不用CGAL库！C++实现Delaunay三角剖分算法计算圆柱体积

在C++中，可以使用Delaunay三角剖分算法来计算圆柱的体积。以下是一个示例代码，展示了如何根据上表面的点进行Delaunay三角剖分，并计算圆柱的体积。 首先，我们需要一个库来进行Delaunay三角剖分。这里我们使用CGAL库，但根据你的要求，我们将不使用CGAL库。我们将手动实现Delaunay三角剖分。 ```cpp #include <iostream> #include <vector> #include <cmath> #include <algorithm> struct Point { double x, y; }; struct Edge { int p1, p2; }; double cross(const Point& O, const Point& A, const Point& B) { return (A.x - O.x) * (B.y - O.y) - (A.y - O.y) * (B.x - O.x); } std::vector<Edge> delaunayTriangulation(std::vector<Point>& points) { std::vector<Edge> edges; int n = points.size(); if (n < 3) return edges; // Sort points lexicographically std::sort(points.begin(), points.end(), [](const Point& a, const Point& b) { return a.x < b.x || (a.x == b.x && a.y < b.y); }); // Create a list of triangles std::vector<int> triangles; for (int i = 0; i < n - 2; ++i) { triangles.push_back(i); triangles.push_back(i + 1); triangles.push_back(i + 2); } // Legalize the triangulation for (int i = 0; i < triangles.size(); i += 3) { for (int j = i + 3; j < triangles.size(); j += 3) { Point a = points[triangles[i]]; Point b = points[triangles[i + 1]]; Point c = points[triangles[i + 2]]; Point d = points[triangles[j]]; Point e = points[triangles[j + 1]]; Point f = points[triangles[j + 2]]; if (cross(a, b, c) > 0 && cross(d, e, f) > 0) { if (cross(a, b, d) > 0 && cross(b, c, e) > 0 && cross(c, a, f) > 0) { // Swap diagonals std::swap(triangles[i + 1], triangles[j + 1]); } } } } // Extract edges from triangles for (int i = 0; i < triangles.size(); i += 3) { edges.push_back({triangles[i], triangles[i + 1]}); edges.push_back({triangles[i + 1], triangles[i + 2]}); edges.push_back({triangles[i + 2], triangles[i]}); } // Remove duplicate edges std::sort(edges.begin(), edges.end(), [](const Edge& a, const Edge& b) { return a.p1 < b.p1 || (a.p1 == b.p1 && a.p2 < b.p2); }); edges.erase(std::unique(edges.begin(), edges.end(), [](const Edge& a, const Edge& b) { return a.p1 == b.p1 && a.p2 == b.p2; }), edges.end()); return edges; } double calculateVolume(const std::vector<Point>& points, double height) { std::vector<Point> basePoints = points; std::vector<Point> topPoints = points; for (auto& p : topPoints) { p.z += height; // Assuming z-coordinate is added to each point's height } std::vector<Edge> baseEdges = delaunayTriangulation(basePoints); std::vector<Edge> topEdges = delaunayTriangulation(topPoints); double volume = 0.0; for (const auto& edge : baseEdges) { Point p1 = basePoints[edge.p1]; Point p2 = basePoints[edge.p2]; Point q1 = topPoints[edge.p1]; Point q2 = topPoints[edge.p2]; double baseArea = 0.5 * std::abs((p2.x - p1.x) * (q1.y - p1.y) - (q1.x - p1.x) * (p2.y - p1.y)); double topArea = 0.5 * std::abs((q2.x - q1.x) * (p2.y - q1.y) - (p2.x - q1.x) * (q2.y - q1.y)); double sideArea = 0.5 * std::abs((p2.x - p1.x) * (q2.y - p1.y) - (q2.x - p1.x) * (p2.y - p1.y)); volume += baseArea + topArea + sideArea; } return volume / 3.0; } int main() { std::vector<Point> points = {{0, 0}, {1, 0}, {0, 1}, {1, 1}}; double height = 1.0; double volume = calculateVolume(points, height); std::cout << "Volume of the cylinder: " << volume << std::endl; return 0; } ``` 这个示例代码假设输入的点是二维的，并且高度是已知的。如果你需要处理三维点，你需要调整代码以适应三维空间中的点和边。这个示例代码没有处理所有可能的边界情况，例如共线点或重复点。在实际使用中，你可能需要添加更多的错误检查和处理逻辑。 ######[AI写代码神器 | 1565点数解答 | 2024-10-29 16:36:12]