full circle

deserialize.lua

@@ -0,0 +1,61 @@
+local global_env = ...
+
+-- local vars for faster access
+local insert, byte, decode_uint16 = table.insert, string.byte, mapsync.decode_uint16
+
+function mapsync.deserialize_chunk(chunk_pos, filename)
+    local f = global_env.io.open(filename)
+    local zip, err_msg = mtzip.unzip(f)
+    if not zip then
+        return false, err_msg
+    end
+
+    -- parse manifest
+    local manifest_str, m_err_msg = zip:get("manifest.json")
+    if not manifest_str then
+        return false, m_err_msg
+    end
+    local manifest = minetest.parse_json(manifest_str)
+
+    -- parse metadata
+    local metadata_str, md_err_msg = zip:get("metadata.json")
+    if not metadata_str then
+        return false, md_err_msg
+    end
+    local metadata = minetest.parse_json(metadata_str)
+
+    -- parse mapdata
+    local mapdata, map_err_msg = zip:get("mapdata.bin")
+    if not mapdata then
+        return false, map_err_msg
+    end
+
+    local min_mapblock = mapsync.get_mapblock_bounds_from_chunk(chunk_pos)
+    local mapblock_count = #manifest.block_pos
+
+    for mbi, rel_mapblock_pos in ipairs(manifest.block_pos) do
+        local blockdata = {
+            node_ids = {},
+            param1 = {},
+            param2 = {},
+            metadata = metadata[minetest.pos_to_string(rel_mapblock_pos)]
+        }
+
+        for i=1,4096 do
+			local node_id = decode_uint16(mapdata, ((mbi-1) * 4096 * 2) + (i * 2) - 2)
+			local param1 = byte(mapdata, (4096 * 2 * mapblock_count) + ((mbi-1) * 4096) + i)
+			local param2 = byte(mapdata, (4096 * 3 * mapblock_count) + ((mbi-1) * 4096) + i)
+
+			insert(blockdata.node_ids, node_id)
+			insert(blockdata.param1, param1)
+			insert(blockdata.param2, param2)
+		end
+
+        mapsync.localize_nodeids(manifest.node_mapping, blockdata.node_ids)
+
+        local mapblock_pos = vector.add(rel_mapblock_pos, min_mapblock)
+        mapsync.deserialize_mapblock(mapblock_pos, blockdata)
+    end
+
+    return true
+end

deserialize_mapblock.lua

@@ -0,0 +1,51 @@
+
+function mapsync.deserialize_mapblock(mapblock_pos, blockdata)
+    local pos1 = vector.multiply(mapblock_pos, 16)
+	local pos2 = vector.add(pos1, 15) -- inclusive
+
+	local manip = minetest.get_voxel_manip()
+	local e1, e2 = manip:read_from_map(pos1, pos2)
+	local area = VoxelArea:new({MinEdge=e1, MaxEdge=e2})
+
+	local node_data = manip:get_data()
+	local param1 = manip:get_light_data()
+	local param2 = manip:get_param2_data()
+
+	local j = 1
+	for z=pos1.z,pos2.z do
+	for x=pos1.x,pos2.x do
+	for y=pos1.y,pos2.y do
+		local i = area:index(x,y,z)
+		node_data[i] = blockdata.node_ids[j]
+		param1[i] = blockdata.param1[j]
+		param2[i] = blockdata.param2[j]
+		j = j + 1
+	end
+	end
+	end
+
+	manip:set_data(node_data)
+	manip:set_light_data(param1)
+	manip:set_param2_data(param2)
+	manip:write_to_map(false)
+
+	-- deserialize metadata
+	if blockdata.metadata and blockdata.metadata.meta then
+		for pos_str, md in pairs(blockdata.metadata.meta) do
+			local relative_pos = minetest.string_to_pos(pos_str)
+			local absolute_pos = vector.add(pos1, relative_pos)
+			minetest.get_meta(absolute_pos):from_table(md)
+		end
+	end
+
+	-- deserialize node timers
+	if blockdata.metadata and blockdata.metadata.timers then
+		for pos_str, timer_data in pairs(blockdata.metadata.timers) do
+			local relative_pos = minetest.string_to_pos(pos_str)
+			local absolute_pos = vector.add(pos1, relative_pos)
+			minetest.get_node_timer(absolute_pos):set(timer_data.timeout, timer_data.elapsed)
+		end
+	end
+
+    return true
+end

encoding.lua

@@ -30,3 +30,9 @@ function mapsync.encode_uint32(v)
 	local b4 = bitand( rshift(v, 24), 0xFF )
 	return string.char(b1, b2, b3, b4)
 end
+
+function mapsync.decode_uint16(str, ofs)
+	ofs = ofs or 0
+	local a, b = string.byte(str, ofs + 1, ofs + 2)
+	return a + b * 0x100
+end

init.lua

@@ -9,7 +9,6 @@ mapsync = {
 
 -- secure/insecure environment
 local global_env = _G
-
 local ie = minetest.request_insecure_environment and minetest.request_insecure_environment()
 if ie then
 	print("[mapsync] using insecure environment")
@@ -17,14 +16,21 @@ if ie then
 	global_env = ie
 end
 
+-- api surface
 dofile(MP.."/api.lua")
-dofile(MP.."/encode.lua")
+
+-- utilities / helpers
+dofile(MP.."/encoding.lua")
+dofile(MP.."/serialize_mapblock.lua")
+dofile(MP.."/deserialize_mapblock.lua")
+dofile(MP.."/localize_nodeids.lua")
 
 -- pass on global env (secure/insecure)
 loadfile(MP.."/functions.lua")(global_env)
 loadfile(MP.."/serialize.lua")(global_env)
-dofile(MP.."/serialize_mapblock.lua")
+loadfile(MP.."/deserialize.lua")(global_env)
 
+-- testing
 if minetest.get_modpath("mtt") and mtt.enabled then
 	dofile(MP.."/mtt.lua")
 end

localize_nodeids.lua

@@ -0,0 +1,30 @@
+local air_content_id = minetest.get_content_id("air")
+
+-- local nodename->id cache
+local local_nodename_to_id_mapping = {} -- name -> id
+
+function mapsync.localize_nodeids(node_mapping, node_ids)
+	local foreign_nodeid_to_name_mapping = {} -- id -> name
+	for k, v in pairs(node_mapping) do
+		foreign_nodeid_to_name_mapping[v] = k
+	end
+
+	for i, node_id in ipairs(node_ids) do
+		local node_name = foreign_nodeid_to_name_mapping[node_id]
+		local local_node_id = local_nodename_to_id_mapping[node_name]
+		if not local_node_id then
+			if minetest.registered_nodes[node_name] then
+				-- node is locally available
+				local_node_id = minetest.get_content_id(node_name)
+			else
+				-- node is not available here
+				-- TODO: make replacements configurable
+				local_node_id = air_content_id
+			end
+			local_nodename_to_id_mapping[node_name] = local_node_id
+
+		end
+
+		node_ids[i] = local_node_id
+	end
+end

mtt.lua

@@ -17,17 +17,20 @@ mtt.register("register and export", function(callback)
     end)
 end)
 
+local pos = { x=0, y=0, z=0 }
+mtt.emerge_area(pos, pos)
+mtt.register("serialize and deserialize chunk", function(callback)
 
-mtt.register("serialize_chunk", function(callback)
-    local pos1 = { x=0, y=0, z=0 }
-    local pos2 = { x=20, y=20, z=20 }
+    local chunk_pos = {x=0, y=0, z=0}
+    local filename = minetest.get_worldpath() .. "/chunk.zip"
 
-    minetest.emerge_area(pos1, pos2, function(_, _, calls_remaining)
-        if calls_remaining == 0 then
-            local success, err_msg = mapsync.serialize_chunk({x=0, y=0, z=0}, minetest.get_worldpath() .. "/chunk.zip")
-            assert(success)
-            assert(not err_msg)
-            callback()
-        end
-    end)
+    local success, err_msg = mapsync.serialize_chunk(chunk_pos, filename)
+    assert(success)
+    assert(not err_msg)
+
+    success, err_msg = mapsync.deserialize_chunk(chunk_pos, filename)
+    assert(success)
+    assert(not err_msg)
+
+    callback()
 end)