抽奖

需求：

　　奖品循环滚动（慢 > 快 > 慢 > 停）停到指定奖励的位置

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

public enum DrawType
{
    Idle,
    Start,
    Center,
    End,
}

public class LotteryDraw : MonoBehaviour
{
    public Transform parent;

    public float position_start;
    public float position_center;
    private float position_end;

    public float speed_start;
    public float speed_add;
    public float speed_min;
    public float speed_max;

    private DrawType _drawState;
    public DrawType drawState
    {
        get
        {
            return _drawState;
        }
        set
        {
            _drawState = value;
            switch (_drawState)
            {
                case DrawType.Idle:
                    move = false;
                    break;
                case DrawType.Start:
                    speed_move = speed_start;
                    speed_add = Mathf.Abs(speed_add);
                    move = true;
                    break;
                case DrawType.Center:
                    dis_cur = 0;
                    GetPrePosition();
                    break;
                case DrawType.End:
                    speed_add = -speed_add;
                    break;
                default:
                    break;
            }
        }
    }

    private float speed_move;
    private float dis_max;
    private float dis_cur;
    private bool move;

    private List<Transform> items;
    private int itemCount = 15;

    //测试要滚动到指定的格子位置
    public int index;

    private void Awake()
    {
        items = new List<Transform>();

        //此处的100表示格子大小
        float position = position_start;
        position_end = position_start + 100 * itemCount;

        for (int i = 0; i < itemCount; i++)
        {
            Object prefab = Resources.Load("Item"); ;
            GameObject go = Instantiate((GameObject)prefab, parent);
            Transform tr = go.transform;
            Text text = tr.GetComponentInChildren<Text>();
            go.name = "Item_" + i;
            text.text = i.ToString();
            tr.localPosition = new Vector3(position, 0, 0);
            position += 100;
            items.Add(tr);
        }
    }

    private void Update()
    {
        //按P开始测试
        if (Input.GetKeyDown(KeyCode.P))
        {
            drawState = DrawType.Start;
        }

        if (move)
        {
            if (drawState == DrawType.Center)
            {
                dis_cur += speed_move;
                if (dis_cur >= dis_max)
                {
                    drawState = DrawType.End;
                }
            }
            else
            {
                speed_move += speed_add;
                if (speed_move >= speed_max)
                {
                    drawState = DrawType.Center;
                }
                if (speed_move <= speed_min)
                {
                    speed_move = speed_min;
                    if (Mathf.Abs(items[index].localPosition.x - position_center) < speed_min)
                    {
                        drawState = DrawType.Idle;
                    }
                }
            }
            if (move)
            {
                Move_Update();
            }
        }
    }

    private void Move_Update()
    {
        for (int i = 0; i < items.Count; i++)
        {
            items[i].Translate(Vector3.right * speed_move);
            if (items[i].localPosition.x >= position_end)
            {
                float out_p = items[i].localPosition.x - position_end;
                items[i].localPosition = new Vector3(position_start + out_p, 0, 0);
            }
            
            //特效：根据格子位置设置大小
            float distance = items[i].localPosition.x - position_center;
            distance = Mathf.Abs(distance);
            if (distance < 50)
            {
                items[i].localScale = Vector3.one * 1.5f;
            }
            else if (distance < 110)
            {
                items[i].localScale = Vector3.one * 1.2f;
            }
            else
            {
                items[i].localScale = Vector3.one;
            }
        }
    }

    private void GetPrePosition()
    {
        dis_max = Mathf.Abs(position_start) + position_end;
        dis_max = dis_max / 2;
        dis_max -= items[index].localPosition.x;
        dis_max -= 400;
    }
}

缺点：

　　若奖励列表过长，走到指定奖励位置 表现效果（以最小速度）不佳