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-rw-r--r--pseudoload.lua121
1 files changed, 121 insertions, 0 deletions
diff --git a/pseudoload.lua b/pseudoload.lua
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+++ b/pseudoload.lua
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+
+--pseudoload.lua
+--responsible for keeping up a database of all rail nodes existant in the world, regardless of whether the mapchunk is loaded.
+
+advtrains.trackdb={}
+--trackdb[y][x][z]={conn1, conn2, rely1, rely2, railheight}
+--serialization format:
+--(2byte x)(2byte y)(2byte z)(4bits conn1, 4bits conn2)[(plain rely1)|(plain rely2)|(plain railheight)]\n
+--[] may be missing if 0,0,0
+
+--load initially
+advtrains.pl_fpath=minetest.get_worldpath().."/advtrains_trackdb"
+local file, err = io.open(advtrains.pl_fpath, "r")
+if not file then
+ local er=err or "Unknown Error"
+ print("[advtrains]Failed loading advtrains trackdb save file "..er)
+else
+ --custom format to save memory
+ while true do
+ local xbytes=file:read(2)
+ if not xbytes then
+ break --eof reached
+ end
+ local ybytes=file:read(2)
+ local zbytes=file:read(2)
+ local x=(string.byte(xbytes[1])-128)*256+(string.byte(xbytes[2]))
+ local y=(string.byte(ybytes[1])-128)*256+(string.byte(ybytes[2]))
+ local z=(string.byte(zbytes[1])-128)*256+(string.byte(zbytes[2]))
+
+ local conn1=string.byte(file:read(1))
+ local conn1=string.byte(file:read(1))
+
+ if not advtrains.trackdb[y] then advtrains.trackdb[y]={} end
+ if not advtrains.trackdb[y][x] then advtrains.trackdb[y][x]={} end
+
+ local rest=file.read("*l")
+ if rest~="" then
+ local rely1, rely2, railheight=string.match(rest, "([^|]+)|([^|]+)|([^|]+)")
+ if rely1 and rely2 and railheight then
+ advtrains.trackdb[y][x][z]={
+ conn1=conn1, conn2=conn2,
+ rely1=rely1, rely2=rely2,
+ railheight=railheight
+ }
+ else
+ advtrains.trackdb[y][x][z]={
+ conn1=conn1, conn2=conn2
+ }
+ end
+ else
+ advtrains.trackdb[y][x][z]={
+ conn1=conn1, conn2=conn2
+ }
+ end
+ end
+ file:close()
+end
+function advtrains.save_trackdb()
+ local file, err = io.open(advtrains.pl_fpath, "w")
+ if not file then
+ local er=err or "Unknown Error"
+ print("[advtrains]Failed saving advtrains trackdb save file "..er)
+ else
+ --custom format to save memory
+ for x,txl in pairs(advtrains.trackdb) do
+ for y,tyl in pairs(txl) do
+ for z,rail in pairs(tyl) do
+ file:write(string.char(math.floor(x/256)+128)..string.char((x%256)))
+ file:write(string.char(math.floor(y/256)+128)..string.char((y%256)))
+ file:write(string.char(math.floor(z/256)+128)..string.char((z%256)))
+ file:write(string.char(rail.conn1))
+ file:write(string.char(rail.conn2))
+ if (rail.rely1 and rail.rely1~=0) or (rail.rely2 and rail.rely2~=0) or (rail.railheight and rail.railheight~=0) then
+ file:write(rail.rely1.."|"..rail.rely2.."|"..rail.railheight)
+ end
+ file:write("\n")
+ end
+ end
+ end
+ file:close()
+ end
+end
+
+--get_node with pseudoload.
+--returns:
+--true, conn1, conn2, rely1, rely2, railheight in case everything's right.
+--false if it's not a rail or the train does not drive on this rail, but it is loaded or
+--nil if the node is neither loaded nor in trackdb
+--the distraction between false and nil will be needed only in special cases.(train initpos)
+function advtrains.get_rail_info_at(pos, traintype)
+ local node=minetest.get_node_or_nil(pos)
+ if not node then
+ --try raildb
+ local rdp=vector.round(rdp)
+ local dbe=advtrains.trackdb[rdp.y][rdp.x][rdp.z]
+ if dbe then
+ return true, dbe.conn1, dbe.conn2, dbe.rely1 or 0, dbe.rely2 or 0, dbe.railheight or 0
+ else
+ return nil
+ end
+ end
+ local nodename=node.name
+ if(not advtrains.is_track_and_drives_on(nodename, advtrains.all_traintypes[traintype].drives_on)) then
+ return false
+ end
+ local conn1, conn2, rely1, rely2, railheight=advtrains.get_track_connections(node.name, node.param2)
+
+ --already in trackdb?
+ local rdp=vector.round(rdp)
+ if not advtrains.trackdb[rdp.y][rdp.x][rdp.z] then--TODO is this write prevention here really needed?
+ advtrains.trackdb[rdp.y][rdp.x][rdp.z]={
+ conn1=conn1, conn2=conn2,
+ rely1=rely1, rely2=rely2,
+ railheight=railheight
+ }
+ end
+
+ return true, conn1, conn2, rely1, rely2, railheight
+end
+
+