Unity代码实现序列帧动画播放器

using UnityEngine;
using UnityEngine.UI;
using System;

/// <summary>
/// 序列帧动画播放器
/// 支持UGUI的Image和Unity2D的SpriteRenderer
/// </summary>
public class FrameAnimator : MonoBehaviour
{
 /// <summary>
 /// 序列帧
 /// </summary>
 public Sprite[] Frames{ get { return frames; } set { frames = value; } }

 [SerializeField]private Sprite[] frames = null;

 /// <summary>
 /// 帧率，为正时正向播放，为负时反向播放
 /// </summary>
 public float Framerate { get { return framerate; } set { framerate = value; } }

 [SerializeField] private float framerate = 20.0f;

 /// <summary>
 /// 是否忽略timeScale
 /// </summary>
 public bool IgnoreTimeScale{ get { return ignoreTimeScale; } set { ignoreTimeScale = value; } }

 [SerializeField]private bool ignoreTimeScale = true;

 /// <summary>
 /// 是否循环
 /// </summary>
 public bool Loop{ get { return loop; } set { loop = value; } }

 [SerializeField]private bool loop = true;

 //动画曲线
 [SerializeField]private AnimationCurve curve = new AnimationCurve (new Keyframe (0, 1, 0, 0), new Keyframe (1, 1, 0, 0));

 /// <summary>
 /// 结束事件
 /// 在每次播放完一个周期时触发
 /// 在循环模式下触发此事件时，当前帧不一定为结束帧
 /// </summary>
 public event Action FinishEvent;

 //目标Image组件
 private Image image;
 //目标SpriteRenderer组件
 private SpriteRenderer spriteRenderer;
 //当前帧索引
 private int currentFrameIndex = 0;
 //下一次更新时间
 private float timer = 0.0f;
 //当前帧率，通过曲线计算而来
 private float currentFramerate = 20.0f;

 /// <summary>
 /// 重设动画
 /// </summary>
 public void Reset ()
 {
 currentFrameIndex = framerate < 0 ? frames.Length - 1 : 0;
 }

 /// <summary>
 /// 从停止的位置播放动画
 /// </summary>
 public void Play ()
 {
 this.enabled = true;
 }

 /// <summary>
 /// 暂停动画
 /// </summary>
 public void Pause ()
 {
 this.enabled = false;
 }

 /// <summary>
 /// 停止动画，将位置设为初始位置
 /// </summary>
 public void Stop ()
 {
 Pause ();
 Reset ();
 }
 
 //自动开启动画
 void Start ()
 {
 image = this.GetComponent<Image> ();
 spriteRenderer = this.GetComponent<SpriteRenderer> ();
 #if UNITY_EDITOR
 if (image == null && spriteRenderer == null) {
 Debug.LogWarning ("No available component found. 'Image' or 'SpriteRenderer' required.", this.gameObject);
 }
 #endif
 }

 void Update ()
 {
 //帧数据无效，禁用脚本
 if (frames == null || frames.Length == 0) {
 this.enabled = false;
 } else {
 //从曲线值计算当前帧率
 float curveValue = curve.Evaluate ((float)currentFrameIndex / frames.Length);
 float curvedFramerate = curveValue * framerate;
 //帧率有效
 if (curvedFramerate != 0) {
 //获取当前时间
 float time = ignoreTimeScale ? Time.unscaledTime : Time.time;
 //计算帧间隔时间
 float interval = Mathf.Abs (1.0f / curvedFramerate);
 //满足更新条件，执行更新操作
 if (time - timer > interval) {
 //执行更新操作
 DoUpdate ();
 }
 }
 #if UNITY_EDITOR
 else {
 Debug.LogWarning ("Framerate got '0' value, animation stopped.");
 }
 #endif
 }
 }

 //具体更新操作
 private void DoUpdate ()
 {
 //计算新的索引
 int nextIndex = currentFrameIndex + (int)Mathf.Sign (currentFramerate);
 //索引越界，表示已经到结束帧
 if (nextIndex < 0 || nextIndex >= frames.Length) {
 //广播事件
 if (FinishEvent != null) {
 FinishEvent ();
 }
 //非循环模式，禁用脚本
 if (loop == false) {
 currentFrameIndex = Mathf.Clamp (currentFrameIndex, 0, frames.Length - 1);
 this.enabled = false;
 return;
 }
 }
 //钳制索引
 currentFrameIndex = nextIndex % frames.Length;
 //更新图片
 if (image != null) {
 image.sprite = frames [currentFrameIndex];
 } else if (spriteRenderer != null) {
 spriteRenderer.sprite = frames [currentFrameIndex];
 }
 //设置计时器为当前时间
 timer = ignoreTimeScale ? Time.unscaledTime : Time.time;
 }
}