ue4 检测扇形和圆检测碰撞

bool IsSectorIntersectCircle(const UObject* WorldContextObject,const FVector& FanOrigin, const FVector& FanForward, float R,
                                                    float HalfAngleRad, const FVector& CirclePos, float r)
{

	FTransform StartTransform = FTransform(FanForward.Rotation());
	StartTransform.SetLocation(FanOrigin);
　　//绘制扇形
	DrawSector(WorldContextObject,StartTransform,R,FMath::RadiansToDegrees(HalfAngleRad*2));

　　//绘制大圆
	UKismetSystemLibrary::DrawDebugSphere(WorldContextObject,CirclePos, r, 32, FLinearColor::Yellow, 15);
	const FVector Oc = CirclePos - FanOrigin;
	const float d = Oc.Size();

	// 1) 快速排斥：两圆不相交
	if (d > R + r || d + R < r) return false;

	// 2) 圆心在扇形角内？
	const float CosTheta = FVector::DotProduct(FanForward, Oc) / d;
	if (CosTheta >= FMath::Cos(HalfAngleRad))
	{
		return true;	
	}

	//计算2条边和圆是否有交集
	// 左右方向
	FVector LeftDir  = FanForward.RotateAngleAxis( FMath::RadiansToDegrees( HalfAngleRad), FVector::UpVector);
	FVector RightDir = FanForward.RotateAngleAxis(-FMath::RadiansToDegrees( HalfAngleRad), FVector::UpVector);
	FVector LeftPoint = FanOrigin + LeftDir*R;
	FVector RightPoint = FanOrigin + RightDir*R;

	UKismetSystemLibrary::DrawDebugPoint(WorldContextObject, LeftPoint, 25.0f, FLinearColor::Yellow, 5);
	UKismetSystemLibrary::DrawDebugPoint(WorldContextObject, RightPoint, 25.0f, FLinearColor::Yellow, 5);


	FVector CLoseLeftPoint =  FMath::ClosestPointOnSegment(CirclePos,FanOrigin,LeftPoint);
	FVector CLoseRightPoint =  FMath::ClosestPointOnSegment(CirclePos,FanOrigin,RightPoint);

	UKismetSystemLibrary::DrawDebugPoint(WorldContextObject, CLoseLeftPoint, 25.0f, FLinearColor::Yellow, 5);
	UKismetSystemLibrary::DrawDebugPoint(WorldContextObject, CLoseRightPoint, 25.0f, FLinearColor::Yellow, 5);

	
	UKismetSystemLibrary::DrawDebugLine(WorldContextObject, CirclePos, CLoseLeftPoint, FLinearColor::Green, 5, 2);
	UKismetSystemLibrary::DrawDebugLine(WorldContextObject, CirclePos, CLoseRightPoint, FLinearColor::Green, 5, 2);
	
	float fCLoseLeftDis = FMath::PointDistToSegment(CirclePos,FanOrigin,LeftPoint);
	float fCLoseRightDis = FMath::PointDistToSegment(CirclePos,FanOrigin,RightPoint);

	if (fCLoseLeftDis<= r || fCLoseRightDis <= r)
	{
		return true;
	}
	else
	{
		return false;
	}
}

bool DrawSector(const UObject* WorldContextObject, const FTransform& StartTransform,float fRadius, float fAngle, float Segments)
{

	TArray<FVector> FanPoints;
	float fAngleStep = fAngle / (Segments-1);
	FRotator ActorStartRotation = StartTransform.GetRotation().Rotator();
	FVector ActorStartLocation = StartTransform.GetLocation();
	
	FanPoints.Add(ActorStartLocation);
	for (int32 i = 0; i < Segments; i++)
	{
		FRotator ActorRotation = ActorStartRotation;
		ActorRotation.Yaw +=  (i-Segments*0.5)*fAngleStep;
		FVector TempVector = ActorStartLocation + ActorRotation.Vector()*fRadius;
		FanPoints.Add(TempVector);
	}
	FanPoints.Add(ActorStartLocation);
	if (FanPoints.Num()<=3)
	{
		return false;
	}
	//绘制形状
	for (int32 i = 0; i < FanPoints.Num()-1; i++)
	{
		FVector Start = FanPoints[i];
		FVector End = FanPoints[i + 1];
		UKismetSystemLibrary::DrawDebugLine(WorldContextObject, Start, End, FLinearColor::Red, 1, 2);
	}
	return true;
}