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	Advtrains mod for minetest.	orwell

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path: root/advtrains/models/advtrains_dtrack_swlcr_45.b3d

	Commit message (Expand)	Author	Age
*	Remove zip release files, move mod to root, exclude assets from Makefile (#92)	rubenwardy	2017-09-20
*	Restructure mod directory	orwell96	2017-01-04
*	Turning mod into a modpack and separating the trains from the core mod	orwell96	2016-12-20

generated by cgit v1.2.3 (git 2.39.1) at 2024-11-14 01:03:35 +0000

-- path.lua
-- Functions for pathpredicting, put in a separate file. 

-- Naming conventions:
-- 'index' - An index of the train.path table.
-- 'offset' - A value in meters that determines how far on the path to walk relative to a certain index
-- 'n' - Referring or pointing towards the 'next' path item, the one with index+1
-- 'p' - Referring or pointing towards the 'prev' path item, the one with index-1
-- 'f' - Referring to the positive end of the path (the end with the higher index)
-- 'b' - Referring to the negative end of the path (the end with the lower index)

-- New path structure of trains:
--Tables:
-- path      - path positions. 'indices' are relative to this. At the moment, at.round_vector_floor_y(path[i])
--              is the node this item corresponds to, however, this will change in the future.
-- path_node - (reserved)
-- path_cn   - Connid of the current node that points towards path[i+1]
-- path_cp   - Connid of the current node that points towards path[i-1]
--     When the day comes on that path!=node, these will only be set if this index represents a transition between rail nodes
-- path_dist - The total distance of this path element from path element 0
-- path_dir  - The direction of this path item's transition to the next path item, which is the angle of conns[path_cn[i]].c
--Variables:
-- path_ext_f/b - how far path[i] is set
-- path_trk_f/b - how far the path extends along a track. beyond those values, paths are generated in a straight line.
-- path_req_f/b - how far path items were requested in the last step
--
--Distance and index:
-- There is an important difference between the path index and the actual distance on the track: The distance between two path items can be larger than 1,
-- but the corresponding index increment is still 1.
-- Indexes in advtrains can be fractional values. If they are, it means that the actual position is interpolated between the 2 adjacent path items.
-- If you need to proceed along the path by a specific actual distance, it does NOT work to simply add it to the index. You should use the path_get_index_by_offset() function.

-- creates the path data structure, reconstructing the train from a position and a connid
-- Important! train.drives_on must exist while calling this method
-- returns: true - successful
--           nil - node not yet available/unloaded, please wait
--         false - node definitely gone, remove train
function advtrains.path_create(train, pos, connid, rel_index)
	local posr = advtrains.round_vector_floor_y(pos)
	local node_ok, conns, rhe = advtrains.get_rail_info_at(pos, train.drives_on)
	if not node_ok then
		return node_ok
	end
	local mconnid = advtrains.get_matching_conn(connid, #conns)
	train.index = rel_index
	train.path = { [0] = { x=posr.x, y=posr.y+rhe, z=posr.z } }
	train.path_cn = { [0] = connid }
	train.path_cp = { [0] = mconnid }
	train.path_dist = { [0] = 0 }
	
	train.path_dir = {
		[0] = advtrains.conn_angle_median(conns[mconnid].c, conns[connid].c)
	}
	
	train.path_ext_f=0
	train.path_ext_b=0
	train.path_trk_f=0
	train.path_trk_b=0
	train.path_req_f=0
	train.path_req_b=0
	
	advtrains.occ.set_item(train.id, posr, 0)
	return true
end

-- Sets position and connid to properly restore after a crash, e.g. in order
-- to save the train or to invalidate its path
-- Assumes that the train is in clean state
-- if invert ist true, setrestore will use the end index
function advtrains.path_setrestore(train, invert)
	local idx = train.index
	if invert then
		idx = train.end_index
	end
	
	local pos, connid, frac = advtrains.path_getrestore(train, idx, invert, true)
	
	train.last_pos = pos
	train.last_connid = connid
	train.last_frac = frac
end
-- Get restore position, connid and frac (in this order) for a train that will originate at the passed index
-- If invert is set, it will return path_cp and multiply frac by -1, in order to reverse the train there.
function advtrains.path_getrestore(train, index, invert)
	local idx = index
	local cns = train.path_cn
	
	if invert then
		cns = train.path_cp
	end
	
	local fli = atfloor(index)
	advtrains.path_get(train, fli)
	if fli > train.path_trk_f then
		fli = train.path_trk_f
	end
	if fli < train.path_trk_b then
		fli = train.path_trk_b
	end
	return advtrains.path_get(train, fli),
			cns[fli],
			(idx - fli) * (invert and -1 or 1)
end

-- Invalidates a path