How can I use 2D Output with S-Function Builder

Hello,

I need to get three 2D array as output from an S-Function Builder but I don't know how can I write to these arrays in my C-Code. Here is my S-Function Builder parameters :

If I try something like

for (row = 0; row < 480; row++)
{
    for (col = 0; col < 640; col++)
    {
        R[row][col] = r_buffer[row][col];
        G[row][col] = g_buffer[row][col];
        B[row][col] = b_buffer[row][col];
    }
}

I get errors like this :

UDPMsgToImg_wrapper.c:90:23: error: subscripted value is neither array nor pointer nor vector
                 R[row][col] = r_buffer[row][col];
                       ^
UDPMsgToImg_wrapper.c:91:23: error: subscripted value is neither array nor pointer nor vector
                 G[row][col] = g_buffer[row][col];
                       ^
UDPMsgToImg_wrapper.c:92:23: error: subscripted value is neither array nor pointer nor vector
                 B[row][col] = b_buffer[row][col];

Which seems to be logical because if I look into the file 'UDPMsgToImg_wrapper.c', R, G and B are defined as simple pointers :

void UDPMsgToImg_Outputs_wrapper(const uint32_T *UDPMsg,
      const uint16_T *msgLength,
      uint8_T *R,
      uint8_T *G,
      uint8_T *B,
      const uint16_T *imgWidth, const int_T p_width0,
      const uint16_T *imgHeight, const int_T p_width1)
{

}

Have you an idea to do this ?

Thanks !

Answer 1

[Frédéric Naud-Dulude]

 * Note1: Matrix signals are stored in column major order.
 * Note2: Access each matrix element by one index not two indices.
 *        For example, if the output signal is a [2x2] matrix signal,
 *        -          - 
 *       | y[0]  y[2] |
 *       | y[1]  y[3] |
 *       -           -
 *       Output elements are stored as follows:
 *           y[0] --> row = 0, col = 0
 *           y[1] --> row = 1, col = 0
 *           y[2] --> row = 0, col = 1
 *           y[3] --> row = 1, col = 1
 */

More on this here :

https://stackoverflow.com/questions/11525701/how-can-i-create-an-s-function-in-simulink-with-an-input-port-that-is-a-2d-array