mirror of
https://github.com/kepler155c/opus
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46 lines
1.4 KiB
Lua
46 lines
1.4 KiB
Lua
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-- Breadth-First search algorithm
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if (...) then
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-- Internalization
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local t_remove = table.remove
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local function breadth_first_search(finder, openList, node, endNode, clearance, toClear)
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local neighbours = finder._grid:getNeighbours(node, finder._walkable, finder._allowDiagonal, finder._tunnel)
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for i = 1,#neighbours do
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local neighbour = neighbours[i]
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if not neighbour._closed and not neighbour._opened then
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local nClearance = neighbour._clearance[finder._walkable]
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local pushThisNode = clearance and nClearance and (nClearance >= clearance)
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if (clearance and pushThisNode) or (not clearance) then
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openList[#openList+1] = neighbour
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neighbour._opened = true
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neighbour._parent = node
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toClear[neighbour] = true
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end
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end
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end
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end
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-- Calculates a path.
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-- Returns the path from location `<startX, startY>` to location `<endX, endY>`.
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return function (finder, startNode, endNode, clearance, toClear)
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local openList = {} -- We'll use a FIFO queue (simple array)
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openList[1] = startNode
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startNode._opened = true
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toClear[startNode] = true
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local node
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while (#openList > 0) do
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node = openList[1]
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t_remove(openList,1)
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node._closed = true
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if node == endNode then return node end
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breadth_first_search(finder, openList, node, endNode, clearance, toClear)
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end
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return nil
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end
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end
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