Slide.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class Slide : MonoBehaviour
{
    [SerializeField] string _texturePropertyName;
    [SerializeField] List<Texture2D> _slideTextureList;

    [SerializeField] MeshRenderer _leftSlide;
    [SerializeField] MeshRenderer _rightSlide;
    int _propertyID;

    [SerializeField] InputField _field;
    Text _placeholder;

    Animator _animator;

    int _index;

    void Start()
    {
        //取得
        _animator = this.gameObject.GetComponent<Animator>();
        _propertyID = Shader.PropertyToID(_texturePropertyName);
        _placeholder = _field.placeholder.GetComponent<Text>();

        //初期化
        _index = 0;
        _leftSlide.sharedMaterial = null;
        _rightSlide.material.SetTexture(_propertyID, _slideTextureList[_index]);

        //index番号を送信
        int displayindex = _index + 1;
        _placeholder.text = displayindex.ToString();
    }

    void Update()
    {

    }

    public void OnBack()  //戻る処理
    {
        if (_index > 0)
        {
            _index--;
            _leftSlide.material.SetTexture(_propertyID, _slideTextureList[_index + 1]);
            _rightSlide.material.SetTexture(_propertyID, _slideTextureList[_index]);
            _animator.Play("Back", 0, 0);

            //index番号を送信
            int displayindex = _index + 1;
            _placeholder.text = displayindex.ToString();
        }
    }

    public void OnNext()  //進む処理
    {
        if (_index < _slideTextureList.Count - 1)
        {
            _index++;
            _leftSlide.material.SetTexture(_propertyID, _slideTextureList[_index]);
            _rightSlide.material.SetTexture(_propertyID, _slideTextureList[_index - 1]);
            _animator.Play("Next", 0, 0);

            //index番号を送信
            int displayindex = _index + 1;
            _placeholder.text = displayindex.ToString();
        }
    }

    public void OnIndex()  //直接数値を入力する処理
    {
        int index = int.Parse(_field.text);

        if (0 <= index - 1 && index - 1 <= _slideTextureList.Count - 1)
        {
            if (index > _index)
            {
                _leftSlide.material.SetTexture(_propertyID, _slideTextureList[index - 1]);
                _rightSlide.material.SetTexture(_propertyID, _slideTextureList[_index]);
                _index = index - 1;
                _animator.Play("Next", 0, 0);
            }
            else if (index < _index)
            {
                _leftSlide.material.SetTexture(_propertyID, _slideTextureList[_index]);
                _rightSlide.material.SetTexture(_propertyID, _slideTextureList[index - 1]);
                _index = index - 1;
                _animator.Play("Back", 0, 0);
            }
        }

        _field.text = null;
        int displayindex = _index + 1;
        _placeholder.text = displayindex.ToString();
    }
}