UE C++ 相机视口变换（World与相机互转）

UFUNCTION(BlueprintCallable, BlueprintPure)
static void ProjectSceneCaptureToWorld(const class USceneCaptureComponent2D* SceneCaptureComponent2D,const FVector2D& SceneCapturePosition, FVector& WorldPosition,FVector& WorldDirection)
{if (!IsValid(SceneCaptureComponent2D)){return;}// 视口矩阵const FTransform& ViewTransform = SceneCaptureComponent2D->GetComponentToWorld();FMatrix ViewMatrix = ViewTransform.ToInverseMatrixWithScale();ViewMatrix = ViewMatrix * FMatrix(FPlane(0, 0, 1, 0), FPlane(1, 0, 0, 0), FPlane(0, 1, 0, 0),FPlane(0, 0, 0, 1));const float FOV = SceneCaptureComponent2D->FOVAngle * (float)PI / 360.0f;const FIntPoint CaptureSize(SceneCaptureComponent2D->TextureTarget->GetSurfaceWidth(),SceneCaptureComponent2D->TextureTarget->GetSurfaceHeight());float XAxisMultiplier;float YAxisMultiplier;if (CaptureSize.X > CaptureSize.Y){XAxisMultiplier = 1.0f;YAxisMultiplier = CaptureSize.X / static_cast<float>(CaptureSize.Y);}else{XAxisMultiplier = CaptureSize.Y / static_cast<float>(CaptureSize.X);YAxisMultiplier = 1.0f;}// 投影矩阵const FMatrix ProjectionMatrix = FReversedZPerspectiveMatrix(FOV, FOV, XAxisMultiplier, YAxisMultiplier,GNearClippingPlane, GNearClippingPlane);//视口矩阵与投影矩阵的逆矩阵                                                           const FMatrix InverseViewMatrix = ViewMatrix.InverseFast();const FMatrix InverseProjectionMatrix = ProjectionMatrix.Inverse();const FIntRect ViewRect = FIntRect(0, 0, CaptureSize.X, CaptureSize.Y);FSceneView::DeprojectScreenToWorld(SceneCapturePosition, ViewRect, InverseViewMatrix, InverseProjectionMatrix,WorldPosition, WorldDirection);
}

	UFUNCTION(BlueprintCallable, BlueprintPure)static bool ProjectWorldToSceneCapture(const FVector& WorldPosition,const class USceneCaptureComponent2D* SceneCaptureComponent2D,FVector2D& SceneCapturePosition){if (!IsValid(SceneCaptureComponent2D)){return false;}//视口矩阵const FTransform& ViewTransform = SceneCaptureComponent2D->GetComponentToWorld();FMatrix ViewMatrix = ViewTransform.ToInverseMatrixWithScale();ViewMatrix = ViewMatrix * FMatrix(FPlane(0, 0, 1, 0), FPlane(1, 0, 0, 0), FPlane(0, 1, 0, 0),FPlane(0, 0, 0, 1));const float FOV = SceneCaptureComponent2D->FOVAngle * (float)PI / 360.0f;const FIntPoint CaptureSize(SceneCaptureComponent2D->TextureTarget->GetSurfaceWidth(),SceneCaptureComponent2D->TextureTarget->GetSurfaceHeight());float XAxisMultiplier;float YAxisMultiplier;if (CaptureSize.X > CaptureSize.Y){XAxisMultiplier = 1.0f;YAxisMultiplier = CaptureSize.X / static_cast<float>(CaptureSize.Y);}else{XAxisMultiplier = CaptureSize.Y / static_cast<float>(CaptureSize.X);YAxisMultiplier = 1.0f;}// 投影矩阵const FMatrix ProjectionMatrix = FReversedZPerspectiveMatrix(FOV, FOV, XAxisMultiplier, YAxisMultiplier,GNearClippingPlane, GNearClippingPlane);const FMatrix ViewProjectionMatrix = ViewMatrix * ProjectionMatrix;const FPlane Result = ViewProjectionMatrix.TransformFVector4(FVector4(WorldPosition, 1.f));const FIntRect viewRect = FIntRect(0, 0, CaptureSize.X, CaptureSize.Y);if (Result.W > 0.0f){// the result of this will be x and y coords in -1..1 projection spaceconst float RHW = 1.0f / Result.W;const FPlane PosInScreenSpace = FPlane(Result.X * RHW, Result.Y * RHW, Result.Z * RHW, Result.W);// Move from projection space to normalized 0..1 UI spaceconst float NormalizedX = (PosInScreenSpace.X / 2.f) + 0.5f;const float NormalizedY = 1.f - (PosInScreenSpace.Y / 2.f) - 0.5f;const FVector2D RayStartViewRectSpace((NormalizedX * static_cast<float>(viewRect.Width())),(NormalizedY * static_cast<float>(viewRect.Height())));SceneCapturePosition = RayStartViewRectSpace + FVector2D(static_cast<float>(viewRect.Min.X),static_cast<float>(viewRect.Min.Y));return true;}return false;}