[游戏开发]UE4判断是否在扇形中的官方代码（C++）

有时候我们需要判断某个物体是否在另一个物体的扇形范围内，可以参考一下UE4源码中的代码。
源码在**“AIHelpers.h”**
命名空间是 FAISystem

	//----------------------------------------------------------------------//
	// CheckIsTargetInSightCone
	//                     F
	//                   *****  
	//              *             *
	//          *                     *
	//       *                           *
	//     *                               *
	//   *                                   * 
	//    \                                 /
	//     \                               /
	//      \                             /
	//       \             X             /
	//        \                         /
	//         \          ***          /
	//          \     *    N    *     /
	//           \ *               * /
	//            N                 N
	//            
	//           
	//           
	//           
	//
	// 
	//                     B 
	//
	// X = StartLocation
	// B = Backward offset
	// N = Near Clipping Radius (from the StartLocation adjusted by Backward offset)
	// F = Far Clipping Radius (from the StartLocation adjusted by Backward offset)
	//----------------------------------------------------------------------//
	bool CheckIsTargetInSightCone(const FVector& StartLocation, const FVector& ConeDirectionNormal, float PeripheralVisionAngleCos,
		float ConeDirectionBackwardOffset, float NearClippingRadiusSq, float const FarClippingRadiusSq, const FVector& TargetLocation)
	{
		const FVector BaseLocation = FMath::IsNearlyZero(ConeDirectionBackwardOffset) ? StartLocation : StartLocation - ConeDirectionNormal * ConeDirectionBackwardOffset;
		const FVector ActorToTarget = TargetLocation - BaseLocation;
		const float DistToTargetSq = ActorToTarget.SizeSquared();
		if (DistToTargetSq <= FarClippingRadiusSq && DistToTargetSq >= NearClippingRadiusSq)
		{
			const FVector DirectionToTarget = ActorToTarget.GetUnsafeNormal();
			return FVector::DotProduct(DirectionToTarget, ConeDirectionNormal) > PeripheralVisionAngleCos;
		}

		return false;
	}