extern "C" __declspec(dllexport) float* ComputeConvexHull(float* points, int count, int* outCount) std::vector<Point_2> pts, result; for (int i = 0; i < count; i++) pts.push_back(Point_2(points[2 i], points[2 i+1])); CGAL::convex_hull_2(pts.begin(), pts.end(), std::back_inserter(result)); outCount = result.size(); float out = new float[2 * result.size()]; for (size_t i = 0; i < result.size(); i++) out[2 i] = CGAL::to_double(result[i].x()); out[2 i+1] = CGAL::to_double(result[i].y());
using System.Runtime.InteropServices; using UnityEngine; public class CGALBridge : MonoBehaviour [DllImport("CGALWrapper")] private static extern System.IntPtr ComputeConvexHull(float[] points, int count, ref int outCount);
: Memory management – always provide a FreeMemory function in your plugin. Approach 2: External Process (Simpler for Complex Workflows) Run a separate C++ executable that uses CGAL and communicate via stdin/stdout, sockets, or files. cgal unity
void TestHull() float[] pts = 0,0, 1,0, 1,1, 0,1, 0.5f,0.5f ; int outCount = 0; IntPtr ptr = ComputeConvexHull(pts, 5, ref outCount); float[] result = new float[outCount * 2]; Marshal.Copy(ptr, result, 0, outCount * 2); // Convert to Vector2[] and use in Unity // Remember to free native memory (expose a free function)
// CGALWrapper.h extern "C" __declspec(dllexport) float* ComputeConvexHull(float* points, int count, int* outCount); Cons : Slower, serialization overhead
// CGALWrapper.cpp #include <CGAL/Exact_predicates_inexact_constructions_kernel.h> #include <CGAL/convex_hull_2.h> typedef CGAL::Exact_predicates_inexact_constructions_kernel K; typedef K::Point_2 Point_2;
: No native plugin complexity, CGAL runs fully isolated. Cons : Slower, serialization overhead. Cons : Slower
return out;
: Native plugins work, but you must ensure the plugin is compiled for the target architecture (x86_64, ARM64).