GridFunction.hpp

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// Copyright (c) 2017 Czech Technical University in Prague | Faculty of Information Technology. All rights reserved.
 
#pragma once
 
#include <alib/pair>
#include <alib/set>
#include <grid/common/GridDirection.hpp>
 
namespace grid {
 
class GridFunction {
// ---------------------------------------------------------------------------------------------------------------------
 public:
 
  template<typename TCoordinate>
  static
  grid::SquareGridDirections
  squareGridDirection(const ext::pair<TCoordinate, TCoordinate> &a,
                      const ext::pair<TCoordinate, TCoordinate> &b);
 
// ---------------------------------------------------------------------------------------------------------------------
  template<typename TCoordinate>
  static
  ext::pair<TCoordinate, TCoordinate>
  squareGridDirectionVector(grid::SquareGridDirections direction);
 
// ---------------------------------------------------------------------------------------------------------------------
 
  static
  ext::set<grid::SquareGridDirections>
  squareGridDirectionDecompose(grid::SquareGridDirections direction);
 
// ---------------------------------------------------------------------------------------------------------------------
 
  static
  bool
  sqaureGridDirectionIsDiagonal(grid::SquareGridDirections direction);
 
  static
  bool
  sqaureGridDirectionIsCardinal(grid::SquareGridDirections direction);
 
// ---------------------------------------------------------------------------------------------------------------------
 
};
 
// =====================================================================================================================
 
template<typename TCoordinate>
grid::SquareGridDirections
GridFunction::squareGridDirection(const ext::pair<TCoordinate, TCoordinate> &a,
                                  const ext::pair<TCoordinate, TCoordinate> &b) {
  using direction_type = grid::SquareGridDirections;
 
  TCoordinate x = b.first - a.first;
  TCoordinate y = b.second - a.second;
 
  if (x < 0 && y == 0) return direction_type::north;
  else if (x > 0 && y == 0) return direction_type::south;
  else if (x == 0 && y < 0) return direction_type::west;
  else if (x == 0 && y > 0) return direction_type::east;
  else if (x < 0 && y < 0) return direction_type::north_west;
  else if (x > 0 && y < 0) return direction_type::south_west;
  else if (x < 0 && y > 0) return direction_type::north_east;
  else if (x > 0 && y > 0) return direction_type::south_east;
  else return direction_type::none;
}
 
// ---------------------------------------------------------------------------------------------------------------------
 
template<typename TCoordinate>
ext::pair<TCoordinate, TCoordinate>
GridFunction::squareGridDirectionVector(grid::SquareGridDirections direction) {
  using direction_type = grid::SquareGridDirections;
  using node_type = ext::pair<TCoordinate, TCoordinate>;
 
  switch (direction) {
    case direction_type::north: return node_type(-1, 0);
    case direction_type::south: return node_type(1, 0);
    case direction_type::west: return node_type(0, -1);
    case direction_type::east: return node_type(0, 1);
    case direction_type::north_west: return node_type(-1, -1);
    case direction_type::south_west: return node_type(1, -1);
    case direction_type::north_east: return node_type(-1, 1);
    case direction_type::south_east: return node_type(1, 1);
    default: return node_type(0, 0);
  }
}
 
// ---------------------------------------------------------------------------------------------------------------------
 
} // namespace grid