工具篇

模型合并

根据原模型创建预制件：
清理旧的合并结果，创建新容器对象
PS：注意 DestroyImmediate仅在 Editor 模式下有效，运行时需用Destroy

var targetObj = GameObject.Find("targetObj");
if (targetObj != null)
{GameObject.DestroyImmediate(targetObj);
}
targetObj = new GameObject("targetObj");
targetObj.transform.localPosition = Vector3.zero;
// ... 其他变换重置 ...

收集网格和材质信息
获取所有需要合并的网格组件，包含静态和蒙皮网格。

MeshRenderer[] allMeshRender = sourceObj.GetComponentsInChildren<MeshRenderer>();
SkinnedMeshRenderer[] SkinnedMeshRenderer = sourceObj.GetComponentsInChildren<SkinnedMeshRenderer>();
MeshFilter[] allfilter = sourceObj.GetComponentsInChildren<MeshFilter>();

填充 MeshInfo 列表
PS: 必须添加：subMeshIndex 因为需要用于处理多材质网格的分段合并。

foreach (var filter in allfilter)
{for (int subMeshIndex = 0; subMeshIndex < filter.sharedMesh.subMeshCount; subMeshIndex++){MeshInfo meshInfo = new MeshInfo();meshInfo.mesh = filter.sharedMesh;meshInfo.subIndex = subMeshIndex;meshInfo.matrix4x4 = filter.transform.localToWorldMatrix;meshInfos.Add(meshInfo);}
}

SkinnedMeshRenderer也需要处理

贴图合并
需要创建一个大的贴图Texture2D，获取所有materials材质球的_MainTex（我只处理了_MainTex，当然也可以处理法线贴图这些其他内容）
PS: COMBINE_TEXTURE_WIDTH是有问题的，后续需要修改，不能这样累加

使用的Texture2D.PackTextures进行打包到图集中的

for (int i = 0; i < materials.Count; i++)
{Texture2D maintexture = materials[i].GetTexture("_MainTex") as Texture2D;COMBINE_TEXTURE_WIDTH += maintexture.width;COMBINE_TEXTURE_HEIGHT += maintexture.height;MainTexs.Add(maintexture);
}
Texture2D newMainTex = new Texture2D(COMBINE_TEXTURE_WIDTH, COMBINE_TEXTURE_HEIGHT, TextureFormat.RGBA32, true);
Rect[] uvs = newMainTex.PackTextures(MainTexs.ToArray(), 0);

UV需要进行偏移

List<Vector2[]> oldUV = new List<Vector2[]>();
Vector2[] uva, uvb;
for (int j = 0; j < combines.Count; j++)
{uva = combines[j].mesh.uv;uvb = new Vector2[uva.Length];for (int k = 0; k < uva.Length; k++){uvb[k] = new Vector2((uva[k].x * uvs[j].width) + uvs[j].x, (uva[k].y * uvs[j].height) + uvs[j].y);}oldUV.Add(uva);combines[j].mesh.uv = uvb;
}

最后保存后记得还原uv：

//重新赋值，以免影响其他对象的Mesh
for (int i = 0; i < combines.Count; i++)
{combines[i].mesh.uv = oldUV[i];
}

最后将贴图赋值到一个新建的材质球上进行保存就好了

Material newMaterial = new Material(mainShader);
newMaterial.SetTexture("_MainTex", newMainTex);

合并网格设置

List<CombineInstance> combines = new List<CombineInstance>();
foreach (var i in meshInfos)
{var ci = new CombineInstance();ci.mesh = i.mesh;ci.subMeshIndex = i.subIndex;ci.transform = i.matrix4x4;combines.Add(ci);
}

需要用到CombineInstance方法进行储存

然后使用CombineMeshes方法进行合并

Mesh mesh = new Mesh();
mesh.CombineMeshes(combines.ToArray(), true, false);

最后进行保存到对应路径：

AssetDatabase.CreateAsset(newMainTex, $"{MaterialTexturePath}CombineTexture.asset");
AssetDatabase.CreateAsset(newMaterial, $"{MaterialTexturePath}CombineMaterial.mat");
AssetDatabase.CreateAsset(mesh, $"{MaterialTexturePath}CombineMaterial.asset");

完整代码：

using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEditor;
using UnityEngine;public struct MeshInfo
{public Mesh mesh;public Matrix4x4 matrix4x4;public int subIndex;
}public class CombineVertexTool
{const string MaterialTexturePath = "Assets/Resources/Material/";public static void CombineFilter(GameObject sourceObj){var targetObj = GameObject.Find("targetObj");if (targetObj != null){GameObject.DestroyImmediate(targetObj);}targetObj = new GameObject("targetObj");targetObj.transform.localPosition = Vector3.zero;targetObj.transform.localRotation = Quaternion.identity;targetObj.transform.localScale = Vector3.one;MeshRenderer[] allMeshRender = sourceObj.GetComponentsInChildren<MeshRenderer>(); //包含MeshRenderer和SkinnedMeshRendererSkinnedMeshRenderer[] SkinnedMeshRenderer = sourceObj.GetComponentsInChildren<SkinnedMeshRenderer>();MeshFilter[] allfilter = sourceObj.GetComponentsInChildren<MeshFilter>(); //网格List<MeshInfo> meshInfos = new List<MeshInfo>();foreach (var filter in allfilter){for (int subMeshIndex = 0; subMeshIndex < filter.sharedMesh.subMeshCount; subMeshIndex++){MeshInfo meshInfo = new MeshInfo();meshInfo.mesh = filter.sharedMesh;meshInfo.subIndex = subMeshIndex;meshInfo.matrix4x4 = filter.transform.localToWorldMatrix;meshInfos.Add(meshInfo);}}//材质球数组List<Material> materials = new List<Material>();foreach (var i in allMeshRender){foreach (var j in i.sharedMaterials){materials.Add(j);}}foreach (SkinnedMeshRenderer i in SkinnedMeshRenderer){foreach (var j in i.sharedMaterials){materials.Add(j);}for (int subMeshIndex = 0; subMeshIndex < i.sharedMesh.subMeshCount; subMeshIndex++){MeshInfo meshInfo = new MeshInfo();meshInfo.mesh = i.sharedMesh;meshInfo.subIndex = subMeshIndex;meshInfo.matrix4x4 = i.transform.localToWorldMatrix;meshInfos.Add(meshInfo);} }Shader mainShader = materials[0].shader; //要求所有shader都必须使用同一个shader// 合并 Mesh// 后去自身和子物体中所有 MsehFilter 组件List<CombineInstance> combines = new List<CombineInstance>();foreach (var i in meshInfos){var ci = new CombineInstance();ci.mesh = i.mesh;ci.subMeshIndex = i.subIndex;//ci.mesh.triangles = i.mesh.triangles; //添加会改变原模型的网格ci.transform = i.matrix4x4;combines.Add(ci);}//收集所有材质贴图List<Texture2D> MainTexs = new List<Texture2D>();int COMBINE_TEXTURE_WIDTH = 0;int COMBINE_TEXTURE_HEIGHT = 0;for (int i = 0; i < materials.Count; i++){Texture2D maintexture = materials[i].GetTexture("_MainTex") as Texture2D;COMBINE_TEXTURE_WIDTH += maintexture.width;COMBINE_TEXTURE_HEIGHT += maintexture.height;MainTexs.Add(maintexture);}//所有贴图合并到newDiffuseTex这张大贴图上Texture2D newMainTex = new Texture2D(COMBINE_TEXTURE_WIDTH, COMBINE_TEXTURE_HEIGHT, TextureFormat.RGBA32, true);Rect[] uvs = newMainTex.PackTextures(MainTexs.ToArray(), 0);List<Vector2[]> oldUV = new List<Vector2[]>();Vector2[] uva, uvb;// 遍历所有合并实例（CombineInstance）for (int j = 0; j < combines.Count; j++){// 获取当前网格的原始UV数组uva = combines[j].mesh.uv;// 创建新UV数组（长度与原始UV相同）uvb = new Vector2[uva.Length];for (int k = 0; k < uva.Length; k++){uvb[k] = new Vector2((uva[k].x * uvs[j].width) + uvs[j].x, (uva[k].y * uvs[j].height) + uvs[j].y);}oldUV.Add(uva);combines[j].mesh.uv = uvb;}Material newMaterial = new Material(mainShader);newMaterial.SetTexture("_MainTex", newMainTex);Mesh mesh = new Mesh();mesh.CombineMeshes(combines.ToArray(), // 合并实例数组true,              // mergeSubMeshes：是否合并子网格false              // useMatrices：是否应用变换矩阵);AssetDatabase.CreateAsset(newMainTex, $"{MaterialTexturePath}CombineTexture.asset");AssetDatabase.CreateAsset(newMaterial, $"{MaterialTexturePath}CombineMaterial.mat");AssetDatabase.CreateAsset(mesh, $"{MaterialTexturePath}CombineMaterial.asset");MeshFilter meshFilter = targetObj.AddComponent<MeshFilter>();meshFilter.sharedMesh = mesh;MeshRenderer meshRenderer = targetObj.AddComponent<MeshRenderer>();meshRenderer.sharedMaterial = newMaterial;//重新赋值，以免影响其他对象的Meshfor (int i = 0; i < combines.Count; i++){combines[i].mesh.uv = oldUV[i];}AssetDatabase.SaveAssets();AssetDatabase.Refresh();}
}

PS：需要开启纹理贴图，模型可读写：

生成动画数据

根据动画时长和帧率计算总帧数，确定纹理尺寸

AnimationClip clip = clips[0];
//foreach (var clip in clips)
//{
//根据动画时长和帧率计算总帧数，确定纹理尺寸
int animLength = Mathf.CeilToInt(clip.frameRate * clip.length);
int texwidth = meshRenderer.sharedMesh.vertexCount;
texwidth = Mathf.NextPowerOfTwo(texwidth);//取顶点数的下一个二次幂（适配 GPU 纹理要求）
int texHeight = animLength;

生成一张纹理：

Texture2D tex = new Texture2D(texwidth, texHeight, TextureFormat.RGBAHalf, false);

逐帧写入纹理

// 步骤3：逐帧处理
for (int i = 0; i < animLength; i++)
{float time = i / clip.frameRate;//Clip.SampleAnimation(GameObject, time)。Clip是我们需要采样的动画剪辑，输入游戏对象后和采样的时间后，就可以在不运行的情况下直接播放动画，加速烘焙过程clip.SampleAnimation(sourceObj, time);// B. 烘焙网格Mesh bakedMesh = new Mesh();//烘焙当前帧顶点数据meshRenderer.BakeMesh(bakedMesh);Vector3[] vertices = bakedMesh.vertices;// 写入纹理行（将没一帧顶点数据转换成color数据保存到图片）for (int frame = 0; frame < meshRenderer.sharedMesh.vertexCount; frame++){// 超出原始顶点数的部分填充黑色Color pixel = Color.black;if (frame <= vertices.Length){Vector3 pos = vertices[frame];pixel = new Color(pos.x, pos.y, pos.z, 1);}tex.SetPixel(frame, i, pixel);//x要设置的像素的 x 坐标。范围为 0 到（纹理宽度 - 1）,y要设置的像素的 y 坐标。范围为 0 到（纹理高度 - 1）,color要设置的颜色。tex.Apply(false); // 可选：分批提交数据（当设置为 true 时，将重新计算多级渐进纹理级别）}
}

完整代码

/// <summary>
/// 生成动画数据（顶点动画）
/// </summary>
public static void CreateVertexAnimaSettingData(GameObject sourceObj)
{var animator = sourceObj.GetComponent<Animator>();var clips = animator.runtimeAnimatorController.animationClips;//检索控制器使用的所有 AnimationClipanimator.speed = 1;//MeshFilter meshFilter = sourceObj.GetComponentInChildren<MeshFilter>();SkinnedMeshRenderer meshRenderer = sourceObj.GetComponentInChildren<SkinnedMeshRenderer>();AnimationClip clip = clips[0];//foreach (var clip in clips)//{//根据动画时长和帧率计算总帧数，确定纹理尺寸int animLength = Mathf.CeilToInt(clip.frameRate * clip.length);int texwidth = meshRenderer.sharedMesh.vertexCount;texwidth = Mathf.NextPowerOfTwo(texwidth);//取顶点数的下一个二次幂（适配 GPU 纹理要求）int texHeight = animLength;Texture2D tex = new Texture2D(texwidth, texHeight, TextureFormat.RGBAHalf, false);// 步骤3：逐帧处理for (int i = 0; i < animLength; i++){float time = i / clip.frameRate;//Clip.SampleAnimation(GameObject, time)。Clip是我们需要采样的动画剪辑，输入游戏对象后和采样的时间后，就可以在不运行的情况下直接播放动画，加速烘焙过程clip.SampleAnimation(sourceObj, time);// B. 烘焙网格Mesh bakedMesh = new Mesh();//烘焙当前帧顶点数据meshRenderer.BakeMesh(bakedMesh);Vector3[] vertices = bakedMesh.vertices;// 写入纹理行（将没一帧顶点数据转换成color数据保存到图片）for (int frame = 0; frame < meshRenderer.sharedMesh.vertexCount; frame++){// 超出原始顶点数的部分填充黑色Color pixel = Color.black;if (frame <= vertices.Length){Vector3 pos = vertices[frame];pixel = new Color(pos.x, pos.y, pos.z, 1);}tex.SetPixel(frame, i, pixel);//x要设置的像素的 x 坐标。范围为 0 到（纹理宽度 - 1）,y要设置的像素的 y 坐标。范围为 0 到（纹理高度 - 1）,color要设置的颜色。tex.Apply(false); // 可选：分批提交数据（当设置为 true 时，将重新计算多级渐进纹理级别）}}tex.Apply(true); // 最终提交tex.name = sourceObj.name;//}AssetDatabase.CreateAsset(tex, $"{MaterialTexturePath}{sourceObj.name}_VerTex.asset");AssetDatabase.SaveAssets();AssetDatabase.Refresh();
}

我的动画计算出来是19帧，所以height为19像素

工具调用：

using System.Collections;
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;
using static Unity.VisualScripting.Member;public class BuildGpuAnimaEditorVertex : EditorWindow
{[MenuItem("Tools/GPU动画处理工具(顶点动画)")]static void CreateSecetionData(){EditorWindow.GetWindow<BuildGpuAnimaEditorVertex>(true, "GPU动画处理工具(顶点动画)", true).Show();}private GameObject source;public void OnGUI(){EditorGUILayout.BeginHorizontal();EditorGUILayout.LabelField("源资源:", GUILayout.Width(60));source = EditorGUILayout.ObjectField(source, typeof(GameObject), true) as GameObject;EditorGUILayout.EndHorizontal();EditorGUILayout.Space();EditorGUILayout.LabelField("根据源资源生成对应动画数据贴图资源", GUILayout.Width(240));EditorGUILayout.Space();if (GUILayout.Button("开始", GUILayout.Height(20))){CombineVertexTool.CreateVertexAnimaSettingData(source);}EditorGUILayout.Space();EditorGUILayout.LabelField("根据shader和模型生成材质贴图和合并网格", GUILayout.Width(240));EditorGUILayout.Space();if (GUILayout.Button("开始", GUILayout.Height(20))){CombineVertexTool.CombineFilter(source);}}
}

Shader处理

需要添加 #pragma multi_compile_instancing开启GPU 实例化
可以参考这位大佬讲解（UnityShader支持GPU Instance的方法）

Shader"XXX"{Properties{...}SubShader{...Pass{...CGPROGRAM#pragma vertex vert#pragma fragment frag#pragma multi_compile_instancing //这里,第一步...struct a2v{...UNITY_VERTEX_INPUT_INSTANCE_ID //这里,第二步};struct v2f{...UNITY_VERTEX_INPUT_INSTANCE_ID //这里,第二步};v2f vert(a2v v){v2f o;UNITY_SETUP_INSTANCE_ID(v); //这里第三步UNITY_TRANSFER_INSTANCE_ID(v,o); //第三步...return o;}fixed4 frag(v2f i):SV_Target{UNITY_SETUP_INSTANCE_ID(i); //最后一步...}ENDCG}}FallBack"Diffuse"
}

完整代码：

Shader "Unlit/yu2"
{Properties{_MainTex ("Texture", 2D) = "white" {} // 主纹理，用于基础颜色_AnimTex ("Texture", 2D) = "white" {}// 动画纹理，存储顶点位置_AnimTime ("AnimTime", float) = 1// 动画速度控制参数}SubShader{Tags { "RenderType"="Opaque" }// 不透明渲染类型LOD 100 // 细节层级Pass{CGPROGRAM#pragma target 3.5      //使用Shader Model 3.5#pragma vertex vert    // 顶点着色器#pragma fragment frag  // 像素着色器// make fog work#pragma multi_compile_instancing // 启用GPU实例化#include "UnityCG.cginc" //引用unity自带的UnityCG//顶点输入与输出结构struct appdata{float4 vertex : POSITION;float2 uv : TEXCOORD0;uint vid : SV_VERTEXID;UNITY_VERTEX_INPUT_INSTANCE_ID};struct v2f{float2 uv : TEXCOORD0;UNITY_FOG_COORDS(1)float4 vertex : SV_POSITION; //通过vid在动画纹理中定位顶点位置UNITY_VERTEX_INPUT_INSTANCE_ID};//CBUFFER_START 常量缓冲区：使用后才会允许支持我们的Shader被SRP Batcher（可编程渲染管线合批）允许，从而节省渲染上的性能CBUFFER_START(UnityPerMaterial)sampler2D _MainTex;sampler2D _AnimTex;//float4 _MainTex_ST;//必须在特殊命名的常量缓冲区中定义每个实例的属性。使用这对宏来包装对每个实例唯一的属性。UNITY_INSTANCING_BUFFER_START(Props)UNITY_DEFINE_INSTANCED_PROP(float4, _AnimTex_TexelSize)//_TexelSize 是一个内置变量，用于获取纹理的像素尺寸信息。这个变量是一个 Vector4，包含了纹理的宽度、高度以及它们的倒数 _AnimTex_TexelSize.xyzw = (1/width, 1/height, width, height)UNITY_DEFINE_INSTANCED_PROP(float4, _MainTex_ST)//是贴图_MainTex的tiling和offset的四元数,_MainTex_ST.xy 是tiling的值,_MainTex_ST.zw 是offset的值 在Material中可以设置的Tiling就是xy，Offset就是zw。UNITY_DEFINE_INSTANCED_PROP(float, _AnimTime)UNITY_INSTANCING_BUFFER_END(Props)CBUFFER_END//UNITY_ACCESS_INSTANCED_PROP : 从缓冲区中获取实例的属性值,arrayName与UNITY_INSTANCING_BUFFER_START(name)对应v2f vert (appdata v){v2f o;UNITY_SETUP_INSTANCE_ID(v);UNITY_TRANSFER_INSTANCE_ID(v, o);// 仅当您要访问片元着色器中的实例化属性时才需要//为什么要加 0.5//像素中心对齐：避免采样时插值到相邻像素。数学原理：将顶点 ID 映射到纹理像素中心坐标。公式推导：纹理U坐标 = (顶点ID + 0.5) * (1.0 / 纹理宽度)float4 uv_anim = float4((v.vid + 0.5) * UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTex_TexelSize).x, _Time.y / UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTime),0.0,0.0);//tex2Dlod 函数,从动画纹理中读取顶点位置   参数说明 _AnimTex：存储顶点位置数据的纹理//uv_anim.xy：计算得到的 UV 坐标//uv_anim.zw：LOD 级别（此处设为 0）v.vertex = float4(tex2Dlod(_AnimTex, uv_anim).xyz,1.0);//v.vertex.y = v.vertex.y - 0.5;o.vertex = UnityObjectToClipPos(v.vertex);//模型空间转到屏幕裁切空间o.uv = v.uv * UNITY_ACCESS_INSTANCED_PROP(Props, _MainTex_ST).xy + UNITY_ACCESS_INSTANCED_PROP(Props, _MainTex_ST).zw; //就是将模型顶点的uv和Tiling、Offset两个变量进行运算，计算出实际显示用的定点uv。return o;}fixed4 frag (v2f i) : SV_Target{UNITY_SETUP_INSTANCE_ID(i);// 仅当要在片元着色器中访问任何实例化属性时才需要fixed4 col = tex2D(_MainTex, i.uv);//采样贴图return col;}ENDCG}}
}

大部分参考和借鉴：[Unity] GPU动画实现1-5这位大佬的文章