aboutsummaryrefslogtreecommitdiff
path: root/advtrains/occupation.lua
blob: da602789ccd9dae2197a76a9f83197f3ad9fe5b9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
-- occupation.lua
--[[
Collects and manages positions where trains occupy and/or reserve/require space

It turned out that, especially for the TSS, some more, even overlapping zones are required.
Packing those into a data structure would just become a huge mess!
Instead, this occupation system will store the path indices of positions in the corresponding.
train's paths.
So, the occupation is a reverse lookup of paths.
Then, a callback system will handle changes in those indices, as follows:

Whenever the train generates new path items (path_get/path_create), their counterpart indices will be filled in here.
Whenever a path gets invalidated or path items are deleted, their index counterpart is erased from here.

When a train needs to know whether a position is blocked by another train, it will (and is permitted to)
query the train.index and train.end_index and compare them to the blocked position's index.

Callback system for 3rd-party path checkers:
advtrains.te_register_on_new_path(func(id, train))
-- Called when a train's path is re-initalized, either when it was invalidated
-- or the saves were just loaded
-- It can be assumed that everything is in the state of when the last run
-- of on_update was made, but all indices are shifted by an unknown amount.

advtrains.te_register_on_update(func(id, train))
-- Called each step and after a train moved, its length changed or some other event occured
-- The path is unmodified, and train.index and train.end_index can be reliably
-- queried for the new position and length of the train.
-- note that this function might be called multiple times per step, and this 
-- function being called does not necessarily mean that something has changed.
-- It is ensured that on_new_path callbacks are executed prior to these callbacks whenever
-- an invalidation or a reload occured.

advtrains.te_register_on_create(func(id, train))
-- Called right after a train is created, right after the initial new_path callback
advtrains.te_register_on_remove(func(id, train))
-- Called right before a train is deleted


All callbacks are allowed to save certain values inside the train table, but they must ensure that
those are reinitialized in the on_new_path callback. The on_new_path callback must explicitly
set ALL OF those values to nil or to a new updated value, and must not rely on their existence.

]]--
local o = {}

local occ = {}
local occ_chg = {}


local function occget(p)
	local t = occ[p.y]
	if not t then
		occ[p.y] = {}
		t = occ[p.y]
	end
	local s = t
	t = t[p.x]
	if not t then
		s[p.x] = {}
		t = s[p.x]
	end
	return t[p.z]
end
local function occgetcreate(p)
	local t = occ[p.y]
	if not t then
		occ[p.y] = {}
		t = occ[p.y]
	end
	local s = t
	t = t[p.x]
	if not t then
		s[p.x] = {}
		t = s[p.x]
	end
	s = t
	t = t[p.z]
	if not t then
		s[p.z] = {}
		t = s[p.z]
	end
	return t
end


function o.set_item(train_id, pos, idx)
	local t = occgetcreate(pos)
	local i = 1
	while t[i] do
		if t[i]==train_id then
			break
		end
		i = i + 2
	end
	t[i] = train_id
	t[i+1] = idx
end


function o.clear_item(train_id, pos)
	local t = occget(pos)
	if not t then return end
	local i = 1
	local moving = false
	while t[i] do
		if t[i]==train_id then
			if moving then
				-- if, for some occasion, there should be a duplicate entry, erase this one too
				atwarn("Duplicate occupation entry at",pos,"for train",train_id,":",t)
				i = i - 2
			end
			moving = true
		end
		if moving then
			t[i]   = t[i+2]
			t[i+1] = t[i+3]
		end
		i = i + 2
	end
end

-- Checks whether some other train (apart from train_id) has it's 0 zone here
function o.check_collision(pos, train_id)
	local npos = advtrains.round_vector_floor_y(pos)
	local t = occget(npos)
	if not t then return end
	local i = 1
	while t[i] do
		local ti = t[i]
		if ti~=train_id then
			local idx = t[i+1]
			local train = advtrains.trains[ti]
			
			--atdebug("checking train",t[i],"index",idx,"<>",train.index,train.end_index)
			if train and idx >= train.end_index and idx <= train.index then
				--atdebug("collides.")				
				return train -- return train it collided with so we can couple when shunting is enabled
			end
		end
		i = i + 2
	end
	return false
end

-- Gets a mapping of train id's to indexes of trains that share this path item with this train
-- The train itself will not be included.
-- If the requested index position is off-track, returns {}.
-- returns (table with train_id->index), position
function o.get_occupations(train, index)
	local ppos, ontrack = advtrains.path_get(train, index)
	if not ontrack then
		atlog("Train",train.id,"get_occupations requested off-track",index)
		return {}, ppos
	end
	local pos = advtrains.round_vector_floor_y(ppos)
	local t = occget(pos)
	if not t then return {} end
	local r = {}
	local i = 1
	local train_id = train.id
	while t[i] do
		if t[i]~=train_id then
			r[t[i]] = t[i+1]
		end
		i = i + 2
	end
	return r, pos
end
-- Gets a mapping of train id's to indexes of trains that stand or drive over
-- returns (table with train_id->index)
function o.get_trains_at(ppos)
	local pos = advtrains.round_vector_floor_y(ppos)
	local t = occget(pos)
	if not t then return {} end
	local r = {}
	local i = 1
	while t[i] do
		local train = advtrains.trains[t[i]]
		local idx = t[i+1]
		if train.end_index - 0.5 <= idx and idx <= train.index + 0.5 then
			r[t[i]] = idx
		end
		i = i + 2
	end
	return r
end

-- Gets a mapping of train id's to indexes of trains that have a path
-- generated over this node
-- returns (table with train_id->index)
function o.get_trains_over(ppos)
	local pos = advtrains.round_vector_floor_y(ppos)
	local t = occget(pos)
	if not t then return {} end
	local r = {}
	local i = 1
	while t[i] do
		local train = advtrains.trains[t[i]]
		local idx = t[i+1]
		r[t[i]] = idx
		i = i + 2
	end
	return r
end

advtrains.occ = o