应对UV问题——Unity中自动展UV小工具

Unity中自动展UV小工具

有时候别人给的unity工程中，有些模型是生成的或者是导入时没有展好uv的，非常头疼，又懒得导出到DCC工具去整理uv，所以做了一个简单的展uv的小工具。效果如下：

这里我做了三种展uv的方式：
**1.平面式。**可以选择X\Y\Z平面去进行uv映射，比较适合一些简单的几何体例如墙、地板或者玻璃什么的。
**2.立方体式。**这种比较适合一些比较硬表面的物体，例如桌子、栏杆什么的。这种方式基于Object Space的法线信息去判断该点应该属于哪一个uv平面，所以在面临比较大的曲面会有一些问题，而且我没有做平铺，所以会有一些uv重叠。
**3.使用Lightmap uv。**这一点是我受到红强的启发，我想既然unity可以自动帮我们整理出第二套用于光照贴图的uv，为什么不用呢，所以我就取出光照贴图的uv，去赋予mesh的第一套uv。这个方案的好处是简单省事，而且基本没有uv重叠，适用于所有模型。唯一需要注意的一点是需要在fbx 导入的时候勾选“Generate Lightmap uv”。

最后是代码部分，记得把它放在Assets目录下的Editor文件夹里，规范操作。

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;

public class unfold : EditorWindow
{

    [MenuItem("Gq_Tools/Unfold")]
    public static void ShowWin()
    {
        EditorWindow.CreateInstance<unfold>().Show();
    }
    private void OnGUI()
    {
        GUILayout.Space(10);
        GUILayout.BeginHorizontal("box");
        GUILayout.Space(10);
        if (GUILayout.Button("Planar-X unfold"))//UI上画一个按钮
        {
            //MonoBehaviour.print("do");
            Unfold0("X");
        }
        if (GUILayout.Button("Planar-Y unfold"))//UI上画一个按钮
        {
            //MonoBehaviour.print("do");
            Unfold0("Y");
        }
        if (GUILayout.Button("Planar-Z unfold"))//UI上画一个按钮
        {
            //MonoBehaviour.print("do");
            Unfold0("Z");
        }
        GUILayout.EndHorizontal();
        GUILayout.Space(10);
        GUILayout.BeginHorizontal("box");
        if (GUILayout.Button("Cubic unfold"))//UI上画一个按钮
        {
            //MonoBehaviour.print("do");
            Unfold1();
        }
        GUILayout.EndHorizontal();
        GUILayout.Space(10);
        GUILayout.BeginHorizontal("box");
        if (GUILayout.Button("unfold by lightmap UV"))//UI上画一个按钮
        {
            //MonoBehaviour.print("do");
            Unfold2();
        }
        GUILayout.EndHorizontal();
    }
    //Planar Unfold
    void Unfold0(string inStr)
    {
        var objs = Selection.objects;
        if (inStr == "X")
        {
            foreach (var obj in objs)//for每个选中的物体
            {
                var go = obj as GameObject;
                Mesh mesh = go.GetComponent<MeshFilter>().sharedMesh;
                Vector3[] vertices = mesh.vertices;
                Vector2[] uvs = new Vector2[vertices.Length];

                //Planar Unfold
                for (int i = 0; i < uvs.Length; i++)
                {
                    uvs[i] = new Vector2( vertices[i].y, vertices[i].z);
                }
                mesh.uv = uvs;
            }
        }
        if (inStr == "Y")
        {
            foreach (var obj in objs)//for每个选中的物体
            {
                var go = obj as GameObject;
                Mesh mesh = go.GetComponent<MeshFilter>().sharedMesh;
                Vector3[] vertices = mesh.vertices;
                Vector2[] uvs = new Vector2[vertices.Length];

                //Planar Unfold
                for (int i = 0; i < uvs.Length; i++)
                {
                    uvs[i] = new Vector2(vertices[i].x,vertices[i].z);
                }
                mesh.uv = uvs;
            }
        }
        if (inStr == "Z")
        {
            foreach (var obj in objs)//for每个选中的物体
            {
                var go = obj as GameObject;
                Mesh mesh = go.GetComponent<MeshFilter>().sharedMesh;
                Vector3[] vertices = mesh.vertices;
                Vector2[] uvs = new Vector2[vertices.Length];

                //Planar Unfold
                for (int i = 0; i < uvs.Length; i++)
                {
                    uvs[i] = new Vector2(vertices[i].x, vertices[i].y);
                }
                mesh.uv = uvs;
            }
        }
    }
    //Cubic Unfold
    void Unfold1()
    {
        var objs = Selection.objects;
        foreach (var obj in objs)//for每个选中的物体
        {
            var go = obj as GameObject;
            Mesh mesh = go.GetComponent<MeshFilter>().sharedMesh;
            Vector3[] vertices = mesh.vertices;
            Vector2[] uvs = new Vector2[vertices.Length];
            Vector3[] normals = mesh.normals;

            //Cubic Unfold
            for (int i = 0; i < normals.Length; i++)
            {
                //X-Plane
                if (Mathf.Abs(normals[i].x) > Mathf.Abs(normals[i].y) && Mathf.Abs(normals[i].x) > Mathf.Abs(normals[i].z))
                {
                    uvs[i] = new Vector2(vertices[i].y, vertices[i].z);
                }
                //Y-Plane
                if (Mathf.Abs(normals[i].y) > Mathf.Abs(normals[i].x) && Mathf.Abs(normals[i].y) > Mathf.Abs(normals[i].z))
                {
                    uvs[i] = new Vector2(vertices[i].x, vertices[i].z);
                }
                //Z-Plane
                if (Mathf.Abs(normals[i].z) > Mathf.Abs(normals[i].x) && Mathf.Abs(normals[i].z) > Mathf.Abs(normals[i].y))
                {
                    uvs[i] = new Vector2(vertices[i].x, vertices[i].y);
                }
            }
            mesh.uv = uvs;
        }
    }
    //use lightmap UV
    void Unfold2()
    {
        var objs = Selection.objects;
        foreach (var obj in objs)//对于每个选中的物体
        {
            var go = obj as GameObject;
            Mesh mesh = go.GetComponent<MeshFilter>().sharedMesh;
            mesh.uv = mesh.uv2;
        }
    }
}