残影特效在网上有很多例子，比如这个，我参考着自己整合了一下，算是整合了一个比较完整且特别简单易用的出来，只需要一个脚本挂上去无需任何设定就能用。
这里只针对SkinnedMeshRenderer的网格（也就是带蒙皮的网格）残影，主要原理是根据设定的间隔时间连续的截取当前SkinnedMeshRenderer的网格数据并使用Graphics.DrawMesh画出网格。
一、首先是我们的残影类，为了能及时的Destroy，所以它最好派生至Object：
class AfterImage : Object
{
//残影网格
public Mesh _Mesh;
//残影纹理
public Material _Material;
//残影位置
public Matrix4x4 _Matrix;
//残影透明度
public float _Alpha;
//残影启动时间
public float _StartTime;
//残影保留时间
public float _Duration;
public AfterImage(Mesh mesh, Material material, Matrix4x4 matrix4x4, float alpha, float startTime, float duration)
{
_Mesh = mesh;
_Material = material;
_Matrix = matrix4x4;
_Alpha = alpha;
_StartTime = startTime;
_Duration = duration;
}
}二、我们再定义一个残影特效类来管理残影：
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
/// <summary>
/// 残影特效
/// </summary>
public class AfterImageEffects : MonoBehaviour {
//开启残影
public bool _OpenAfterImage;
//残影颜色
public Color _AfterImageColor = Color.black;
//残影的生存时间
public float _SurvivalTime = 1;
//生成残影的间隔时间
public float _IntervalTime = 0.2f;
private float _Time = 0;
//残影初始透明度
[Range(0.1f, 1.0f)]
public float _InitialAlpha = 1.0f;
private List<AfterImage> _AfterImageList;
private SkinnedMeshRenderer _SkinnedMeshRenderer;
void Awake () {
_AfterImageList = new List<AfterImage>();
_SkinnedMeshRenderer = GetComponent<SkinnedMeshRenderer>();
}
void Update () {
if (_OpenAfterImage && _AfterImageList != null)
{
if (_SkinnedMeshRenderer == null)
{
_OpenAfterImage = false;
return;
}
_Time += Time.deltaTime;
//生成残影
CreateAfterImage();
//刷新残影
UpdateAfterImage();
}
}
}属性描述：《残影的生存时间》为每个残影从创建开始到销毁经历的时间，《生成残影的间隔时间》为残影创建后到下一个残影创建的时间，每个残影都会从《初始透明度》逐渐变化到0透明度并销毁。
生成残影：
/// <summary>
/// 生成残影
/// </summary>
void CreateAfterImage()
{
//生成残影
if (_Time >= _IntervalTime)
{
_Time = 0;
Mesh mesh = new Mesh();
_SkinnedMeshRenderer.BakeMesh(mesh);
Material material = new Material(_SkinnedMeshRenderer.material);
SetMaterialRenderingMode(material, RenderingMode.Fade);
_AfterImageList.Add(new AfterImage(
mesh,
material,
transform.localToWorldMatrix,
_InitialAlpha,
Time.realtimeSinceStartup,
_SurvivalTime));
}
}刷新残影：
/// <summary>
/// 刷新残影
/// </summary>
void UpdateAfterImage()
{
//刷新残影，根据生存时间销毁已过时的残影
for (int i = 0; i < _AfterImageList.Count; i++)
{
float _PassingTime = Time.realtimeSinceStartup - _AfterImageList[i]._StartTime;
if (_PassingTime > _AfterImageList[i]._Duration)
{
_AfterImageList.Remove(_AfterImageList[i]);
Destroy(_AfterImageList[i]);
continue;
}
if (_AfterImageList[i]._Material.HasProperty("_Color"))
{
_AfterImageList[i]._Alpha *= (1 - _PassingTime / _AfterImageList[i]._Duration);
_AfterImageColor.a = _AfterImageList[i]._Alpha;
_AfterImageList[i]._Material.SetColor("_Color", _AfterImageColor);
}
Graphics.DrawMesh(_AfterImageList[i]._Mesh, _AfterImageList[i]._Matrix, _AfterImageList[i]._Material, gameObject.layer);
}
}残影存在透明通道，所以必须要设置纹理的渲染模式为fade模式：
/// <summary>
/// 设置纹理渲染模式
/// </summary>
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;
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;
}
}三、效果图如下：
四、我将完整的源码贴一遍，只需要新建一个脚本AfterImageEffects，复制以下源码到其中，然后挂在有SkinnedMeshRenderer组件的模型上，并勾选OpenAfterImage，运行便可以看到效果：
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
/// <summary>
/// 残影特效
/// </summary>
public class AfterImageEffects : MonoBehaviour {
//开启残影
public bool _OpenAfterImage;
//残影颜色
public Color _AfterImageColor = Color.black;
//残影的生存时间
public float _SurvivalTime = 1;
//生成残影的间隔时间
public float _IntervalTime = 0.2f;
private float _Time = 0;
//残影初始透明度
[Range(0.1f, 1.0f)]
public float _InitialAlpha = 1.0f;
private List<AfterImage> _AfterImageList;
private SkinnedMeshRenderer _SkinnedMeshRenderer;
void Awake () {
_AfterImageList = new List<AfterImage>();
_SkinnedMeshRenderer = GetComponent<SkinnedMeshRenderer>();
}
void Update () {
if (_OpenAfterImage && _AfterImageList != null)
{
if (_SkinnedMeshRenderer == null)
{
_OpenAfterImage = false;
return;
}
_Time += Time.deltaTime;
//生成残影
CreateAfterImage();
//刷新残影
UpdateAfterImage();
}
}
/// <summary>
/// 生成残影
/// </summary>
void CreateAfterImage()
{
//生成残影
if (_Time >= _IntervalTime)
{
_Time = 0;
Mesh mesh = new Mesh();
_SkinnedMeshRenderer.BakeMesh(mesh);
Material material = new Material(_SkinnedMeshRenderer.material);
SetMaterialRenderingMode(material, RenderingMode.Fade);
_AfterImageList.Add(new AfterImage(
mesh,
material,
transform.localToWorldMatrix,
_InitialAlpha,
Time.realtimeSinceStartup,
_SurvivalTime));
}
}
/// <summary>
/// 刷新残影
/// </summary>
void UpdateAfterImage()
{
//刷新残影，根据生存时间销毁已过时的残影
for (int i = 0; i < _AfterImageList.Count; i++)
{
float _PassingTime = Time.realtimeSinceStartup - _AfterImageList[i]._StartTime;
if (_PassingTime > _AfterImageList[i]._Duration)
{
_AfterImageList.Remove(_AfterImageList[i]);
Destroy(_AfterImageList[i]);
continue;
}
if (_AfterImageList[i]._Material.HasProperty("_Color"))
{
_AfterImageList[i]._Alpha *= (1 - _PassingTime / _AfterImageList[i]._Duration);
_AfterImageColor.a = _AfterImageList[i]._Alpha;
_AfterImageList[i]._Material.SetColor("_Color", _AfterImageColor);
}
Graphics.DrawMesh(_AfterImageList[i]._Mesh, _AfterImageList[i]._Matrix, _AfterImageList[i]._Material, gameObject.layer);
}
}
/// <summary>
/// 设置纹理渲染模式
/// </summary>
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;
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;
}
}
}
public enum RenderingMode
{
Opaque,
Cutout,
Fade,
Transparent,
}
class AfterImage : Object
{
//残影网格
public Mesh _Mesh;
//残影纹理
public Material _Material;
//残影位置
public Matrix4x4 _Matrix;
//残影透明度
public float _Alpha;
//残影启动时间
public float _StartTime;
//残影保留时间
public float _Duration;
public AfterImage(Mesh mesh, Material material, Matrix4x4 matrix4x4, float alpha, float startTime, float duration)
{
_Mesh = mesh;
_Material = material;
_Matrix = matrix4x4;
_Alpha = alpha;
_StartTime = startTime;
_Duration = duration;
}
}