【Unity3D】《跳舞的线》游戏的方块单方向拉伸实现案例

通过网盘分享的文件：CubeMoveMusic.unitypackage
链接: https://pan.baidu.com/s/1Rq-HH4H9qzVNtpQ84WXyUA?pwd=a7xn 提取码: a7xn 

运行游戏点击空格动态创建拉伸的方块，由Speed控制速度，新方向是随机上下左右生成。 

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

public class CubeMoveGameCamera : MonoBehaviour
{
    private Vector3 constDir;

    public GeneMap geneMap;

    void Start()
    {
        constDir = transform.position - geneMap.defaultPos;
    }

    // Update is called once per frame
    void Update()
    {
        transform.position = constDir + geneMap.GetPos();
    }
}

生成移动方块以及单方向拉伸方块脚本：

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

public class GeneMap : MonoBehaviour
{
    public enum Side
    {
        Top, Bottom, Left, Right
    }

    public GameObject cubePrefab;

    private GameObject movingCubeGo;
    private Transform movingCubeTrans;
    private Side moveSide;

    public Vector3 defaultPos;

    public float speed = 1f;

    private Matrix4x4 rotationMatrix4x4;

    private void Start()
    {
        rotationMatrix4x4 = Matrix4x4.TRS(Vector3.zero, cubePrefab.transform.localRotation, Vector3.one);
    }

    Side MirrorSide(Side side)
    {
        if (side == Side.Top)
        {
            return Side.Bottom;
        }
        if (side == Side.Bottom)
        {
            return Side.Top;
        }
        if (side == Side.Left)
        {
            return Side.Right;
        }
        if (side == Side.Right)
        {
            return Side.Left;
        }
        Debug.LogError("?");
        return Side.Top;
    }

    public bool IsMoving()
    {
        return movingCubeGo != null;
    }

    public Vector3 GetPos()
    {
        Vector3 pos = defaultPos;
        if (IsMoving())
        {
            //利用上一个移动物体的方向，通过不同方向的移动物体局部大小得到偏移量，而0.5f是下一个新物体一半的偏移
            Vector3 oldOffset = Vector3.zero;
            switch (moveSide)
            {
                case Side.Top:
                    oldOffset = new Vector3(0, 0, movingCubeTrans.localScale.z - 0.5f);
                    break;
                case Side.Bottom:
                    oldOffset = new Vector3(0, 0, -movingCubeTrans.localScale.z + 0.5f);
                    break;
                case Side.Left:
                    oldOffset = new Vector3(-movingCubeTrans.localScale.x + 0.5f, 0, 0);
                    break;
                case Side.Right:
                    //例如上一个物体是右方向，则使用局部大小x作为偏移量数值，并且需要-0.5f来让新物体的整体恰好在前一个延伸物体的内部。
                    oldOffset = new Vector3(movingCubeTrans.localScale.x - 0.5f, 0, 0);
                    break;
                default:
                    break;
            }
            pos = movingCubeTrans.position + rotationMatrix4x4.MultiplyPoint(oldOffset);
        }
        return pos;
    }

    private void Update()
    {
        if (movingCubeGo != null)
        {
            if (moveSide == Side.Top || moveSide == Side.Bottom)
            {
                movingCubeTrans.localScale = new Vector3(1, 1, movingCubeTrans.localScale.z + speed * Time.deltaTime);
            }
            else
            {
                movingCubeTrans.localScale = new Vector3(movingCubeTrans.localScale.x + speed * Time.deltaTime, 1, 1);
            }
        }
        if (Input.GetKeyDown(KeyCode.Space))
        {
            Vector3 pos = GetPos();
            movingCubeGo = GameObject.Instantiate(cubePrefab);
            movingCubeTrans = movingCubeGo.transform;

            List<int> sideList = new List<int>();
            for (int i = 0; i < 4; i++)
            {
                if (i != (int)moveSide && i != (int)MirrorSide(moveSide))
                {
                    sideList.Add(i);
                }
            }
            int randomIndex = Random.Range(0, sideList.Count);
            moveSide = (Side)sideList[randomIndex];

            //1、新物体在进行朝着新方向移动时，需要对子物体Cube调整局部位置（目的：锚点轴心偏移，实现单方向延伸）
            //2、newOffset用于将新移动物体偏移到新移动方向的上一个物体边缘位置点
            Vector3 newOffset = Vector3.zero;
            Vector3 newLocalScale = Vector3.one;
            Transform childTrans = movingCubeTrans.Find("Cube");
            childTrans.GetComponent<MeshRenderer>().material.SetColor("_Color", new Color(Random.Range(0, 256) / 255f, Random.Range(0, 256) / 255f, Random.Range(0, 256) / 255f, 1));
            switch (moveSide)
            {
                case Side.Top:
                    childTrans.localPosition = new Vector3(0, 0, 0.5f);
                    newOffset = new Vector3(0, 0, 0.5f);
                    newLocalScale = new Vector3(1, 1, 0);
                    break;
                case Side.Bottom:
                    childTrans.localPosition = new Vector3(0, 0, -0.5f);
                    newOffset = new Vector3(0, 0, -0.5f);
                    newLocalScale = new Vector3(1, 1, 0);
                    break;
                case Side.Left:
                    childTrans.localPosition = new Vector3(-0.5f, 0, 0);
                    newOffset = new Vector3(-0.5f, 0, 0);
                    newLocalScale = new Vector3(0, 1, 1);
                    break;
                case Side.Right:
                    //例如右方向的Cube子物体需要偏移(0.5f,0,0)保证锚点是在物体左侧
                    childTrans.localPosition = new Vector3(0.5f, 0, 0);
                    //右方向的新物体起点要在上一个物体的右侧边缘点作为起点，故x轴+0.5f
                    newOffset = new Vector3(0.5f, 0, 0);
                    //右方向的新物体大小X轴要从0开始
                    newLocalScale = new Vector3(0, 1, 1);
                    break;
                default:
                    break;
            }
            movingCubeTrans.position = pos + rotationMatrix4x4.MultiplyPoint(newOffset);
            movingCubeTrans.localScale = newLocalScale;
        }
    }
}