获取鼠标在世界中的位置

-获取鼠标位置有很多方法，这里说三种，但只是提供方法，具体并不是很清楚

一、GetHitResultUnderCursorByChannel

FHitResult TraceHitResult;//检测结果
GetHitResultUnderCursorByChannel(TraceTypeQuery1, true, TraceHitResult);    
FVector pos = TraceHitResult.Location;//位置

看一下源码

bool APlayerController::GetHitResultUnderCursorByChannel(ETraceTypeQuery TraceChannel, bool bTraceComplex, FHitResult& HitResult) const
{ULocalPlayer* LocalPlayer = Cast<ULocalPlayer>(Player);bool bHit = false;if (LocalPlayer && LocalPlayer->ViewportClient){FVector2D MousePosition;if (LocalPlayer->ViewportClient->GetMousePosition(MousePosition)){bHit = GetHitResultAtScreenPosition(MousePosition, TraceChannel, bTraceComplex, HitResult);}}if(!bHit)   //If there was no hit we reset the results. This is redundant but helps Blueprint users{HitResult = FHitResult();}return bHit;
}

我推测是根据追踪类型进行定位，不是很清楚

二、GetHitResultUnderCursor

FHitResult bTraceHitResult;
GetHitResultUnderCursor(ECC_Visibility, true, bTraceHitResult);
FVector pos = bTraceHitResult.Location;//位置

看一下源码

bool APlayerController::GetHitResultUnderCursor(ECollisionChannel TraceChannel, bool bTraceComplex, FHitResult& HitResult) const
{ULocalPlayer* LocalPlayer = Cast<ULocalPlayer>(Player);bool bHit = false;if (LocalPlayer && LocalPlayer->ViewportClient){FVector2D MousePosition;if (LocalPlayer->ViewportClient->GetMousePosition(MousePosition)){bHit = GetHitResultAtScreenPosition(MousePosition, TraceChannel, bTraceComplex, HitResult);}}if(!bHit)   //If there was no hit we reset the results. This is redundant but helps Blueprint users{HitResult = FHitResult();}return bHit;
}

和第一种很像，只有一个参数是变化的，推测是根据碰撞类型进行定位，因为在碰撞设置的时候也会设置对于Trace的反应。

三、LineTraceSingleByChannel，之前说过LineTraceSingleForObjects，这里是ByChannel

        FHitResult HitResult,Start, Dir, End, ;DeprojectMousePositionToWorld(Start, Dir);//获取初始位置和方向End = Start + (Dir*8000.0f);//设置追踪终点GetWorld()->LineTraceSingleByChannel(HitResult, Start, End, ECC_Visibility);FVector pos = HitResult.Location;//位置

只看一下DeprojectMousePositionToWorld的源码吧

bool APlayerController::DeprojectMousePositionToWorld(FVector& WorldLocation, FVector& WorldDirection) const
{ULocalPlayer* const LocalPlayer = GetLocalPlayer();if (LocalPlayer && LocalPlayer->ViewportClient){FVector2D ScreenPosition;if (LocalPlayer->ViewportClient->GetMousePosition(ScreenPosition)){return UGameplayStatics::DeprojectScreenToWorld(this, ScreenPosition, WorldLocation, WorldDirection);}}return false;
}//被调用的方法
bool UGameplayStatics::DeprojectScreenToWorld(APlayerController const* Player, const FVector2D& ScreenPosition, FVector& WorldPosition, FVector& WorldDirection)
{ULocalPlayer* const LP = Player ? Player->GetLocalPlayer() : nullptr;if (LP && LP->ViewportClient){// get the projection dataFSceneViewProjectionData ProjectionData;if (LP->GetProjectionData(LP->ViewportClient->Viewport, eSSP_FULL, /*out*/ ProjectionData)){FMatrix const InvViewProjMatrix = ProjectionData.ComputeViewProjectionMatrix().InverseFast();FSceneView::DeprojectScreenToWorld(ScreenPosition, ProjectionData.GetConstrainedViewRect(), InvViewProjMatrix, /*out*/ WorldPosition, /*out*/ WorldDirection);return true;}}// something went wrong, zero things and return falseWorldPosition = FVector::ZeroVector;WorldDirection = FVector::ZeroVector;return false;
}