Unity 网格 绘制
网格绘制主要用是对Mesh进行操作,通过对vertex和triangles进行操作生成对应的面片;
这里首先得用到一个类:Triangulator(根据vertex生成triangles数组)
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
using UnityEngine; using System.Collections.Generic; public class Triangulator { private static List<Vector2> points; private static Vector3 cameraPosition; public static Vector2[] ToVector2(Vector3[] m_points) { Vector2[] vertices2d = new Vector2[m_points.Length]; for (int i = 0; i < m_points.Length; i++) { Vector3 pos = m_points[i]; vertices2d[i] = new Vector2(pos.x, pos.z); } return vertices2d; } public static int[] Triangulate(Vector2[] m_points, Vector3 m_cameraPosition) { points = new List<Vector2>(m_points); cameraPosition = m_cameraPosition; List<int> indices = new List<int>(); int n = points.Count; if (n < 3) return indices.ToArray(); int[] V = new int[n]; if (Area() > 0) { for (int v = 0; v < n; v++) V[v] = v; } else { for (int v = 0; v < n; v++) V[v] = (n - 1) - v; } int nv = n; int count = 2 * nv; for (int m = 0, v = nv - 1; nv > 2;) { if ((count--) <= 0) break; int u = v; if (nv <= u) u = 0; v = u + 1; if (nv <= v) v = 0; int w = v + 1; if (nv <= w) w = 0; if (Snip(u, v, w, nv, V)) { int a, b, c, s, t; a = V[u]; b = V[v]; c = V[w]; indices.Add(a); indices.Add(b); indices.Add(c); m++; for (s = v, t = v + 1; t < nv; s++, t++) V[s] = V[t]; nv--; count = 2 * nv; } } bool reversFlag = true; int i0 = indices[0]; int i1 = indices[1]; int i2 = indices[2]; Vector3 pos0 = new Vector3(points[i0].x, 0f, points[i0].y); Vector3 pos1 = new Vector3(points[i1].x, 0f, points[i1].y); Vector3 pos2 = new Vector3(points[i2].x, 0f, points[i2].y); Vector3 v1 = pos1 - pos0; Vector3 v2 = pos2 - pos1; Vector3 crossVec = Vector3.Cross(v1, v2); if (Vector3.Dot(cameraPosition, crossVec) > 0) { reversFlag = false; } if (reversFlag) { indices.Reverse(); } return indices.ToArray(); } private static float Area() { int n = points.Count; float A = 0.0f; for (int p = n - 1, q = 0; q < n; p = q++) { Vector2 pval = points[p]; Vector2 qval = points[q]; A += pval.x * qval.y - qval.x * pval.y; } return (A * 0.5f); } private static bool Snip(int u, int v, int w, int n, int[] V) { int p; Vector2 A = points[V[u]]; Vector2 B = points[V[v]]; Vector2 C = points[V[w]]; if (Mathf.Epsilon > (((B.x - A.x) * (C.y - A.y)) - ((B.y - A.y) * (C.x - A.x)))) return false; for (p = 0; p < n; p++) { if ((p == u) || (p == v) || (p == w)) continue; Vector2 P = points[V[p]]; if (InsideTriangle(A, B, C, P)) return false; } return true; } private static bool InsideTriangle(Vector2 A, Vector2 B, Vector2 C, Vector2 P) { float ax, ay, bx, by, cx, cy, apx, apy, bpx, bpy, cpx, cpy; float cCROSSap, bCROSScp, aCROSSbp; ax = C.x - B.x; ay = C.y - B.y; bx = A.x - C.x; by = A.y - C.y; cx = B.x - A.x; cy = B.y - A.y; apx = P.x - A.x; apy = P.y - A.y; bpx = P.x - B.x; bpy = P.y - B.y; cpx = P.x - C.x; cpy = P.y - C.y; aCROSSbp = ax * bpy - ay * bpx; cCROSSap = cx * apy - cy * apx; bCROSScp = bx * cpy - by * cpx; return ((aCROSSbp >= 0.0f) && (bCROSScp >= 0.0f) && (cCROSSap >= 0.0f)); } }
然后我们创建一个脚本:DrawMesh.cs
using UnityEngine; using System.Collections; using System.Collections.Generic; using System; public class DrawMesh : MonoBehaviour { #region 公共变量 /// <summary> /// 绘制模式,间断、连续 /// </summary> public enum DrawMeshModel { Intermittently, Continuously }; /// <summary> /// 线段材质、网格材质 /// </summary> public Material lineMat, meshMat; /// <summary> /// 绘制模式 /// </summary> public DrawMeshModel drawModel = DrawMeshModel.Intermittently; public float lineWidth = 0.5f;//线段宽度 public float meshAlpha = 0.2f;//网格透明度 #endregion #region 私有变量 Vector3[] points = new Vector3[0]; LineRenderer lineTemp; GameObject lineObject; MeshFilter meshFilter; GameObject meshObject; Mesh mesh;//网格 Ray ray; RaycastHit hit; /// <summary> /// 记录上一点位置 /// </summary> Vector3 last = Vector3.zero; #endregion void Start() { lineObject = new GameObject("LineGameObject"); lineTemp = lineObject.AddComponent<LineRenderer>(); lineTemp.SetWidth(lineWidth, lineWidth); lineTemp.material = lineMat; meshObject = new GameObject("MeshGameObject"); meshFilter = meshObject.AddComponent<MeshFilter>(); meshObject.AddComponent<MeshRenderer>(); meshObject.GetComponent<Renderer>().material = meshMat; Color tempColor = meshMat.color; tempColor.a = meshAlpha; meshMat.color = tempColor; mesh = new Mesh(); lineObject.SetActive(false); } void Update() { if (Input.GetMouseButton(2) && drawModel == DrawMeshModel.Continuously
|| Input.GetMouseButtonDown(2) && drawModel == DrawMeshModel.Intermittently) { if (!lineObject.activeInHierarchy) lineObject.SetActive(true); ray = Camera.main.ScreenPointToRay(Input.mousePosition); if (Physics.Raycast(ray, out hit)) { if (drawModel == DrawMeshModel.Continuously) { if (last == Vector3.zero) { last = hit.point; return; } else if (Vector3.Distance(last, hit.point) < 1f) { return; } last = hit.point; } Array.Resize(ref points, points.Length + 1); points[points.Length - 1] = hit.point + new Vector3(0, 0.25f, 0); lineTemp.SetVertexCount(points.Length); lineTemp.SetPosition(points.Length - 1, points[points.Length - 1]); if (points.Length > 2) { mesh.vertices = points; mesh.triangles = Triangulator.Triangulate(Triangulator.ToVector2(points), Camera.main.transform.position); meshFilter.mesh = mesh; } } } } }
将DrawMesh脚本放置到物体上,给LineRenderer和Mesh赋上材质,这里我创建了一个枚举:DrawMeshModel;
通过选择Draw Model为Intermittently进行点击绘图,选择Continuously进行连续绘图;
设置线段宽度Line Width,网格透明度Mesh Alpha;
最后通过鼠标在Collider上绘制Mesh形状。
最终效果1:
最终效果2:
截图和GIF并非同一次画的,录的视频没上传成功,只好转成了gif,另外又截了图。