ANTM/Assets/MakeShotScript.cs

#if(UNITY_EDITOR)
using System.Collections;
using System.Collections.Generic;
using System.IO;
using UnityEditor;
using UnityEngine;

public class MakeShotScript : MonoBehaviour {

    [SerializeField]
    public NPC npc;
    [SerializeField]
    public RenderTexture render_texture;

    public void button_function()
    {
        Texture2D tex2d = new Texture2D(256, 256);
        RenderTexture.active = render_texture;
        tex2d.ReadPixels(new Rect(0, 0, render_texture.width, render_texture.height), 0, 0);
        tex2d.Apply();
        SaveSprite(tex2d);
    }

    void SaveSprite(Texture2D tex)
    {
        string assetPath = "Assets/Resources/Avatar/NPC/" + npc.Name+"_2.png";

        Sprite sp = Sprite.Create(
            tex,
            new Rect(0, 0, tex.width, tex.height),
            new Vector2(0, 0),
            30);

        sp.name = "SpriteName";

        //Debug.Log("Saved PPU: " + sp.pixelsPerUnit); // Saved PPU: 30

        // Would prefer a Unity specific way to do this but AssetDatabase.CreateAsset wasn't working.
        // Due to it being a .png instead of .asset?
        File.WriteAllBytes(Application.dataPath + "/../" + assetPath, tex.EncodeToPNG());
        AssetDatabase.Refresh();
        AssetDatabase.AddObjectToAsset(sp, assetPath);
        AssetDatabase.SaveAssets();

        sp = AssetDatabase.LoadAssetAtPath(assetPath, typeof(Sprite)) as Sprite;

        //Debug.Log("Loaded PPU: " + sp.pixelsPerUnit); // Loaded PPU: 100
    }
}
#endif