テクスチャをひたすらマテリアルにアタッチするスクリプト

SetLightmapsMaterials.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;
using System.IO;
using System;
using UnityEditor.Events;
using UnityEditor.Animations;
#endif

public class SetLightmapsMaterials : MonoBehaviour {
    public Texture2D[] texs = new Texture2D[2];
    public Material[] materials;
    public float _Mix0;
    public float _Mix1;
#if UNITY_EDITOR
    
    private void Generate() {
        for(int i=0; i<materials.Length; i++){
            materials[i].SetTexture("_LightMap1", texs[0]);
            materials[i].SetTexture("_LightMap2", texs[1]);
            materials[i].SetFloat("_Mix1", _Mix0);
            materials[i].SetFloat("_Mix2", _Mix1);
        }
        
        Debug.Log("Set Texture End");
    }

    [CustomEditor(typeof(SetLightmapsMaterials))]
    public class TextureGeneratorEditor : Editor {
        public override void OnInspectorGUI() {
            var t = target as SetLightmapsMaterials;
            drawArrayProperty("materials");
            t.texs[0] = (Texture2D)EditorGUILayout.ObjectField("LightMap Texture 1", t.texs[0], typeof(Texture2D), t.texs[0]);
            t.texs[1] = (Texture2D)EditorGUILayout.ObjectField("LightMap Texture 2", t.texs[1], typeof(Texture2D), t.texs[1]);
            t._Mix1 = EditorGUILayout.FloatField( "Mix0", t._Mix0 );
            t._Mix2 = EditorGUILayout.FloatField( "Mix1", t._Mix1 );
            if (GUILayout.Button("Set Lightmap Textures")) {
                t.Generate();
            }
        }

        //https://gist.github.com/Suzeep/7257058
        private void drawArrayProperty( string prop_name ){
            EditorGUIUtility.LookLikeInspector(); //Legacy
            SerializedProperty prop = this.serializedObject.FindProperty( prop_name );
            EditorGUI.BeginChangeCheck();
            EditorGUILayout.PropertyField( prop, true );
            if( EditorGUI.EndChangeCheck() ){
                this.serializedObject.ApplyModifiedProperties();
            }
    }
    }
#endif
}