Method: Core::Game::Map#astar

Defined in:

lib/game/map/map.rb

#astar(node_start, node_goal) ⇒ Object

# File 'lib/game/map/map.rb', line 171

def astar(node_start, node_goal)
  iterations = 0
  open = AStar::PriorityQueue.new()
  closed = AStar::PriorityQueue.new()
  node_start.calc_h(node_goal)
  open.push(node_start)
  costmap = generate_costmap
  while !open.empty? do
    iterations += 1 #keep track of how many times this itersates
    node_current = open.find_best
    if node_current == node_goal
      #puts("Iterations: #{iterations}")
      #show_path(node_current)
      return node_current 
    end       
    generate_successor_nodes(node_current, costmap) { |node_successor|
      #now doing for each successor node of node_current
      node_successor.calc_g(node_current)
      #skip to next node_successor if better one already on open or closed list
      if open_successor=open.find(node_successor) then 
        if open_successor<=node_successor then next end  #need to account for nil result
      end
      if closed_successor=closed.find(node_successor) then
        if closed_successor<=node_successor then next end 
      end
      #still here, then there's no better node yet, so remove any copies of this node on open/closed lists
      open.remove(node_successor)
      closed.remove(node_successor)
      # set the parent node of node_successor to node_current
      node_successor.parent=node_current
      # set h to be the estimated distance to node_goal using the heuristic
      node_successor.calc_h(node_goal)
      # so now we know this is the best copy of the node so far, so put it onto the open list
      open.push(node_successor)
    }
    #now we've gone through all the successors, so the current node can be closed
    closed.push(node_current)
  end
end