Unity图片转换为法线贴图

Unity图片转换为法线贴图

using UnityEngine;
using System.IO;
using UnityEditor;

public class NormalTexture : MonoBehaviour
{
    public Texture2D tex1;
    private int W;
    private int H;

    void Start()
    {
        int W = tex1.width;
        int H = tex1.height;
        Texture2D tex2 = new Texture2D(W,H);
        for (int i = 1; i < W-1; i++)
            for (int j = 1; j < H-1; j++)
            {
            	//转换可修改算法，实现更加优质的贴图
                Color c;
                c = tex1.GetPixel(i-1, j);
                float left = (c.r + c.g + c.b) / 3;
                c = tex1.GetPixel(i+1,j);
                float right = (c.r + c.g + c.b) / 3;
                c = tex1.GetPixel(i, j + 1);
                float top = (c.r + c.g + c.b) / 3;
                c = tex1.GetPixel(i, j - 1);
                float bottom = (c.r + c.g + c.b) / 3;

                float u = left - right;
                float v = top - bottom;

                Vector3 ve3_U = new Vector3(1,0,u);
                Vector3 ve3_V = new Vector3(0,1,v);

                Vector3 N = Vector3.Cross(ve3_U, ve3_V).normalized;

                float r = N.x * 0.5f + 0.5f;
                float g = N.y * 0.5f + 0.5f;
                float b = N.z * 0.5f + 0.5f;

                tex2.SetPixel(i, j, new Color(r, g, b));
            }
        tex2.Apply(false);

        byte[] arr = tex2.EncodeToPNG();
        using(FileStream fs = new FileStream(Application.dataPath + "/MyTexture.png", FileMode.OpenOrCreate))
        {
            fs.Write(arr, 0, arr.Length);
        }
        Debug.Log("法线贴图创建完毕");
        AssetDatabase.Refresh();
    }
}