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-rw-r--r--advtrains/tracks.lua57
1 files changed, 54 insertions, 3 deletions
diff --git a/advtrains/tracks.lua b/advtrains/tracks.lua
index fa7f84d..3771090 100644
--- a/advtrains/tracks.lua
+++ b/advtrains/tracks.lua
@@ -430,20 +430,71 @@ end
advtrains.detector = {}
advtrains.detector.on_node = {}
-function advtrains.detector.enter_node(pos, train_id)
+--Returns true when position is occupied by a train other than train_id, false when occupied by the same train as train_id and nil in case there's no train at all
+function advtrains.detector.occupied(pos, train_id)
+ local ppos=advtrains.round_vector_floor_y(pos)
+ local pts=minetest.pos_to_string(ppos)
+ local s=advtrains.detector.on_node[pts]
+ if not s then return nil end
+ if s==train_id then return false end
+ --in case s is a table, it's always occupied by another train
+ return true
+end
+-- If given a train id as second argument, this is considered as 'not there'.
+-- Returns the train id of (one of, nondeterministic) the trains at this position
+function advtrains.detector.get(pos, train_id)
local ppos=advtrains.round_vector_floor_y(pos)
local pts=minetest.pos_to_string(ppos)
- advtrains.detector.on_node[pts]=train_id
+ local s=advtrains.detector.on_node[pts]
+ if not s then return nil end
+ if type(s)=="table" then
+ for _,t in ipairs(s) do
+ if t~=train_id then return t end
+ end
+ return nil
+ end
+ return s
+end
+
+function advtrains.detector.enter_node(pos, train_id)
+ advtrains.detector.stay_node(pos, train_id)
+ local ppos=advtrains.round_vector_floor_y(pos)
advtrains.detector.call_enter_callback(ppos, train_id)
end
function advtrains.detector.leave_node(pos, train_id)
local ppos=advtrains.round_vector_floor_y(pos)
+ local pts=minetest.pos_to_string(ppos)
+ local s=advtrains.detector.on_node[pts]
+ if type(s)=="table" then
+ local i
+ for j,t in ipairs(s) do
+ if t==train_id then i=j end
+ end
+ if not i then return end
+ s=table.remove(s,i)
+ if #s==0 then
+ s=nil
+ elseif #s==1 then
+ s=s[1]
+ end
+ advtrains.detector.on_node[pts]=s
+ else
+ advtrains.detector.on_node[pts]=nil
+ end
advtrains.detector.call_leave_callback(ppos, train_id)
end
function advtrains.detector.stay_node(pos, train_id)
local ppos=advtrains.round_vector_floor_y(pos)
local pts=minetest.pos_to_string(ppos)
- advtrains.detector.on_node[pts]=train_id
+
+ local s=advtrains.detector.on_node[pts]
+ if not s then
+ advtrains.detector.on_node[pts]=train_id
+ elseif type(s)=="string" then
+ advtrains.detector.on_node[pts]={s, train_id}
+ elseif type(s)=="table" then
+ advtrains.detector.on_node[pts]=table.insert(s, train_id)
+ end
end