qt Ear Clipping算法代码实现将一个多边形划分为三角形和凸多边形
时间: 2024-05-04 08:15:30 浏览: 10
可以回答,以下是Ear Clipping算法的实现代码:
```c++
#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
using namespace std;
vector<vector<double>> earClipping(vector<vector<double>> poly) {
vector<vector<double>> triangles;
while (poly.size() > 3) {
for (int i = 0; i < poly.size(); i++) {
int prev = i == 0 ? poly.size() - 1 : i - 1;
int next = i == poly.size() - 1 ? 0 : i + 1;
if (isConvex(poly[prev], poly[i], poly[next])) {
bool earFound = true;
for (int j = 0; j < poly.size(); j++) {
if (j != prev && j != i && j != next && isInsideTriangle(poly[prev], poly[i], poly[next], poly[j])) {
earFound = false;
break;
}
}
if (earFound) {
triangles.push_back({poly[prev][0], poly[prev][1], poly[i][0], poly[i][1], poly[next][0], poly[next][1]});
poly.erase(poly.begin() + i);
break;
}
}
}
}
triangles.push_back({poly[0][0], poly[0][1], poly[1][0], poly[1][1], poly[2][0], poly[2][1]});
return triangles;
}
bool isConvex(vector<double> p1, vector<double> p2, vector<double> p3) {
double crossProduct = (p3[1] - p2[1]) * (p2[0] - p1[0]) - (p3[0] - p2[0]) * (p2[1] - p1[1]);
return crossProduct > 0;
}
bool isInsideTriangle(vector<double> p1, vector<double> p2, vector<double> p3, vector<double> p) {
bool b1 = isOnSameSide(p1, p2, p3, p);
bool b2 = isOnSameSide(p2, p3, p1, p);
bool b3 = isOnSameSide(p3, p1, p2, p);
return b1 && b2 && b3;
}
bool isOnSameSide(vector<double> p1, vector<double> p2, vector<double> a, vector<double> b) {
double cp1 = (b[0] - a[0]) * (p1[1] - a[1]) - (b[1] - a[1]) * (p1[0] - a[0]);
double cp2 = (b[0] - a[0]) * (p2[1] - a[1]) - (b[1] - a[1]) * (p2[0] - a[0]);
return cp1 * cp2 >= 0;
}
int main() {
vector<vector<double>> poly = {{0, 0}, {2, 0}, {2, 2}, {1, 3}, {0, 2}};
vector<vector<double>> triangles = earClipping(poly);
for (auto triangle : triangles) {
cout << "(" << triangle[0] << ", " << triangle[1] << "), (" << triangle[2] << ", " << triangle[3] << "), (" << triangle[4] << ", " << triangle[5] << ")" << endl;
}
return 0;
}
```
以上是使用C++实现的Ear Clipping算法,用于将一个多边形划分为三角形和凸多边形。