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一.制作了基于USplineComponent的画线插件，就是我们常说的样条线。
直接看怎么用，关于插件实现细节，后续会更新，看思路就行。通过ID,管理每一条线。移除删掉上一帧的线条Mesh。第一个点，是本身直接放过去。第二个点是使用AddSplinePoint放进去。让后算两个点的距离，通过材质参数集合，设置UV。最后生成三角形面构成线条。
void UDrawLineSubsystem::UpdateLinePath(int id,FVector First, FVector Second)
{int32 pointsNum = 2;if (pointsNum <= 1) return;int32 tmpPathID = id;if (LinePathMap.Find(tmpPathID)){ASplineActor* tmpFlightPath = *LinePathMap.Find(tmpPathID);tmpFlightPath->SetActorHiddenInGame(true);LinePathMap.Remove(tmpPathID);//删除旧的同序号航迹线tmpFlightPath->Destroy();}// //生成轨迹线UClass* tmpSplineClass = LoadClass<ASplineActor>(nullptr, TEXT("/Script/Engine.Blueprint'/HMSLineSystem/Blueprints/BP_ConnectLine.BP_ConnectLine_C'"));ASplineActor* LinePathActor = Cast<ASplineActor>(GetWorld()->SpawnActor(tmpSplineClass));if (!LinePathActor){UE_LOG(LogTemp, Error, TEXT("failed to spawn spline actor! UProject2444System::UpdateFlightPath"));return;}LinePathActor->DeleteSplinePointByIndex(1);if (!Georeference)InitialGeoreference();if (!Georeference) return;if (!First.IsZero()){//处理点位信息FVector tmpDataPosition = FVector(First);FVector tmpUELocation = Georeference->TransformLongitudeLatitudeHeightPositionToUnreal(tmpDataPosition);LinePathActor->SetActorLocation(tmpUELocation);First = tmpUELocation;//FTransform LocalTransform;//LocalTransform.SetLocation(tmpUELocation);//LinePathActor->AddSplinePoint(LocalTransform, EPointTransformMode::world);}if (!Second.IsZero()){//处理点位信息FVector tmpDataPosition = FVector(Second);FVector tmpUELocation = Georeference->TransformLongitudeLatitudeHeightPositionToUnreal(tmpDataPosition);FTransform LocalTransform;LocalTransform.SetLocation(tmpUELocation);LinePathActor->AddSplinePoint(LocalTransform, EPointTransformMode::world);Second = tmpUELocation;}LinePathActor->SplineMeshData.MeshSlice = 1;LinePathActor->SplineMeshData.FacesCount = 2;LinePathActor->SplineMeshData.EdgeLength = 200;LinePathActor->SplineMeshData.MeshMode = EMeshMode::BaseOnPoint;LinePathActor->SetAllPointsMode(ESplineMode::Curve);LinePathActor->SetAllPointsMode(LinePathActor->SplineMeshData.SplineMode);LinePathMap.Add(tmpPathID, LinePathActor);//TPADataMap.Add(tmpPathID, _TPAData);///Script/Engine.MaterialInstanceConstant'/Game/ZOthers/Other/Materials/M_Border_Anim_10.M_Border_Anim_10'// //设置材质UMaterial* SplineMaterial;SplineMaterial = LoadObject<UMaterial>(nullptr, TEXT("/Script/Engine.Material'/Game/ZOthers/Other/Materials/Link.Link'"));// switch (tmpPathID)// {// case 1: SplineMaterial = LoadObject<UMaterial>(nullptr, FLIGHT_PATH_MATERIAL1); break;// case 2: SplineMaterial = LoadObject<UMaterial>(nullptr, FLIGHT_PATH_MATERIAL2); break;// case 3: SplineMaterial = LoadObject<UMaterial>(nullptr, FLIGHT_PATH_MATERIAL3); break;// default:SplineMaterial = LoadObject<UMaterial>(nullptr, FLIGHT_PATH_MATERIAL1); break;// }if (SplineMaterial)LinePathActor->SplineMeshMaterial = SplineMaterial;//// //描绘航迹线if (!M_ParamCollection){UMaterialParameterCollection* MPC = LoadObject<UMaterialParameterCollection>(nullptr, TEXT("/Script/Engine.MaterialParameterCollection'/Game/ZOthers/Other/Materials/1'"));M_ParamCollection = GetWorld()->GetParameterCollectionInstance(MPC);}if (!M_ParamCollection) return;double dis = FVector::Dist(First,Second);dis *= 0.01;if (id == int(DTypeIdPlatform::A)){M_ParamCollection->SetScalarParameterValue(FName("ATOB"), dis);}LinePathActor->CreateSplineMesh();
}二.材质参数集合在C++使用
材质参数需要的头文件
#include "Materials/MaterialParameterCollection.h"
#include "Materials/MaterialParameterCollectionInstance.h"材质参数集合，它的改动，在上面的代码里。它在材质里的如下图，只设置了V的平铺，没设置U的平铺。
UMaterialParameterCollectionInstance* M_ParamCollection;