Unity中3D模型淡入淡出

        通常我们淡入一个模型只会传入这个模型的GameObject，所以这里自写一个类来处理这个模型淡入的一些事件。FadeModel 代码如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using DG.Tweening;

public class FadeModel
{

    private GameObject model;//传入的模型
    private float fadeTime = 2f;//默认淡入时间为2s
    private List materials = new List();

    public FadeModel(GameObject model, float fadeTime = 2f)
    {
        this.model = model;
        this.fadeTime = fadeTime;
        MeshRenderer[] meshRenderers = model.GetComponentsInChildren();
        foreach (MeshRenderer mr in meshRenderers)
        {
            Material[] materals = mr.materials;
            foreach (Material m in materals)
            {
                if (!materials.Contains(m))
                {
                    materials.Add(m);
                }
            }
        }
    }
    //隐藏模型的淡隐效果
    public void HideModel()
    {
        for (int i = 0; i < materials.Count; i++)
        {
            Material m = materials[i];
            Color color = m.color;
            m.color = new Color(color.r, color.g, color.b, 1);//这里一定要重新设置下Fade模式下的color a值 为1 不然 经过一次显示他会一直显示为0
            setMaterialRenderingMode(m, RenderingMode.Fade);
            m.DOColor(new Color(color.r, color.g, color.b, 0), fadeTime).OnComplete(()=> {
                if (i == materials.Count - 1)
                    model.SetActive(false);
            });
        }
    }
    //当我们隐藏完后还需要设置回来 不然他下次显示使用就是透明状态
    public void ShowModel()
    {

        for (int i = 0; i < materials.Count; i++)
        {
            Material m = materials[i];
            Color color = m.color;
            setMaterialRenderingMode(m, RenderingMode.Opaque);
        }
        model.SetActive(true);
    }
    public enum RenderingMode
    {
        Opaque,
        Cutout,
        Fade,
        Transparent
    }
    //设置材质的渲染模式 
    private void setMaterialRenderingMode(Material material, RenderingMode renderingMode)
    {
        switch (renderingMode)
        {
            case RenderingMode.Opaque:
                material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
                material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);
                material.SetInt("_ZWrite", 1);
                material.DisableKeyword("_ALPHATEST_ON");
                material.DisableKeyword("_ALPHABLEND_ON");
                material.DisableKeyword("_ALPHAPREMULTIPLY_ON");
                material.renderQueue = -1;
                break;
            case RenderingMode.Cutout:
                material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
                material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);
                material.SetInt("_ZWrite", 1);
                material.EnableKeyword("_ALPHATEST_ON");
                material.DisableKeyword("_ALPHABLEND_ON");
                material.DisableKeyword("_ALPHAPREMULTIPLY_ON");
                material.renderQueue = 2450;
                break;
            case RenderingMode.Fade:
                material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
                material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
                material.SetInt("_ZWrite", 0);
                material.DisableKeyword("_ALPHATEST_ON");
                material.EnableKeyword("_ALPHABLEND_ON");
                material.DisableKeyword("_ALPHAPREMULTIPLY_ON");
                material.renderQueue = 3000;
                //material.SetFloat("" _Mode & quot;", 2); 
                break;
            case RenderingMode.Transparent:
                material.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
                material.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
                material.SetInt("_ZWrite", 0);
                material.DisableKeyword("_ALPHATEST_ON");
                material.DisableKeyword("_ALPHABLEND_ON");
                material.EnableKeyword("_ALPHAPREMULTIPLY_ON");
                material.renderQueue = 3000;
                break;
        }
    }


}

        用的Dotween来做的淡出效果，然后我们就可以在我们需要的地方来调用淡出效果了

public class Test : MonoBehaviour {
 public GameObject model;
 FadeModel fadeModel;
 // Use this for initialization
 void Start ()
 {
 fadeModel = new FadeModel(model);
 fadeModel.HideModel();
 }
  
 private void OnDisable()
 {
 fadeModel.ShowModel();
 }
}

Tips：

        在用人物做这个淡出效果测试时发现效果很不好。半透明效果有时候会让后面的辫子渲染到前面了。所以对于精细显示的效果我们还是去求助我们的shader程序员吧，让他写一个贴图消融的shader。但是对于工业级别的粗糙显示，我们这个方案还是完全够用的。

        还有一个，我们在获取一个物体下的所有组件时，使用的代码是：

MeshRenderer[] meshRenderers = model.GetComponentsInChildren();

        当时当我们model下的子物体setactive是false的时候是不能被找到的。如果我们也想找到这些物体，我们就需要在上面代码括号里加一个true。如下：

MeshRenderer[] meshRenderers = model.GetComponentsInChildren(true);