【unity实战】使用unity制作一个类似Rust的3D生存建造建筑系统，具有很好的吸附性（附项目源码）

public class Connector : MonoBehaviour
{
    [Header("连接器位置")]
    public ConnectorPosition connectorPosition;
    [Header("连接器所属建筑类型")]
    public SelectedBuildType connectorParentType;
    [Header("是否可以连接地面")]
    private bool canConnectToFloor = true;
    [Header("是否可以连接墙壁")]
    private bool canConnectToWall = true;
    [HideInInspector] public bool isConnectedToFloor = false; // 是否连接到地面
    [HideInInspector] public bool isConnectedToWall = false; // 是否连接到墙壁
    [HideInInspector] public bool canConnectTo = true; // 是否可以连接其他建筑


    //在场景中绘制连接器的可视化表示
    private void OnDrawGizmos()
    {
        // 根据 canConnectTo 变量设置颜色
        Gizmos.color = isConnectedToFloor ? (isConnectedToFloor ? Color.red : Color.blue) : (!isConnectedToWall ? Color.green : Color.yellow);
        // 在连接器位置绘制一个圆形表示连接状态
        Gizmos.DrawWireSphere(transform.position, transform.lossyScale.x / 2f);
    }

    // 更新连接器和附近的其他连接器的连接状态
    public void updateConnectors(bool rootCall = false)
    {
        Collider[] colliders = Physics.OverlapSphere(transform.position, transform.lossyScale.x / 2f); // 获取连接范围内的所有碰撞体
        isConnectedToFloor = !canConnectToFloor;
        isConnectedToWall = !canConnectToWall;

        foreach (Collider collider in colliders)
        {
            // 忽略自身的碰撞体
            if (collider.GetInstanceID() == GetComponent<Collider>().GetInstanceID())
            {
                continue;
            }

            //忽略处于非激活状态的碰撞体
            if (!collider.gameObject.activeInHierarchy)
            {
                continue;
            }
            if (collider.gameObject.layer == gameObject.layer)
            {
                
                // 获取相邻连接器的信息
                Connector foundConnector = collider.GetComponent<Connector>();
                if(!foundConnector) continue; 
                // 如果相邻连接器是地面连接器，则更新 isConnectedToFloor 为 true
                if (foundConnector.connectorParentType == SelectedBuildType.floor)
                    isConnectedToFloor = true;

                // 如果相邻连接器是墙壁连接器，则更新 isConnectedToWall 为 true
                if (foundConnector.connectorParentType == SelectedBuildType.wall)
                    isConnectedToWall = true;

                // 如果是根调用，则继续递归更新相邻连接器的状态
                if (rootCall)
                    foundConnector.updateConnectors();
            }
        }

        // 根据连接状态更新 canConnectTo 的值
        canConnectTo = true;

        if (isConnectedToFloor && isConnectedToWall)
        {
            canConnectTo = false;
        }
    }
}

// 连接器位置枚举
[System.Serializable]
public enum ConnectorPosition
{
    left, // 左侧
    right, // 右侧
    top, // 顶部
    bottom // 底部
}

public class BuildingManager : MonoBehaviour
{
    [Header("建筑物对象列表")]
    [SerializeField] private List<GameObject> floorObjects = new List<GameObject>();  // 地板建筑物的列表
    [SerializeField] private List<GameObject> wallObjects = new List<GameObject>();   // 墙壁建筑物的列表

    [Header("建筑设置")]
    [SerializeField] private SelectedBuildType currentBuildType;   // 当前选中的建筑类型
    [SerializeField] private LayerMask connectorLayer;   // 连接器所在的层

    [Header("鬼影设置")]
    [SerializeField] private Material ghostMaterialValid;   // 鬼影建筑物有效时的材质
    [SerializeField] private Material ghostMaterialInvalid;   // 鬼影建筑物无效时的材质
    [SerializeField] private float connectorOverlapRadius = 1f;   // 寻找附近连接器的检测半径
    [SerializeField] private float maxGroundAngle = 45f;   // 地面的最大可放置倾斜角度
    [SerializeField] private float placementDistance = 20f;   // 放置距离

    [Header("内部状态")]
    [SerializeField] private bool isBuilding = false;   // 是否正在建造中
    [SerializeField] private int currentBuildingIndex;   // 当前建造物的索引
    private GameObject ghostBuildGameobject;   // 鬼影建筑物对象
    private bool isGhostInValidPosition = false;   // 鬼影建筑物是否在有效位置
    private Transform ModelParent = null;   // 模型父对象的Transform

    [Header("拆除设置")]
    [SerializeField] private bool isDestroying = false;   // 是否在拆除建筑物
    private Transform lastHitDestroyTransform;   // 上次点击的拆除目标的Transform
    private List<Material> lastHitMaterials = new List<Material>();   // 上次点击的拆除目标的材质列表

    private void Update()
    {
        // 遍历数字1到7
        for (int i = 1; i <= 8; i++)
        {
            // 检查是否按下对应的数字键
            if (Input.GetKeyDown(KeyCode.Alpha0 + i))
            {
                select(i);
            }
        }

        if (Input.GetKeyDown(KeyCode.X))   // 按下X键切换拆除模式
            isDestroying = !isDestroying;

        if (isBuilding && !isDestroying)   // 如果正在建造且不在拆除状态
        {
            ghostBuild();   // 显示鬼影建筑物
            if (Input.GetMouseButtonDown(0)) placeBuild();   // 点击鼠标左键放置建筑物
        }
        else if (ghostBuildGameobject)   // 如果没有在建造且鬼影建筑物存在，则销毁鬼影建筑物对象
        {
            Destroy(ghostBuildGameobject);
            ghostBuildGameobject = null;
        }

        if (isDestroying)   // 如果在拆除状态
        {
            ghostDestroy();   // 显示拆除的鬼影效果
            if (Input.GetMouseButtonDown(0)) destroyBuild();   // 点击鼠标左键拆除建筑物
        }
    }

    //选择建造测试
    void select(int number)
    {
        isBuilding = !isBuilding;
        if (number == 1)
        {
            currentBuildingIndex = 0;
            currentBuildType = SelectedBuildType.floor;
        }
        if (number == 2)
        {
            currentBuildingIndex = 1;
            currentBuildType = SelectedBuildType.floor;
        }
        if (number == 3)
        {
            currentBuildingIndex = 0;
            currentBuildType = SelectedBuildType.wall;
        }
        if (number == 4)
        {
            currentBuildingIndex = 1;
            currentBuildType = SelectedBuildType.wall;
        }
        if (number == 5)
        {
            currentBuildingIndex = 2;
            currentBuildType = SelectedBuildType.wall;
        }
        if (number == 6)
        {
            currentBuildingIndex = 3;
            currentBuildType = SelectedBuildType.wall;
        }
    }

    private void ghostBuild()
    {
        GameObject currentBuild = getCurrentBuild();   // 获取当前建筑物类型
        createGhostPrefab(currentBuild);   // 创建鬼影建筑物
        moveGhostPrefabToRaycast();   // 将鬼影建筑物移动到光线投射点
        checkBuildValidity();   // 检查建筑物的有效性
    }

    //创建鬼影建筑物
    private void createGhostPrefab(GameObject currentBuild)
    {
        if (ghostBuildGameobject == null)   // 如果鬼影建筑物对象不存在，则创建
        {
            ghostBuildGameobject = Instantiate(currentBuild);

            ModelParent = ghostBuildGameobject.transform.GetChild(0);   // 获取模型父对象的Transform
            ghostifyModel(ModelParent, ghostMaterialValid);   // 设置模型为鬼影材质
            ghostifyModel(ghostBuildGameobject.transform);   // 设置建筑物为鬼影材质
        }
    }

    //将鬼影建筑物移动到光线投射点
    private void moveGhostPrefabToRaycast()
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;
        if (Physics.Raycast(ray, out hit, placementDistance))   // 光线投射检测
        {
            ghostBuildGameobject.transform.position = hit.point;   // 将鬼影建筑物移动到光线投射点
        }
    }

    //检查建筑物的有效性
    private void checkBuildValidity()
    {
        Collider[] colliders = Physics.OverlapSphere(ghostBuildGameobject.transform.position, connectorOverlapRadius, connectorLayer);   // 检测鬼影建筑物附近的连接器碰撞体
        if (colliders.Length > 0)   // 如果有连接器碰撞体
        {
            ghostConnectBuild(colliders);   // 连接鬼影建筑物到连接器上
        }
        else   // 如果没有连接器碰撞体
        {
            ghostSeparateBuild();   // 鬼影建筑物与连接器分离
            if (isGhostInValidPosition)   // 如果鬼影建筑物在有效位置
            {
                Collider[] overlapColliders = Physics.OverlapBox(ghostBuildGameobject.transform.position, new Vector3(2f, 2f, 2f), ghostBuildGameobject.transform.rotation);   // 检测鬼影建筑物周围是否与其他物体重叠
                foreach (Collider overlapCollider in overlapColliders)
                {
                    if (overlapCollider.gameObject != ghostBuildGameobject && overlapCollider.transform.root.CompareTag("Buildables"))   // 如果与其他可建造物体重叠，则设置鬼影建筑物为无效状态
                    {
                        ghostifyModel(ModelParent, ghostMaterialInvalid);
                        isGhostInValidPosition = false;
                        return;
                    }
                }
            }
        }
    }

    // 连接鬼影建筑物到连接器上
    private void ghostConnectBuild(Collider[] colliders)
    {
        Connector bestConnector = null;
        foreach (Collider collider in colliders)   // 遍历连接器碰撞体
        {
            Connector connector = collider.GetComponent<Connector>();
            if (connector && connector.canConnectTo)   // 如果连接器存在且可连接
            {
                bestConnector = connector;
                break;
            }
        }

        if (bestConnector == null || currentBuildType == SelectedBuildType.floor && bestConnector.isConnectedToFloor || currentBuildType == SelectedBuildType.wall && bestConnector.isConnectedToWall)   // 如果没有找到合适的连接器或者当前建筑类型与连接器不匹配，则设置鬼影建筑物为无效状态
        {
            // 如果建筑无法连接或连接不合法，则将建筑模型设为不可放置的材质
            ghostifyModel(ModelParent, ghostMaterialInvalid);
            isGhostInValidPosition = false;
            return;
        }

        snapGhostPrefabToConnector(bestConnector);   // 将鬼影建筑物对齐到连接器上
    }

    //将鬼影建筑物对齐到连接器上
    private void snapGhostPrefabToConnector(Connector connector)
    {
        Transform ghostConnector = findSnapConnector(connector.transform, ghostBuildGameobject.transform.GetChild(1));   // 查找鬼影建筑物中对应的连接器
        ghostBuildGameobject.transform.position = connector.transform.position - (ghostConnector.position - ghostBuildGameobject.transform.position);   // 将鬼影建筑物移动到连接器位置

        if (currentBuildType == SelectedBuildType.wall)   // 如果当前建筑类型为墙壁，则调整鬼影建筑物的旋转角度
        {
            Quaternion newRotation = ghostBuildGameobject.transform.rotation;
            newRotation.eulerAngles = new Vector3(newRotation.eulerAngles.x, connector.transform.rotation.eulerAngles.y, newRotation.eulerAngles.z);
            ghostBuildGameobject.transform.rotation = newRotation;
        }

        // 将建筑模型设为可放置的材质
        ghostifyModel(ModelParent, ghostMaterialValid);
        isGhostInValidPosition = true;
    }

    // 鬼影建筑物与连接器分离
    private void ghostSeparateBuild()
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;
        if (Physics.Raycast(ray, out hit))
        {
            if (currentBuildType == SelectedBuildType.wall) // 如果当前建筑类型为墙，则将建筑模型设为不可放置的材质
            {
                ghostifyModel(ModelParent, ghostMaterialInvalid);
                isGhostInValidPosition = false;
                return;
            }

            if (Vector3.Angle(hit.normal, Vector3.up) < maxGroundAngle) // 如果当前建筑类型为地板且法线与y轴夹角小于最大可放置角度，则将建筑模型设为可放置的材质
            {
                ghostifyModel(ModelParent, ghostMaterialValid);
                isGhostInValidPosition = true;
            }
            else // 否则，将模型修改为不可放置的材质
            {
                ghostifyModel(ModelParent, ghostMaterialInvalid);
                isGhostInValidPosition = false;
            }
        }
    }

    // 查找鬼影建筑物中对应的连接器
    private Transform findSnapConnector(Transform snapConnector, Transform ghostConnectorParent)
    {
        // 查找鬼影建筑预制体中与连接器相对应的连接器
        ConnectorPosition oppositeConnectorTag = getOppositePosition(snapConnector.GetComponent<Connector>());
        foreach (Connector connector in ghostConnectorParent.GetComponentsInChildren<Connector>())
        {
            if (connector.connectorPosition == oppositeConnectorTag)
            {
                return connector.transform;
            }
        }
        return null;
    }

    // 查找鬼影建筑预制体中与连接器相对应的连接器
    private ConnectorPosition getOppositePosition(Connector connector)
    {
        // 获取连接器的相反位置
        ConnectorPosition position = connector.connectorPosition;
        // 如果当前建筑类型是墙且连接点的父级类型是地板，则返回底部连接点
        if (currentBuildType == SelectedBuildType.wall && connector.connectorParentType == SelectedBuildType.floor)
            return ConnectorPosition.bottom;

        // 如果当前建筑类型是地板、连接点的父级类型是墙且连接点位置为顶部
        if (currentBuildType == SelectedBuildType.floor && connector.connectorParentType == SelectedBuildType.wall && connector.connectorPosition == ConnectorPosition.top)
        {
            // 如果连接点所在物体的Y轴旋转角度为0（即朝向为正面），则返回离玩家最近的连接点
            if (connector.transform.root.rotation.y == 0)
            {
                return getConnectorClosestToPlayer(true);
            }
            else
            {
                // 否则返回离玩家最近的连接点
                return getConnectorClosestToPlayer(false);
            }
        }


        // 根据连接点位置返回相反的连接点位置
        switch (position)
        {
            case ConnectorPosition.left:
                return ConnectorPosition.right;
            case ConnectorPosition.right:
                return ConnectorPosition.left;
            case ConnectorPosition.bottom:
                return ConnectorPosition.top;
            case ConnectorPosition.top:
                return ConnectorPosition.bottom;
            default:
                return ConnectorPosition.bottom;
        }
    }

    // 获取距离玩家最近的连接点
    private ConnectorPosition getConnectorClosestToPlayer(bool topBottom)
    {
        Transform cameraTransform = Camera.main.transform;
        // 如果topBottom为true，根据玩家位置返回顶部或底部连接点
        if (topBottom)
        {
            return cameraTransform.position.z >= ghostBuildGameobject.transform.position.z ? ConnectorPosition.bottom : ConnectorPosition.top;
        }
        else
        {
            // 否则，根据玩家位置返回左侧或右侧连接点
            return cameraTransform.position.x >= ghostBuildGameobject.transform.position.x ? ConnectorPosition.left : ConnectorPosition.right;
        }
    }

    // 修改模型为鬼影材质
    private void ghostifyModel(Transform modelParent, Material ghostMaterial = null)
    {
        // 如果提供了鬼影材质，将模型的材质设为鬼影材质
        if (ghostMaterial != null)
        {
            foreach (MeshRenderer meshRenderer in modelParent.GetComponentsInChildren<MeshRenderer>())
            {
                meshRenderer.material = ghostMaterial;
            }
        }
        else
        {
            // 否则，禁用模型的碰撞器
            foreach (Collider modelColliders in modelParent.GetComponentsInChildren<Collider>())
            {
                modelColliders.enabled = false;
            }
        }
    }

    // 获取当前建筑对象
    private GameObject getCurrentBuild()
    {
        switch (currentBuildType)
        {
            case SelectedBuildType.floor:
                return floorObjects[currentBuildingIndex];
            case SelectedBuildType.wall:
                return wallObjects[currentBuildingIndex];
        }
        return null;
    }

    // 放置建筑
    private void placeBuild()
    {
        // 如果鬼影模型存在且在有效位置上
        if (ghostBuildGameobject != null & isGhostInValidPosition)
        {
            // 在鼠标指针位置实例化新的建筑物并销毁鬼影模型
            GameObject newBuild = Instantiate(getCurrentBuild(), ghostBuildGameobject.transform.position, ghostBuildGameobject.transform.rotation);
            Destroy(ghostBuildGameobject);
            ghostBuildGameobject = null;
            isBuilding = false;

            // 更新新建筑物的连接点
            foreach (Connector connector in newBuild.GetComponentsInChildren<Connector>())
            {
                connector.updateConnectors(true);
            }
        }
    }

    //显示拆除的鬼影效果
    private void ghostDestroy()
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;

        if (Physics.Raycast(ray, out hit))
        {
            if (hit.transform.root.CompareTag("Buildables")) // 判断是否是可建造的对象
            {
                if (!lastHitDestroyTransform) // 如果上一次点击的建筑物为空，则记录当前点击的建筑物
                {
                    lastHitDestroyTransform = hit.transform.root;
                    lastHitMaterials.Clear();

                    // 获取建筑物的所有 MeshRenderer 组件的材质，并添加到材质列表
                    foreach (MeshRenderer meshRenderer in lastHitDestroyTransform.GetComponentsInChildren<MeshRenderer>())
                    {
                        lastHitMaterials.Add(meshRenderer.material);
                    }

                    // 将建筑物设置为鬼影材质
                    ghostifyModel(lastHitDestroyTransform.GetChild(0), ghostMaterialInvalid);
                }
                else if (hit.transform.root != lastHitDestroyTransform) // 如果当前点击的建筑物与上次不同，则重置上一次点击的建筑物
                {
                    resetLastHitDestroyTransform();
                }
            }
            else // 如果点击的不是可建造的对象，则重置上一次点击的建筑物
            {
                resetLastHitDestroyTransform();
            }
        }
    }

    //重置上一个选中的建筑的材质
    private void resetLastHitDestroyTransform()
    {
        int counter = 0;
        foreach (MeshRenderer meshRenderer in lastHitDestroyTransform.GetComponentsInChildren<MeshRenderer>())
        {
            meshRenderer.material = lastHitMaterials[counter];
            counter++;
        }

        lastHitDestroyTransform = null;
    }

    //拆除建筑物
    private void destroyBuild()
    {
        if (lastHitDestroyTransform)
        {
            // 禁用建筑物的所有连接点
            foreach (Connector connector in lastHitDestroyTransform.GetComponentsInChildren<Connector>())
            {
                connector.gameObject.SetActive(false);
                connector.updateConnectors(true);
            }

            Destroy(lastHitDestroyTransform.gameObject); // 销毁建筑物
            isDestroying = false;
            lastHitDestroyTransform = null;
        }
    }
}

// 建筑类型枚举
[System.Serializable]
public enum SelectedBuildType
{
    floor,//地面
    wall//墙
}