Unity中代码创建的奇怪网格纹理答案

【问题标题】：Strange mesh texture created by code in UnityUnity中代码创建的奇怪网格纹理
【发布时间】：2020-04-13 22:09:02
【问题描述】：

我正在学习如何在 Unity 中通过代码进行网格划分，但纹理与图像中的一样奇怪，有人知道这是为什么吗？我在代码中创建了 UV 贴图，搜索了很多 Google 和 Unity 文档，发现我应该使用数组顶点来映射 UV，但我认为我做错了什么

我的代码：

public Vector3[] verts = {
    new Vector3(-0.5f, 0.5f, 0f), new Vector3(0.5f, 0.5f, 0f),
    new Vector3(0.5f, -0.5f, 0f), new Vector3(-0.5f, -0.5f, 0f),
    new Vector3(-0.2f, 0.3f, 0f), new Vector3(0.2f, 0.3f, 0f),
    new Vector3(0.2f, -0.1f, 0f), new Vector3(-0.2f, -0.1f, 0f),
    new Vector3(-0.2f, 0.3f, 0f), new Vector3(0.2f, 0.3f, 0f),
    new Vector3(0.2f, -0.1f, 0f), new Vector3(-0.2f, -0.1f, 0f),
    new Vector3(-0.2f, 0.3f, 0.1f), new Vector3(0.2f, 0.3f, 0.1f),
    new Vector3(0.2f, -0.1f, 0.1f), new Vector3(-0.2f, -0.1f, 0.1f),
    new Vector3(-0.2f, 0.3f, 0.1f), new Vector3(0.2f, 0.3f, 0.1f),
    new Vector3(0.2f, -0.1f, 0.1f), new Vector3(-0.2f, -0.1f, 0.1f),
    new Vector3(-0.5f, 0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(-0.5f, -0.5f, 0.1f), new Vector3(-0.5f, -0.5f, 0.1f),
    new Vector3(0.5f, 0.5f, 0.1f), new Vector3(0.5f, -0.5f, 0.1f)
 };
 public int[] tris = {
     0,1,4,1,5,4,1,2,5,2,6,5,2,3,6,3,7,6,3,0,7,0,4,7,8,9,12,9,13,12,9,10,13,10,14,13,10,11,14,11,15,14,11,8,15,8,12,15,20,0,3,20,3,21,0,20,46,0,46,1,1,46,47,1,47,2,3,2,42,2,47,45,46,20,17,20,16,17,20,19,16,20,32,15,31,14,15,31,47,14,47,46,14,46,17,14
 };

MeshFilter mF = gameObject.GetComponent<MeshFilter> ();
Mesh msh = new Mesh ();
msh.vertices = verts;
msh.triangles = tris;
Vector2[] uvs = new Vector2[verts.Length];
for (int i = 0; i < uvs.Length; i++){ //uv map
    uvs[i] = new Vector2(verts[i].x, verts[i].y);
 }
 msh.uv = uvs;
 msh.RecalculateNormals ();
 mF.mesh = msh;

【问题讨论】：

标签： c# unity3d textures mesh uv-mapping

【解决方案1】：

我怀疑在您的情况下禁用了透视纹理校正，因为

Unity 2019.3：♫ 一切都很棒♫

【讨论】：

我刚换了shader，它工作了，但是侧面变形了，你怎么不变形？ imgur.com/JUTNbEd
我使用了一个使用全局位置作为纹理的着色器，但它不适用于这个着色器，你能帮我解释一下为什么吗？ codeshare.io/G7jdkk
这个着色器可能禁用了与“透视纹理校正”相关的东西。因为标准（内置）的没有这样的问题
在我的情况下，侧面也变形了，只是由于纹理不同而不太明显。那是因为你模拟了一种正面投影
如果您不熟悉着色器并正在使用 Unity 2019.3，我建议您在 Shader Graph 中制作着色器

【解决方案2】：

由于您已经发现共享顶点导致了此问题，因此您可能需要测试此代码是否有效。可能在某个时候变得有用。它旨在在网格计算时分配 UV（不再需要特殊的着色器），但 要求在其独立法线之间具有角度的相邻三角形 > PI/4 在任何地方都没有共享顶点（换句话说：不同边之间没有共享顶点立方体）

using UnityEngine;
public class NewBehaviourScript : MonoBehaviour
{
    [SerializeField] MeshFilter meshFilter = null;
    Vector3[] vertices = { vertices goes here };
    int[] triangles = { indices goes here };
    void Start ()
    {
        Mesh mesh = new Mesh();
        meshFilter.mesh = mesh;

        Vector2[] uvs = new Vector2[ vertices.Length ];
        int numTriangles = triangles.Length / 3;
        for( int t=0 ; t<numTriangles ; t++ )
        {
            int ia = triangles[ t*3 ];
            int ib = triangles[ t*3+1 ];
            int ic = triangles[ t*3+2 ];

            Vector3 va = vertices[ ia ];
            Vector3 vb = vertices[ ib ];
            Vector3 vc = vertices[ ic ];

            Vector3 normal = Vector3.Cross( vb-va , vc-va ).normalized;
            float dotForward = Vector3.Dot( normal , Vector3.forward );
            float dotRight = Vector3.Dot( normal , Vector3.right );
            float dotUp = Vector3.Dot( normal , Vector3.up );

            if( dotForward>0.7071f )
            {
                // front projection
                uvs[ ia ] = new Vector2{ x=-va.x , y=va.y };
                uvs[ ib ] = new Vector2{ x=-vb.x , y=vb.y };
                uvs[ ic ] = new Vector2{ x=-vc.x , y=vc.y };
            }
            else if( dotForward<-0.7071f  )
            {
                // back projection
                uvs[ ia ] = new Vector2{ x=va.x , y=va.y };
                uvs[ ib ] = new Vector2{ x=vb.x , y=vb.y };
                uvs[ ic ] = new Vector2{ x=vc.x , y=vc.y };
            }
            else if( dotRight>0.7071f )
            {
                // right projection
                uvs[ ia ] = new Vector2{ x=-va.z , y=va.y };
                uvs[ ib ] = new Vector2{ x=-vb.z , y=vb.y };
                uvs[ ic ] = new Vector2{ x=-vc.z , y=vc.y };
            }
            else if( dotRight<-0.7071f )
            {
                // left projection
                uvs[ ia ] = new Vector2{ x=va.z , y=va.y };
                uvs[ ib ] = new Vector2{ x=vb.z , y=vb.y };
                uvs[ ic ] = new Vector2{ x=vc.z , y=vc.y };
            }
            else if( dotUp>0.7071f )
            {
                // top projection
                uvs[ ia ] = new Vector2{ x=-va.x , y=va.z };
                uvs[ ib ] = new Vector2{ x=-vb.x , y=vb.z };
                uvs[ ic ] = new Vector2{ x=-vc.x , y=vc.z };
            }
            else
            {
                // bottom projection
                uvs[ ia ] = new Vector2{ x=va.x , y=va.z };
                uvs[ ib ] = new Vector2{ x=vb.x , y=vb.z };
                uvs[ ic ] = new Vector2{ x=vc.x , y=vc.z };
            }
        }

        mesh.vertices = vertices;
        mesh.triangles = triangles;
        mesh.uv = uvs;

        mesh.RecalculateNormals();
    }
}

【讨论】：