Unity 控制物体透明度变化

1.需求

        给物体绑定一个脚本，这个脚本实现物体的透明度渐变变化，并且可以重置回原来的颜色。物体为Unity自带的材质Shader为Standard。

2.代码

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

public class TransparentChanger : MonoBehaviour
{
    /// <summary>
    /// 保存原颜色
    /// </summary>
    private Color[] oldColors;

    /// <summary>
    /// 控制透明度变化
    /// </summary>
    [Range(0, 1)]
    public float nalpha;
    
    private void Start()
    {
        Init();
    }

    private void Update()
    {
        SetOpacity(nalpha);
    }

    public void Init()
    {
        int num = 0;
        foreach (Renderer r in GetComponentsInChildren<Renderer>(true))
        {
            num += r.materials.Length;
        }
        oldColors = new Color[num];
        num = 0;
        foreach (Renderer r in GetComponentsInChildren<Renderer>(true))
        {
            foreach (Material m in r.materials)
            {
                try
                {
                    oldColors[num++] = m.color;
                }
                catch (System.Exception e)
                {
                    Debug.Log(e.Message);
                }
            }
        }
    }

    /// <summary>
    /// 重置回原来的颜色
    /// </summary>
    public void Reset()
    {
        int num = 0;
        foreach (Renderer r in GetComponentsInChildren<Renderer>(true))
        {
            foreach (Material m in r.materials)
            {
                try
                {
                    m.color = oldColors[num++];
                    if (m.color.a >= 1)
                    {
                        ChangeMaterialType(0, m);
                        m.renderQueue = -1;
                    }
                }
                catch (System.Exception e)
                {
                    Debug.Log(e.Message);
                }
            }
        }
    }

    public void SetOpacity(float alpha)
    {
        int num = 0;
        foreach (Renderer r in GetComponentsInChildren<Renderer>(true))
        {
            foreach (Material m in r.materials)
            {
                try
                {
                    float mA = Mathf.Min(alpha, oldColors[num++].a);
                    m.color = new Color(m.color.r, m.color.g, m.color.b, mA);
                    if (mA >= 0.98f)
                    {
                        ChangeMaterialType(0, m);
                    }
                    else
                    {
                        ChangeMaterialType(1, m);
                    }
                }
                catch (System.Exception e)
                {
                    Debug.Log(e.Message);
                }
            }
        }
    }
    /// <summary>
    /// 切换材质的Standard Shader 渲染类型
    /// </summary>
    /// <param name="mType">0-Opaque, 1-Transparent</param>
    /// <param name="m">材质</param>
    void ChangeMaterialType(int mType, Material m)
    {
        if(mType == 0)
        {
            m.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
            m.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);
            m.SetInt("_ZWrite", 1);
            m.DisableKeyword("_ALPHATEST_ON");
            m.DisableKeyword("_ALPHABLEND_ON");
            m.DisableKeyword("_ALPHAPREMULTIPLY_ON");
            m.renderQueue = -1;
        }
        else if(mType == 1)
        {
            m.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
            m.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
            m.SetInt("_ZWrite", 0);
            m.DisableKeyword("_ALPHATEST_ON");
            m.DisableKeyword("_ALPHABLEND_ON");
            m.EnableKeyword("_ALPHAPREMULTIPLY_ON");
            m.renderQueue = 3000;
        }
    }
}