Unity中 利用Line Renderer || Trail Renderer制作飘烟拖尾

在Unity中粒子特效就可以制作飘烟拖尾，但是如果运动过快难免会有不自然的断开。虽然粒子中加入了Trail，但是我让拖尾转角圆滑比较困难（这方面还得请教特效同学）。当然如果对转角没有要求，粒子还是最简单的。

粒子拖尾效果:

Line Renderer拖尾

我们在unity中创建gameobject，添加line renderer组件。

我们的目的是为line添加轨迹点坐标，让line随时间上升。

[code]//获取组件
lineRenderer = gameObject.GetComponent<LineRenderer>();
//设置transform
tr = this.transform;

float timeSinceUpdate = 0.0f;
float updateSpeed = 0.025f;
//在update中我们用笨办法限制记录轨迹的间隔
timeSinceUpdate += Time.deltaTime; // 新时间

// 线段更新了
if (timeSinceUpdate > updateSpeed)
{
timeSinceUpdate -= updateSpeed;

//设一个最大轨迹点数
if (point < pCount)
{
list.Add(tr.position);

}

}

if (list.Count>0)
{
//这里是简单的上升动画，为每一个line点赋值
for (i = 0; i < list.Count; i++)
{

list[i] += new Vector3(0, upSpeed, 0) * Time.deltaTime;

}

drawBezierCurve();
}

private void drawBezierCurve()
{

List<Vector3> bcList;
BezierPath bc = new BezierPath();

bcList = bc.CreateCurve(list);//  通过贝塞尔曲线 平滑
//	Debug.Log(bcList.Count + " " + list.Count);

//bcList = CreateCurve(list);//  通过贝塞尔曲线 平滑
if ( point < pCount)
{

lineRenderer.positionCount = bcList.Count;
}
//	Debug.Log(bcList.Count);
for (int i = 0; i < bcList.Count; i++)
{
Vector3 v = bcList[i];
//v += new Vector3(0, 0.5f, 0);
lineRenderer.SetPosition(i, v);
}
point = bcList.Count;

}

[code]//这里的曲线平滑是网上找的没有深入研究
using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class BezierPath
{

public List<Vector3> pathPoints;
private int segments;
public int pointCount;

public BezierPath()
{
pathPoints = new List<Vector3>();
pointCount = 100;//最大点数
}

public void DeletePath()
{
pathPoints.Clear();
}
//t就是两点之间几分之几的位置
Vector3 BezierPathCalculation(Vector3 p0, Vector3 p1, Vector3 p2, Vector3 p3, float t)
{
float tt = t * t;
float ttt = t * tt;
float u = 1.0f - t;
float uu = u * u;
float uuu = u * uu;

Vector3 B = new Vector3();
B = uuu * p0;
B += 3.0f * uu * t * p1;
B += 3.0f * u * tt * p2;
B += ttt * p3;

return B;
}

public List<Vector3> CreateCurve(List<Vector3> controlPoints)
{
segments = controlPoints.Count / 3;//以3为间隔进行平滑 算出分段数量
pointCount = controlPoints.Count;//这里最大点数就是本身
for (int s = 0; s < controlPoints.Count - 3; s += 3)//以3为间隔遍历所有点
{
Vector3 p0 = controlPoints[s];
Vector3 p1 = controlPoints[s + 1];
Vector3 p2 = controlPoints[s + 2];
Vector3 p3 = controlPoints[s + 3];
//第一个点的处理
if (s == 0)
{
pathPoints.Add(BezierPathCalculation(p0, p1, p2, p3, 0.0f));
}
//
for (int p = 0; p < (pointCount / segments); p++)
{
float t = (1.0f / (pointCount / segments)) * p;
Vector3 point = new Vector3();
point = BezierPathCalculation(p0, p1, p2, p3, t);
pathPoints.Add(point);
}
}
return pathPoints;
}
}

到此line的跟随坐标路径做上升动画就完成了，想要添加其他动画可以在update中完成。

Trail Renderer

trail相比line 我们需要做的就简单多了。

[code]//老规矩
_trail = GetComponent<TrailRenderer>();
tr = this.transform;

_trail.emitting = true;

//update
time += Time.deltaTime;
if (time > VanishTime && !isOk)
{
StartCoroutine(starTime());
}

//t = Random.RandomRange(-0.5f,0.5f);
if (_trail.positionCount > 0)
{
for (int i = 0; i < _trail.positionCount; i++)
{
var v = new Vector3();
v = _trail.GetPosition(i);
v += new Vector3(0, ascentSpeed, 0);
//  v += new Vector3(Random.RandomRange(-0.1f,0.1f), ascentSpeed, Mathf.Sin(0.1f));
_trail.SetPosition(i, v);
}
}

trail本身是可以在组件中设置更多参数的

严格来说这只是拖尾，至于是不是烟雾还是要靠材质球表现了