gistfile1.txt

NSArray *NSArrayOfTilesFromCoordinateRectWithinTile(OSPCoordinateRect r, double maxOverspill, OSPTile t)
{
    OSPCoordinateRect tileRect = OSPCoordinateRectFromTile(t);
    
    if (OSPCoordinateRectIntersectsRect(r, tileRect))
    {
        BOOL splitVertically = OSPCoordinateRectGetMinLongitude(r) - maxOverspill > OSPCoordinateRectGetMinLongitude(tileRect) || OSPCoordinateRectGetMaxLongitude(r) + maxOverspill < OSPCoordinateRectGetMaxLongitude(tileRect);
        BOOL splitHorizontally = OSPCoordinateRectGetMinLatitude(r) - maxOverspill > OSPCoordinateRectGetMinLatitude(tileRect) || OSPCoordinateRectGetMaxLatitude(r) + maxOverspill < OSPCoordinateRectGetMaxLatitude(tileRect);
        
        if (splitVertically || splitHorizontally)
        {
            NSArray *bottomLeft  = NSArrayOfTilesFromCoordinateRectWithinTile(r, maxOverspill, (OSPTile){.x = t.x * 2    , .y = t.y * 2    , .zoom = t.zoom + 1});
            NSArray *bottomRight = NSArrayOfTilesFromCoordinateRectWithinTile(r, maxOverspill, (OSPTile){.x = t.x * 2 + 1, .y = t.y * 2    , .zoom = t.zoom + 1});
            NSArray *topLeft     = NSArrayOfTilesFromCoordinateRectWithinTile(r, maxOverspill, (OSPTile){.x = t.x * 2    , .y = t.y * 2 + 1, .zoom = t.zoom + 1});
            NSArray *topRight    = NSArrayOfTilesFromCoordinateRectWithinTile(r, maxOverspill, (OSPTile){.x = t.x * 2 + 1, .y = t.y * 2 + 1, .zoom = t.zoom + 1});
            return [[bottomLeft arrayByAddingObjectsFromArray:bottomRight] arrayByAddingObjectsFromArray:[topLeft arrayByAddingObjectsFromArray:topRight]];
        }
        else
        {
            return [NSArray arrayWithObject:[OSPValue valueWithTile:t]];
        }
    }
    
    return [NSArray array];
}