NavMesh名字、层索引、层值之间的转换

    // Nav层名字-->层的值，1、2、4、8、16

    public static int AgentLayerNameToValue(string name)

    {

        int idx = NavMesh.GetNavMeshLayerFromName(name);

        return 0x1 << idx;

    }

    // Nav层名字-->层索引，0、1、2、3、4

    public static int AgentLayerNameToIndex(string name)

    {

        return NavMesh.GetNavMeshLayerFromName(name);

    }

    // 获取角色当前所在的层值，1、2、4、8、16

    public static int GetAgentLayer(NavMeshAgent agent)

    {

        NavMeshHit hit;

        // 不要使用agent.raduis为采样范围，因为当该值为0时，函数将返回0

        bool reach = NavMesh.SamplePosition(agent.transform.position, out hit, 1f, -);

        return hit.mask;

    }

    public static Vector3 SampleNavMeshPosition(Vector3 logicPosition, out bool reachable)

    {

        NavMeshHit hit;

        reachable = NavMesh.SamplePosition(logicPosition, out hit, 1f, -);

        return reachable ? hit.position : logicPosition;

    }

    // 开启导航层

    public static void EnableNavMeshLayer(NavMeshAgent agent, string layerName)

    {

        if (agent == null)

            return;

        int layerValue = NavMesh.GetNavMeshLayerFromName(layerName);

        if (layerValue == -)

            return;

        int mask = agent.walkableMask | 0x1 << layerValue;

        WalkArbiter.SetWalkableMask(agent, mask);

    }

    // 关闭导航层

    public static void DisableNavMeshLayer(NavMeshAgent agent, string layerName)

    {

        if (agent == null)

            return;

        int layerValue = NavMesh.GetNavMeshLayerFromName(layerName);

        if (layerValue == -)

            return;

        int mask = agent.walkableMask & ~(0x1 << layerValue);

        WalkArbiter.SetWalkableMask(agent, mask);

    }

    // 检查某个层是否为开启

    public static bool IsNavMeshLayerOpen(NavMeshAgent agent, string layerName)

    {

        int layerValue = NavMesh.GetNavMeshLayerFromName(layerName);

        if (layerValue == -)

            return true;

        int ret = agent.walkableMask & (0x1 << layerValue);

        return ret >  ? true : false;

    }