最近在做動畫優(yōu)化插件，花了一周時間寫代碼調試效果，總算在大幅降低內存的基礎上做出了美術同學滿意的效果，目前優(yōu)化過的動畫文件是未優(yōu)化的動畫文件的7.5%左右的內存，寫篇博客記錄一下。

1、為什么要做動畫優(yōu)化：

? ? 動畫文件在游戲包體和內存中占的比例僅次于貼圖，優(yōu)化好動畫文件，就優(yōu)化了一小半游戲內存。拿我們正在開發(fā)的游戲舉例，優(yōu)化后的包體和內存比優(yōu)化前減少了一百多兆，大概優(yōu)化掉了五分之一的內存。

2、優(yōu)化思路：

• 設置Animation.Compression：Animation.Compression默認選擇的是Optimal，AnimationPositionError默認0.2，AnimationRotationError默認0.1，AnimationScaleError大部分需要丟棄，所以默認就可以。具體值需要根據自己游戲調整，我們游戲由于戰(zhàn)斗需要拉近鏡頭所以對動畫精度要求較高，調的壓縮值比較小。

• 默認不開啟Resample Curves選項：Unity官方給的建議是開啟，但是開啟會增大內存，所以在動畫沒有問題的情況下建議關閉該選項。

• 減少幀信息的精度：將幀信息精度減少為小數點后四位，網上大多數文章也是給出的是小數點后三位，但是優(yōu)化到小數點后三位導致我們游戲一些角色的披風抖動時會穿幫，所以精度優(yōu)化到了小數點后四位。??

• 優(yōu)化未改變的Rotation、Position序列幀和剔除Scale序列幀：如果需要用到Scale變化就在骨骼節(jié)點上加關鍵字區(qū)分。Position、Rotation有很多骨骼節(jié)點其實并未發(fā)生變化，但是由于我們Animation.Compression這兩個優(yōu)化值設置的比較小，所以這里我們手動優(yōu)化掉沒有變化的Position、Rotation序列幀，只留頭尾兩幀，保證Position和Rotation初始值正確，這么處理一下會降不少內存。

3、源碼：

using System.IO; using System.Linq; using Assets.Scripts.Common.Util; using UnityEditor; using UnityEngine; using FileUtil = Assets.Scripts.Common.Util.FileUtil;namespace Assets.Scripts.Editor.MenuItemEx {public class OptimizeFBX{private const float AnimationPositionError = 0.2f;private const float AnimationRotationError = 0.1f;private const ModelImporterAnimationCompression Compression = ModelImporterAnimationCompression.Optimal;private const int DecimalAccuracy = 10000;private static string _fbxPath;[MenuItem("Assets/Optimize/Optimize FBX", false, 1000)]private static void OptimizeFbx(){EditorSettings.serializationMode = SerializationMode.ForceText;var objs = Selection.GetFiltered(typeof(Object), SelectionMode.DeepAssets);var count = objs.Length;var index = 0;foreach (var obj in objs){var isCancel = EditorUtility.DisplayCancelableProgressBar("優(yōu)化FBX文件",string.Format("正在優(yōu)化中...{0}/{1}", ++index, count), (float) index / count);if (isCancel){EditorUtility.ClearProgressBar();return;}OptimizeObject(obj);}EditorUtility.ClearProgressBar();}public static void OptimizeObject(Object obj){var path = AssetDatabase.GetAssetPath(obj);if (path != null && Path.GetExtension(path).ToLower() == ".fbx"){_fbxPath = path;OptimizeModleImporter(path);OptimizeAnimationClip(path);}}/// <summary>/// 設置fbx動畫導入格式，默認AnimationPositionError = 0.2，AnimationRotationError = 0.1，根據項目調整，值越低優(yōu)化壓縮越少。/// </summary>/// <param name="fbxPath"></param>private static void OptimizeModleImporter(string fbxPath){var modelImporter = AssetImporter.GetAtPath(fbxPath) as ModelImporter;if (modelImporter != null){var isChange = false;if (Compression != modelImporter.animationCompression){isChange = true;modelImporter.animationCompression = Compression;modelImporter.animationPositionError = AnimationPositionError;modelImporter.animationRotationError = AnimationRotationError;modelImporter.resampleCurves = false;}else{if (!Mathf.Approximately(modelImporter.animationPositionError, AnimationPositionError)){isChange = true;modelImporter.animationPositionError = AnimationPositionError;}if (!Mathf.Approximately(modelImporter.animationRotationError, AnimationRotationError)){isChange = true;modelImporter.animationRotationError = AnimationRotationError;}if (modelImporter.resampleCurves){isChange = true;modelImporter.resampleCurves = false;}}if (isChange){modelImporter.SaveAndReimport();AssetDatabase.Refresh();}}}private static void OptimizeAnimationClip(string fbxPath){var objs = AssetDatabase.LoadAllAssetsAtPath(fbxPath);var index = 0;var folderPath = string.Empty;foreach (var o in objs){if (o is AnimationClip){if (o.name == "__preview__Take 001")continue;if (index++ == 0) //只在第一次創(chuàng)建文件夾{folderPath = _fbxPath.Substring(0, _fbxPath.LastIndexOf('.'));FileUtil.RecreateDirectory(PathUtil.AssetPathToAbsolutePath(folderPath)); //刪除原來文件夾，重新創(chuàng)建新文件夾}OptimizeAnimationCurveData(o as AnimationClip, folderPath);}}}/// <summary>/// 優(yōu)化動畫片段，刪除不需要的序列幀，并降低幀信息的精度/// </summary>/// <param name="clip"></param>/// <param name="folderPath"></param>/// <returns></returns>public static bool OptimizeAnimationCurveData(AnimationClip clip, string folderPath){if (clip == null){Debug.LogError("No Clip error, please tell zhanglingyun" + "? " + _fbxPath);return false;}var curveDatas = AnimationUtility.GetAllCurves(clip, true);if (curveDatas == null || curveDatas.Length == 0){Debug.LogError("No AnimationClipCurveData error, please tell zhanglingyun!" + "? " + _fbxPath + "? " +clip.name);return false;}var newClip = new AnimationClip();EditorUtility.CopySerialized(clip, newClip);newClip.name = clip.name;newClip.ClearCurves();foreach (var dt in curveDatas){var nodeName = dt.path.ToLower().Split('/').Last();// 進行過濾if (IsFilterCurveData(dt, nodeName))continue;var keys = dt.curve.keys;for (var i = 0; i < keys.Length; i++){keys[i].time = Mathf.Round(keys[i].time * DecimalAccuracy) / DecimalAccuracy;keys[i].value = Mathf.Round(keys[i].value * DecimalAccuracy) / DecimalAccuracy;keys[i].outTangent = Mathf.Round(keys[i].outTangent * DecimalAccuracy) / DecimalAccuracy;keys[i].inTangent = Mathf.Round(keys[i].inTangent * DecimalAccuracy) / DecimalAccuracy;}//過濾位移值沒有變化的幀動畫//因為幀信息有初始位置，所有要保留頭尾兩幀，如果全部刪除會出現初始位置為默認值的問題if (IsFilterApproximateKeyFrame(ref keys)){var newKeys = new Keyframe[2];newKeys[0] = keys[0];newKeys[1] = keys[keys.Length - 1];keys = newKeys;}dt.curve.keys = keys;//設置新數據newClip.SetCurve(dt.path, dt.type, dt.propertyName, dt.curve);}AssetDatabase.CreateAsset(newClip, folderPath + @"/" + newClip.name + ".anim");AssetDatabase.Refresh();return true;}/// <summary>/// 過濾值一樣的序列幀/// </summary>/// <param name="keys"></param>/// <returns></returns>private static bool IsFilterApproximateKeyFrame(ref Keyframe[]keys){for (var i = 0; i < keys.Length - 1; i++){if (Mathf.Abs(keys[i].value - keys[i + 1].value) > 0 ||Mathf.Abs(keys[i].outTangent - keys[i + 1].outTangent) > 0|| Mathf.Abs(keys[i].inTangent - keys[i + 1].inTangent) > 0){return false;}}return true;}/// <summary>/// 動畫默認不導出Scale序列幀，除非該節(jié)點包含scale關鍵詞(加scale關鍵詞表示該節(jié)點需要進行scale變換)/// </summary>/// <param name="dt"></param>/// <returns></returns>private static bool IsFilterCurveData(AnimationClipCurveData dt, string nodeName){if (dt.propertyName.ToLower().Contains("scale") && !nodeName.Contains("scale"))return true;return false;}} }

4、優(yōu)化對比圖：

優(yōu)化前：

? ? ? ? ? ? ? ??

優(yōu)化后：

? ? ? ? ? ? ? ??

參考鏈接：https://blog.uwa4d.com/archives/Optimization_Animation.html

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