unity C# 计算3D空间任意多边形面积,距离,角度测量工具
效果图
代码：
using UnityEngine;
using System.Collections.Generic;
using System;
///
/// 划线面积,距离,角度
///
public class UnderlinedMeasureTool : MonoBehaviour
{
///
/// 相机
///
public Camera _camera;
public int size = 30;//文字大小
//圆点的预制体
public GameObject aim;
public LineRenderer lineRender;
bool sb = false;
//GL 绘制的顶点数组 顺序是 0->1 2->3 4->5 取法 0 1 3 5 7 9
//参考UI界面
private List lv;//划线的点
private List lv1;//存坐标的点
public List aims;
public int type = 3;
void Start()
{
lv = new List();
lv1 = new List();
aims = new List();
}
void Update()
{
if (Input.GetMouseButtonDown(0))//绘制多边形
{
Ray ray = _camera.ScreenPointToRay(Input.mousePosition);
RaycastHit hit;
if (Physics.Raycast(ray, out hit, Mathf.Infinity))
{
//创建圆点
GameObject go = Instantiate(aim, new Vector3(hit.point.x, hit.point.y, hit.point.z), Quaternion.Euler(90, 0, 0)) as GameObject;
aims.Add(go);
lv1.Add(hit.point);
if (type == 1)
{
if (lv.Count >= 2)
{
ClearLines();
GameObject go1 = Instantiate(aim, new Vector3(hit.point.x, hit.point.y, hit.point.z), Quaternion.Euler(90, 0, 0)) as GameObject;
aims.Add(go1);
lv1.Add(hit.point);
lv.Add(hit.point);
}
else
{
lv.Add(hit.point);
}
}
else if (type == 2)
{
if (lv.Count >= 3)
{
ClearLines();
GameObject go1 = Instantiate(aim, new Vector3(hit.point.x, hit.point.y, hit.point.z), Quaternion.Euler(90, 0, 0)) as GameObject;
aims.Add(go1);
lv1.Add(hit.point);
lv.Add(hit.point);
}
else if (lv.Count >= 2)
{
if (sb)
{
lv.RemoveAt(lv.Count - 1);
lv.RemoveAt(lv.Count - 1);
}
lv.Add(hit.point);
sb = true;
}
else
{
lv.Add(hit.point);
}
}
else if (type == 3)
{
if (lv.Count >= 2)
{
//存入点就是反复存入来自动连线，0--1 1--2 2--3.。。。。类似这格式存储点
if (sb)
{
lv.RemoveAt(lv.Count - 1);
lv.RemoveAt(lv.Count - 1);
}
lv.Add(lv[lv.Count - 1]);
lv.Add(hit.point);
lv.Add(lv[0]);
lv.Add(hit.point);
sb = true;
}
else
{
lv.Add(hit.point);
}
}
}
//print(lv.Count);
lineRender.positionCount = lv.Count;
lineRender.SetPositions(lv.ToArray());
}
}
void OnGUI()
{
GUIStyle text = new GUIStyle();
text.fontSize = size;
// 利用gui 为了实时动态更新画线数据
if (lv.Count >= 2)
{
//除了第一个点和最后个点，其它点都是存了两遍
for (int i = 0; i < lv.Count - 1; i = i + 2)
{
Vector3 s = new Vector3((lv[i].x + lv[i + 1].x) / 2, (lv[i].y + lv[i + 1].y) / 2, (lv[i].z + lv[i + 1].z) / 2);
Vector3 a = _camera.WorldToScreenPoint(s);
//注意屏幕坐标系与GUI的ui坐标系y轴相反,ToString(".000")保留小数点后3位数，几个零几位数
//显示线段的长度
GUI.Label(new Rect(a.x- size, Screen.height - a.y, 50, 20), "" + Vector3.Distance(lv[i], lv[i + 1]).ToString(".000") + "" + "" + "m" + "",text);
}
}
//显示面积
if (lv1.Count > 2 && type == 3)
{
Vector3 a = _camera.WorldToScreenPoint(lv1[0]);
GUI.Label(new Rect(a.x - 0, Screen.height - a.y, 50, 20), "" + Compute_3D_polygon_area(lv1).ToString(".00") + "" + "" + "㎡" + "", text);
}
//显示角度
if (lv1.Count == 3 && type == 2)
{
Vector3 a = _camera.WorldToScreenPoint(lv1[1]);
GUI.Label(new Rect(a.x, Screen.height - a.y, 50, 20), "" + Angle(lv1[1], lv1[0], lv1[lv1.Count - 1]).ToString(".000") + "" + "" + "℃" + "", text);
}
}
// 清除重新测量
public void ClearLines()
{
if (lv == null) return;
sb = false;
for (int i = 0; i < aims.Count; i++)
{
Destroy(aims[i]);
}
lv.Clear();
lv1.Clear();
aims.Clear();
lineRender.positionCount = 0;
}
//计算任意多边形的面积，顶点按照顺时针或者逆时针方向排列，不需要考虑y轴的坐标. 2D
public double ComputePolygonArea(List points)
{
int point_num = points.Count;
if (point_num < 3) return 0.0;
float s = points[0].y * (points[point_num - 1].x - points[1].x);
for (int i = 1; i < point_num; ++i)
s += points[i].y * (points[i - 1].x - points[(i + 1) % point_num].x);
return Mathf.Abs(s / 2.0f);
}
public double Compute_3D_polygon_area(List points)
{
//points为任意多边形的点集合 注意输入时要按环的流动输入，不能乱序输入
//此方法是3D空间的，相较于2D更具有普适性
if (points.Count < 3) return 0.0;
var P1X = points[0][0];
var P1Y = points[0][1];
var P1Z = points[0][2];
var P2X = points[1][0];
var P2Y = points[1][1];
var P2Z = points[1][2];
var P3X = points[2][0];
var P3Y = points[2][1];
var P3Z = points[2][2];
var a = Mathf.Pow(((P2Y - P1Y) * (P3Z - P1Z) - (P3Y - P1Y) * (P2Z - P1Z)), 2) + Mathf.Pow(((P3X - P1X) * (P2Z - P1Z) - (P2X - P1X) * (P3Z - P1Z)), 2) + Mathf.Pow(((P2X - P1X) * (P3Y - P1Y) - (P3X - P1X) * (P2Y - P1Y)), 2);
var cosnx = ((P2Y - P1Y) * (P3Z - P1Z) - (P3Y - P1Y) * (P2Z - P1Z)) / (Mathf.Pow(a, 0.5f));
var cosny = ((P3X - P1X) * (P2Z - P1Z) - (P2X - P1X) * (P3Z - P1Z)) / (Mathf.Pow(a, 0.5f));
var cosnz = ((P2X - P1X) * (P3Y - P1Y) - (P3X - P1X) * (P2Y - P1Y)) / (Mathf.Pow(a, 0.5f));
var s = cosnz * ((points[points.Count - 1][0]) * (P1Y) - (P1X) * (points[points.Count - 1][1])) + cosnx * ((points[points.Count - 1][1]) * (P1Z) - (P1Y) * (points[points.Count - 1][2])) + cosny * ((points[points.Count - 1][2]) * (P1X) - (P1Z) * (points[points.Count - 1][0]));
for (int i = 0; i < points.Count-1; i++)
{
var p1 = points[i];
var p2 = points[i + 1];
var ss = cosnz * ((p1[0]) * (p2[1]) - (p2[0]) * (p1[1])) + cosnx * ((p1[1]) * (p2[2]) - (p2[1]) * (p1[2])) + cosny * ((p1[2]) * (p2[0]) - (p2[2]) * (p1[0]));
s += ss;
}
return Mathf.Abs(s / 2.0f);
}
//计算夹角
public double Angle(Vector3 cen, Vector3 first, Vector3 second)
{
double M_PI = 3.1415926535897931;
double ma_x = first.x - cen.x;
double ma_y = first.y - cen.y;
double ma_z = first.z - cen.z;
double mb_x = second.x - cen.x;
double mb_y = second.y - cen.y;
double mb_z = second.z - cen.z;
double v1 = (ma_x * mb_x) + (ma_y * mb_y) + (ma_z * mb_z);
double ma_val = Math.Sqrt(ma_x * ma_x + ma_y * ma_y + ma_z * ma_z);
double mb_val = Math.Sqrt(mb_x * mb_x + mb_y * mb_y + mb_z * mb_z);
double cosM = v1 / (ma_val * mb_val);
double angleAMB = Math.Acos(cosM) * 180 / M_PI;
return angleAMB;
}
}
原文链接：https://blog.csdn.net/qq_22972867/article/details/120452678