Use a variable directly(data return are same in an

Question

I had two flock of bird sensor and i have refer to example code #8 in manual, the c++ code is working for me.

But i only get one sensor data from the c sharp project. The problem is that in the C# example, bird_data[1] and bird_data[2] appear to have same position data. In the C++ example both bird_data[1] and bird_data[2] have correct data.I get the same position output data from below code.

text output in the LBird1X is same LBird2X,LBird1Y is same LBird2Y and LBird1Z is same LBird2Z.

Could this be to do with the lack of pointing ? Or i done something wrong in import the bird.dll stucture data?

C++ code:

birdStartFrameStream(GROUP_ID);
do // Until Keypress
{
  if(birdFrameReady(GROUP_ID)) // Check if there's data available 
  {
    birdGetMostRecentFrame(GROUP_ID,&frame);//Get data from bird BIRDREADING *bird_data; // Transfers data into structure
    BIRDREADING *bird_data;
    for(int i=1; i<DEVCOUNT+1; i++ ) // Loop to get data from birds
    {
      // Change pointer to index of first bird (1)
      bird_data = &frame.reading[i]; // Convert data into inches and degrees and scale
      pos[0] = bird_data->position.nX * 36 / 32767.;
      pos[1] = bird_data->position.nY * 36 / 32767.;
      pos[2] = bird_data->position.nZ * 36 / 32767.;
      ang[0] = bird_data->angles.nAzimuth * 180. / 32767.;
      ang[1] = bird_data->angles.nElevation * 180. / 32767.;
      ang[2] = bird_data->angles.nRoll * 180. / 32767.;
      // print data
      printf("%i> %+6.1f %+6.1f %+6.1f ", i,pos[0], pos[1],pos[2]);
      //  printf("%+6.1f %+6.1f %+6.1f \n",ang[0], ang[1], ang[2]);
    } // end move data from structure to screen loop
  } // end if frame ready loop
} while(!kbhit()); // loop until any key is pressed

C sharp that have same data

if (birdFrameReady(GROUP_ID))
        {
            birdGetMostRecentFrame(GROUP_ID, ref frame);

           BIRDREADING bird_data = new BIRDREADING();

            bird_data = frame.readings[i];

            for (i = 1; i < DEVCOUNT + 1; i++)
            {

                bird_data = frame.readings[i];
                string x, y, z;
                x = (bird_data.position.nX * 36 / 32767.0).ToString();
                y = (bird_data.position.nY * 36 / 32767.0).ToString();
                z = (bird_data.position.nZ * 36 / 32767.0).ToString();
                switch (i)
                {

                    case 1:
                        LBird1X.Text = i.ToString() + ":  " + x;
                        LBird1Y.Text = i.ToString() + ":  " + y;
                        LBird1Z.Text = i.ToString() + ":  " + z;
                        break;
                    case 2:
                        LBird2X.Text = i.ToString() + ":  " + x;
                        LBird2Y.Text = i.ToString() + ":  " + y;
                        LBird2Z.Text = i.ToString() + ":  " + z;
                        break;
                    default:
                        LBird2X.Text = "error";
                        LBird2Y.Text = "error";
                        LBird2Z.Text = "error";
                        break;
                }

            }

C++ Struct

#pragma pack(1) // pack the following structures on one-byte boundaries

// Bird position structure
typedef struct tagBIRDPOSITION
{
    short   nX;         // x-coordinate
    short   nY;         // y-coordinate
    short   nZ;         // z-coordinate
}
BIRDPOSITION;

// Bird angles structure
typedef struct tagBIRDANGLES
{
    short   nAzimuth;   // azimuth angle
    short   nElevation; // elevation angle
    short   nRoll;      // roll angle
}
BIRDANGLES;

// Bird matrix structure
typedef struct tagBIRDMATRIX
{
    short   n[3][3];    // array of matrix elements
}
BIRDMATRIX;

// Bird quaternion structure
typedef struct tagBIRDQUATERNION
{
    short   nQ0;        // q0
    short   nQ1;        // q1
    short   nQ2;        // q2
    short   nQ3;        // q3
}
BIRDQUATERNION;

#pragma pack()  // resume normal packing of structures

// Bird reading structure
typedef struct tagBIRDREADING
{
    BIRDPOSITION    position;   // position of receiver
    BIRDANGLES      angles;     // orientation of receiver, as angles
    BIRDMATRIX      matrix;     // orientation of receiver, as matrix
    BIRDQUATERNION  quaternion; // orientation of receiver, as quaternion
    WORD            wButtons;   // button states
}
BIRDREADING;

// Bird frame structure
//
// NOTE: In stand-alone mode, the bird reading is stored in reading[0], and
//  all other array elements are unused.  In master/slave mode, the "reading"
//  array is indexed by bird number - for example, bird #1 is at reading[1],
//  bird #2 is at reading[2], etc., and reading[0] is unused.
typedef struct tagBIRDFRAME
{
    DWORD           dwTime;     // time at which readings were taken, in msecs
    BIRDREADING     reading[BIRD_MAX_DEVICE_NUM + 1];  // reading from each bird
}
BIRDFRAME;

// Bird system configuration structure
//
// NOTE: In TCP/IP mode, the following fields are NOT used:
//  byXtalSpeed
//
// NOTE: In RS232 and ISA modes, the following fields are NOT used:
//  bits BSS_FBB_ERROR, BSS_LOCAL_ERROR, BSS_LOCAL_POWER, and BSS_MASTER of bySystemStatus
//  byNumServers
//  byChassisNum
//  byNumChassisDevices
//  byFirstDeviceNum

C sharp Stuct

[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct BIRDPOSITION
{
    public short nX;            // x-coordinate
    public short nY;            // y-coordinate
    public short nZ;            // z-coordinate
}


// Bird angles structure
[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct BIRDANGLES
{
    public short nAzimuth;  // azimuth angle
    public short nElevation;    // elevation angle
    public short nRoll;     // roll angle
}

[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct BIRDMATRIX
{
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 9)]
    public short[,] n;


}


[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct BIRDQUATERNION
{
    public short nQ0;       // q0
    public short nQ1;       // q1
    public short nQ2;       // q2
    public short nQ3;       // q3
}




[StructLayout(LayoutKind.Sequential, Pack = 0)]
public struct BIRDREADING
{
    public BIRDPOSITION position;   // position of receiver
    public BIRDANGLES angles;       // orientation of receiver, as angles
    public BIRDMATRIX matrix;       // orientation of receiver, as matrix
    public BIRDQUATERNION quaternion; // orientation of receiver, as quaternion
    public ushort wButtons; // button states
}



[StructLayout(LayoutKind.Sequential, Pack = 0)]
public struct BIRDFRAME
{
    public uint dwTime;     // time at which readings were taken, in msecs
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 127)]
    public BIRDREADING[] readings; // reading from each bird
}

Answer 1

Try to use StructLayout(LayoutKind.Explicit)