restructure

turtle/apis/jumper/core/node.lua

@@ -0,0 +1,41 @@
+--- The Node class.
+-- The `node` represents a cell (or a tile) on a collision map. Basically, for each single cell (tile)
+-- in the collision map passed-in upon initialization, a `node` object will be generated
+-- and then cached within the `grid`.
+--
+-- In the following implementation, nodes can be compared using the `<` operator. The comparison is
+-- made with regards of their `f` cost. From a given node being examined, the `pathfinder` will expand the search
+-- to the next neighbouring node having the lowest `f` cost. See `core.bheap` for more details.
+--
+if (...) then
+
+	local Node = {}
+	Node.__index = Node
+
+	function Node:new(x,y,z)
+		return setmetatable({x = x, y = y, z = z }, Node)
+	end
+
+	-- Enables the use of operator '<' to compare nodes.
+	-- Will be used to sort a collection of nodes in a binary heap on the basis of their F-cost
+	function Node.__lt(A,B) return (A._f < B._f) end
+
+	function Node:getX() return self.x end
+	function Node:getY() return self.y end
+	function Node:getZ() return self.z end
+
+	--- Clears temporary cached attributes of a `node`.
+	-- Deletes the attributes cached within a given node after a pathfinding call.
+	-- This function is internally used by the search algorithms, so you should not use it explicitely.
+	function Node:reset()
+		self._g, self._h, self._f = nil, nil, nil
+		self._opened, self._closed, self._parent = nil, nil, nil
+		return self
+	end
+
+	return setmetatable(Node,
+		{__call = function(_,...)
+			return Node:new(...)
+		end}
+	)
+end