您当前的位置: 手机硬件限制，很多PC上的渲染优化技术是没办法直接拿过来用的。目前有些游戏为了实现多部队战斗的效果，各种降低骨骼数目，模型面数的方案，但都逃不过骨骼动画计算这一环节。
在上个公司的时候，自己瞎想了一张方案，没想到最后还写出来了， 没想到最后还用上了。。。
先上张图，里面有100个士兵和10个萌宝宝的场景，每个角色的动作是分开控制的，在小米3上可以60fps的帧率流畅运行，之前也尝试过，300多个角色带动画也可以55左右的fps运行
先说明一下这套方案的优缺点：
优点：可不用计算骨骼动画，并能流畅播放骨骼动画（其实已经不是骨骼动画了）；每个角色动作也可以单独控制；对cpu很小消耗；
缺点：动作切换没有过渡(群体作战的时候，这点基本不影响审美)；对内存占用有一点消耗（其实也还好）
再说明方案思路：
为了省掉骨骼动画计算这一环节，就不能用现有骨骼动画系统。那么可选的方案也只有顶点变形动画了，而传统的顶点动画不管是内存占用还是不低的，而且unity支持也不算好。
那么既然只能选顶点动画且为了降低内存消耗，那么可以通过改写shader，通过gpu来插值实现顶点动画播放骨骼动画的效果。
shader插值的方案确实也不少，但结合具体实现上来，我选了两种实现相对简单的方案：
1.vertex shader里通过每帧采样的uv偏移采样纹理来控制顶点的位置，当我已经在pc端实现的时候才突然发现一个显而易见的问题：在vertex shader里采样纹理，pc端部分显卡是支持的，但手机gpu就不要想了。
2.于是只能第二种方案:还是vextex shader里插值顶点来播放动画，那么就有一个问题，vertex data从哪里来？ unity的mesh结构有很多通道，顶点，颜色，uv，uv2，法线，切线。。这些通道里面除了color（主要是精度问题）和uv（还是必须给纹理坐标一个位置的）通道以外我都可以用来存顶点数据，然后通过控制时间点来组合顶点进行插值，然而还有个问题需要解决，这种方式一个mesh只能插值4个关键顶点，那么较长的动画怎么办呢，可以通过提前生成多个mesh，来切换。
动画截取可以通过unity的BakeMesh函数或者美工来帮助实现，下面是组合mesh 的代码：
byte[] Make(Mesh mesh1, Mesh mesh2, Mesh mesh3, Mesh mesh4, float clipTimeLenghts, float frame2Pos, float frame3Pos) { Mesh[] meshs = new Mesh[] { mesh1, mesh2, mesh3, mesh4}; VertexAnimationResManager.ClipMeshData meshData = new VertexAnimationResManager.ClipMeshData(); meshData.subMeshCount = meshs[0].subMeshCount; int count = meshs[0].vertices.Length; //顶点 if (meshs[0].vertices != null && meshs[0].vertices.Length > 0) { meshData.vertexBuffer = new float[count * 3]; for (int i = 0; i < meshs[0].vertices.Length; i++) { meshData.vertexBuffer[i * 3] = meshs[0].vertices[i].x; meshData.vertexBuffer[i * 3 + 1] = meshs[0].vertices[i].y; meshData.vertexBuffer[i * 3 + 2] = meshs[0].vertices[i].z; } } //uv if (meshs[0].uv != null && meshs[0].uv.Length > 0) { meshData.uvBuffer = new float[count * 2]; for (int i = 0; i < meshs[0].vertices.Length; i++) { meshData.uvBuffer[i * 2] = meshs[0].uv[i].x; meshData.uvBuffer[i * 2 + 1] = meshs[0].uv[i].y; } //GCHandle verSrcHand = GCHandle.Alloc(meshs[0].uv, GCHandleType.Pinned); //Marshal.Copy(verSrcHand.AddrOfPinnedObject(), meshData.uvBuffer, 0, meshData.uvBuffer.Length); //verSrcHand.Free(); } //法线 这里用来存动画第二帧的顶点信息 if (meshs[1].vertices != null && meshs[1].vertices.Length > 0) { meshData.normalBuffer = new float[count * 3]; for (int i = 0; i < meshs[0].vertices.Length; i++) { meshData.normalBuffer[i * 3] = meshs[1].vertices[i].x; meshData.normalBuffer[i * 3 + 1] = meshs[1].vertices[i].y; meshData.normalBuffer[i * 3 + 2] = meshs[1].vertices[i].z; } } //切线 这里用来存动画第三帧的顶点信息 if (meshs[2].vertices != null && meshs[2].vertices.Length > 0) { meshData.tangentBuffer = new float[count * 4]; for (int i = 0; i < meshs[0].vertices.Length; i++) { meshData.tangentBuffer[i * 4] = meshs[2].vertices[i].x; meshData.tangentBuffer[i * 4 + 1] = meshs[2].vertices[i].y; meshData.tangentBuffer[i * 4 + 2] = meshs[2].vertices[i].z; meshData.tangentBuffer[i * 4 + 3] = meshs[3].vertices[i].x; } } //UV2 用来存第四个关键帧率的 顶点YZ 坐标 X坐标由切线的W通道来存 if (meshs[3].vertices != null && meshs[3].vertices.Length > 0) { meshData.uv2Buffer = new float[count * 2]; for (int i = 0; i < meshs[0].vertices.Length; i++) { meshData.uv2Buffer[i * 2] = meshs[3].vertices[i].y; meshData.uv2Buffer[i * 2 + 1] = meshs[3].vertices[i].z; } } //颜色 用来存第5个顶点信息 //if (meshs[Indexs[4]].vertices != null && meshs[Indexs[4]].vertices.Length > 0) //{ // //颜色通道貌似没有负数,且范围为0到1 所有这里需要将模型顶点映射到[0,1]之间，映射范围为[-1,1]之间 // meshData.colorBuffer = new float[count * 4]; // for (int i = 0; i < meshs[Indexs[4]].vertices.Length; i++) // { // meshData.colorBuffer[i * 4] = (meshs[Indexs[4]].vertices[i].x * 0.5f) + 0.5f; // meshData.colorBuffer[i * 4 + 1] = (meshs[Indexs[4]].vertices[i].y * 0.5f) + 0.5f; // meshData.colorBuffer[i * 4 + 2] = (meshs[Indexs[4]].vertices[i].z * 0.5f) + 0.5f; // } //} count = 0; int len = 0; meshData.subMeshTriangleLens = new int[meshData.subMeshCount]; for (int i = 0; i < meshData.subMeshCount; i++) { len = meshs[0].GetTriangles(i).Length; count += len; meshData.subMeshTriangleLens[i] = len; } meshData.triangleBuffer = new int[count]; len = 0; for (int i = 0; i < meshData.subMeshCount; i++) { meshs[0].GetTriangles(i).CopyTo(meshData.triangleBuffer, len); len += meshData.subMeshTriangleLens[i]; } ByteBuffer bbuffer = new ByteBuffer(); bbuffer.WriteFloat(clipTimeLenghts); bbuffer.WriteFloat(frame2Pos); bbuffer.WriteFloat(frame3Pos); bbuffer.WriteInt(meshs[0].subMeshCount); for(int i=0;i<meshData.subMeshTriangleLens.Length;i++ ) { bbuffer.WriteInt(meshData.subMeshTriangleLens[i]); } bbuffer.WriteInt(meshData.triangleBuffer.Length); for (int i = 0; i < meshData.triangleBuffer.Length; i++) { bbuffer.WriteInt(meshData.triangleBuffer[i]); } bbuffer.WriteInt(meshData.vertexBuffer.Length); for (int i = 0; i < meshData.vertexBuffer.Length; i++) { bbuffer.WriteFloat(meshData.vertexBuffer[i]); } bbuffer.WriteInt(meshData.normalBuffer.Length); for (int i = 0; i < meshData.normalBuffer.Length; i++) { bbuffer.WriteFloat(meshData.normalBuffer[i]); } bbuffer.WriteInt(meshData.tangentBuffer.Length); for (int i = 0; i < meshData.tangentBuffer.Length; i++) { bbuffer.WriteFloat(meshData.tangentBuffer[i]); } bbuffer.WriteInt(meshData.uvBuffer.Length); for (int i = 0; i < meshData.uvBuffer.Length; i++) { bbuffer.WriteFloat(meshData.uvBuffer[i]); } bbuffer.WriteInt(meshData.uv2Buffer.Length); for (int i = 0; i < meshData.uv2Buffer.Length; i++) { bbuffer.WriteFloat(meshData.uv2Buffer[i]); } return bbuffer.ToBytes(); }
截取好后，保存为自己的二进制文件，运行的时候加载并 解析的代码如下：
public void AddAnimationInfo(string aniName, byte[] clipData) { VertexAnimationClipInfo clipInfo = null; AnimationClipInfos.TryGetValue(aniName, out clipInfo); if(clipInfo!=null) { Debug.LogError("animation clip has exits！"); return; } clipInfo = new VertexAnimationClipInfo(); ByteBuffer bbuffer = new ByteBuffer(clipData); int Count = bbuffer.ReadInt(); for (int i = 0; i < Count; i++) { ClipMeshData meshData = GetMeshData(bbuffer); clipInfo.clipTotalTimeLen += meshData.timeLenth; clipInfo.clipLenghts.Add(meshData.timeLenth); clipInfo.everyClipFrameTimePoints.Add(new Vector3(meshData.Frame2TimePoint, meshData.Frame3TimePoint)); //,meshData.Frame4TimePoint clipInfo.clipMeshs.Add(meshData.GenMesh()); } bbuffer.Close(); AnimationClipInfos.Add(aniName, clipInfo); }
VertexAnimationClipInfo定义如下：
[Serializable] public class VertexAnimationClipInfo { public float clipTotalTimeLen = 0; public List<Mesh> clipMeshs = new List<Mesh>(); public List<Vector2> everyClipFrameTimePoints = new List<Vector2>(); public List<float> clipLenghts = new List<float>(); }
ClipMeshData定义如下：
public class ClipMeshData { public float timeLenth; ///Frame1TimePoint =0 Frame4TimePoint = 1 public float Frame2TimePoint = 0.333f; public float Frame3TimePoint = 0.666f; //public float Frame4TimePoint = 0.75f; public int subMeshCount; public int[] subMeshTriangleLens; public int[] triangleBuffer; public float[] vertexBuffer; public float[] normalBuffer; public float[] tangentBuffer; public float[] uvBuffer; public float[] uv2Buffer; //public float[] colorBuffer; public Mesh GenMesh() { Mesh mesh = new Mesh(); int vertexCount = vertexBuffer.Length / 3; mesh.subMeshCount = subMeshCount; //顶点 Vector3[] vertexs = new Vector3[vertexCount]; for (int i = 0; i < vertexCount; i++) { vertexs[i] = new Vector3(vertexBuffer[i * 3], vertexBuffer[i * 3 + 1], vertexBuffer[i * 3 + 2]); } mesh.vertices = vertexs; //uv Vector2[] uv = new Vector2[vertexCount]; for (int i = 0; i < uv.Length; i++) { uv[i] = new Vector2(uvBuffer[i * 2], uvBuffer[i * 2 + 1]); } mesh.uv = uv; //uv2 Vector2[] uv2 = new Vector2[vertexCount]; for (int i = 0; i < uv.Length; i++) { uv2[i] = new Vector2(uv2Buffer[i * 2], uv2Buffer[i * 2 + 1]); } mesh.uv2 = uv2; //法线 Vector3[] normals = new Vector3[vertexCount]; for (int i = 0; i < normals.Length; i++) { normals[i] = new Vector3(normalBuffer[i * 3], normalBuffer[i * 3 + 1], normalBuffer[i * 3 + 2]); } mesh.normals = normals; //切线 var tangents = new Vector4[vertexCount]; for (int i = 0; i < tangents.Length; i++) { tangents[i] = new Vector4(tangentBuffer[i * 4], tangentBuffer[i * 4 + 1], tangentBuffer[i * 4 + 2], tangentBuffer[i * 4 + 3]); } mesh.tangents = tangents; ////颜色 //Color[] colors = new Color[colorBuffer.Length / 4]; //for (int i = 0; i < colors.Length; i++) //{ // colors[i] = new Vector4(colorBuffer[i * 4], colorBuffer[i * 4 + 1], colorBuffer[i * 4 + 2], 1); //} //mesh.colors = colors; //三角形 int startIndex = 0; int bufferLen = 0; for (int i = 0; i < subMeshCount; i++) { bufferLen = subMeshTriangleLens[i]; if (bufferLen <= 0) continue; var triIndexBuffer = new int[bufferLen]; Array.Copy(triangleBuffer, startIndex, triIndexBuffer, 0, bufferLen); mesh.SetTriangles(triIndexBuffer, i); startIndex += bufferLen; } return mesh; } }
播放动画切换对应的mesh就可以了，下面是gpu插值所用的shader代码：
Shader "LXZ_TEST/VertexAnimation-NoColorBuf" { Properties { _MainTex ("Base (RGB)", 2D) = "white" {} _CurTime("Time", Float) = 0 _Frame2Time("Frame2Time", Float) = 0.333 _Frame3Time("Frame3Time", Float) = 0.666 _Color ("MainColor", color) = (1,1,1,1) } SubShader { // Tags { "QUEUE"="Geometry" "RenderType"="Opaque" } Pass { Blend SrcAlpha OneMinusSrcAlpha CGPROGRAM #pragma vertex vert #pragma fragment frag // #include "UnityCG.cginc" #pragma glsl_no_auto_normalization sampler2D _MainTex; float _CurTime; float _Frame2Time; float _Frame3Time; float4 _Color; struct appdata { float4 vertex : POSITION; float3 vertex1 : NORMAL; float4 vertex2 : TANGENT; float2 texcoord : TEXCOORD0; float2 vertex3: TEXCOORD1; //float3 vertex4: COLOR; }; struct v2f { float4 pos : POSITION; float2 uv : TEXCOORD0; }; v2f vert(appdata v) { v2f result; float a = _CurTime - _Frame2Time; float b = _CurTime - _Frame3Time; float3 vec; float3 vertex3 = float3(v.vertex2.w,v.vertex3.xy); if(a<0) vec = v.vertex.xyz + (v.vertex1 - v.vertex.xyz)* _CurTime/_Frame2Time; else if(a>=0 && b<0) { vec = v.vertex1 + (v.vertex2.xyz - v.vertex1)* a/(_Frame3Time-_Frame2Time); } else vec = v.vertex2.xyz + (vertex3 - v.vertex2.xyz)* b/(1-_Frame3Time); result.pos = mul(UNITY_MATRIX_MVP, float4(vec,1)); //result.pos = mul(UNITY_MATRIX_MVP, float4(v.vertex1.xyz,1)); //result.pos = mul(UNITY_MATRIX_MVP, float4(v.vertex2.xyz,1)); // result.pos = mul(UNITY_MATRIX_MVP, float4(vertex3.xyz,1)); // result.pos = mul(UNITY_MATRIX_MVP, float4(vertex4.xyz,1)); result.uv = v.texcoord; return result; } float4 frag(v2f i) : COLOR { float4 color = tex2D(_MainTex, i.uv); return color *_Color; } ENDCG } } FallBack "Diffuse" }
如果各位还有更好的方案，欢迎交流。。不擅长文字的东西，所以直接贴代码了，有需要可以与我连续交流。。。
- 1楼博客园团队
- 您好，为了更好的阅读体验，建议给代码加上高亮。