Unity3d之将terrain转化成mesh

  1 using UnityEditor;
  2 using UnityEngine;
  3 
  4 public class TerrainToMeshConverter : ScriptableObject
  5 {
  6     [MenuItem("Custom/Convert terrain to mesh")]
  7     static void Init()
  8     {
  9         if (Selection.objects.Length <= 0)
 10         {
 11             DevDebug.Log("Selection.objects.Length <= 0");
 12             return;
 13         }
 14 
 15         var terrainObj = Selection.objects[0] as GameObject;
 16         if (terrainObj == null)
 17         {
 18             DevDebug.Log("terrainObj == null");
 19             return;
 20         }
 21 
 22         var terrain = terrainObj.GetComponent<Terrain>();
 23         if (terrain == null)
 24         {
 25             DevDebug.Log("terrain == null");
 26             return;
 27         }
 28 
 29         var terrainData = terrain.terrainData;
 30         if (terrainData == null)
 31         {
 32             DevDebug.Log("terrainData == null");
 33             return;
 34         }
 35 
 36         int vertexCountScale = 4;       // [dev] 将顶点数稀释 vertexCountScale*vertexCountScale 倍
 37         int w = terrainData.heightmapWidth;
 38         int h = terrainData.heightmapHeight;
 39         Vector3 size = terrainData.size;
 40         float[, ,] alphaMapData = terrainData.GetAlphamaps(0, 0, terrainData.alphamapWidth, terrainData.alphamapHeight);
 41         Vector3 meshScale = new Vector3(size.x / (w - 1f) * vertexCountScale, 1, size.z / (h - 1f) * vertexCountScale);
 42         Vector2 uvScale = new Vector2(1f / (w - 1f), 1f / (h - 1f)) * vertexCountScale * (size.x / terrainData.splatPrototypes[0].tileSize.x);     // [dev] 此处有问题，若每个图片大小不一，则出问题。日后改善
 43 
 44         w = (w - 1) / vertexCountScale + 1;
 45         h = (h - 1) / vertexCountScale + 1;
 46         Vector3[] vertices = new Vector3[w * h];
 47         Vector2[] uvs = new Vector2[w * h];
 48         Vector4[] alphasWeight = new Vector4[w * h];            // [dev] 只支持4张图片
 49 
 50         // 顶点，uv，每个顶点每个图片所占比重
 51         for (int i = 0; i < w; i++)
 52         {
 53             for (int j = 0; j < h; j++)
 54             {
 55                 int index = j * w + i;
 56                 float z = terrainData.GetHeight(i * vertexCountScale, j * vertexCountScale);
 57                 vertices[index] = Vector3.Scale(new Vector3(i, z, j), meshScale);
 58                 uvs[index] = Vector2.Scale(new Vector2(i, j), uvScale);
 59 
 60                 // alpha map
 61                 int i2 = (int)(i * terrainData.alphamapWidth / (w - 1f));
 62                 int j2 = (int)(j * terrainData.alphamapHeight / (h - 1f));
 63                 i2 = Mathf.Min(terrainData.alphamapWidth - 1, i2);
 64                 j2 = Mathf.Min(terrainData.alphamapHeight - 1, j2);
 65                 var alpha0 = alphaMapData[j2, i2, 0];
 66                 var alpha1 = alphaMapData[j2, i2, 1];
 67                 var alpha2 = alphaMapData[j2, i2, 2];
 68                 var alpha3 = alphaMapData[j2, i2, 3];
 69                 alphasWeight[index] = new Vector4(alpha0, alpha1, alpha2, alpha3);
 70             }
 71         }
 72 
 73         /*
 74          * 三角形
 75          *     b       c
 76          *      *******
 77          *      *   * *
 78          *      * *   *
 79          *      *******
 80          *     a       d
 81          */
 82         int[] triangles = new int[(w - 1) * (h - 1) * 6];
 83         int triangleIndex = 0;
 84         for (int i = 0; i < w - 1; i++)
 85         {
 86             for (int j = 0; j < h - 1; j++)
 87             {
 88                 int a = j * w + i;
 89                 int b = (j + 1) * w + i;
 90                 int c = (j + 1) * w + i + 1;
 91                 int d = j * w + i + 1;
 92 
 93                 triangles[triangleIndex++] = a;
 94                 triangles[triangleIndex++] = b;
 95                 triangles[triangleIndex++] = c;
 96 
 97                 triangles[triangleIndex++] = a;
 98                 triangles[triangleIndex++] = c;
 99                 triangles[triangleIndex++] = d;
100             }
101         }
102 
103         Mesh mesh = new Mesh();
104         mesh.vertices = vertices;
105         mesh.uv = uvs;
106         mesh.triangles = triangles;
107         mesh.tangents = alphasWeight;
108         mesh.Optimize();
109 
110         // 地形渲染  [dev] 目前不支持光照，有待改善
111         var mat = new Material(Shader.Find("Custom/TerrainDiffuse"));
112         for (int i = 0; i < terrainData.splatPrototypes.Length; i++)
113         {
114             var sp = terrainData.splatPrototypes[i];
115             mat.SetTexture("_Texture" + i, sp.texture);
116         }
117 
118         string transName = "[dev]MeshFromTerrainData";
119         var t = terrainObj.transform.parent.Find(transName);
120         if (t == null)
121         {
122             GameObject go = new GameObject(transName, typeof(MeshFilter), typeof(MeshRenderer), typeof(MeshCollider));
123             t = go.transform;
124         }
125 
126         t.parent = terrainObj.transform.parent;
127         t.position = terrainObj.transform.position;
128         t.gameObject.layer = terrainObj.layer;
129         t.GetComponent<MeshFilter>().sharedMesh = mesh;
130         t.GetComponent<MeshCollider>().sharedMesh = mesh;
131         t.GetComponent<MeshRenderer>().sharedMaterial = mat;
132 
133         t.gameObject.SetActive(true);
134         terrainObj.SetActive(false);
135     }
136 }

 1 Shader "Custom/TerrainDiffuse"
 2 {
 3     Properties
 4     {
 5         _Texture0 ("Texture 1", 2D) = "white" {}
 6         _Texture1 ("Texture 2", 2D) = "white" {}
 7         _Texture2 ("Texture 3", 2D) = "white" {}
 8         _Texture3 ("Texture 4", 2D) = "white" {}
 9     }
10     
11     SubShader
12     {
13         Tags { "RenderType"="Opaque" }
14         LOD 200
15         
16         Pass
17         {
18             CGPROGRAM
19             #pragma vertex Vert
20             #pragma fragment Frag
21 
22             sampler2D _Texture0;
23             sampler2D _Texture1;
24             sampler2D _Texture2;
25             sampler2D _Texture3;
26 
27             struct VertexData
28             {
29                 float4 Pos : POSITION;
30                 float4 Tangent : TANGENT;
31                 float2 uv : TEXCOORD0;
32             };
33 
34             struct V2F
35             {
36                 float4 Pos : SV_POSITION;
37                 float4 Color : COLOR;
38                 float2 uv : TEXCOORD0;
39             };
40 
41             V2F Vert(VertexData v)
42             {
43                 V2F o;
44                 o.Pos = mul(UNITY_MATRIX_MVP, v.Pos);
45                 o.Color = v.Tangent;
46                 o.uv = v.uv;
47                 return o;
48             }
49 
50             float4 Frag(V2F i) : COLOR
51             {
52                 float4 t0 = tex2D(_Texture0, i.uv);
53                 float4 t1 = tex2D(_Texture1, i.uv);
54                 float4 t2 = tex2D(_Texture2, i.uv);
55                 float4 t3 = tex2D(_Texture3, i.uv);
56 
57                 return t0 * i.Color.x + t1 * i.Color.y + t2 * i.Color.z + t3 * i.Color.w;
58             }
59 
60             ENDCG
61         }
62     } 
63 }