Unity动画文件优化探究

2017-06-14

主要思路

压缩浮点数精度
去除scale曲线

各Size含义

在参考了王亮的代码后，我也尝试优化了动画文件，发现一个很奇怪的现象。下图中Inspector中显示的大小并没有任何变化，但是文件大小和Profiler中的内存大小确实是减小了。那么Inspector中显示的Size是什么含义呢？
下图中的动画文件不包含Scale曲线，所以这次优化中只压缩了浮点数精度。

我分别对比了动画文件优化前和优化后的大小

FileSize
- FileInfo.Length取得的文件大小
- 可以在操作系统的文件系统中看到
MemorySize
- Profiler.GetRuntimeMemorySize取得的内存大小
- 可以在Profiler中通过采样看到
BlobSize
- 反射取得的AnimationClipStats.size二进制大小
- 显示在AnimationClip的Inspector的面板上

前后	FileSize	Editor MemorySize	真机MemorySize	BlobSize
优化前	11.75kb	8.75kb	3.1kb	2.8kb
优化后	5.87kb	3.63kb	3.1kb	2.8kb
对比	-50%	-58%	-0%	-0%

红色框内即是BlobSize，在我的理解，FileSize是指文件在硬盘中占的大小，BlobSize是从文件反序列化出来的对象的二进制大小。Editor下的MemorySize不仅有序列化后的内存大小，还维护了一份原文件的内存。就像我们在Editor下加载一张Texture内存是双份一样，而真机下就约等于BlobSize。真机下的MemorySize和Inspector里的BlobSize非常接近，BlobSize可以认为是真机上的内存大小，这个大小更有参考意义。

下面这次测试证实了我的想法，下图这个动画文件原来Inspector中Scale的值为4，即有Scale曲线。所以BlobSize减小了27%。

前后	FileSize	Editor MemorySize	真机MemorySize
优化前	85.43kb	46.29kb	10.2kb
优化后	23.34kb	18.69kb	7.4kb
对比	-73%	-60	-27%

Curve减少导致内存减小

从上面的实验可以看出来，只动画文件的压缩精度，没有引起Curve减少。BlobSize是不会有任何变化的，因为每个浮点数固定占32bit。而文件大小、AB大小、Editor下的内存大小，压缩精度后不管有没有引起Curve的变化，都会变小。
裁剪动画文件的精度，意味着点的位置发生了变化，所以Constant Curve和Dense Curve的数量也有可能发生变化。由于是裁剪精度所以动画的点更稀疏了，而连续相同的点更多了。所以Dense Curve是减少了，Constant Curve是增多了，总的内存是减小了。

Constant Curve只需要最左边的点就可以描述一个曲线段

总结

隔壁项目组对他们项目中所有的动画文件都进行了优化。其中文件大小从820m->225, ab大小从72m->64m, 内存大小从50m->40m。总的来说动画文件的scale越多优化越明显。

取BlobSize代码

AnimationClip aniClip = AssetDatabase.LoadAssetAtPath<AnimationClip> (path);
var fileInfo = new System.IO.FileInfo(path);
Debug.Log(fileInfo.Length);//FileSize
Debug.Log(Profiler.GetRuntimeMemorySize (aniClip));//MemorySize

Assembly asm = Assembly.GetAssembly(typeof(Editor));
MethodInfo getAnimationClipStats = typeof(AnimationUtility).GetMethod("GetAnimationClipStats", BindingFlags.Static | BindingFlags.NonPublic);
Type aniclipstats = asm.GetType("UnityEditor.AnimationClipStats");
FieldInfo sizeInfo = aniclipstats.GetField ("size", BindingFlags.Public | BindingFlags.Instance);

var stats = getAnimationClipStats.Invoke(null, new object[]{aniClip});
Debug.Log(EditorUtility.FormatBytes((int)sizeInfo.GetValue(stats)));//BlobSize

工具代码

最后附上工具的代码和简要使用说明，选中想要优化的文件夹或文件，右键Animation->裁剪浮点数去除Scale。

//****************************************************************************
//
//  File:      OptimizeAnimationClipTool.cs
//
//  Copyright (c) SuiJiaBin
//
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.
//
//****************************************************************************
using System;
using System.Collections.Generic;
using UnityEngine;
using System.Reflection;
using UnityEditor;
using System.IO;

namespace EditorTool
{
    class AnimationOpt
    {
        static Dictionary<uint,string> _FLOAT_FORMAT;
        static MethodInfo getAnimationClipStats;
        static FieldInfo sizeInfo;
        static object[] _param = new object[1];

        static AnimationOpt ()
        {
            _FLOAT_FORMAT = new Dictionary<uint, string> ();
            for (uint i = 1; i < 6; i++) {
                _FLOAT_FORMAT.Add (i, "f" + i.ToString ());
            }
            Assembly asm = Assembly.GetAssembly (typeof(Editor));
            getAnimationClipStats = typeof(AnimationUtility).GetMethod ("GetAnimationClipStats", BindingFlags.Static | BindingFlags.NonPublic);
            Type aniclipstats = asm.GetType ("UnityEditor.AnimationClipStats");
            sizeInfo = aniclipstats.GetField ("size", BindingFlags.Public | BindingFlags.Instance);
        }

        AnimationClip _clip;
        string _path;

        public string path { get{ return _path;} }

        public long originFileSize { get; private set; }

        public int originMemorySize { get; private set; }

        public int originInspectorSize { get; private set; }

        public long optFileSize { get; private set; }

        public int optMemorySize { get; private set; }

        public int optInspectorSize { get; private set; }

        public AnimationOpt (string path, AnimationClip clip)
        {
            _path = path;
            _clip = clip;
            _GetOriginSize ();
        }

        void _GetOriginSize ()
        {
            originFileSize = _GetFileZie ();
            originMemorySize = _GetMemSize ();
            originInspectorSize = _GetInspectorSize ();
        }

        void _GetOptSize ()
        {
            optFileSize = _GetFileZie ();
            optMemorySize = _GetMemSize ();
            optInspectorSize = _GetInspectorSize ();
        }

        long _GetFileZie ()
        {
            FileInfo fi = new FileInfo (_path);
            return fi.Length;
        }

        int _GetMemSize ()
        {
            return Profiler.GetRuntimeMemorySize (_clip);
        }

        int _GetInspectorSize ()
        {
            _param [0] = _clip;
            var stats = getAnimationClipStats.Invoke (null, _param);
            return (int)sizeInfo.GetValue (stats);
        }

        void _OptmizeAnimationScaleCurve ()
        {
            if (_clip != null) {
                //去除scale曲线
                foreach (EditorCurveBinding theCurveBinding in AnimationUtility.GetCurveBindings(_clip)) {
                    string name = theCurveBinding.propertyName.ToLower ();
                    if (name.Contains ("scale")) {
                        AnimationUtility.SetEditorCurve (_clip, theCurveBinding, null);
                        Debug.LogFormat ("关闭{0}的scale curve", _clip.name);
                    }
                } 
            }
        }

        void _OptmizeAnimationFloat_X (uint x)
        {
            if (_clip != null && x > 0) {
                //浮点数精度压缩到f3
                AnimationClipCurveData[] curves = null;
                curves = AnimationUtility.GetAllCurves (_clip);
                Keyframe key;
                Keyframe[] keyFrames;
                string floatFormat;
                if (_FLOAT_FORMAT.TryGetValue (x, out floatFormat)) {
                    if (curves != null && curves.Length > 0) {
                        for (int ii = 0; ii < curves.Length; ++ii) {
                            AnimationClipCurveData curveDate = curves [ii];
                            if (curveDate.curve == null || curveDate.curve.keys == null) {
                                //Debug.LogWarning(string.Format("AnimationClipCurveData {0} don't have curve; Animation name {1} ", curveDate, animationPath));
                                continue;
                            }
                            keyFrames = curveDate.curve.keys;
                            for (int i = 0; i < keyFrames.Length; i++) {
                                key = keyFrames [i];
                                key.value = float.Parse (key.value.ToString (floatFormat));
                                key.inTangent = float.Parse (key.inTangent.ToString (floatFormat));
                                key.outTangent = float.Parse (key.outTangent.ToString (floatFormat));
                                keyFrames [i] = key;
                            }
                            curveDate.curve.keys = keyFrames;
                            _clip.SetCurve (curveDate.path, curveDate.type, curveDate.propertyName, curveDate.curve);
                        }
                    }
                } else {
                    Debug.LogErrorFormat ("目前不支持{0}位浮点", x);
                }
            }
        }

        public void Optimize (bool scaleOpt, uint floatSize)
        {
            if (scaleOpt) {
                _OptmizeAnimationScaleCurve ();
            }
            _OptmizeAnimationFloat_X (floatSize);
            _GetOptSize ();
        }

        public void Optimize_Scale_Float3 ()
        {
            Optimize (true, 3);
        }

        public void LogOrigin ()
        {
            _logSize (originFileSize, originMemorySize, originInspectorSize);
        }

        public void LogOpt ()
        {
            _logSize (optFileSize, optMemorySize, optInspectorSize);
        }

        public void LogDelta ()
        {

        }

        void _logSize (long fileSize, int memSize, int inspectorSize)
        {
            Debug.LogFormat ("{0} \nSize=[ {1} ]", _path, string.Format ("FSize={0} ; Mem->{1} ; inspector->{2}",
                EditorUtility.FormatBytes (fileSize), EditorUtility.FormatBytes (memSize), EditorUtility.FormatBytes (inspectorSize)));
        }
    }

    public class OptimizeAnimationClipTool
    {
        static List<AnimationOpt> _AnimOptList = new List<AnimationOpt> ();
        static List<string> _Errors = new List<string>();
        static int _Index = 0;

        [MenuItem("Assets/Animation/裁剪浮点数去除Scale")]
        public static void Optimize()
        {
            _AnimOptList = FindAnims ();
            if (_AnimOptList.Count > 0)
            {
                _Index = 0;
                _Errors.Clear ();
                EditorApplication.update = ScanAnimationClip;
            }
        }

        private static void ScanAnimationClip()
        {
            AnimationOpt _AnimOpt = _AnimOptList[_Index];
            bool isCancel = EditorUtility.DisplayCancelableProgressBar("优化AnimationClip", _AnimOpt.path, (float)_Index / (float)_AnimOptList.Count);
            _AnimOpt.Optimize_Scale_Float3();
            _Index++;
            if (isCancel || _Index >= _AnimOptList.Count)
            {
                EditorUtility.ClearProgressBar();
                Debug.Log(string.Format("--优化完成--    错误数量: {0}    总数量: {1}/{2}    错误信息↓:\n{3}\n----------输出完毕----------", _Errors.Count, _Index, _AnimOptList.Count, string.Join(string.Empty, _Errors.ToArray())));
                Resources.UnloadUnusedAssets();
                GC.Collect();
                AssetDatabase.SaveAssets();
                EditorApplication.update = null;
                _AnimOptList.Clear();
                _cachedOpts.Clear ();
                _Index = 0;
            }
        }

        static Dictionary<string,AnimationOpt> _cachedOpts = new Dictionary<string, AnimationOpt> ();

        static AnimationOpt _GetNewAOpt (string path)
        {
            AnimationOpt opt = null;
            if (!_cachedOpts.ContainsKey(path)) {
                AnimationClip clip = AssetDatabase.LoadAssetAtPath<AnimationClip> (path);
                if (clip != null) {
                    opt = new AnimationOpt (path, clip);
                    _cachedOpts [path] = opt;
                }
            }
            return opt;
        }

        static List<AnimationOpt> FindAnims()
        {
            string[] guids = null;
            List<string> path = new List<string>();
            List<AnimationOpt> assets = new List<AnimationOpt> ();
            UnityEngine.Object[] objs = Selection.GetFiltered(typeof(object), SelectionMode.Assets);
            if (objs.Length > 0)
            {
                for(int i = 0; i < objs.Length; i++)
                {
                    if (objs [i].GetType () == typeof(AnimationClip))
                    {
                        string p = AssetDatabase.GetAssetPath (objs [i]);
                        AnimationOpt animopt = _GetNewAOpt (p);
                        if (animopt != null)
                            assets.Add (animopt);
                    }
                    else
                        path.Add(AssetDatabase.GetAssetPath (objs [i]));
                }
                guids = AssetDatabase.FindAssets (string.Format ("t:{0}", typeof(AnimationClip).ToString().Replace("UnityEngine.", "")), path.ToArray());
            }
            else
            {
                guids = AssetDatabase.FindAssets (string.Format ("t:{0}", typeof(AnimationClip).ToString().Replace("UnityEngine.", "")));
            }
            for(int i = 0; i < guids.Length; i++)
            {
                string assetPath = AssetDatabase.GUIDToAssetPath (guids [i]);
                AnimationOpt animopt = _GetNewAOpt (assetPath);
                if (animopt != null)
                    assets.Add (animopt);
            }
            return assets;
        }
    }
}