using UnityEditor;
using UnityEngine;

[ExecuteAlways]
public class Test : MonoBehaviour
{
    private Material material;
    private Texture2D oriTexture;
    private Texture2D cvtTexture;

    private void Start()
    {
        material = GetComponent<MeshRenderer>().sharedMaterial;
        oriTexture = material.GetTexture("_MainTex") as Texture2D;
        ConvertAlpha();
    }

    void ConvertAlpha()
    {
        cvtTexture = new Texture2D(oriTexture.width, oriTexture.height, TextureFormat.ARGB32, false);
        for (int i = 0; i < cvtTexture.width; i++)
        {
            for (int j = 0; j < cvtTexture.height; j++)
            {
                var col = oriTexture.GetPixel(i, j);
                //col.r = Mathf.Pow(col.r, 1/2.2f);
                //col.g = Mathf.Pow(col.g, 1/2.2f);
                //col.b = Mathf.Pow(col.b, 1/2.2f);
                cvtTexture.SetPixel(i,j, col);
            }
        }
        cvtTexture.Apply();
    }

    [ContextMenu("Use Converted")]
    private void UseAlpha()
    {
    }

    [ContextMenu("Use Original")]
    private void UseOriginal()
    {
        material.SetTexture("_MainTex", oriTexture);
    }
}