Marshalling complex struct to c#

Question

i\'m still struggeling to marshal a quite complex struct from c++ to c#.

The struct in c++ is the following:

typedef struct {
    DWORD Flags;                


        

Answer 1

I have already told you. You can't use fixed byte as an universal solution to problems.

This

public fixed byte NodeRots[NUM_GYROS];

must be

public fixed Matrix NodeRots[NUM_GYROS];

Then this:

Marshal.Copy((IntPtr)ptr, array, 0, CHANNEL_ARRAY_SIZE)

must be

Marshal.Copy((IntPtr)ptr, array, 0, CHANNEL_ARRAY_SIZE * sizeof(float));

Then for the nodeRots getter you don't really need the Marshal.PtrToStructure, because your struct can be marshaled directly.

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public unsafe struct Frame
{
    public uint Flags;
    public uint TimeCode;
    public uint NodeMoving;
    public fixed float nodeRots[NUM_GYROS * 9];
    public Vector Position;
    public uint ContactPoints;
    public fixed float channel[CHANNEL_ARRAY_SIZE];

    public unsafe float[] Channel
    {
        get
        {
            fixed (float* ptr = channel)
            {
                float[] array = new float[CHANNEL_ARRAY_SIZE];

                Marshal.Copy((IntPtr)ptr, array, 0, CHANNEL_ARRAY_SIZE * sizeof(float));
                return array;
            }
        }
    }

    public unsafe Matrix[] NodeRots
    {
        get
        {
            fixed (float* ptr = nodeRots)
            {
                Matrix[] array = new Matrix[NUM_GYROS];

                for (int i = 0, y = 0; i < array.Length; i++, y += 9)
                {
                    array[i].xx = ptr[y + 0];
                    array[i].xy = ptr[y + 1];
                    array[i].xz = ptr[y + 2];

                    array[i].yx = ptr[y + 3];
                    array[i].yy = ptr[y + 4];
                    array[i].yz = ptr[y + 5];

                    array[i].zx = ptr[y + 6];
                    array[i].zy = ptr[y + 7];
                    array[i].zz = ptr[y + 8];
                }

                return array;
            }
        }
    }
}