最近一直在思考如何能更好的做优化渲染，本篇文章只是另一种实现的思路，其实我也没完全想好怎么应用到实际游戏中来统计，希望各位看官多多提宝贵意见。 1.本例Unity的版本是Unity2019.3.
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最近一直在思考如何能更好的做优化渲染，本篇文章只是另一种实现的思路，其实我也没完全想好怎么应用到实际游戏中来统计，希望各位看官多多提宝贵意见。
1.本例Unity的版本是Unity2019.3.1.4
2.采用URP渲染管线，老的渲染管线没有试过，大家可以试试看。
3.FrameDebugger会将每一这数据存入RT中，名字对应如下。
实际代码中就可以这样取到它的Texture了
Texture texture = Shader.GetGlobalTexture("_CameraColorTexture");if (!texture){texture = Shader.GetGlobalTexture("_CameraOpaqueTexture");}
并非所有都能取，比如shadowmap的RT，这名字是没有意义的，如果真想取，那就用C#反射吧。但其实有上面两个基本已经够用了。
4.为了让代码更快的比较两帧图片的颜色，我采用了Burst编译比暴力的for循环快的可不是一点点。
5.为了让工具更加方便，不得不在代码中做了很多反射FrameDebugger的代码。
工具使用之前，大家可以先用FrameDebugger看一下自己需要截那些帧的数据。接着运行Unity，填入开始和结束帧的索引后，点击开始截取按钮即可。
截取完毕后，左边会保存每帧截取的图片，最后还会生成一张第1张和最后一张的中像素变化的图片（红色的区域就表示变化）还会输出最终像素数，重复像素数，总渲染顶点数。
在回到优化上来
1.重复像素数越多，其实就是半透明overdraw比较多。
2.最终像素数表示，光栅化后mesh最终呈现的颜色数。
3.总渲染顶点数，这个数值就很重要的。比如模型参与渲染了好几万个顶点，然而结果最终只贡献给屏幕20个像素，那这显然就不太合理了。
一些问题
1.如果摄像机会移动，那么就会造成有时候离模型近，有时候离的远，这样统计就不准确的。
2.如果使用RenderDoc能看到的信息会更多，我也比较推荐用Renderdoc，这篇文章只是开放一下思路。
上代码
using System;using System.Collections;using System.IO;using System.Reflection;using UnityEditor;using UnityEngine;using Unity.EditorCoroutines.Editor;using Unity.Collections;using Unity.Burst;using Unity.Jobs;using Unity.Mathematics;public class FrameDebugExamplle : EditorWindow{static Type s_frameDebugType = Type.GetType("UnityEditorInternal.FrameDebuggerUtility,UnityEditor");static Type s_frameDebugWindowsType = Type.GetType("UnityEditor.FrameDebuggerWindow,UnityEditor");static bool s_HasLatSample;static NativeArray<Color> s_LastSample2DColor;static NativeArray<Color> s_FirstSample2DColor;static int s_FinalPixel = 0;static int s_ProcessPixel = 0;static int s_VertexCount = 0;static int s_StartDC;static int s_EndDC;static string s_Result;static string DirectoryPath = "Assets/采样";static EditorWindow s_FrameDebugWindows;[MenuItem("Example/开始")]public static void ShowWindow(){OpenAndEnableFrameDebugger();}void OnGUI(){int count = (int)s_frameDebugType.GetProperty("count", BindingFlags.Instance | BindingFlags.Public | BindingFlags.Static).GetValue(null);if (count == 0){OpenAndEnableFrameDebugger();}GUILayout.Label(string.Format($"DC区间 0 - {count}"));s_StartDC = Mathf.Clamp(EditorGUILayout.IntField("开始", s_StartDC),0,count - 1);s_EndDC = Mathf.Max(Mathf.Clamp(EditorGUILayout.IntField("结束", s_EndDC),0,count), s_StartDC);if (GUILayout.Button($"开始截取: {s_StartDC}DC-{s_EndDC}DC", GUILayout.Width(200), GUILayout.Height(50))){OpenAndEnableFrameDebugger();EditorCoroutineUtility.StartCoroutineOwnerless(StartGetData());}GUILayout.Label(s_Result);}IEnumerator WaitFive(int count){for (int i = 0; i < count; i++){yield return null;}}IEnumerator StartGetData(){s_VertexCount = 0;s_ProcessPixel = 0;s_FinalPixel = 0;s_Result = string.Empty;s_HasLatSample = false;FileUtil.DeleteFileOrDirectory(DirectoryPath);Directory.CreateDirectory(DirectoryPath);for (int i = s_StartDC; i <= s_EndDC; i++){s_frameDebugType.GetProperty("limit", BindingFlags.Instance | BindingFlags.Public | BindingFlags.Static).SetValue(null, i);yield return WaitFive(1);RefreshFrameDebuggerWindows();yield return WaitFive(1);Texture2D textureSample = TextureSample();Color[] colorBuffer = textureSample.GetPixels();if (textureSample){File.WriteAllBytes($"{DirectoryPath}/开始{i}.jpg", textureSample.EncodeToJPG());if (!s_FirstSample2DColor.IsCreated){s_FirstSample2DColor = new NativeArray<Color>(colorBuffer, Allocator.Persistent);}if (s_HasLatSample){var Job = new JobDiff{result = new NativeArray<int>(1, Allocator.TempJob),current = new NativeArray<Color>(colorBuffer, Allocator.TempJob),last = s_LastSample2DColor,};Job.Schedule(s_LastSample2DColor.Length, new JobHandle()).Complete();s_ProcessPixel += Job.result[0];Job.current.Dispose();Job.result.Dispose();s_LastSample2DColor.Dispose();EditorWindow windows = EditorWindow.GetWindow(s_frameDebugWindowsType);FieldInfo info = windows.GetType().GetField("m_CurEventData", BindingFlags.Instance | BindingFlags.NonPublic);object FrameDebuggerEventData = info.GetValue(windows);if (FrameDebuggerEventData != null){s_VertexCount += (int)FrameDebuggerEventData.GetType().GetField("vertexCount", BindingFlags.Instance | BindingFlags.Public).GetValue(FrameDebuggerEventData);}}if (i != s_EndDC){s_HasLatSample = true;s_LastSample2DColor = new NativeArray<Color>(colorBuffer, Allocator.Persistent);}else{Texture2D diff = textureSample;var Job = new JobFinalDiff{result = new NativeArray<int>(1, Allocator.TempJob),first = s_FirstSample2DColor,end = new NativeArray<Color>(colorBuffer, Allocator.TempJob),};Job.Schedule(s_FirstSample2DColor.Length, new JobHandle()).Complete();s_FinalPixel = Job.result[0];diff.SetPixels(Job.end.ToArray());Job.end.Dispose();Job.result.Dispose();s_FirstSample2DColor.Dispose();File.WriteAllBytes($"{DirectoryPath}/变化.jpg", diff.EncodeToJPG());}}}int pixelSqrt = (int)Mathf.Sqrt((s_ProcessPixel - s_FinalPixel));int finalPixelSqrt = (int)Mathf.Sqrt(s_FinalPixel);s_Result = $"最终像素 {finalPixelSqrt} X {finalPixelSqrt} 重复像素 {pixelSqrt} x {pixelSqrt} 总渲染顶点数 {s_VertexCount}";AssetDatabase.Refresh();}static Texture2D TextureSample(){try{Texture texture = Shader.GetGlobalTexture("_CameraColorTexture");if (!texture){texture = Shader.GetGlobalTexture("_CameraOpaqueTexture");}if (!texture){Debug.LogError("没有截到图输出错误");}if (texture){var width = texture.width;var height = texture.height;RenderTexture previous = RenderTexture.active;RenderTexture tmp = RenderTexture.GetTemporary(width, height, 0, RenderTextureFormat.Default, RenderTextureReadWrite.sRGB);Graphics.Blit(texture, tmp);RenderTexture.active = tmp;Texture2D @new = new Texture2D(width, height);@new.ReadPixels(new Rect(0, 0, width, height), 0, 0);@new.Apply();RenderTexture.active = previous;return @new;}}catch (Exception e){Debug.LogError("没有截到图输出错误: " + e);}return null;}static void OpenAndEnableFrameDebugger(){EditorWindow.GetWindow(typeof(FrameDebugExamplle), true, "标题", true);s_FrameDebugWindows = EditorWindow.GetWindow(s_frameDebugWindowsType);s_frameDebugWindowsType.GetMethod("EnableIfNeeded", BindingFlags.Instance | BindingFlags.Public).Invoke(s_FrameDebugWindows, null);}static void RefreshFrameDebuggerWindows(){Type windowsType = Type.GetType("UnityEditor.FrameDebuggerWindow,UnityEditor");var windows = EditorWindow.GetWindow(windowsType);windowsType.GetMethod("RepaintOnLimitChange", BindingFlags.Instance | BindingFlags.NonPublic).Invoke(windows, null);}[BurstCompile]struct JobDiff : IJobFor{[ReadOnly] public NativeArray<Color> current;[ReadOnly] public NativeArray<Color> last;public NativeArray<int> result;public void Execute(int index){result[0] += math.select(0, 1, current[index] != last[index]);}}[BurstCompile]struct JobFinalDiff : IJobFor{[ReadOnly] public NativeArray<Color> first;public NativeArray<Color> end;public NativeArray<int> result;public void Execute(int index){if(end[index] != first[index]){end[index] = Color.red;result[0]++;}}}}
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作者：雨松MOMO
原文：https://www.xuanyusong.com/archives/4745
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