Unity中Mesh分解与边缘高亮加上深度检测
一个比较简单的需求，不过遇到些坑，记录下。
房间有多个模型，每个模型可能多个SubMesh,点击后，需要能具体到是那个SubMesh,并且在这个SubMesh上显示边缘高光，以及能个性这单个SubMesh对应的Material。如一个桌子的Mesh,其实有二个材质，分别对应二个SubMesh,一个桌面和一个桌脚，点击桌面后，只有这个桌面高光，而不是整个桌子，并且能单独更换这个桌面的Material.
我们知道Unity中，Mesh和Ogre一样，也是可以有多个SubMesh，每个SubMesh有自己的Material,但是不同Ogre每个Submesh可以有不同的顶点数据，Unity中Mesh所有SubMesh共享相同顶点数据，分别使用不同的顶点索引。我原来做过一个项目，用Ogre里的Renderable与MovableObject组合形成这种格式，里面的所有模型都是用的这种格式显示，而不是Ogre本身的Entiy,当时就发现这种更容易理解，好用。
下面这个脚本文件是这个功能的具体实现，包含分解Mesh,检查具体是那个SubMesh碰撞等功能。
using UnityEngine; using System.Collections; using System.Collections.Generic; using System; using UnityEngine.EventSystems; public class RayCheck : MonoBehaviour { //public MaterialUI ui; public NewUIControl ui; private Collider preCollider; private int cIndex = -1; private Material lineMat = null; private Material selectMat = null; //private Material showMat = null; private MeshFilter meshFilter = null; private MeshRenderer meshRender = null; private MeshCollider meshCollider = null; private BoxCollider boxCollider = null; private new Transform transform = null; private LineRenderer lineRender = null; private HighlightableObject hightLight = null; private float vminDist = 1.0f; private List<int> indexLay = new List<int>(); private bool bPreObject = false; private int preIndex = 0; private Mesh mesh = null; //如果为true,所有模型都能切换texture public bool defaultAdd = true; private RaycastHit preHit = new RaycastHit(); private bool bHold = false; private Vector3 oldLocation = Vector3.zero; private Dictionary<string, List<string>> matTextures = new Dictionary<string, List<string>>(); void Start() { lineMat = Resources.Load<Material>("LineMat"); //showMat = Resources.Load<Material>("ShowMat"); meshFilter = checkDefault<MeshFilter>(); meshCollider = checkDefault<MeshCollider>(); meshRender = checkDefault<MeshRenderer>(); boxCollider = checkDefault<BoxCollider>(); transform = checkDefault<Transform>(); lineRender = checkDefault<LineRenderer>(); hightLight = checkDefault<HighlightableObject>(); lineRender.useWorldSpace = false; lineRender.sharedMaterial = lineMat; lineRender.SetWidth(0.01f, 0.01f); //meshRender.sharedMaterial = showMat; //单独添加层，在正常渲染时，让摄像机不渲染这个模型，我们只需要在高光时渲染 this.gameObject.layer = 4; mesh = new Mesh(); StartCoroutine(XmlReader.GetXML("materialtextures.xml", matTextures, XmlReader.ParseMatXml, this.InitUiMatTextures)); //ui.onApply = ApplyMaterial; } public void InitUiMatTextures() { ui.SetMatTextures(matTextures); } T checkDefault<T>() where T : Component { T t = this.gameObject.GetComponent<T>(); if (t == null) { t = this.gameObject.AddComponent<T>(); } return t; } // Update is called once per frame void Update() { //!ui.isActiveAndEnabled && #if UNITY_EDITOR if (Input.GetMouseButtonDown(0) && !EventSystem.current.IsPointerOverGameObject()) #elif UNITY_ANDROID || UNITY_IPHONE if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began && !EventSystem.current.IsPointerOverGameObject(Input.GetTouch(0).fingerId)) #endif { Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition); RaycastHit hit; var bAxis = Physics.Raycast(ray, out hit, 10000.0f, 2 << 7); if (bAxis) { preHit = hit; bHold = true; oldLocation = preCollider.transform.position; return; } //与当前camera最近交点 if (GetMinDist(ray, out hit)) { if (preCollider != null) { lineRender.enabled = false; } //如果不是同一个模型，indexLay清空 bPreObject = hit.collider == preCollider; if (!bPreObject && preCollider != null) { preCollider.gameObject.SetActive(true); indexLay.Clear(); } preCollider = hit.collider; //得到选择的gameObject模型 if (checkIsRender(hit.collider, ray)) { //preCollider.gameObject.SetActive(false); if (selectMat != null) { var haveTexture = ui.SetSelectMat(selectMat); //当前材质有对应能够更新的纹理 if (defaultAdd || haveTexture) ui.gameObject.SetActive(true); else ui.gameObject.SetActive(false); //显示高亮 hightLight.ReinitMaterials(); hightLight.FlashingOn(2f); if (defaultAdd || haveTexture) hightLight.On(); else hightLight.Off(); } } } } #if UNITY_EDITOR if (Input.GetMouseButtonUp(0)) #elif UNITY_ANDROID || UNITY_IPHONE if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Ended) #endif { bHold = false; } } public void FixedUpdate() { DragAxis(); } public void DragAxis() { #if UNITY_EDITOR if (bHold && Input.GetMouseButton(0)) #elif UNITY_ANDROID || UNITY_IPHONE if (bHold && Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Moved) #endif { Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition); var newPot = ray.origin + ray.direction * preHit.distance - preHit.point; preCollider.transform.position = newPot; } } public bool GetMinDist(Ray ray, out RaycastHit rayHit) { rayHit = new RaycastHit(); var hits = Physics.RaycastAll(ray); var origin = Camera.main.transform.position; float minDist = float.MaxValue; bool result = false; foreach (var hit in hits) { if (hit.collider == meshCollider || hit.collider == boxCollider) continue; var sqrLenght = (hit.point - origin).sqrMagnitude; if (sqrLenght < minDist) { minDist = sqrLenght; rayHit = hit; result = true; } } return result; } public bool checkIsRender(Collider collider, Ray ray) { var render = collider.GetComponent<Renderer>(); var filter = collider.GetComponent<MeshFilter>(); if (render != null && filter != null) { //设置成当成位置 transform.position = render.transform.position; transform.rotation = render.transform.rotation; transform.localScale = render.transform.localScale; transform.parent = render.transform.parent; //初始化信息 float minDist = float.MaxValue; AABB minAABB = new AABB(); cIndex = 0; selectMat = null; mesh.Clear(); Collider currentCollider = null; mesh.vertices = filter.mesh.vertices; mesh.normals = filter.mesh.normals; mesh.uv = filter.mesh.uv; mesh.uv2 = filter.mesh.uv2; //使用如下语句，颜色包含GI能正确使用，描边不能用，可能与UV有关。 //不使用，模型对应GI颜色不对，但是描边能用。 //解决方法: 定义raycheck自己的gameObject的层为单独一层,这样当前模型不渲染，只渲染描边 //meshRender.useLightProbes = render.useLightProbes; //meshRender.lightmapIndex = render.lightmapIndex; //meshRender.lightmapScaleOffset = render.lightmapScaleOffset; //meshRender.realtimeLightmapIndex = render.realtimeLightmapIndex; //meshRender.realtimeLightmapScaleOffset = render.realtimeLightmapScaleOffset; //如果有多个SubMesh,重新分割每个SubMesh,并重新验证相交，取最近subMesh if (filter.mesh.subMeshCount > 1) { for (int meshIndex = 0; meshIndex < filter.mesh.subMeshCount; meshIndex++) { meshCollider.enabled = false; boxCollider.enabled = false; var indexs = filter.mesh.GetIndices(meshIndex); mesh.SetIndices(indexs, filter.mesh.GetTopology(meshIndex), 0); if (indexs.Length / 3 > 255) { boxCollider.enabled = true; boxCollider.center = mesh.bounds.center; boxCollider.size = mesh.bounds.size; currentCollider = boxCollider; } else { meshCollider.enabled = true; meshCollider.sharedMesh = mesh; currentCollider = meshCollider; } RaycastHit hit; if (currentCollider.Raycast(ray, out hit, 10000)) { float sqrLenght = (Camera.main.transform.position - hit.point).sqrMagnitude; //模型有多个subMesh,但是无论怎么点击，其中一个subMesh总是最近。 if (Mathf.Abs(sqrLenght - minDist) < vminDist) { if (!indexLay.Contains(cIndex)) { indexLay.Add(cIndex); } if (!indexLay.Contains(meshIndex)) { indexLay.Add(meshIndex); } } if (sqrLenght < minDist) { minDist = sqrLenght; cIndex = meshIndex; minAABB.Min = mesh.bounds.center - mesh.bounds.size / 2f; minAABB.Max = mesh.bounds.center + mesh.bounds.size / 2f; } } } } //一个模型有多个SubMesh,并且每个SubMesh边框相重。 if (indexLay.Count > 1 && preCollider) { if (indexLay.Contains(preIndex)) { var nIndex = indexLay.IndexOf(preIndex); cIndex = ++nIndex % indexLay.Count; } preIndex = cIndex; } if (cIndex >= 0 && render.materials.Length > cIndex) { selectMat = render.materials[cIndex]; //显示自己的Mesh var indexs = filter.mesh.GetIndices(cIndex); mesh.SetIndices(indexs, filter.mesh.GetTopology(cIndex), 0); meshFilter.mesh = mesh; //重新设置材质 meshRender.material = selectMat; var vertexs = minAABB.LinePositions(); lineRender.SetVertexCount(vertexs.Length); lineRender.SetPositions(vertexs); //重置状态 //lineRender.enabled = true; meshRender.enabled = true; return true; } } return false; } public void ApplyMaterial() { meshRender.enabled = false; ui.gameObject.SetActive(false); } } public class AABB { private bool cornerDirty = true; private Vector3 min = Vector3.zero; private Vector3 max = Vector3.zero; public Vector3[] mCorners = new Vector3[8]; public Vector3[] Corners { get { if (cornerDirty) { GetAllCorners(); } return mCorners; } } public Vector3 Min { get { return min; } set { min = value; cornerDirty = true; } } public Vector3 Max { get { return max; } set { max = value; cornerDirty = true; } } private void makeFloor(Vector3 cmp) { if (cmp.x < min.x) min.x = cmp.x; if (cmp.y < min.y) min.y = cmp.y; if (cmp.z < min.z) min.z = cmp.z; } private void makeCeil(Vector3 cmp) { if (cmp.x > max.x) max.x = cmp.x; if (cmp.y > max.y) max.y = cmp.y; if (cmp.z > max.z) max.z = cmp.z; } public void Merge(Vector3 cmp) { makeCeil(cmp); makeFloor(cmp); cornerDirty = true; } public void SetNull() { min = Vector3.zero; max = Vector3.zero; cornerDirty = true; } /// <summary> /// private void GetAllCorners() { mCorners[0] = min; mCorners[1].x = min.x; mCorners[1].y = max.y; mCorners[1].z = min.z; mCorners[2].x = max.x; mCorners[2].y = max.y; mCorners[2].z = min.z; mCorners[3].x = max.x; mCorners[3].y = min.y; mCorners[3].z = min.z; mCorners[4] = max; mCorners[5].x = min.x; mCorners[5].y = max.y; mCorners[5].z = max.z; mCorners[6].x = min.x; mCorners[6].y = min.y; mCorners[6].z = max.z; mCorners[7].x = max.x; mCorners[7].y = min.y; mCorners[7].z = max.z; } public Vector3[] LinePositions() { int i = 0; Vector3[] pos = new Vector3[16]; //前面 pos[i++] = this.Corners[0]; pos[i++] = this.Corners[1]; pos[i++] = this.Corners[2]; //下边 pos[i++] = this.Corners[3]; pos[i++] = this.Corners[0]; pos[i++] = this.Corners[6]; //右边 pos[i++] = this.Corners[7]; pos[i++] = this.Corners[3]; pos[i++] = this.Corners[2]; //后面 pos[i++] = this.Corners[4]; pos[i++] = this.Corners[7]; pos[i++] = this.Corners[6]; //左边 上边 pos[i++] = this.Corners[5]; pos[i++] = this.Corners[1]; pos[i++] = this.Corners[5]; pos[i++] = this.Corners[4]; return pos; } public AABB Clone() { AABB ab = new AABB(); ab.min = this.min; ab.max = this.max; ab.cornerDirty = true; return ab; } }
需要注意的点是：
1 如果几个模型有多个SubMesh分散在各个位置，故需要把所有RaycastHit上碰撞点与眼睛求出最近点。
2 LineRender中是N点组成N-1条线，而不是N/2,如A-B-C-D,并不是显示AB，CD.而是AB,BC,CD.
3 模型的SubMesh可能边框重合，这样的话，就会导致可能永远都是选的其中一个。
4 我们根据SubMesh生成新的Mesh,并不需要在主摄像头中渲染(通过Layer与cullingMask组合)，不然和原来模型的SubMesh显示不清。
5 鼠标按下，是否在UI上面，鼠标弹起，电脑与移动平台要不同的处理。
6 安卓平台下，用WWW加载资源，必需用yield return,故相应加载完成的处理可以用函数指针传入。
到这模型就差不多了，然后添加边缘高亮组件highightingSystem，这个的思路也是比较简单的。
首先在主摄像机渲染场景前，把边缘高亮的模型给一个单独的层，并且修改相应材质为我们需要高亮的颜色，然后复制主摄像头新生成一个摄像头，新摄像头的cullingMask只渲染前面边缘高亮模型的层的那些模型到一张Stencil的RTT中保存，然后把原来的边缘高亮的模型的层和材质换回来。
然后是主摄像头正常渲染，渲染完后，在OnRenderImage中先把在上面的那张RTT进行简单的Blur模糊，保存为Blur的RTT。最后把上面的Stencil的RTT，Blur的RTT，主摄像头渲染的source,我们并不渲染stencil本身，只渲染stencil模糊后的边缘部分。
嗯，现在有个麻烦，老大要在看不到的部分不显示高亮，如下这样：
第一张图是现在的显示效果，老大要的是第二张，说实话，我最开始以为很简单，好吧，做完后就加了点东东，确实不复杂，但是因为对Unity的相关理解有误，把采过的坑说下。
说实话，这个需求就是加个深度检测就行了，那么在原来基础上添加如下一些代码。
shaderCamera.CopyFrom(refCam); shaderCamera.projectionMatrix = refCam.projectionMatrix; // Uncomment this line if you have problems using Highlighting System with custom projection matrix on your camera shaderCamera.cullingMask = layerMask; shaderCamera.rect = new Rect(0f, 0f, 1f, 1f); shaderCamera.renderingPath = RenderingPath.Forward; shaderCamera.hdr = false; shaderCamera.useOcclusionCulling = false; shaderCamera.backgroundColor = new Color(0f, 0f, 0f, 0f); shaderCamera.clearFlags = CameraClearFlags.Color; shaderCamera.targetTexture = stencilBuffer; //我们因为直接在渲染highlight object，故可以直接算出深度，并不需要在前面多渲染一次 shaderCamera.depthTextureMode = DepthTextureMode.None; //通过culling mask(layerMask),只渲染highlight object shaderCamera.Render(); //渲染深度 depthBuffer = RenderTexture.GetTemporary((int)GetComponent<Camera>().pixelWidth, (int)GetComponent<Camera>().pixelHeight, 16, RenderTextureFormat.RHalf); shaderCamera.targetTexture = depthBuffer; shaderCamera.RenderWithShader(DepthShader, null);
Shader.
Shader "Custom/Render depth buffer" { SubShader { Tags{ "RenderType" = "Opaque" } Pass { ZWrite Off ZTest Always Lighting Off Fog{ Mode Off } CGPROGRAM #pragma vertex vert #pragma fragment frag #include "UnityCG.cginc" //sampler2D_float _LastCameraDepthTexture; //sampler2D_float _CameraDepthTexture; struct v2f { float4 vertex : POSITION; float2 uv : TEXCOORD0; float depth : TEXCOORD1; }; v2f vert(appdata_img v) { v2f o; o.vertex = mul(UNITY_MATRIX_MVP, v.vertex); o.uv = v.texcoord.xy; //float2(v.texcoord.x, 1 - v.texcoord.y); //v.texcoord.xy; o.depth = COMPUTE_DEPTH_01; return o; } float4 frag(v2f i) : COLOR { //float depth = SAMPLE_DEPTH_TEXTURE(_LastCameraDepthTexture, i.uv); //float depthSample = Linear01Depth(SAMPLE_DEPTH_TEXTURE(_LastCameraDepthTexture, i.uv));//_CameraDepthTexture _LastCameraDepthTexture //return float4(depthSample, 0, 0, 0); return float4(i.depth,0,0,0); } ENDCG } } FallBack Off }
在这我进行一次尝试，结果不对，在shaderCamera.Render()渲染之前，设定depthTextureMode为Depth,我在Shader开始应用_CameraDepthTexture，发现结果不对，网上查找说是这个RTT一直是主摄像头的，后面使用_LastCameraDepthTexture，结果很奇怪，和后面主摄像头的_CameraDepthTexture比对结果完全对不上，深度值不是0或1，但是渲染出来看，深度值又没看到变化，后来仔细想了下，应该是主摄像头Graphics.Blit后的值，因为这个只是渲染一个正方形，深度显示出来就会这样。
最后去Unity5Shader里面找_CameraDepthTexture这个RTT是如何渲染的，我们找到这个值COMPUTE_DEPTH_01是放入深度RTT中的，具体意思大家去unityCG.cginc里去找就行了,因为这个值就是根据当前顶点的位置算出来的，所以在这我们放入顶点着色器就行。
然后就是在第一张Blur模糊图上比较上一张深度RTT的深度值，相应DEPTH_COMP_ON位置为新增加的。
// Downsamples source texture private void DownSample4x(RenderTexture source, RenderTexture dest) { float off = 1.0f; blurMaterial.SetFloat("_OffsetScale", off); blurMaterial.SetTexture("_DepthTex", depthBuffer); if (bBlueDepthTest) { blurMaterial.EnableKeyword("DEPTH_COMP_ON"); } //blurMaterial.DisableKeyword("DEPTH_COMP_OFF"); Graphics.Blit(source, dest, blurMaterial); }
Shader "Hidden/Highlighted/Blur" { Properties { _MainTex("", 2D) = "" {} _Intensity("", Range(0.25,0.5)) = 0.3 _DepthTex("", 2D) = "" {} } SubShader { Pass { ZTest Always Cull Off ZWrite Off Lighting Off Fog { Mode Off } CGPROGRAM #pragma vertex vert #pragma fragment frag #pragma fragmentoption ARB_precision_hint_fastest #pragma multi_compile __ DEPTH_COMP_ON //DEPTH_COMP_OFF #include "UnityCG.cginc" uniform sampler2D _MainTex; uniform half4 _MainTex_TexelSize; uniform half _OffsetScale; uniform fixed _Intensity; #if defined(DEPTH_COMP_ON) uniform sampler2D _DepthTex; sampler2D_float _CameraDepthTexture; #endif struct v2f { float4 pos : POSITION; half2 duv : TEXCOORD0; half2 uv[4] : TEXCOORD1; }; v2f vert(appdata_img v) { // Shader code optimized for the Unity shader compiler v2f o; o.pos = mul(UNITY_MATRIX_MVP, v.vertex); half2 offs = _MainTex_TexelSize.xy * _OffsetScale; o.uv[0].x = v.texcoord.x - offs.x; o.uv[0].y = v.texcoord.y - offs.y; o.uv[1].x = v.texcoord.x + offs.x; o.uv[1].y = v.texcoord.y - offs.y; o.uv[2].x = v.texcoord.x + offs.x; o.uv[2].y = v.texcoord.y + offs.y; o.uv[3].x = v.texcoord.x - offs.x; o.uv[3].y = v.texcoord.y + offs.y; o.duv = v.texcoord.xy; if (_MainTex_TexelSize.y < 0) o.duv.y = 1 - o.duv.y; return o; } fixed4 frag(v2f i) : COLOR { fixed4 color1 = tex2D(_MainTex, i.uv[0]); fixed4 color2 = tex2D(_MainTex, i.uv[1]); fixed4 color3 = tex2D(_MainTex, i.uv[2]); fixed4 color4 = tex2D(_MainTex, i.uv[3]); fixed4 color; color.rgb = max(color1.rgb, color2.rgb); color.rgb = max(color.rgb, color3.rgb); color.rgb = max(color.rgb, color4.rgb); color.a = (color1.a + color2.a + color3.a + color4.a) * _Intensity; #if defined(DEPTH_COMP_ON) float cDepth = Linear01Depth(SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, i.duv)); float oDepth = tex2D(_DepthTex, i.duv).r; //当Blur桢的深度 大于 当前桢的深度 if (abs(oDepth - cDepth) > 0.001) { color.rgba = fixed4(0,0,0,0); } #endif return color; } ENDCG } } Fallback off }
注意：
1 我们只需要比较第一张模糊图的深度，后面的模糊都是根据这张再重新模糊，因此我们在着色器定义编译符，使之第一次与后面几次根据编译符不同的执行。
2 在深度比较的Shader中，我们其实已经取不到原顶点pos相应的值了，因为我们并不是渲染原来的模型，而是相当于Ogre中的后处理PassQuad(只渲染一个正方形)，因此，在这之前，需要将主摄像根据情况，先把设定主摄像头的depthTextureMode为Depth，这样在OnPreRender之后，主摄像头正常渲染前，先调用UpdateDepthTexture，渲染场景内所有模型的深度到_CameraDepthTexture上，这样在后面的OnRenderImage中，我们才能取到正常的深度值。
3 在这，二张深度图里默认的精度都只有16位，因此需要定义一个范围。
有几次试错，都在于没搞清Unity里的执行过程，后来结合Untiy提供的Frame Debugger,才搞定这个简单的修改。
