mirror of https://github.com/kepler155c/opus
67 lines
1.9 KiB
Lua
67 lines
1.9 KiB
Lua
--- The Path class.
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-- The `path` class is a structure which represents a path (ordered set of nodes) from a start location to a goal.
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-- An instance from this class would be a result of a request addressed to `Pathfinder:getPath`.
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--
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-- This module is internally used by the library on purpose.
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-- It should normally not be used explicitely, yet it remains fully accessible.
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--
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if (...) then
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local t_remove = table.remove
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local Path = {}
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Path.__index = Path
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function Path:new()
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return setmetatable({_nodes = {}}, Path)
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end
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--- Iterates on each single `node` along a `path`. At each step of iteration,
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-- returns the `node` plus a count value. Aliased as @{Path:nodes}
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-- @usage
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-- for node, count in p:iter() do
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-- ...
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-- end
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function Path:nodes()
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local i = 1
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return function()
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if self._nodes[i] then
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i = i+1
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return self._nodes[i-1],i-1
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end
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end
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end
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--- `Path` compression modifier. Given a `path`, eliminates useless nodes to return a lighter `path`
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-- consisting of straight moves. Does the opposite of @{Path:fill}
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-- @class function
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-- @treturn path self (the calling `path` itself, can be chained)
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-- @see Path:fill
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-- @usage p:filter()
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function Path:filter()
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local i = 2
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local xi,yi,zi,dx,dy,dz, olddx, olddy, olddz
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xi,yi,zi = self._nodes[i].x, self._nodes[i].y, self._nodes[i].z
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dx, dy,dz = xi - self._nodes[i-1].x, yi-self._nodes[i-1].y, zi-self._nodes[i-1].z
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while true do
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olddx, olddy, olddz = dx, dy, dz
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if self._nodes[i+1] then
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i = i+1
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xi, yi, zi = self._nodes[i].x, self._nodes[i].y, self._nodes[i].z
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dx, dy, dz = xi - self._nodes[i-1].x, yi - self._nodes[i-1].y, zi - self._nodes[i-1].z
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if olddx == dx and olddy == dy and olddz == dz then
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t_remove(self._nodes, i-1)
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i = i - 1
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end
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else break end
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end
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return self
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end
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return setmetatable(Path,
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{__call = function(_,...)
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return Path:new(...)
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end
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})
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end |