Rewrite feature covering. Use a simpler approach and remove stream optimizer.

1 files changed, 55 insertions, 302 deletions

diff --git a/geometry/covering.hpp b/geometry/covering.hpp
index c774191275..f7fd6869af 100644
--- a/geometry/covering.hpp
+++ b/geometry/covering.hpp
@@ -3,31 +3,26 @@
 #include "../base/assert.hpp"
 #include "../base/base.hpp"
 #include "../base/logging.hpp"
-#include "../base/set_operations.hpp"
-#include "../base/stl_add.hpp"
+#include "../base/math.hpp"
 #include "../std/algorithm.hpp"
-#include "../std/array.hpp"
-#include "../std/functional.hpp"
-#include "../std/iterator.hpp"
-#include "../std/map.hpp"
-#include "../std/queue.hpp"
 #include "../std/utility.hpp"
 #include "../std/vector.hpp"
 
 namespace covering
 {
 
-enum CellTriangleIntersection
+enum CellObjectIntersection
 {
-  CELL_TRIANGLE_NO_INTERSECTION = 0,
-  CELL_TRIANGLE_INTERSECT = 1,
-  CELL_INSIDE_TRIANGLE = 2,
-  TRIANGLE_INSIDE_CELL = 3
+  CELL_OBJECT_NO_INTERSECTION = 0,
+  CELL_OBJECT_INTERSECT = 1,
+  CELL_INSIDE_OBJECT = 2,
+  OBJECT_INSIDE_CELL = 3
 };
 
 template <class CellIdT>
-CellTriangleIntersection IntersectCellWithTriangle(
-    CellIdT const cell, m2::PointD const & a, m2::PointD const & b, m2::PointD const & c)
+inline CellObjectIntersection IntersectCellWithLine(CellIdT const cell,
+                                                    m2::PointD const & a,
+                                                    m2::PointD const & b)
 {
   pair<uint32_t, uint32_t> const xy = cell.XY();
   uint32_t const r = cell.Radius();
@@ -39,308 +34,66 @@ CellTriangleIntersection IntersectCellWithTriangle(
     m2::PointD(xy.first + r, xy.second - r)
   };
   for (int i = 0; i < 4; ++i)
-  {
-    m2::PointD const & p1 = cellCorners[i];
-    m2::PointD const & p2 = cellCorners[i == 0 ? 3 : i - 1];
-    if (m2::SegmentsIntersect(a, b, p1, p2)) return CELL_TRIANGLE_INTERSECT;
-    if (m2::SegmentsIntersect(b, c, p1, p2)) return CELL_TRIANGLE_INTERSECT;
-    if (m2::SegmentsIntersect(c, a, p1, p2)) return CELL_TRIANGLE_INTERSECT;
-  }
+    if (m2::SegmentsIntersect(a, b, cellCorners[i], cellCorners[i == 0 ? 3 : i - 1]))
+      return CELL_OBJECT_INTERSECT;
   if (xy.first - r <= a.x && a.x <= xy.first + r && xy.second - r <= a.y && a.y <= xy.second + r)
-    return TRIANGLE_INSIDE_CELL;
-  if (m2::IsPointStrictlyInsideTriangle(cellCorners[0], a, b, c))
-    return CELL_INSIDE_TRIANGLE;
-  return CELL_TRIANGLE_NO_INTERSECTION;
+    return OBJECT_INSIDE_CELL;
+  return CELL_OBJECT_NO_INTERSECTION;
 }
 
-template <class CellIdT, typename F>
-void CoverTriangle(m2::PointD const & a, m2::PointD const & b, m2::PointD const & c,
-                   F const & output, uint8_t const level = CellIdT::DEPTH_LEVELS - 1,
-                   CellIdT const startCell = CellIdT::Root())
+template <class CellIdT>
+CellObjectIntersection IntersectCellWithTriangle(
+    CellIdT const cell, m2::PointD const & a, m2::PointD const & b, m2::PointD const & c)
 {
-  ASSERT_LESS_OR_EQUAL(startCell.Level(), level, (a, b, c));
-  CellTriangleIntersection intersection = IntersectCellWithTriangle(startCell, a, b, c);
-
-  if (intersection == CELL_TRIANGLE_NO_INTERSECTION)
-    return;
-
-  if (startCell.Level() == level || intersection == CELL_INSIDE_TRIANGLE)
-  {
-    output(startCell);
-    return;
-  }
-
-  for (uint8_t child = 0; child < 4; ++child)
-    CoverTriangle(a, b, c, output, level, startCell.Child(child));
+  CellObjectIntersection const i1 = IntersectCellWithLine(cell, a, b);
+  if (i1 == CELL_OBJECT_INTERSECT)
+    return CELL_OBJECT_INTERSECT;
+  CellObjectIntersection const i2 = IntersectCellWithLine(cell, b, c);
+  if (i2 == CELL_OBJECT_INTERSECT)
+    return CELL_OBJECT_INTERSECT;
+  CellObjectIntersection const i3 = IntersectCellWithLine(cell, c, a);
+  if (i3 == CELL_OBJECT_INTERSECT)
+    return CELL_OBJECT_INTERSECT;
+  ASSERT_EQUAL(i1, i2, (cell, a, b, c));
+  ASSERT_EQUAL(i2, i3, (cell, a, b, c));
+  ASSERT_EQUAL(i3, i1, (cell, a, b, c));
+  return i1;
 }
 
-template <class CellIdT>
-class Covering
+template <class CellIdT, typename IntersectF>
+void CoverObject(IntersectF const & intersect, uint64_t cellPenaltyArea, vector<CellIdT> & out,
+                 CellIdT cell = CellIdT::Root())
 {
-public:
-  typedef CellIdT CellId;
-  typedef typename CellId::LessQueueOrder LessQueueOrder;
-
-  Covering() : m_Size(0) {}
-
-  explicit Covering(CellId cell) : m_Size(1)
-  {
-    m_Covering[cell.Level()].push_back(cell);
-  }
-
-  explicit Covering(vector<CellId> const & v, int64_t minId = 0)
-  {
-    for (size_t i = 0; i < v.size(); ++i)
-      m_Covering[v[i].Level()].push_back(v[i]);
-    Sort();
-    Unique();
-    RemoveDuplicateChildren();
-    RemoveFullSquares(minId);
-    m_Size = CalculateSize();
-  }
-
-  // Cover triangle.
-  Covering(m2::PointD const & a, m2::PointD const & b, m2::PointD const & c,
-           int level = CellId::DEPTH_LEVELS - 1)
-  {
-    // TODO: ASSERT(a != b), ASSERT(b != c), ASSERT(a != c) ?
-    ASSERT(0 <= level && level <= CellId::DEPTH_LEVELS, (level, CellId::Root()));
-    CoverTriangleInfo info;
-    info.m_pCovering = this;
-    info.m_A = a;
-    info.m_B = b;
-    info.m_C = c;
-    info.m_Level = level;
-    CoverTriangleImpl(info, CellId::Root());
-    Sort();
-    RemoveFullSquares();
-    m_Size = CalculateSize();
-  }
-
-  size_t Size() const
-  {
-    ASSERT_EQUAL(m_Size, CalculateSize(), ());
-    return m_Size;
-  }
-
-  void Append(Covering<CellId> const & c)
-  {
-    AppendWithoutNormalize(c);
-    RemoveDuplicateChildren();
-    RemoveFullSquares();
-    m_Size = CalculateSize();
-  }
-
-  void OutputToVector(vector<CellId> & result) const
-  {
-    for (int level = 0; level < CellId::DEPTH_LEVELS; ++level)
-        result.insert(result.end(), m_Covering[level].begin(), m_Covering[level].end());
-  }
-
-  void OutputToVector(vector<int64_t> & result) const
-  {
-    for (int level = 0; level < CellId::DEPTH_LEVELS; ++level)
-      for (size_t i = 0; i < m_Covering[level].size(); ++i)
-        result.push_back(m_Covering[level][i].ToInt64());
-  }
-
-  void Simplify(int64_t minId = 0)
-  {
-    int cellsSimplified = 0;
-    int const initialSize = m_Size;
-    for (int level = CellId::DEPTH_LEVELS - 1; level > 1; --level)
-    {
-      if (m_Covering[level].size() >= 2)
-      {
-        int const initialLevelSize = static_cast<int>(m_Covering[level].size());
-        SimplifyLevel(level, minId);
-        cellsSimplified += initialLevelSize - static_cast<int>(m_Covering[level].size());
-        if (cellsSimplified > initialSize / 2)
-          break;
-      }
-    }
-    RemoveDuplicateChildren();
-    RemoveFullSquares(minId);
-    m_Size = CalculateSize();
-  }
-
-private:
-
-  void SimplifyLevel(int level, int64_t minId)
-  {
-    map<CellId, uint32_t, LessQueueOrder> parentCellCounts;
-    typedef typename vector<CellId>::const_iterator ConstIteartor;
-    for (ConstIteartor it = m_Covering[level].begin(); it != m_Covering[level].end(); ++it)
-      if (it->Parent().ToInt64() >= minId)
-        ++parentCellCounts[it->Parent()];
-
-    vector<CellId> parentCells, childCells;
-    for (ConstIteartor it = m_Covering[level].begin(); it != m_Covering[level].end(); ++it)
-    {
-      if (parentCellCounts[it->Parent()] > 1)
-        parentCells.push_back(it->Parent());
-      else
-        childCells.push_back(*it);
-    }
-    ASSERT(IsSorted(parentCells.begin(), parentCells.end(), LessQueueOrder()), (parentCells));
-    ASSERT(IsSorted(childCells.begin(), childCells.end(), LessQueueOrder()), (childCells));
-    m_Covering[level].swap(childCells);
-    parentCells.erase(unique(parentCells.begin(), parentCells.end()), parentCells.end());
-    AppendToVector(m_Covering[level - 1], parentCells);
-  }
-
-  static void AppendToVector(vector<CellId> & a, vector<CellId> const & b)
-  {
-    ASSERT(IsSortedAndUnique(a.begin(), a.end(), LessQueueOrder()), (a));
-    ASSERT(IsSortedAndUnique(b.begin(), b.end(), LessQueueOrder()), (b));
-    vector<CellId> merged;
-    set_union(a.begin(), a.end(), b.begin(), b.end(), back_inserter(merged), LessQueueOrder());
-    a.swap(merged);
-  }
-
-  template <typename CompareT>
-  struct CompareCellsAtLevel
-  {
-    explicit CompareCellsAtLevel(int level) : m_Level(level) {}
-
-    bool operator() (CellId id1, CellId id2) const
-    {
-      return m_Comp(id1.AncestorAtLevel(m_Level), id2.AncestorAtLevel(m_Level));
-    }
-
-    CompareT m_Comp;
-    int m_Level;
-  };
-
-  void AppendWithoutNormalize(Covering const & c)
-  {
-    for (int level = CellId::DEPTH_LEVELS - 1; level >= 0; --level)
-      AppendToVector(m_Covering[level], c.m_Covering[level]);
-  }
-
-  void Sort()
-  {
-    for (int level = 0; level < CellId::DEPTH_LEVELS; ++level)
-      sort(m_Covering[level].begin(), m_Covering[level].end(), LessQueueOrder());
-  }
-
-  void Unique()
-  {
-    for (int level = 0; level < CellId::DEPTH_LEVELS; ++level)
-    {
-      vector<CellId> & covering = m_Covering[level];
-      ASSERT(IsSorted(covering.begin(), covering.end(), LessQueueOrder()), (covering));
-      covering.erase(unique(covering.begin(), covering.end()), covering.end());
-    }
-  }
+  uint64_t const cellArea = my::sq(uint64_t(1 << (CellIdT::DEPTH_LEVELS - 1 - cell.Level())));
+  CellObjectIntersection const intersection = intersect(cell);
 
-  void RemoveDuplicateChildren()
-  {
-    RemoveDuplicateChildrenImpl();
-#ifdef DEBUG
-    // Assert that all duplicate children were removed.
-    vector<int64_t> v1, v2;
-    OutputToVector(v1);
-    RemoveDuplicateChildrenImpl();
-    OutputToVector(v2);
-    ASSERT_EQUAL(v1, v2, ());
-#endif
-  }
-
-  void RemoveDuplicateChildrenImpl()
-  {
-    for (int parentLevel = 0; parentLevel < static_cast<int>(m_Covering.size()) - 1; ++parentLevel)
-    {
-      if (m_Covering[parentLevel].empty())
-        continue;
-      for (int childLevel = parentLevel + 1; childLevel < static_cast<int>(m_Covering.size());
-           ++childLevel)
-      {
-        vector<CellId> substracted;
-        CompareCellsAtLevel<LessQueueOrder> comparator(parentLevel);
-        ASSERT(IsSorted(m_Covering[childLevel].begin(), m_Covering[childLevel].end(), comparator),
-               (m_Covering[childLevel]));
-        ASSERT(IsSorted(m_Covering[parentLevel].begin(), m_Covering[parentLevel].end(), comparator),
-               (m_Covering[parentLevel]));
-        SetDifferenceUnlimited(m_Covering[childLevel].begin(), m_Covering[childLevel].end(),
-                               m_Covering[parentLevel].begin(), m_Covering[parentLevel].end(),
-                               back_inserter(substracted), comparator);
-        m_Covering[childLevel].swap(substracted);
-      }
-    }
-  }
-
-  void RemoveFullSquares(int64_t minId = 0)
-  {
-    vector<CellId> cellsToAppend;
-    for (int level = m_Covering.size() - 1; level >= 0; --level)
-    {
-      // a -> b + parents
-      vector<CellId> const & a = m_Covering[level];
-      vector<CellId> b;
-      vector<CellId> parents;
-      b.reserve(a.size());
-      for (size_t i = 0; i < a.size(); ++i)
-      {
-        if (i + 3 < a.size())
-        {
-          CellId const parent = a[i].Parent();
-          if (parent == a[i+1].Parent() &&
-              parent == a[i+2].Parent() &&
-              parent == a[i+3].Parent() &&
-              parent.ToInt64() >= minId)
-          {
-            parents.push_back(parent);
-            i += 3;
-            continue;
-          }
-        }
-        b.push_back(a[i]);
-      }
-      m_Covering[level].swap(b);
-      if (level > 0)
-        AppendToVector(m_Covering[level - 1], parents);
-    }
-  }
-
-  size_t CalculateSize() const
+  if (intersection == CELL_OBJECT_NO_INTERSECTION)
+    return;
+  if (intersection == CELL_INSIDE_OBJECT ||
+      cell.Level() == CellIdT::DEPTH_LEVELS - 1 ||
+      cellPenaltyArea >= cellArea)
   {
-    size_t size = 0;
-    for (int level = 0; level < CellId::DEPTH_LEVELS; ++level)
-      size += m_Covering[level].size();
-    return size;
+    out.push_back(cell);
+    return;
   }
 
-  struct CoverTriangleInfo
-  {
-    m2::PointD m_A, m_B, m_C;
-    int m_Level;
-    Covering<CellId> * m_pCovering;
-  };
-
-  static void CoverTriangleImpl(CoverTriangleInfo const & info, CellId const cell)
-  {
-    ASSERT_LESS_OR_EQUAL(cell.Level(), info.m_Level, (info.m_A, info.m_B, info.m_C));
-    CellTriangleIntersection intersection =
-        IntersectCellWithTriangle(cell, info.m_A, info.m_B, info.m_C);
-
-    if (intersection == CELL_TRIANGLE_NO_INTERSECTION)
-      return;
+  vector<CellIdT> subdiv;
+  for (uint8_t i = 0; i < 4; ++i)
+    CoverObject(intersect, cellPenaltyArea, subdiv, cell.Child(i));
 
-    if (cell.Level() == info.m_Level || intersection == CELL_INSIDE_TRIANGLE)
-    {
-      info.m_pCovering->m_Covering[cell.Level()].push_back(cell);
-      return;
-    }
 
-    for (uint8_t child = 0; child < 4; ++child)
-      CoverTriangleImpl(info, cell.Child(child));
-  }
+  uint64_t subdivArea = 0;
+  for (size_t i = 0; i < subdiv.size(); ++i)
+    subdivArea += my::sq(uint64_t(1 << (CellIdT::DEPTH_LEVELS - 1 - subdiv[i].Level())));
 
+  ASSERT(!subdiv.empty(), (cellPenaltyArea, out, cell));
 
-  array<vector<CellId>, CellId::DEPTH_LEVELS> m_Covering; // Covering by level.
-  size_t m_Size;
-};
+  if (subdiv.empty() ||
+      cellPenaltyArea * (int(subdiv.size()) - 1) >= cellArea - subdivArea)
+    out.push_back(cell);
+  else
+    out.insert(out.end(), subdiv.begin(), subdiv.end());
+}
 
 
-}
+} // namespace covering