mirror of https://github.com/kepler155c/opus
41 lines
1.5 KiB
Lua
41 lines
1.5 KiB
Lua
--- The Node class.
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-- The `node` represents a cell (or a tile) on a collision map. Basically, for each single cell (tile)
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-- in the collision map passed-in upon initialization, a `node` object will be generated
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-- and then cached within the `grid`.
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--
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-- In the following implementation, nodes can be compared using the `<` operator. The comparison is
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-- made with regards of their `f` cost. From a given node being examined, the `pathfinder` will expand the search
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-- to the next neighbouring node having the lowest `f` cost. See `core.bheap` for more details.
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--
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if (...) then
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local Node = {}
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Node.__index = Node
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function Node:new(x,y,z)
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return setmetatable({x = x, y = y, z = z }, Node)
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end
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-- Enables the use of operator '<' to compare nodes.
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-- Will be used to sort a collection of nodes in a binary heap on the basis of their F-cost
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function Node.__lt(A,B) return (A._f < B._f) end
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function Node:getX() return self.x end
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function Node:getY() return self.y end
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function Node:getZ() return self.z end
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--- Clears temporary cached attributes of a `node`.
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-- Deletes the attributes cached within a given node after a pathfinding call.
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-- This function is internally used by the search algorithms, so you should not use it explicitely.
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function Node:reset()
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self._g, self._h, self._f = nil, nil, nil
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self._opened, self._closed, self._parent = nil, nil, nil
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return self
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end
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return setmetatable(Node,
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{__call = function(_,...)
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return Node:new(...)
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end}
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)
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end |