using System;

public class Program

{

    unsafe static void BlueFilter (int[,] bitmap)

{

  int length = bitmap.Length;

  fixed (int* b = bitmap)

  {

    int* p = b;

    for (int i = 0; i < length; i++)

      *p++ &= 0xFF;

  }

}

​

static void Main()

{

    int[,] bitmap = { {0x101010, 0x808080, 0xFFFFFF}, {0x101010, 0x808080, 0xFFFFFF} };

    BlueFilter (bitmap);

    bitmap.Dump();

}

}