unity 绘制Bezier曲线

绘制Bezier曲线

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

namespace MyTools{
[System.Serializable]

/// <summary>
/// 贝塞尔曲线
/// </summary>
public class Bezier :System.Object {
private List <Vector3> m_Points;
private List <Line> createdLine;
/// <summary>
/// Initializes a new instance of the <see cref="MyTools.Bezier"/> class.
/// </summary>
/// <param name="points">Points.</param>
public Bezier(List<Vector3> points){
if (points.Count < 2) {
throw(new ArgumentException ("实例化贝塞尔曲线至少需要2个点"));
} else {
m_Points = new List<Vector3> ();
createdLine = new List<Line> ();
CreateLine (points);
}
}
#region 修改参数的方法
public void AddPoint(Vector3 point){
m_Points.Add (point);
CreateLine (m_Points);
}

public void AddPointAt(int index,Vector3 point){
m_Points.Add (point);
var buf = m_Points [index];
m_Points [index] = point;
m_Points [m_Points.Count - 1] = buf;
CreateLine (m_Points);
}

public void RemovePoint(Vector3 point){
if (m_Points.Count > 2) {
for (int i = 0; i < m_Points.Count; i++) {
if (m_Points [i] == point) {
m_Points.RemoveAt (i);
CreateLine (m_Points);
} else {
continue;
}
}
} else {
Exception ex = new Exception ("当前曲线锚点数量已经最低，不能移除锚点");
throw(ex);
}
}

public void RemovePointAt(int index){
if (m_Points.Count > 2) {
m_Points.RemoveAt (index);
CreateLine (m_Points);
} else {
Exception ex = new Exception ("当前曲线锚点数量已经最低，不能移除锚点");
throw(ex);
}
}

public void UpdatePoint(int ListIndex, Vector3 point){
if (ListIndex < 0) {
throw (new ArgumentException ("坐标索引参数错误（取值必须大于0）"));
} else if (ListIndex >= m_Points.Count) {
throw (new ArgumentException ("坐标索引参数错误（取值必须x小于曲线顶点的个数）"));
} else {
m_Points [ListIndex] = point;
CreateLine (m_Points);
}
}

#endregion

/// <summary>
/// 根据传入的参数获取曲线上某一点的值
/// </summary>
/// <returns>The point.</returns>
/// <param name="T">取值参数（0-1）.</param>
public Vector3 GetPoint(float T){
var point = new Vector3 ();
if (T < 0) {
T = 0;
} else if (T > 1) {

T = 1;
}
var bufListLine = createdLine;
if (bufListLine == null) {
throw(new NullReferenceException ("曲线锚点为空"));
}
while (bufListLine.Count > 1) {

bufListLine = CaculateResoultLine (bufListLine, T);
}
if (bufListLine.Count == 1) {
point = bufListLine [0].GetPoint (T);
} else {
throw(new Exception("Program Error : Current Line Count is: " + bufListLine.Count));
}

return point;

}
/// <summary>
/// 根据当前的线段以及取值参数T，创建新的线段链表（新的链表长度始终等于原始链表长度-1）。
/// 使用迭代计算的方式降低程序的复杂性
/// </summary>
/// <param name="Lines">Lines.</param>
/// <param name="T">T.</param>
private List<Line> CaculateResoultLine(List<Line> Lines,float T){
var ListLine = new List<Line>();
for (int i = 0; i < Lines.Count-1; i++) {
var j = i + 1;
Line bufLine = new Line (Lines [i].GetPoint (T),Lines [j].GetPoint (T));
ListLine.Add (bufLine);
}
return ListLine;
}
/// <summary>
/// 根据已知的锚点依次创建一条连续的折线
/// </summary>
/// <param name="points">Points.</param>
private void CreateLine(List<Vector3> points){
createdLine = new List<Line> ();
m_Points = points;
for (int i = 0; i < points.Count; i++) {
var j = i + 1;
if (j >= points.Count) {
break;
} else {
Line curLine = new Line (points [i], points [j]);
createdLine.Add (curLine);
}
}
}
}
/// <summary>
/// 线段，包含起点和终点
/// </summary>
public struct Line{
public Line(Vector3 start,Vector3 end){
StartPoint = start;
EndPoint = end;
}
/// <summary>
/// 线段的起点
/// </summary>
/// <value>The start point.</value>
public Vector3 StartPoint {
get;
set;
}
/// <summary>
/// 线段的终点
/// </summary>
/// <value>The end point.</value>
public Vector3 EndPoint{
get;
set;
}
/// <summary>
/// 判断一个点是否是自己的起点或者终点
/// </summary>
/// <returns><c>true</c>, if me was ised, <c>false</c> otherwise.</returns>
/// <param name="point">Point.</param>
public bool isMe(Vector3 point){
if (StartPoint == point || EndPoint == point) {
return true;
} else {
return false;
}
}
/// <summary>
/// 根据传入的值获取这条线段上的任意一点，T>=0&&T<=1
/// T=0时返回起点
/// T=1时返回终点
/// </summary>
/// <returns>The point.</returns>
/// <param name="T">T.</param>
public Vector3 GetPoint(float T){
var point = new Vector3 ();
if (T < 0) {
T = 0;
} else if (T > 1) {
T = 1;
}
point = (EndPoint - StartPoint) * T + StartPoint;
return point;
}
}
}