From 5355cb1d87f60bc5548a8a9311e597b9c6046013 Mon Sep 17 00:00:00 2001
From: HybridDog <3192173+HybridDog@users.noreply.github.com>
Date: Wed, 22 Apr 2020 16:43:48 +0200
Subject: minetest.serialize: Reversible number serialization (#9722)

* minetest.serialize: Reversible number to string conversion

The %a format is not supported in Lua 5.1.
This commit also adds two tests for number serialization.
---
 builtin/common/serialize.lua            | 11 ++---------
 builtin/common/tests/serialize_spec.lua | 12 ++++++++++++
 2 files changed, 14 insertions(+), 9 deletions(-)

(limited to 'builtin/common')

diff --git a/builtin/common/serialize.lua b/builtin/common/serialize.lua
index 163aa67ad..300b394c6 100644
--- a/builtin/common/serialize.lua
+++ b/builtin/common/serialize.lua
@@ -120,15 +120,8 @@ function core.serialize(x)
 		elseif tp == "function" then
 			return string.format("loadstring(%q)", string.dump(x))
 		elseif tp == "number"   then
-			-- Serialize integers with string.format to prevent
-			-- scientific notation, which doesn't preserve
-			-- precision and breaks things like node position
-			-- hashes.  Serialize floats normally.
-			if math.floor(x) == x then
-				return string.format("%d", x)
-			else
-				return tostring(x)
-			end
+			-- Serialize numbers reversibly with string.format
+			return string.format("%.17g", x)
 		elseif tp == "table" then
 			local vals = {}
 			local idx_dumped = {}
diff --git a/builtin/common/tests/serialize_spec.lua b/builtin/common/tests/serialize_spec.lua
index c41b0a372..17c6a60f7 100644
--- a/builtin/common/tests/serialize_spec.lua
+++ b/builtin/common/tests/serialize_spec.lua
@@ -18,6 +18,18 @@ describe("serialize", function()
 		assert.same(test_in, test_out)
 	end)
 
+	it("handles precise numbers", function()
+		local test_in = 0.2695949158945771
+		local test_out = core.deserialize(core.serialize(test_in))
+		assert.same(test_in, test_out)
+	end)
+
+	it("handles big integers", function()
+		local test_in = 269594915894577
+		local test_out = core.deserialize(core.serialize(test_in))
+		assert.same(test_in, test_out)
+	end)
+
 	it("handles recursive structures", function()
 		local test_in = { hello = "world" }
 		test_in.foo = test_in
-- 
cgit v1.2.3


From 6c607e20828f97f950038dfb86891a74afb6f755 Mon Sep 17 00:00:00 2001
From: Yaman Qalieh <ybq987@gmail.com>
Date: Wed, 13 May 2020 07:57:05 -0400
Subject: Allow placing auto-rotating nodes on other nodes in on_rightclick
 (#9859)

---
 builtin/common/misc_helpers.lua | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'builtin/common')

diff --git a/builtin/common/misc_helpers.lua b/builtin/common/misc_helpers.lua
index 715f89bc4..1a0c71efd 100644
--- a/builtin/common/misc_helpers.lua
+++ b/builtin/common/misc_helpers.lua
@@ -290,7 +290,8 @@ if INIT == "game" then
 			return
 		end
 		local undef = core.registered_nodes[unode.name]
-		if undef and undef.on_rightclick then
+		local sneaking = placer and placer:get_player_control().sneak
+		if undef and undef.on_rightclick and not sneaking then
 			return undef.on_rightclick(pointed_thing.under, unode, placer,
 					itemstack, pointed_thing)
 		end
-- 
cgit v1.2.3


From 11723cffe011e99c1092388958fb1a047ab1c09c Mon Sep 17 00:00:00 2001
From: sfan5 <sfan5@live.de>
Date: Fri, 15 May 2020 16:38:19 +0200
Subject: builtin: Move common/async_event.lua to mainmenu/async_event.lua

It only works in the context of the mainmenu.
---
 builtin/common/async_event.lua   | 40 ----------------------------------------
 builtin/mainmenu/async_event.lua | 32 ++++++++++++++++++++++++++++++++
 builtin/mainmenu/init.lua        |  4 +---
 3 files changed, 33 insertions(+), 43 deletions(-)
 delete mode 100644 builtin/common/async_event.lua
 create mode 100644 builtin/mainmenu/async_event.lua

(limited to 'builtin/common')

diff --git a/builtin/common/async_event.lua b/builtin/common/async_event.lua
deleted file mode 100644
index 988af79b9..000000000
--- a/builtin/common/async_event.lua
+++ /dev/null
@@ -1,40 +0,0 @@
-
-core.async_jobs = {}
-
-local function handle_job(jobid, serialized_retval)
-	local retval = core.deserialize(serialized_retval)
-	assert(type(core.async_jobs[jobid]) == "function")
-	core.async_jobs[jobid](retval)
-	core.async_jobs[jobid] = nil
-end
-
-if core.register_globalstep then
-	core.register_globalstep(function(dtime)
-		for i, job in ipairs(core.get_finished_jobs()) do
-			handle_job(job.jobid, job.retval)
-		end
-	end)
-else
-	core.async_event_handler = handle_job
-end
-
-function core.handle_async(func, parameter, callback)
-	-- Serialize function
-	local serialized_func = string.dump(func)
-
-	assert(serialized_func ~= nil)
-
-	-- Serialize parameters
-	local serialized_param = core.serialize(parameter)
-
-	if serialized_param == nil then
-		return false
-	end
-
-	local jobid = core.do_async_callback(serialized_func, serialized_param)
-
-	core.async_jobs[jobid] = callback
-
-	return true
-end
-
diff --git a/builtin/mainmenu/async_event.lua b/builtin/mainmenu/async_event.lua
new file mode 100644
index 000000000..04bfb78d6
--- /dev/null
+++ b/builtin/mainmenu/async_event.lua
@@ -0,0 +1,32 @@
+
+core.async_jobs = {}
+
+local function handle_job(jobid, serialized_retval)
+	local retval = core.deserialize(serialized_retval)
+	assert(type(core.async_jobs[jobid]) == "function")
+	core.async_jobs[jobid](retval)
+	core.async_jobs[jobid] = nil
+end
+
+core.async_event_handler = handle_job
+
+function core.handle_async(func, parameter, callback)
+	-- Serialize function
+	local serialized_func = string.dump(func)
+
+	assert(serialized_func ~= nil)
+
+	-- Serialize parameters
+	local serialized_param = core.serialize(parameter)
+
+	if serialized_param == nil then
+		return false
+	end
+
+	local jobid = core.do_async_callback(serialized_func, serialized_param)
+
+	core.async_jobs[jobid] = callback
+
+	return true
+end
+
diff --git a/builtin/mainmenu/init.lua b/builtin/mainmenu/init.lua
index 130c3e73c..c17e79270 100644
--- a/builtin/mainmenu/init.lua
+++ b/builtin/mainmenu/init.lua
@@ -20,20 +20,18 @@ mt_color_blue  = "#6389FF"
 mt_color_green = "#72FF63"
 mt_color_dark_green = "#25C191"
 
---for all other colors ask sfan5 to complete his work!
-
 local menupath = core.get_mainmenu_path()
 local basepath = core.get_builtin_path()
 local menustyle = core.settings:get("main_menu_style")
 defaulttexturedir = core.get_texturepath_share() .. DIR_DELIM .. "base" ..
 					DIR_DELIM .. "pack" .. DIR_DELIM
 
-dofile(basepath .. "common" .. DIR_DELIM .. "async_event.lua")
 dofile(basepath .. "common" .. DIR_DELIM .. "filterlist.lua")
 dofile(basepath .. "fstk" .. DIR_DELIM .. "buttonbar.lua")
 dofile(basepath .. "fstk" .. DIR_DELIM .. "dialog.lua")
 dofile(basepath .. "fstk" .. DIR_DELIM .. "tabview.lua")
 dofile(basepath .. "fstk" .. DIR_DELIM .. "ui.lua")
+dofile(menupath .. DIR_DELIM .. "async_event.lua")
 dofile(menupath .. DIR_DELIM .. "common.lua")
 dofile(menupath .. DIR_DELIM .. "pkgmgr.lua")
 dofile(menupath .. DIR_DELIM .. "textures.lua")
-- 
cgit v1.2.3


From 65a6a316d081d3951438bbbcfce74c9c65db407a Mon Sep 17 00:00:00 2001
From: Wuzzy <Wuzzy2@mail.ru>
Date: Tue, 26 May 2020 02:11:19 +0200
Subject: Add minetest.is_creative_enabled

---
 builtin/common/misc_helpers.lua           | 10 ++--------
 builtin/game/item.lua                     |  2 +-
 builtin/game/misc.lua                     |  6 ++++++
 doc/lua_api.txt                           |  7 +++++++
 games/devtest/mods/util_commands/init.lua |  2 +-
 5 files changed, 17 insertions(+), 10 deletions(-)

(limited to 'builtin/common')

diff --git a/builtin/common/misc_helpers.lua b/builtin/common/misc_helpers.lua
index 1a0c71efd..a88adf96d 100644
--- a/builtin/common/misc_helpers.lua
+++ b/builtin/common/misc_helpers.lua
@@ -345,18 +345,12 @@ if INIT == "game" then
 --Wrapper for rotate_and_place() to check for sneak and assume Creative mode
 --implies infinite stacks when performing a 6d rotation.
 --------------------------------------------------------------------------------
-	local creative_mode_cache = core.settings:get_bool("creative_mode")
-	local function is_creative(name)
-		return creative_mode_cache or
-				core.check_player_privs(name, {creative = true})
-	end
-
 	core.rotate_node = function(itemstack, placer, pointed_thing)
 		local name = placer and placer:get_player_name() or ""
 		local invert_wall = placer and placer:get_player_control().sneak or false
 		return core.rotate_and_place(itemstack, placer, pointed_thing,
-				is_creative(name),
-				{invert_wall = invert_wall}, true)
+			core.is_creative_enabled(name),
+			{invert_wall = invert_wall}, true)
 	end
 end
 
diff --git a/builtin/game/item.lua b/builtin/game/item.lua
index 3aaa71ef2..f680ce0d4 100644
--- a/builtin/game/item.lua
+++ b/builtin/game/item.lua
@@ -582,7 +582,7 @@ function core.node_dig(pos, node, digger)
 			wielded = wdef.after_use(wielded, digger, node, dp) or wielded
 		else
 			-- Wear out tool
-			if not core.settings:get_bool("creative_mode") then
+			if not core.is_creative_enabled(diggername) then
 				wielded:add_wear(dp.wear)
 				if wielded:get_count() == 0 and wdef.sound and wdef.sound.breaks then
 					core.sound_play(wdef.sound.breaks, {
diff --git a/builtin/game/misc.lua b/builtin/game/misc.lua
index 0ed11ada0..341e613c2 100644
--- a/builtin/game/misc.lua
+++ b/builtin/game/misc.lua
@@ -164,6 +164,12 @@ function core.record_protection_violation(pos, name)
 	end
 end
 
+-- To be overridden by Creative mods
+
+local creative_mode_cache = core.settings:get_bool("creative_mode")
+function core.is_creative_enabled(name)
+	return creative_mode_cache
+end
 
 -- Checks if specified volume intersects a protected volume
 
diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index c4310aa5b..bb9df5373 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -5475,6 +5475,13 @@ Misc.
 * `minetest.record_protection_violation(pos, name)`
     * This function calls functions registered with
       `minetest.register_on_protection_violation`.
+* `minetest.is_creative_enabled(name)`: returns boolean
+    * Returning `true` means that Creative Mode is enabled for player `name`.
+    * `name` will be `""` for non-players or if the player is unknown.
+    * This function should be overridden by Creative Mode-related mods to
+      implement a per-player Creative Mode.
+    * By default, this function returns `true` if the setting
+      `creative_mode` is `true` and `false` otherwise.
 * `minetest.is_area_protected(pos1, pos2, player_name, interval)`
     * Returns the position of the first node that `player_name` may not modify
       in the specified cuboid between `pos1` and `pos2`.
diff --git a/games/devtest/mods/util_commands/init.lua b/games/devtest/mods/util_commands/init.lua
index ad8d3f9ba..3a0e91a41 100644
--- a/games/devtest/mods/util_commands/init.lua
+++ b/games/devtest/mods/util_commands/init.lua
@@ -66,7 +66,7 @@ if s_infplace == "true" then
 elseif s_infplace == "false" then
 	infplace = false
 else
-	infplace = minetest.settings:get_bool("creative_mode", false)
+	infplace = minetest.is_creative_enabled("")
 end
 
 minetest.register_chatcommand("infplace", {
-- 
cgit v1.2.3


From b16f841756ef86e83710ad2fddf2cd5bafdf4bcc Mon Sep 17 00:00:00 2001
From: Paul Ouellette <oue.paul18@gmail.com>
Date: Tue, 9 Jun 2020 13:37:25 -0400
Subject: LuaItemStack: Add __tostring metamethod (#8785)

* LuaItemStack: Add __tostring metamethod

* Clean up LuaItemStack::checkobject
---
 builtin/common/misc_helpers.lua |  2 ++
 src/inventory.cpp               | 29 ++++++++++++++++-------------
 src/inventory.h                 |  4 ++--
 src/script/lua_api/l_item.cpp   | 25 ++++++++++++++++++-------
 src/script/lua_api/l_item.h     |  3 +++
 5 files changed, 41 insertions(+), 22 deletions(-)

(limited to 'builtin/common')

diff --git a/builtin/common/misc_helpers.lua b/builtin/common/misc_helpers.lua
index a88adf96d..e29a9f422 100644
--- a/builtin/common/misc_helpers.lua
+++ b/builtin/common/misc_helpers.lua
@@ -20,6 +20,8 @@ local function basic_dump(o)
 	-- dump's output is intended for humans.
 	--elseif tp == "function" then
 	--	return string.format("loadstring(%q)", string.dump(o))
+	elseif tp == "userdata" then
+		return tostring(o)
 	else
 		return string.format("<%s>", tp)
 	end
diff --git a/src/inventory.cpp b/src/inventory.cpp
index 77ecf5876..349ee503d 100644
--- a/src/inventory.cpp
+++ b/src/inventory.cpp
@@ -56,28 +56,31 @@ ItemStack::ItemStack(const std::string &name_, u16 count_,
 		count = 1;
 }
 
-void ItemStack::serialize(std::ostream &os) const
+void ItemStack::serialize(std::ostream &os, bool serialize_meta) const
 {
 	if (empty())
 		return;
 
 	// Check how many parts of the itemstring are needed
 	int parts = 1;
-	if(count != 1)
-		parts = 2;
-	if(wear != 0)
-		parts = 3;
 	if (!metadata.empty())
 		parts = 4;
+	else if (wear != 0)
+		parts = 3;
+	else if (count != 1)
+		parts = 2;
 
-	os<<serializeJsonStringIfNeeded(name);
-	if(parts >= 2)
-		os<<" "<<count;
-	if(parts >= 3)
-		os<<" "<<wear;
+	os << serializeJsonStringIfNeeded(name);
+	if (parts >= 2)
+		os << " " << count;
+	if (parts >= 3)
+		os << " " << wear;
 	if (parts >= 4) {
 		os << " ";
-		metadata.serialize(os);
+		if (serialize_meta)
+			metadata.serialize(os);
+		else
+			os << "<metadata size=" << metadata.size() << ">";
 	}
 }
 
@@ -240,10 +243,10 @@ void ItemStack::deSerialize(const std::string &str, IItemDefManager *itemdef)
 	deSerialize(is, itemdef);
 }
 
-std::string ItemStack::getItemString() const
+std::string ItemStack::getItemString(bool include_meta) const
 {
 	std::ostringstream os(std::ios::binary);
-	serialize(os);
+	serialize(os, include_meta);
 	return os.str();
 }
 
diff --git a/src/inventory.h b/src/inventory.h
index 2828d3e5a..67a7859ed 100644
--- a/src/inventory.h
+++ b/src/inventory.h
@@ -40,13 +40,13 @@ struct ItemStack
 	~ItemStack() = default;
 
 	// Serialization
-	void serialize(std::ostream &os) const;
+	void serialize(std::ostream &os, bool serialize_meta = true) const;
 	// Deserialization. Pass itemdef unless you don't want aliases resolved.
 	void deSerialize(std::istream &is, IItemDefManager *itemdef = NULL);
 	void deSerialize(const std::string &s, IItemDefManager *itemdef = NULL);
 
 	// Returns the string used for inventory
-	std::string getItemString() const;
+	std::string getItemString(bool include_meta = true) const;
 	// Returns the tooltip
 	std::string getDescription(IItemDefManager *itemdef) const;
 
diff --git a/src/script/lua_api/l_item.cpp b/src/script/lua_api/l_item.cpp
index 0a403acbd..d67cab76f 100644
--- a/src/script/lua_api/l_item.cpp
+++ b/src/script/lua_api/l_item.cpp
@@ -37,6 +37,15 @@ int LuaItemStack::gc_object(lua_State *L)
 	return 0;
 }
 
+// __tostring metamethod
+int LuaItemStack::mt_tostring(lua_State *L)
+{
+	LuaItemStack *o = checkobject(L, 1);
+	std::string itemstring = o->m_stack.getItemString(false);
+	lua_pushfstring(L, "ItemStack(\"%s\")", itemstring.c_str());
+	return 1;
+}
+
 // is_empty(self) -> true/false
 int LuaItemStack::l_is_empty(lua_State *L)
 {
@@ -433,12 +442,9 @@ int LuaItemStack::create(lua_State *L, const ItemStack &item)
 	return 1;
 }
 
-LuaItemStack* LuaItemStack::checkobject(lua_State *L, int narg)
+LuaItemStack *LuaItemStack::checkobject(lua_State *L, int narg)
 {
-	luaL_checktype(L, narg, LUA_TUSERDATA);
-	void *ud = luaL_checkudata(L, narg, className);
-	if(!ud) luaL_typerror(L, narg, className);
-	return *(LuaItemStack**)ud;  // unbox pointer
+	return *(LuaItemStack **)luaL_checkudata(L, narg, className);
 }
 
 void LuaItemStack::Register(lua_State *L)
@@ -448,9 +454,10 @@ void LuaItemStack::Register(lua_State *L)
 	luaL_newmetatable(L, className);
 	int metatable = lua_gettop(L);
 
+	// hide metatable from Lua getmetatable()
 	lua_pushliteral(L, "__metatable");
 	lua_pushvalue(L, methodtable);
-	lua_settable(L, metatable);  // hide metatable from Lua getmetatable()
+	lua_settable(L, metatable);
 
 	lua_pushliteral(L, "__index");
 	lua_pushvalue(L, methodtable);
@@ -460,12 +467,16 @@ void LuaItemStack::Register(lua_State *L)
 	lua_pushcfunction(L, gc_object);
 	lua_settable(L, metatable);
 
+	lua_pushliteral(L, "__tostring");
+	lua_pushcfunction(L, mt_tostring);
+	lua_settable(L, metatable);
+
 	lua_pop(L, 1);  // drop metatable
 
 	luaL_openlib(L, 0, methods, 0);  // fill methodtable
 	lua_pop(L, 1);  // drop methodtable
 
-	// Can be created from Lua (LuaItemStack(itemstack or itemstring or table or nil))
+	// Can be created from Lua (ItemStack(itemstack or itemstring or table or nil))
 	lua_register(L, className, create_object);
 }
 
diff --git a/src/script/lua_api/l_item.h b/src/script/lua_api/l_item.h
index 6fab58045..98744c071 100644
--- a/src/script/lua_api/l_item.h
+++ b/src/script/lua_api/l_item.h
@@ -34,6 +34,9 @@ private:
 	// garbage collector
 	static int gc_object(lua_State *L);
 
+	// __tostring metamethod
+	static int mt_tostring(lua_State *L);
+
 	// is_empty(self) -> true/false
 	static int l_is_empty(lua_State *L);
 
-- 
cgit v1.2.3


From 7148834440d10bc211628aa2652e31166bdd58a0 Mon Sep 17 00:00:00 2001
From: NetherEran <55532075+NetherEran@users.noreply.github.com>
Date: Tue, 9 Jun 2020 17:38:39 +0000
Subject: Some vector functions useful for working with rotations (#9572)

* added vector.rotate

* added vector.forward_from_rotation and vector.up_from_rotation

* added vector.forward_up_to_rotatiton

* fixed some bugs and formatting with vector functions

* shortened name of some new vector functions and added documentation

* made vector.rotate not require a unit vector as axis

* fixed crash with vector.forward_up_to_rot

* renamed new vector functions, made vector.rotate apply a rotation matrix, old vector.rotate is now called vector.rotate_around_axis

* documented vector function changes

* removed some whitespace to appease luacheck

* implemented and fixed optimization of vector.rotate_around_axis by SmallJoker

* added some unit tests for rotation vector functions

* clarified that rotation vectors are in radians and according to the left hand rule

* hopefully appeased luacheck

* renamed rotation_to_horizontal to forward_at_rotation, rotation_to_vertical to up_at_rotation

* handled cases where sin or cos are 0 in rotation vector functions

* added more comments

* clarified documentation of rotation vector functions

* added more unit tests

* changed way in which vector.rotate_around_axis is adjusted for left handed coordinate systems

* made vector.rotate_around_axis actually left handed

* unrolled matrix multiplication

* removed vector.forward_at_rotation and vector.up_at_rotation

* prettified vector.rotate_around_axis, made previous commits not break anything

* removed references to removed vector.forward_at_rotation and vector.up_at_rotation

* removed documentation of removed vector functions

* clarified documentation and fixed styling of rotation vector functions

* restyled comments minorly

* spelling fixes and some hopefully better comments

* allowed 'up' to be missing from vector.directions_to_rotation and removed requirement for unit vectors as arguments

* made vector.rotate_around_axis() right handed again for consistency

* documented previous changes

* made matrix multiplication actually multiply

* renamed vector.directions_to_rotation() to vector.dir_to_rotation()

* optimized a distance comparison

* Fixed potential false positive in unit tests.

Co-authored-by: NetherEran <nethereran@hotmail.com>
---
 builtin/common/tests/vector_spec.lua | 142 +++++++++++++++++++++++++++++++++++
 builtin/common/vector.lua            |  93 +++++++++++++++++++++++
 doc/lua_api.txt                      |  18 +++++
 3 files changed, 253 insertions(+)

(limited to 'builtin/common')

diff --git a/builtin/common/tests/vector_spec.lua b/builtin/common/tests/vector_spec.lua
index 79f032f28..6f308a4a8 100644
--- a/builtin/common/tests/vector_spec.lua
+++ b/builtin/common/tests/vector_spec.lua
@@ -43,4 +43,146 @@ describe("vector", function()
 	it("add()", function()
 		assert.same({ x = 2, y = 4, z = 6 }, vector.add(vector.new(1, 2, 3), { x = 1, y = 2, z = 3 }))
 	end)
+
+	-- This function is needed because of floating point imprecision.
+	local function almost_equal(a, b)
+		if type(a) == "number" then
+			return math.abs(a - b) < 0.00000000001
+		end
+		return vector.distance(a, b) < 0.000000000001
+	end
+
+	describe("rotate_around_axis()", function()
+		it("rotates", function()
+			assert.True(almost_equal({x = -1, y = 0, z = 0},
+				vector.rotate_around_axis({x = 1, y = 0, z = 0}, {x = 0, y = 1, z = 0}, math.pi)))
+			assert.True(almost_equal({x = 0, y = 1, z = 0},
+				vector.rotate_around_axis({x = 0, y = 0, z = 1}, {x = 1, y = 0, z = 0}, math.pi / 2)))
+			assert.True(almost_equal({x = 4, y = 1, z = 1},
+				vector.rotate_around_axis({x = 4, y = 1, z = 1}, {x = 4, y = 1, z = 1}, math.pi / 6)))
+		end)
+		it("keeps distance to axis", function()
+			local rotate1 = {x = 1, y = 3, z = 1}
+			local axis1 = {x = 1, y = 3, z = 2}
+			local rotated1 = vector.rotate_around_axis(rotate1, axis1, math.pi / 13)
+			assert.True(almost_equal(vector.distance(axis1, rotate1), vector.distance(axis1, rotated1)))
+			local rotate2 = {x = 1, y = 1, z = 3}
+			local axis2 = {x = 2, y = 6, z = 100}
+			local rotated2 = vector.rotate_around_axis(rotate2, axis2, math.pi / 23)
+			assert.True(almost_equal(vector.distance(axis2, rotate2), vector.distance(axis2, rotated2)))
+			local rotate3 = {x = 1, y = -1, z = 3}
+			local axis3 = {x = 2, y = 6, z = 100}
+			local rotated3 = vector.rotate_around_axis(rotate3, axis3, math.pi / 2)
+			assert.True(almost_equal(vector.distance(axis3, rotate3), vector.distance(axis3, rotated3)))
+		end)
+		it("rotates back", function()
+			local rotate1 = {x = 1, y = 3, z = 1}
+			local axis1 = {x = 1, y = 3, z = 2}
+			local rotated1 = vector.rotate_around_axis(rotate1, axis1, math.pi / 13)
+			rotated1 = vector.rotate_around_axis(rotated1, axis1, -math.pi / 13)
+			assert.True(almost_equal(rotate1, rotated1))
+			local rotate2 = {x = 1, y = 1, z = 3}
+			local axis2 = {x = 2, y = 6, z = 100}
+			local rotated2 = vector.rotate_around_axis(rotate2, axis2, math.pi / 23)
+			rotated2 = vector.rotate_around_axis(rotated2, axis2, -math.pi / 23)
+			assert.True(almost_equal(rotate2, rotated2))
+			local rotate3 = {x = 1, y = -1, z = 3}
+			local axis3 = {x = 2, y = 6, z = 100}
+			local rotated3 = vector.rotate_around_axis(rotate3, axis3, math.pi / 2)
+			rotated3 = vector.rotate_around_axis(rotated3, axis3, -math.pi / 2)
+			assert.True(almost_equal(rotate3, rotated3))
+		end)
+		it("is right handed", function()
+			local v_before1 = {x = 0, y = 1, z = -1}
+			local v_after1 = vector.rotate_around_axis(v_before1, {x = 1, y = 0, z = 0}, math.pi / 4)
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after1, v_before1)), {x = 1, y = 0, z = 0}))
+
+			local v_before2 = {x = 0, y = 3, z = 4}
+			local v_after2 = vector.rotate_around_axis(v_before2, {x = 1, y = 0, z = 0},  2 * math.pi / 5)
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after2, v_before2)), {x = 1, y = 0, z = 0}))
+
+			local v_before3 = {x = 1, y = 0, z = -1}
+			local v_after3 = vector.rotate_around_axis(v_before3, {x = 0, y = 1, z = 0}, math.pi / 4)
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after3, v_before3)), {x = 0, y = 1, z = 0}))
+
+			local v_before4 = {x = 3, y = 0, z = 4}
+			local v_after4 = vector.rotate_around_axis(v_before4, {x = 0, y = 1, z = 0}, 2 * math.pi / 5)
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after4, v_before4)), {x = 0, y = 1, z = 0}))
+
+			local v_before5 = {x = 1, y = -1, z = 0}
+			local v_after5 = vector.rotate_around_axis(v_before5, {x = 0, y = 0, z = 1}, math.pi / 4)
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after5, v_before5)), {x = 0, y = 0, z = 1}))
+
+			local v_before6 = {x = 3, y = 4, z = 0}
+			local v_after6 = vector.rotate_around_axis(v_before6, {x = 0, y = 0, z = 1}, 2 * math.pi / 5)
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after6, v_before6)), {x = 0, y = 0, z = 1}))
+		end)
+	end)
+
+	describe("rotate()", function()
+		it("rotates", function()
+			assert.True(almost_equal({x = -1, y = 0, z = 0},
+				vector.rotate({x = 1, y = 0, z = 0}, {x = 0, y = math.pi, z = 0})))
+			assert.True(almost_equal({x = 0, y = -1, z = 0},
+				vector.rotate({x = 1, y = 0, z = 0}, {x = 0, y = 0, z = math.pi / 2})))
+			assert.True(almost_equal({x = 1, y = 0, z = 0},
+				vector.rotate({x = 1, y = 0, z = 0}, {x = math.pi / 123, y = 0, z = 0})))
+		end)
+		it("is counterclockwise", function()
+			local v_before1 = {x = 0, y = 1, z = -1}
+			local v_after1 = vector.rotate(v_before1, {x = math.pi / 4, y = 0, z = 0})
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after1, v_before1)), {x = 1, y = 0, z = 0}))
+
+			local v_before2 = {x = 0, y = 3, z = 4}
+			local v_after2 = vector.rotate(v_before2, {x = 2 * math.pi / 5, y = 0, z = 0})
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after2, v_before2)), {x = 1, y = 0, z = 0}))
+
+			local v_before3 = {x = 1, y = 0, z = -1}
+			local v_after3 = vector.rotate(v_before3, {x = 0, y = math.pi / 4, z = 0})
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after3, v_before3)), {x = 0, y = 1, z = 0}))
+
+			local v_before4 = {x = 3, y = 0, z = 4}
+			local v_after4 = vector.rotate(v_before4, {x = 0, y = 2 * math.pi / 5, z = 0})
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after4, v_before4)), {x = 0, y = 1, z = 0}))
+
+			local v_before5 = {x = 1, y = -1, z = 0}
+			local v_after5 = vector.rotate(v_before5, {x = 0, y = 0, z = math.pi / 4})
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after5, v_before5)), {x = 0, y = 0, z = 1}))
+
+			local v_before6 = {x = 3, y = 4, z = 0}
+			local v_after6 = vector.rotate(v_before6, {x = 0, y = 0, z = 2 * math.pi / 5})
+			assert.True(almost_equal(vector.normalize(vector.cross(v_after6, v_before6)), {x = 0, y = 0, z = 1}))
+		end)
+	end)
+
+	it("dir_to_rotation()", function()
+		-- Comparing rotations (pitch, yaw, roll) is hard because of certain ambiguities,
+		-- e.g. (pi, 0, pi) looks exactly the same as (0, pi, 0)
+		-- So instead we convert the rotation back to vectors and compare these.
+		local function forward_at_rot(rot)
+			return vector.rotate(vector.new(0, 0, 1), rot)
+		end
+		local function up_at_rot(rot)
+			return vector.rotate(vector.new(0, 1, 0), rot)
+		end
+		local rot1 = vector.dir_to_rotation({x = 1, y = 0, z = 0}, {x = 0, y = 1, z = 0})
+		assert.True(almost_equal({x = 1, y = 0, z = 0}, forward_at_rot(rot1)))
+		assert.True(almost_equal({x = 0, y = 1, z = 0}, up_at_rot(rot1)))
+		local rot2 = vector.dir_to_rotation({x = 1, y = 1, z = 0}, {x = 0, y = 0, z = 1})
+		assert.True(almost_equal({x = 1/math.sqrt(2), y = 1/math.sqrt(2), z = 0}, forward_at_rot(rot2)))
+		assert.True(almost_equal({x = 0, y = 0, z = 1}, up_at_rot(rot2)))
+		for i = 1, 1000 do
+			local rand_vec = vector.new(math.random(), math.random(), math.random())
+			if vector.length(rand_vec) ~= 0 then
+				local rot_1 = vector.dir_to_rotation(rand_vec)
+				local rot_2 = {
+					x = math.atan2(rand_vec.y, math.sqrt(rand_vec.z * rand_vec.z + rand_vec.x * rand_vec.x)),
+					y = -math.atan2(rand_vec.x, rand_vec.z),
+					z = 0
+				}
+				assert.True(almost_equal(rot_1, rot_2))
+			end
+		end
+
+	end)
 end)
diff --git a/builtin/common/vector.lua b/builtin/common/vector.lua
index ca6541eb4..1fd784ce2 100644
--- a/builtin/common/vector.lua
+++ b/builtin/common/vector.lua
@@ -141,3 +141,96 @@ function vector.sort(a, b)
 	return {x = math.min(a.x, b.x), y = math.min(a.y, b.y), z = math.min(a.z, b.z)},
 		{x = math.max(a.x, b.x), y = math.max(a.y, b.y), z = math.max(a.z, b.z)}
 end
+
+local function sin(x)
+	if x % math.pi == 0 then
+		return 0
+	else
+		return math.sin(x)
+	end
+end
+
+local function cos(x)
+	if x % math.pi == math.pi / 2 then
+		return 0
+	else
+		return math.cos(x)
+	end
+end
+
+function vector.rotate_around_axis(v, axis, angle)
+	local cosangle = cos(angle)
+	local sinangle = sin(angle)
+	axis = vector.normalize(axis)
+	-- https://en.wikipedia.org/wiki/Rodrigues%27_rotation_formula
+	local dot_axis = vector.multiply(axis, vector.dot(axis, v))
+	local cross = vector.cross(v, axis)
+	return vector.new(
+		cross.x * sinangle + (v.x - dot_axis.x) * cosangle + dot_axis.x,
+		cross.y * sinangle + (v.y - dot_axis.y) * cosangle + dot_axis.y,
+		cross.z * sinangle + (v.z - dot_axis.z) * cosangle + dot_axis.z
+	)
+end
+
+function vector.rotate(v, rot)
+	local sinpitch = sin(-rot.x)
+	local sinyaw = sin(-rot.y)
+	local sinroll = sin(-rot.z)
+	local cospitch = cos(rot.x)
+	local cosyaw = cos(rot.y)
+	local cosroll = math.cos(rot.z)
+	-- Rotation matrix that applies yaw, pitch and roll
+	local matrix = {
+		{
+			sinyaw * sinpitch * sinroll + cosyaw * cosroll,
+			sinyaw * sinpitch * cosroll - cosyaw * sinroll,
+			sinyaw * cospitch,
+		},
+		{
+			cospitch * sinroll,
+			cospitch * cosroll,
+			-sinpitch,
+		},
+		{
+			cosyaw * sinpitch * sinroll - sinyaw * cosroll,
+			cosyaw * sinpitch * cosroll + sinyaw * sinroll,
+			cosyaw * cospitch,
+		},
+	}
+	-- Compute matrix multiplication: `matrix` * `v`
+	return vector.new(
+		matrix[1][1] * v.x + matrix[1][2] * v.y + matrix[1][3] * v.z,
+		matrix[2][1] * v.x + matrix[2][2] * v.y + matrix[2][3] * v.z,
+		matrix[3][1] * v.x + matrix[3][2] * v.y + matrix[3][3] * v.z
+	)
+end
+
+function vector.dir_to_rotation(forward, up)
+	forward = vector.normalize(forward)
+	local rot = {x = math.asin(forward.y), y = -math.atan2(forward.x, forward.z), z = 0}
+	if not up then
+		return rot
+	end
+	assert(vector.dot(forward, up) < 0.000001,
+			"Invalid vectors passed to vector.dir_to_rotation().")
+	up = vector.normalize(up)
+	-- Calculate vector pointing up with roll = 0, just based on forward vector.
+	local forwup = vector.rotate({x = 0, y = 1, z = 0}, rot)
+	-- 'forwup' and 'up' are now in a plane with 'forward' as normal.
+	-- The angle between them is the absolute of the roll value we're looking for.
+	rot.z = vector.angle(forwup, up)
+
+	-- Since vector.angle never returns a negative value or a value greater
+	-- than math.pi, rot.z has to be inverted sometimes.
+	-- To determine wether this is the case, we rotate the up vector back around
+	-- the forward vector and check if it worked out.
+	local back = vector.rotate_around_axis(up, forward, -rot.z)
+
+	-- We don't use vector.equals for this because of floating point imprecision.
+	if (back.x - forwup.x) * (back.x - forwup.x) +
+			(back.y - forwup.y) * (back.y - forwup.y) +
+			(back.z - forwup.z) * (back.z - forwup.z) > 0.0000001 then
+		rot.z = -rot.z
+	end
+	return rot
+end
diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index 898531880..ed060c4ad 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -3007,6 +3007,24 @@ For the following functions `x` can be either a vector or a number:
 * `vector.divide(v, x)`:
     * Returns a scaled vector or Schur quotient.
 
+For the following functions `a` is an angle in radians and `r` is a rotation
+vector ({x = <pitch>, y = <yaw>, z = <roll>}) where pitch, yaw and roll are
+angles in radians.
+
+* `vector.rotate(v, r)`:
+    * Applies the rotation `r` to `v` and returns the result.
+    * `vector.rotate({x = 0, y = 0, z = 1}, r)` and
+      `vector.rotate({x = 0, y = 1, z = 0}, r)` return vectors pointing
+      forward and up relative to an entity's rotation `r`.
+* `vector.rotate_around_axis(v1, v2, a)`:
+    * Returns `v1` rotated around axis `v2` by `a` radians according to
+      the right hand rule.
+* `vector.dir_to_rotation(direction[, up])`:
+    * Returns a rotation vector for `direction` pointing forward using `up`
+      as the up vector.
+    * If `up` is omitted, the roll of the returned vector defaults to zero.
+    * Otherwise `direction` and `up` need to be vectors in a 90 degree angle to each other.
+
 
 
 
-- 
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