Unity3D利用UGUI模拟《海岛奇兵》收获资源的爆炸效果

《海岛奇兵》是由芬兰Supercell Oy公司开发，Supercell Oy及昆仑游戏发行的一款战斗策略类、全球同服的手机游戏。估计大部分人都玩过，即使没有玩过也应该知道这款游戏吧。本人之前就热衷于这款游戏，对于热爱游戏开发的我来说，看见这款游戏的效果，实在是叹为观止，甚至想把所有的效果都模拟过来放入自己的游戏中。这不，现在就来用Unity模拟它收获资源产生大量资源图标飞入到背包的效果。

我就取名为WeiButEffectC#脚本，主要就是这个类实现的所有功能，先上源码。

using System.Collections.Generic;
using UnityEngine;
/// <summary>
/// 模拟《海岛奇兵》收获资源的爆炸效果
/// weibut.com
/// </summary>
public class WeiButEffect : MonoBehaviour {
    /// <summary>
    /// 移动到的目标
    /// </summary>
    public Transform target;
    /// <summary>
    /// 运动时间
    /// </summary>
    public float factor = 1f;
    /// <summary>
    /// 生成个数
    /// </summary>
    public int amount;
    /// <summary>
    /// 需要生成的物体
    /// </summary>
    public Transform prefab;
    /// <summary>
    /// 爆炸范围
    /// </summary>
    public float explosionRadius = 200;

    public System.Action onFinish;//完成后回调

    float time0 = 0;
    List<Vector3> ctrlPoints = new List<Vector3>();
    List<Transform> particles = new List<Transform>();

    public void PlayEffect()
    {
        int n = Mathf.Max(1, amount);
        for (int i = 0; i < n; i++)
        {
            if (prefab)
            {
                GenerateParticle(prefab);
            }
        }

        time0 = Time.time;
    }

    void GenerateParticle(Transform prefab)
    {
        var p = Instantiate(prefab, Vector3.zero, Quaternion.identity).gameObject;
        p.transform.SetParent(transform, false);
        particles.Add(p.transform);
        ctrlPoints.Add(Random.insideUnitSphere * explosionRadius);
    }

    // Update is called once per frame
    void Update () {
        if (!this.target)
        {
            OnFinish();
            return;
        }
        float t = (Time.time - time0) / Mathf.Max(0.1f, factor);

        if (t > 1)
        {
            t = 1;

            OnFinish();
        }

        Vector3 target = GetTargetPositionLocal();

        for (int i = 0; i < ctrlPoints.Count; i++)
        {
            Vector3 ctrl = ctrlPoints[i];
            Vector3 begin = Vector3.zero;


            Vector3 pos = Vector3.Lerp(Vector3.Lerp(begin, ctrl, t), Vector3.Lerp(ctrl, target, t), t);

            particles[i].localPosition = pos;
        }
    }

    void OnFinish()
    {
        Destroy(gameObject);

        if (onFinish != null)
        {
            onFinish();
        }
    }

    Vector3 GetTargetPositionLocal()
    {
        var screenPoint = target.GetScreenPoint();

        Vector2 localPoint = Vector2.zero;
        GetComponent<RectTransform>().ScreenPointToLocalPosition(screenPoint, out localPoint);
        return localPoint;
    }


    /// <summary>
    /// 模拟《海岛奇兵》收获资源的爆炸效果
    /// </summary>
    /// <param name="parent">创建在哪</param>
    /// <param name="target">移动到哪</param>
    /// <param name="prefab">移动物体</param>
    /// <param name="amount">个数</param>
    /// <param name="explosionRadius">扩散范围</param>
    /// <param name="onFinish">移动完成回调</param>
    /// <returns></returns>
    public static WeiButEffect CreateEffect(Transform parent, Transform target, Transform prefab, int amount, float explosionRadius = 200, System.Action onFinish = null)
    {
        GameObject instance = new GameObject(prefab.name);
        instance.transform.SetParent(parent, false);
        instance.AddComponent<RectTransform>();
        var effect = instance.AddComponent<WeiButEffect>();
        effect.prefab = prefab;
        effect.amount = amount;
        effect.target = target;
        effect.onFinish = onFinish;
        effect.explosionRadius = explosionRadius;
        effect.PlayEffect();
        return effect;
    }
}


/// <summary>
/// TransForm的扩展
/// </summary>
public static class TRE
{
    /// <summary>
    /// 获取Canvas里transform的屏幕坐标
    /// </summary>
    /// <param name="trans"></param>
    /// <returns></returns>
    public static Vector3 GetScreenPoint(this Transform trans)
    {
        var canvas = trans.GetComponentInParent<Canvas>();
        if (canvas)
        {
            var uiCamera = canvas.worldCamera ?? Camera.main;
            if (canvas.renderMode == RenderMode.WorldSpace)
            {
                uiCamera.WorldToScreenPoint(trans.position);
            }
            else if (uiCamera && canvas.renderMode != RenderMode.ScreenSpaceOverlay)
            {
                return uiCamera.WorldToScreenPoint(trans.position);
            }
            else
            {
                return trans.position;
            }
        }
        return Camera.main.WorldToScreenPoint(trans.position);
    }

    public static bool ScreenPointToLocalPosition(this RectTransform rect, Vector2 screenPoint, out Vector2 localPoint)
    {
        if (rect)
        {
            Transform current = rect;
            Canvas canvas = null;
            for (; current != null; current = current.parent)
            {
                canvas = current.GetComponent<Canvas>();
                if (canvas != null)
                {
                    break;
                }
            }

            var cam = canvas.renderMode == RenderMode.ScreenSpaceOverlay ? null : (canvas.renderMode == RenderMode.ScreenSpaceCamera ? canvas.worldCamera : canvas.worldCamera ?? Camera.main);
            return RectTransformUtility.ScreenPointToLocalPointInRectangle(rect.parent.GetComponent<RectTransform>(), screenPoint, cam, out localPoint);
        }
        localPoint = Vector2.zero;
        return false;
    }
}

代码这么多，其实很简单，就只调用CreateEffect静态函数就可以了，参数的意思也都有注释。还有一个静态类TRE，主要是transform的扩展。

可以这样

也可以这样

甚至还可以这样

当然你想怎样就怎样！！！

这个版本是无音效版的，如果需要请自行扩展。