From 0d433daa238139a90ab5cf38da4430bad8b5d354 Mon Sep 17 00:00:00 2001
From: Wuzzy <Wuzzy2@mail.ru>
Date: Tue, 27 Aug 2019 06:42:14 +0200
Subject: [PATCH] Refuse to teleport outside of map

---
 README.md |  1 -
 init.lua  | 22 +++++++++++++++++-----
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index 683146f..e6f84ed 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,6 @@ Version: 0.2.0
 
 ## Known bugs and limitations
 - Will only search for biomes in the same height as you.
-- Might teleport you outside the map boundaries if you're close to one.
 
 ## Authors
 - paramat (MIT License)
diff --git a/init.lua b/init.lua
index 06f87d0..f1c6a15 100644
--- a/init.lua
+++ b/init.lua
@@ -1,6 +1,12 @@
 local S = minetest.get_translator("findbiome")
-local mg_name = minetest.get_mapgen_setting("mg_name")
+
 local mod_biomeinfo = minetest.get_modpath("biomeinfo") ~= nil
+local mg_name = minetest.get_mapgen_setting("mg_name")
+
+-- Calculate the maximum playable limit
+local mapgen_limit = tonumber(minetest.get_mapgen_setting("mapgen_limit"))
+local chunksize = tonumber(minetest.get_mapgen_setting("chunksize"))
+local playable_limit = math.max(mapgen_limit - (chunksize + 1) * 16, 0)
 
 -- Parameters
 -------------
@@ -22,6 +28,10 @@ local dirs = {
 	{x = 1, y = 0, z = 0},
 }
 
+local function is_valid_pos(pos)
+	return math.abs(pos.x) > playable_limit or math.abs(pos.y) > playable_limit or math.abs(pos.z) > playable_limit
+end
+
 function find_biome(pos, biomes)
 	pos = vector.round(pos)
 	-- Pos: Starting point for biome checks. This also sets the y co-ordinate for all
@@ -69,8 +79,9 @@ function find_biome(pos, biomes)
 					local spawn_y = minetest.get_spawn_level(pos.x, pos.z)
 					if spawn_y then
 						spawn_pos = {x = pos.x, y = spawn_y, z = pos.z}
-						-- FIXME: Don't return true when spawn_pos is out of map bounds
-						return true
+						if is_valid_pos(spawn_pos) then
+							return true
+						end
 					end
 				end
 			end
@@ -95,8 +106,9 @@ function find_biome(pos, biomes)
 					local spawn_y = minetest.get_spawn_level(pos.x, pos.z)
 					if spawn_y then
 						spawn_pos = {x = pos.x, y = spawn_y, z = pos.z}
-						-- FIXME: Don't return true when spawn_pos is out of map bounds
-						return true
+						if is_valid_pos(spawn_pos) then
+							return true
+						end
 					end
 				end
 			end