Complex enum

// =============================================================================
// =============================================================================
// IMPORTANT NOTE: The order of elements in this enum is INCREDIBLY important.
// Because this is three enums in one, they share some pieces of data that must
// not get overridden.
// =============================================================================
// =============================================================================
enum E_AREA
{
    //union
    //{
    //    struct
    //    {
            #if YSIM_HAS_MASTER
                E_AREA_MASTER,
            #endif
            Float:E_AREA_POS[4],
            PlayerArray:E_AREA_PLAYERS<MAX_PLAYERS>,
            // This MUST go between "E_AREA_PLAYERS" and "E_AREA_FLAGS" to
            // remain constant in subsequent unions.
            #if defined AREA_VERY_FAST
                Float:E_AREA_BOUNDING[4],
            #endif
            // As must this.
            #if AREA_WORLDS > 0
                BitArray:E_AREA_WORLDS<AREA_WORLDS>,
            #endif
            // ALWAYS last (actually used by EVERY type).
            e_AREA_FLAGS:E_AREA_FLAGS,
    //    }
    //    // Start of poly data.
    //    struct
    //    {
            // Reset the enum counter to 0 (on the next item).
            _E_AREA_RESET_@1 = -1,
            // Now restart.
            #if YSIM_HAS_MASTER
                // Skip the master flag if it exists.
                _E_AREA_MASTER_@1,
            #endif
            // This is where polys differ from all others.
            Float:E_AREA_POLY_POS[2],
            E_AREA_POLY_COUNT,
            E_AREA_POLY_NEXT,
            // Skip all the array and flag data, they stay the same.
            _E_AREA_ARRAYS_@1[E_AREA_FLAGS - E_AREA_PLAYERS + E_AREA:1],
    //    }
    //    // Start of poly child data.
    //    struct
    //    {
            // Reset the enum counter to 0 (on the next item).
            _E_AREA_RESET_@2 = -1,
            // Now restart.
            #if YSIM_HAS_MASTER
                // Skip the master flag if it exists.
                _E_AREA_MASTER_@2,
            #endif
            // Store a link to the parent of this poly child.
            E_AREA_CHILD_PARENT,
            #if _:(E_AREA_FLAGS - E_AREA_CHILD_PARENT) & 1
                // There are an ODD number of available slots.  We can store an
                // extra pair iff we don't need to use "NEXT".
                //_E_AREA_SKIP_@2,
                E_AREA_CHILD_OPT_X,
            #endif
            // And the next one in VERY rare cases (I hope).
            E_AREA_CHILD_NEXT,
            E_AREA_CHILD_OPT_Y = E_AREA_CHILD_NEXT,
            // Just store a vast number of X/Y pairs in this child.
            E_AREA_CHILD_ELEMS[_:E_AREA_FLAGS - _:E_AREA_CHILD_NEXT - 1],
            // Skip the flags.
            _E_AREA_FLAGS_@2
    //    }
}

#define CHILD_AREA_SLOTS ((_:E_AREA_FLAGS - _:E_AREA_CHILD_ELEMS) / 2)