The TBlock class

        TLevel* Level() { return level; };

        float   GetMaxZ(void)   { return maxZ; };
        float   GetMinZ(void)   { return minZ; };

        // Return the row and column address of this physical block in the map grid
        UINT    Row()   { return blockRow; };
        UINT    Col()   { return blockCol; };

        // Return a pointer to the South West post in this block (array element 0)
        Tpost*  Posts() { return posts; };

        // Return a pointer to the specified post (in local row/col coordinates)
        Tpost*  Post( UINT r, UINT c )          {       ShiAssert(r<(UINT)POSTS_ACROSS_BLOCK);
                                                                                        ShiAssert(c<(UINT)POSTS_ACROSS_BLOCK);
                                                                                        return posts+(r*POSTS_ACROSS_BLOCK+c);  };

  protected:
        // Block coordinates of this block within its level
        UINT    blockRow;
        UINT    blockCol;

        // Offset of this block's data in the disk file
        DWORD   fileOffset;

        // Max and min z values within this block
        float   maxZ;
        float   minZ;

        // The level to which this block belongs
        TLevel *level;

        // Pointer to the array of posts (NULL when not loaded in memory)
        Tpost  *posts;

        // How many viewers are using this block -- if none, this block should be removed
        int             owners;
 

        // Intialize and release block headers - only allowed from within a TLevel's critical section.
        void Setup( TLevel *Level, UINT r, UINT c );
        void Cleanup();

        // Set and check ownership of this block (block may belong to multiple viewers)
        // These should only be called from within the level's critical section
        void    Reference( void );                                                      // Request use of this block
        int             Release( void );                                                        // Express disinterest in this block
        BOOL    IsOwned( void )  { return (owners > 0); };      // Are we in use by any entity?
 

        // Allow the level which owns each block to get at the private functions of this class.
        // Specificly, the reference and release functions.
        friend TLevel;
 

#ifdef USE_SH_POOLS
  public:
        // Overload new/delete to use a SmartHeap fixed size pool
        void *operator new(size_t size) { ShiAssert( size == sizeof(TBlock) ); return MemAllocFS(pool); };
        void operator delete(void *mem) { if (mem) MemFreeFS(mem); };
        static void InitializeStorage() { pool = MemPoolInitFS( sizeof(TBlock), 4, 0 ); };
        static void ReleaseStorage()    { MemPoolFree( pool ); };
        static MEM_POOL pool;
#endif