[mcl_maps] Center, slightly optimize, use position to calculate ID

mods/ITEMS/mcl_maps/init.lua

@@ -1,11 +1,12 @@
 mcl_maps = {}
 
 local S = minetest.get_translator("mcl_maps")
-local storage = minetest.get_mod_storage()
 local modpath = minetest.get_modpath("mcl_maps")
 local worldpath = minetest.get_worldpath()
 local map_textures_path = worldpath .. "/mcl_maps/"
-local last_finished_id = storage:get_int("next_id") - 1
+
+local math_min = math.min
+local math_max = math.max
 
 minetest.mkdir(map_textures_path)
 
@@ -27,14 +28,12 @@ local loaded_maps = {}
 local c_air = minetest.get_content_id("air")
 
 function mcl_maps.create_map(pos)
-	local minp = vector.multiply(vector.floor(vector.divide(pos, 128)), 128)
+	local minp = vector.subtract(vector.floor(pos), 64)
-	local maxp = vector.add(minp, vector.new(127, 127, 127))
+	local maxp = vector.add(minp, 127)
 
 	local itemstack = ItemStack("mcl_maps:filled_map")
 	local meta = itemstack:get_meta()
-	local next_id = storage:get_int("next_id")
+	local id = string.format(".0f", minetest.hash_node_position(pos))
-	storage:set_int("next_id", next_id + 1)
-	local id = tostring(next_id)
 	meta:set_string("mcl_maps:id", id)
 	meta:set_string("mcl_maps:minp", minetest.pos_to_string(minp))
 	meta:set_string("mcl_maps:maxp", minetest.pos_to_string(maxp))
@@ -49,19 +48,31 @@ function mcl_maps.create_map(pos)
 		local emin, emax = vm:read_from_map(minp, maxp)
 		local data = vm:get_data()
 		local param2data = vm:get_param2_data()
-		local area = VoxelArea:new({MinEdge = emin, MaxEdge = emax})
+		local offset_x, offset_y, offset_z = minp.x - emin.x, minp.y - emin.y, minp.z - emin.z
+		local dx = emax.x - emin.x + 1
+		local dy = (emax.y - emin.y + 1) * dx
+		local offset = offset_z * dy + offset_y * dx + offset_x
+		local map_y_start = 64 * dx
+		local map_y_limit = 127 * dx
+
 		local pixels = {}
 		local last_heightmap
 		for x = 1, 128 do
-			local map_x = minp.x - 1 + x
+			local map_x = x + offset
 			local heightmap = {}
 			for z = 1, 128 do
-				local map_z = minp.z - 1 + z
+				local map_z = (z-1) * dy + map_x
 				local color, height
-				for map_y = maxp.y, minp.y, -1 do
+
-					local index = area:index(map_x, map_y, map_z)
+				local map_y = map_z + map_y_start
-					local c_id = data[index]
+				local map_y_limit = map_z + map_y_limit
-					if c_id ~= c_air then
+				while data[map_y] ~= c_air and map_y < map_y_limit do
+					map_y = map_y + dx
+				end
+				while data[map_y] == c_air and map_y > map_z do
+					map_y = map_y - dx
+				end
+				local c_id = data[map_y]
 				color = color_cache[c_id]
 				if color == nil then
 					local nodename = minetest.get_name_from_content_id(c_id)
@@ -89,31 +100,30 @@ function mcl_maps.create_map(pos)
 				end
 
 				if color and color.palette then
-							color = color.palette[param2data[index] + 1]
+					color = color.palette[param2data[map_y] + 1]
 				else
 					color_cache[c_id] = color or false
 				end
 
 				if color and last_heightmap then
 					local last_height = last_heightmap[z]
-							if last_height < map_y then
+					local y = map_y - map_z
+					if last_height < y then
 						color = {
-									math.min(255, color[1] + 16),
+							math_min(255, color[1] + 16),
-									math.min(255, color[2] + 16),
+							math_min(255, color[2] + 16),
-									math.min(255, color[3] + 16),
+							math_min(255, color[3] + 16),
 						}
-							elseif last_height > map_y then
+					elseif last_height > y then
 						color = {
-									math.max(0, color[1] - 16),
+							math_max(0, color[1] - 16),
-									math.max(0, color[2] - 16),
+							math_max(0, color[2] - 16),
-									math.max(0, color[3] - 16),
+							math_max(0, color[3] - 16),
 						}
 					end
 				end
-						height = map_y
+				height = map_y - map_z
-						break
+
-					end
-				end
 				heightmap[z] = height or minp.y
 				pixels[z] = pixels[z] or {}
 				pixels[z][x] = color or {0, 0, 0}