c# - Unity插件:编码(marshal)C++ double *将C#中的数组翻倍

Question

我正在努力使用Unity和使用C++ Dll的插件系统。
基本上，我在C++中有一个Dll，可以知道相机的固有参数来查找相机的外部参数。
创建.exe时，该功能运行平稳。

我想做的是通过C++中的Dll在Unity中使用该函数来获取存储在一维双数组中的外部参数。

我已经阅读了很多有关在Dll中导出函数并在C#中导入它们的知识，但是我花了4天的时间，但没有任何效果。

我总是得到相同的错误:运行时错误和Unity崩溃(我认为是内存访问问题)。

这是C++代码

#include <opencv2\opencv.hpp>
#include <stdio.h>


#ifdef CALIBRATION_EXPORTS
#define CALIBRATION_API  __declspec(dllexport)
#else
#define CALIBRATION_API __declspec(dllimport)
#endif

using namespace cv;
using namespace std;


class CALIBRATION_API calib
{
 public:
calib();
virtual ~calib();
void calcBoardCornerPosititions(Size boardSize, double squareSize, vector<Point3f>&   corners);
Mat Nextimage(VideoCapture camera);
void find_extrinsic(double* Mat_Ext, double mat_int[], double mat_dist[], int size_ext, int size_int, int size_dist);

private :
VideoCapture camera;
};

extern "C" CALIBRATION_API calib* CreateCalib()
{
return new calib();
}
extern "C" CALIBRATION_API void DisposeCalib( calib* pObject)
{
if (pObject != NULL)
{
    delete pObject;
    pObject = NULL;
}
}

void calib::find_extrinsic(double *Mat_Ext, double mat_int[], double mat_dist[], int size_ext, int size_int, int size_dist)
{

    if (size_ext == 16 && size_int == 9 && size_dist == 5)
    {       
        Size boardSize = Size(9, 6);
        double squareSize = 245;
        //Matrices de résultats param ext
        Mat_<double> rvecs_ext(3, 3);
        Mat_<double> tvecs_ext(3, 1);
        vector<Point3f> objectPoints_ext;
        int id = 0;
        Mat_<double> cameraMatrix(3, 3);
        for (int i = 0; i < 3; i++)
        {
            for (int j = 0; j < 3; j++)
            {
                cameraMatrix.data[i, j] = mat_int[id];
                id++;
            }
        }

        Mat_<double> distCoeffs(5, 1);
        for (int i = 0; i < 5; i++)
        {
            distCoeffs.data[i, 1] = mat_dist[i];
        }
        Mat result = Nextimage(camera);
        Size imageSize = result.size();
        vector<Point2f> pointBuf;

        bool found = findChessboardCorners(result, boardSize, pointBuf, CALIB_CB_FAST_CHECK + CALIB_CB_FILTER_QUADS);
        if (found)
        {

            calcBoardCornerPosititions(boardSize, squareSize, objectPoints_ext);
            solvePnP(objectPoints_ext, pointBuf, cameraMatrix, distCoeffs, rvecs_ext, tvecs_ext, false, CV_ITERATIVE);

            Mat_Ext[0] = rvecs_ext.at<double>(0, 0);
            Mat_Ext[1] = rvecs_ext.at<double>(0, 1);
            Mat_Ext[2] = rvecs_ext.at<double>(0, 2);
            Mat_Ext[3] = tvecs_ext.at<double>(0, 0);
            Mat_Ext[4] = rvecs_ext.at<double>(1, 0);
            Mat_Ext[5] = rvecs_ext.at<double>(1, 1);
            Mat_Ext[6] = rvecs_ext.at<double>(1, 2);
            Mat_Ext[7] = tvecs_ext.at<double>(0, 2);
            Mat_Ext[8] = rvecs_ext.at<double>(2, 0);
            Mat_Ext[9] = rvecs_ext.at<double>(2, 1);
            Mat_Ext[10] = rvecs_ext.at<double>(2, 2);
            Mat_Ext[11] = rvecs_ext.at<double>(0, 3);
            Mat_Ext[12] = rvecs_ext.at<double>(3, 0);
            Mat_Ext[13] = rvecs_ext.at<double>(3, 1);
            Mat_Ext[14] = rvecs_ext.at<double>(3, 2);
            Mat_Ext[15] = 1;

            }
        }
        }
}

extern"C" CALIBRATION_API void Call_find_extrinsic(calib* pObject, double *Mat_Ext, double mat_int[], double mat_dist[], int size_ext, int size_int, int size_dist)
{
if (pObject != NULL)
{
    pObject->find_extrinsic(Mat_Ext, mat_int, mat_dist,size_ext,size_int,size_dist);
}
}

以及相关的C#代码:

[DllImport("Beta.dll")]
public static extern IntPtr CreateCalib();


[DllImport("Beta.dll")]
public static extern void DisposeCalib(IntPtr pCalibObject);


[DllImport("Beta.dll")]
public static extern void Call_find_extrinsic(IntPtr pCalibObject, double[] pMat_Ext, double[] mat_int, double[] mat_dist,
                                              int size_ext, int size_int, int size_dist);

pCalibClass = CreateCalib();
double[]test_ext = new double[16];
Call_find_extrinsic(pCalibClass, test_ext,Intrinsic_mat,Dist_mat,test_ext.Length,Intrinsic_mat.Length,Dist_mat.Length);

我尝试用find_extrinsic方法计算的值填充test_ext。

您能帮我解决这个问题吗？

非常感谢!

Answer 1

rvecs_ext不应该是3x3矩阵，而是3x1 vector 。因此，当您访问禁止的内存空间时，它会崩溃。

3x1 vector 是旋转矩阵的对角线，其他元素视为空值。为什么呢？看看this