包头int16 flag; // 标志位int64 timestamp; // 时间戳int16 validPointCount; // 轨迹有效点数 最大值1000，轨迹有效点数为N1时读取N1个轨迹点数据int16 reserved1; // 预留接口1int16 reserved2; // 预留接口2int16 reserved3; // 预留接口3int32 reserved4; // 预留接口4int32 reserved5; // 预留接口5FTPAData_Point TPAData_Point[1000]; // 轨迹点数组int16 checksum; // 校验值
};#pragma pack()如果想让蓝图认识，需要加BlueprintType。如果想让变量能在蓝图中访问,可用Break/Make，需要使用UPROPERTY修饰符(BlueprintReadWrite)。
二.画线插件
不多废话，直接上代码
UCLASS()
class HMSLINESYSTEM_API UDrawLineSubsystem : public UGameInstanceSubsystem
{GENERATED_BODY()
public:void UpdateLinePath(int id,FVector First,FVector Second);//void UpdateLinePath2(int id,FVector First, FVector Second);//void LinePatch(FVector Fi);
private:void InitialGeoreference();
public:
private:ACesiumGeoreference* Georeference;//航迹线，航迹线idTMap<int8, ASplineActor*> LinePathMap;TMap<int8, ALinePatchActor*> LinePatchPathMap;UMaterialParameterCollectionInstance* M_ParamCollection;int num = 100.f;};先介绍，这种简单一点的通过，UE自带的LinePatchComponent进行画线，给一头一尾就能画。将Cesium的点换为UE坐标系的点，再去画。
//void UpdateLinePath2(int id,FVector First, FVector Second);
void UDrawLineSubsystem::UpdateLinePath2(int id, FVector First, FVector Second)
{int32 tmpPathID = id;if (LinePatchPathMap.Find(tmpPathID)){if (!Georeference)InitialGeoreference();if (!Georeference) return;if (!First.IsZero()){//处理点位信息FVector tmpDataPosition = FVector(First);FVector FirstUELocation = Georeference->TransformLongitudeLatitudeHeightPositionToUnreal(tmpDataPosition);LinePatchPathMap[tmpPathID]->SetActorLocation(FirstUELocation);First = FirstUELocation;}if (!Second.IsZero()){//处理点位信息FVector tmpDataPosition = FVector(Second);FVector SecondUELocation = Georeference->TransformLongitudeLatitudeHeightPositionToUnreal(tmpDataPosition);Second = SecondUELocation;}LinePatchPathMap[tmpPathID]->CreateLine(First, Second);//M_ParamCollection->SetScalarParameterValue(FName("CollisionHeightLow"), CollisionRender.HightLow * 100.f);}else{ALinePatchActor* LinePatchActor = GetWorld()->SpawnActor<ALinePatchActor>();if (!LinePatchActor){UE_LOG(LogTemp, Error, TEXT("failed to spawn LinePathActor! UDrawLineSubsystem::UpdateLinePath2"));return;}else{LinePatchPathMap.Add(tmpPathID, LinePatchActor);}}
}这个是画线的，把头和组件加上就行了。
#include "Components/LineBatchComponent.h"// Sets default values
ALinePatchActor::ALinePatchActor()
{// Set this actor to call Tick() every frame. You can turn this off to improve performance if you don't need it.PrimaryActorTick.bCanEverTick = true;SetRootComponent(CreateDefaultSubobject<USceneComponent>(TEXT("DefaultSceneRoot")));LineBatchComponent = CreateDefaultSubobject<ULineBatchComponent>(TEXT("LineBatchComponent"));LineBatchComponent->SetupAttachment(RootComponent);
}void ALinePatchActor::CreateLine(FVector First, FVector Second)
{LineBatchComponent->Flush();LineBatchComponent->DrawLine(First, Second, FColor::Purple, 1.f, 50.f, 0); // Adjust the colors and thickness as needed
}
用UGameInstanceSubsystem做插件的好处，有很多。自己能管理生命周期，获取方便。
把模块和头加上就能从GameInstance里获得GameSubsystem,再转换为自己的system。
UDrawLineSubsystem* LineSystem = GetWorld()->GetGameInstance()->GetSubsystem<UDrawLineSubsystem>();
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