mirror of https://github.com/kepler155c/opus
105 lines
3.0 KiB
Lua
105 lines
3.0 KiB
Lua
--[[
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The following License applies to all files within the jumper directory.
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Note that this is only a partial copy of the full jumper code base. Also,
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the code was modified to support 3D maps.
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--]]
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--[[
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This work is under MIT-LICENSE
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Copyright (c) 2012-2013 Roland Yonaba.
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-- https://opensource.org/licenses/MIT
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--]]
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local _VERSION = ""
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local _RELEASEDATE = ""
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if (...) then
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-- Dependencies
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local _PATH = (...):gsub('%.pathfinder$','')
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local Utils = require (_PATH .. '.core.utils')
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-- Internalization
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local pairs = pairs
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local assert = assert
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local setmetatable = setmetatable
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--- Finders (search algorithms implemented). Refers to the search algorithms actually implemented in Jumper.
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-- <li>[A*](http://en.wikipedia.org/wiki/A*_search_algorithm)</li>
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local Finders = {
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['ASTAR'] = require (_PATH .. '.search.astar'),
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}
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-- Will keep track of all nodes expanded during the search
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-- to easily reset their properties for the next pathfinding call
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local toClear = {}
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-- Performs a traceback from the goal node to the start node
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-- Only happens when the path was found
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local Pathfinder = {}
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Pathfinder.__index = Pathfinder
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function Pathfinder:new(heuristic)
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local newPathfinder = {}
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setmetatable(newPathfinder, Pathfinder)
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self._finder = Finders.ASTAR
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self._heuristic = heuristic
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return newPathfinder
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end
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function Pathfinder:setGrid(grid)
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self._grid = grid
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return self
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end
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--- Calculates a `path`. Returns the `path` from start to end location
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-- Both locations must exist on the collision map. The starting location can be unwalkable.
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-- @treturn path a path (array of nodes) when found, otherwise nil
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-- @usage local path = myFinder:getPath(1,1,5,5)
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function Pathfinder:getPath(startX, startY, startZ, ih, endX, endY, endZ, oh)
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self:reset()
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local startNode = self._grid:getNodeAt(startX, startY, startZ)
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local endNode = self._grid:getNodeAt(endX, endY, endZ)
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if not startNode or not endNode then
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return nil
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end
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startNode.heading = ih
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endNode.heading = oh
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assert(startNode, ('Invalid location [%d, %d, %d]'):format(startX, startY, startZ))
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assert(endNode and self._grid:isWalkableAt(endX, endY, endZ),
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('Invalid or unreachable location [%d, %d, %d]'):format(endX, endY, endZ))
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local _endNode = self._finder(self, startNode, endNode, toClear)
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if _endNode then
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return Utils.traceBackPath(self, _endNode, startNode)
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end
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return nil
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end
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--- Resets the `pathfinder`. This function is called internally between
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-- successive pathfinding calls, so you should not
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-- use it explicitely, unless under specific circumstances.
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-- @class function
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-- @treturn pathfinder self (the calling `pathfinder` itself, can be chained)
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-- @usage local path, len = myFinder:getPath(1,1,5,5)
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function Pathfinder:reset()
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for node in pairs(toClear) do node:reset() end
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toClear = {}
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return self
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end
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-- Returns Pathfinder class
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Pathfinder._VERSION = _VERSION
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Pathfinder._RELEASEDATE = _RELEASEDATE
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return setmetatable(Pathfinder,{
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__call = function(self,...)
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return self:new(...)
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end
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})
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end
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