Game_CodeMM/Assets/00_scripts/MapScripts/MapBuildPlacer.cs

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class MapBuildPlacer : MonoBehaviour
{
    [HideInInspector] public HomeMapSO SO_HomeMap; // 地图SO数据
    [HideInInspector] public GameObject startPositionObject; // 坐标起始点
    [HideInInspector] public int cellSize = 2; // 单元格大小
    [HideInInspector] public Camera mainCamera;
    [Tooltip("可建造格子的图层")] public LayerMask buildableCellLayer;

    private Color spriteRenderColor;
    private SpriteRenderer spriteRenderChildren;
    private MapBuildableCell adsorb_component;
    private bool is_trigger_with_has_build = false;
    private SpriteRenderer stopUI_sprite_render;
    private bool isSnaping = false;

    private void Start()
    {
        spriteRenderChildren = transform.GetChild(0).GetComponent<SpriteRenderer>();
        spriteRenderColor = spriteRenderChildren.color;
        stopUI_sprite_render = spriteRenderChildren.transform.Find("StopUI").GetComponent<SpriteRenderer>();
    }

    private void Update()
    {
        // m_move_with_mouse_with_overlay();
        m_move_with_mouse_with_ray();
    }


    // 跟随鼠标移动使用射线检测
    private void m_move_with_mouse_with_ray()
    {
        // 获取鼠标的世界坐标
        Vector3 mouse_world_position = mainCamera.ScreenToWorldPoint(Input.mousePosition);
        mouse_world_position.z = 0;

        // 射线检测
        RaycastHit2D hit = Physics2D.Raycast(
            origin: mouse_world_position,
            direction: Vector2.zero,
            distance: 0.1f,
            layerMask: buildableCellLayer);
        // 命中格子
        if (hit.collider)
        {
            // 吸附到格子坐标
            adsorb_component = hit.collider.GetComponent<MapBuildableCell>();
            Vector3 adsorb_position = startPositionObject.transform.position +
                                      adsorb_component.get_grid_position_with_vector3() * cellSize;
            transform.position = adsorb_position;
            isSnaping = true;
            // 判断是否与以建造的建筑物触发器接触
            if (is_trigger_with_has_build == false)
            {
                // 更改颜色并取消激活边框
                spriteRenderChildren.color = spriteRenderColor;
                stopUI_sprite_render.enabled = false;
            }
        }
        else
        {
            // 鼠标不在格子上时触发, 还原默认状态
            if (adsorb_component)
            {
                stopUI_sprite_render.enabled = true;
                adsorb_component = null;
            }
            isSnaping = false;
            // 没有命中格子, 自由移动
            transform.position = mouse_world_position;
            // 更改颜色并激活边框
            spriteRenderChildren.color = new Color32(166, 73, 73, 215);
        }
    }


    public bool get_placer_is_snap() => isSnaping;

    // trigger 
    private void m_on_trigger_event(Collider2D other, bool status)
    {
        // 检测是否与某个图层的碰撞器相交
        if (other.gameObject.layer == LayerMask.NameToLayer("AlreadyBuild"))
        {
            is_trigger_with_has_build = status;
        }
    }

    private void OnTriggerStay2D(Collider2D other)
    {
        m_on_trigger_event(other, true);
    }

    private void OnTriggerEnter2D(Collider2D other)
    {
        m_on_trigger_event(other, true);
    }

    private void OnTriggerExit2D(Collider2D other)
    {
        m_on_trigger_event(other, false);
    }

    // 跟随鼠标移动使用overlay方法
    private void m_move_with_mouse_with_overlay()
    {
        // 跟随鼠标移动
        Vector3 mouse_world_position = mainCamera.ScreenToWorldPoint(Input.mousePosition);
        mouse_world_position.z = 0;


        // 碰撞器射线检测
        Collider2D hit = Physics2D.OverlapPoint(mouse_world_position,
            LayerMask.GetMask("BuildableCell"));
        if (hit)
        {
            MapBuildableCell adsorb_component = hit.GetComponent<MapBuildableCell>();
            if (adsorb_component)
            {
                // 鼠标在格子上时触发, 吸附到格子的坐标上
                transform.position = startPositionObject.transform.position +
                                     adsorb_component.get_grid_position_with_vector3() * cellSize;
            }
        }
        else
        {
            // 没有检测到格子, 自由移动
            transform.position = mouse_world_position;
        }
    }
}