Initial commit

sys/apis/jumper/search/bfs.lua

@@ -0,0 +1,46 @@
+-- Breadth-First search algorithm
+
+if (...) then
+  -- Internalization
+  local t_remove = table.remove
+
+  local function breadth_first_search(finder, openList, node, endNode, clearance, toClear)
+    local neighbours = finder._grid:getNeighbours(node, finder._walkable, finder._allowDiagonal, finder._tunnel)
+    for i = 1,#neighbours do
+      local neighbour = neighbours[i]
+      if not neighbour._closed and not neighbour._opened then
+				local nClearance = neighbour._clearance[finder._walkable]
+				local pushThisNode = clearance and nClearance and (nClearance >= clearance)			
+        if (clearance and pushThisNode) or (not clearance) then
+					openList[#openList+1] = neighbour
+					neighbour._opened = true
+					neighbour._parent = node
+					toClear[neighbour] = true
+				end
+      end
+    end
+
+  end
+
+  -- Calculates a path.
+  -- Returns the path from location `<startX, startY>` to location `<endX, endY>`.
+  return function (finder, startNode, endNode, clearance, toClear)
+
+    local openList = {} -- We'll use a FIFO queue (simple array)
+    openList[1] = startNode
+    startNode._opened = true
+    toClear[startNode] = true
+
+    local node
+    while (#openList > 0) do
+      node = openList[1]
+      t_remove(openList,1)
+      node._closed = true
+      if node == endNode then return node end
+      breadth_first_search(finder, openList, node, endNode, clearance, toClear)
+    end
+
+    return nil
+  end
+
+end