Split liquid_viscosity to liquid_viscosity and move_resistance (#10810)

15 files changed, 289 insertions, 45 deletions

diff --git a/doc/client_lua_api.txt b/doc/client_lua_api.txt
index 24d23b0b5..32be8c849 100644
--- a/doc/client_lua_api.txt
+++ b/doc/client_lua_api.txt
@@ -1030,8 +1030,8 @@ Methods:
     * returns true if player is in a liquid (This oscillates so that the player jumps a bit above the surface)
 * `is_in_liquid_stable()`
     * returns true if player is in a stable liquid (This is more stable and defines the maximum speed of the player)
-* `get_liquid_viscosity()`
-    * returns liquid viscosity (Gets the viscosity of liquid to calculate friction)
+* `get_move_resistance()`
+    * returns move resistance of current node, the higher the slower the player moves
 * `is_climbing()`
     * returns true if player is climbing
 * `swimming_vertical()`
@@ -1233,7 +1233,7 @@ It can be created via `Raycast(pos1, pos2, objects, liquids)` or
 		liquid_type = <string>,         -- A string containing "none", "flowing", or "source" *May not exist*
 		liquid_alternative_flowing = <string>, -- Alternative node for liquid *May not exist*
 		liquid_alternative_source = <string>, -- Alternative node for liquid *May not exist*
-		liquid_viscosity = <number>,    -- How fast the liquid flows *May not exist*
+		liquid_viscosity = <number>,    -- How slow the liquid flows *May not exist*
 		liquid_renewable = <boolean>,   -- Whether the liquid makes an infinite source *May not exist*
 		liquid_range = <number>,        -- How far the liquid flows *May not exist*
 		drowning = bool,                -- Whether the player will drown in the node
@@ -1248,6 +1248,7 @@ It can be created via `Raycast(pos1, pos2, objects, liquids)` or
 		},
 		legacy_facedir_simple = bool,   -- Whether to use old facedir
 		legacy_wallmounted = bool       -- Whether to use old wallmounted
+		move_resistance = <number>,     -- How slow players can move through the node *May not exist*
 	}
 ```
 
diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index 4fab78841..9efe1afe7 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -1804,7 +1804,7 @@ to games.
       - (14)                                           -- constant tolerance
   Negative damage values are discarded as no damage.
 * `falling_node`: if there is no walkable block under the node it will fall
-* `float`: the node will not fall through liquids
+* `float`: the node will not fall through liquids (`liquidtype ~= "none"`)
 * `level`: Can be used to give an additional sense of progression in the game.
      * A larger level will cause e.g. a weapon of a lower level make much less
        damage, and get worn out much faster, or not be able to get drops
@@ -4147,7 +4147,7 @@ differences:
 
 ### Other API functions operating on a VoxelManip
 
-If any VoxelManip contents were set to a liquid node,
+If any VoxelManip contents were set to a liquid node (`liquidtype ~= "none"`),
 `VoxelManip:update_liquids()` must be called for these liquid nodes to begin
 flowing. It is recommended to call this function only after having written all
 buffered data back to the VoxelManip object, save for special situations where
@@ -4958,8 +4958,8 @@ Call these functions only at load time!
     * You should have joined some channels to receive events.
     * If message comes from a server mod, `sender` field is an empty string.
 * `minetest.register_on_liquid_transformed(function(pos_list, node_list))`
-    * Called after liquid nodes are modified by the engine's liquid transformation
-      process.
+    * Called after liquid nodes (`liquidtype ~= "none"`) are modified by the
+      engine's liquid transformation process.
     * `pos_list` is an array of all modified positions.
     * `node_list` is an array of the old node that was previously at the position
       with the corresponding index in pos_list.
@@ -5301,7 +5301,8 @@ Environment access
     * `pos1`: start of the ray
     * `pos2`: end of the ray
     * `objects`: if false, only nodes will be returned. Default is `true`.
-    * `liquids`: if false, liquid nodes won't be returned. Default is `false`.
+    * `liquids`: if false, liquid nodes (`liquidtype ~= "none"`) won't be
+                 returned. Default is `false`.
 * `minetest.find_path(pos1,pos2,searchdistance,max_jump,max_drop,algorithm)`
     * returns table containing path that can be walked on
     * returns a table of 3D points representing a path from `pos1` to `pos2` or
@@ -5325,7 +5326,7 @@ Environment access
 * `minetest.spawn_tree (pos, {treedef})`
     * spawns L-system tree at given `pos` with definition in `treedef` table
 * `minetest.transforming_liquid_add(pos)`
-    * add node to liquid update queue
+    * add node to liquid flow update queue
 * `minetest.get_node_max_level(pos)`
     * get max available level for leveled node
 * `minetest.get_node_level(pos)`
@@ -6978,7 +6979,8 @@ It can be created via `Raycast(pos1, pos2, objects, liquids)` or
 * `pos1`: start of the ray
 * `pos2`: end of the ray
 * `objects`: if false, only nodes will be returned. Default is true.
-* `liquids`: if false, liquid nodes won't be returned. Default is false.
+* `liquids`: if false, liquid nodes (`liquidtype ~= "none"`) won't be
+             returned. Default is false.
 
 ### Methods
 
@@ -7462,6 +7464,8 @@ Used by `minetest.register_node`, `minetest.register_craftitem`, and
         range = 4.0,
 
         liquids_pointable = false,
+        -- If true, item points to all liquid nodes (`liquidtype ~= "none"`),
+        -- even those for which `pointable = false`
 
         light_source = 0,
         -- When used for nodes: Defines amount of light emitted by node.
@@ -7647,14 +7651,21 @@ Used by `minetest.register_node`.
 
         climbable = false,  -- If true, can be climbed on (ladder)
 
+        move_resistance = 0,
+        -- Slows down movement of players through this node (max. 7).
+        -- If this is nil, it will be equal to liquid_viscosity.
+        -- Note: If liquid movement physics apply to the node
+        -- (see `liquid_move_physics`), the movement speed will also be
+        -- affected by the `movement_liquid_*` settings.
+
         buildable_to = false,  -- If true, placed nodes can replace this node
 
         floodable = false,
         -- If true, liquids flow into and replace this node.
         -- Warning: making a liquid node 'floodable' will cause problems.
 
-        liquidtype = "none",  -- specifies liquid physics
-        -- * "none":    no liquid physics
+        liquidtype = "none",  -- specifies liquid flowing physics
+        -- * "none":    no liquid flowing physics
         -- * "source":  spawns flowing liquid nodes at all 4 sides and below;
         --              recommended drawtype: "liquid".
         -- * "flowing": spawned from source, spawns more flowing liquid nodes
@@ -7668,12 +7679,26 @@ Used by `minetest.register_node`.
 
         liquid_alternative_source = "",  -- Source version of flowing liquid
 
-        liquid_viscosity = 0,  -- Higher viscosity = slower flow (max. 7)
+        liquid_viscosity = 0,
+        -- Controls speed at which the liquid spreads/flows (max. 7).
+        -- 0 is fastest, 7 is slowest.
+        -- By default, this also slows down movement of players inside the node
+        -- (can be overridden using `move_resistance`)
 
         liquid_renewable = true,
         -- If true, a new liquid source can be created by placing two or more
         -- sources nearby
 
+        liquid_move_physics = nil, -- specifies movement physics if inside node
+        -- * false: No liquid movement physics apply.
+        -- * true: Enables liquid movement physics. Enables things like
+        --   ability to "swim" up/down, sinking slowly if not moving,
+        --   smoother speed change when falling into, etc. The `movement_liquid_*`
+        --   settings apply.
+        -- * nil: Will be treated as true if `liquidype ~= "none"`
+        --   and as false otherwise.
+        -- Default: nil
+
         leveled = 0,
         -- Only valid for "nodebox" drawtype with 'type = "leveled"'.
         -- Allows defining the nodebox height without using param2.
diff --git a/games/devtest/mods/testnodes/liquids.lua b/games/devtest/mods/testnodes/liquids.lua
index 3d2ea17f5..be33814af 100644
--- a/games/devtest/mods/testnodes/liquids.lua
+++ b/games/devtest/mods/testnodes/liquids.lua
@@ -40,9 +40,11 @@ for d=0, 8 do
 		liquid_range = d,
 	})
 
+	if d <= 7 then
+
 	local mod = "^[colorize:#000000:127"
 	minetest.register_node("testnodes:vliquid_"..d, {
-		description = "Test Liquid Source, Viscosity "..d,
+		description = "Test Liquid Source, Viscosity/Resistance "..d,
 		drawtype = "liquid",
 		tiles = {"testnodes_liquidsource_r"..d..".png"..mod},
 		special_tiles = {
@@ -61,7 +63,7 @@ for d=0, 8 do
 	})
 
 	minetest.register_node("testnodes:vliquid_flowing_"..d, {
-		description = "Flowing Test Liquid, Viscosity "..d,
+		description = "Flowing Test Liquid, Viscosity/Resistance "..d,
 		drawtype = "flowingliquid",
 		tiles = {"testnodes_liquidflowing_r"..d..".png"..mod},
 		special_tiles = {
@@ -80,4 +82,53 @@ for d=0, 8 do
 		liquid_viscosity = d,
 	})
 
+	mod = "^[colorize:#000000:192"
+	local v = 4
+	minetest.register_node("testnodes:vrliquid_"..d, {
+		description = "Test Liquid Source, Viscosity "..v..", Resistance "..d,
+		drawtype = "liquid",
+		tiles = {"testnodes_liquidsource_r"..d..".png"..mod},
+		special_tiles = {
+			{name = "testnodes_liquidsource_r"..d..".png"..mod, backface_culling = false},
+			{name = "testnodes_liquidsource_r"..d..".png"..mod, backface_culling = true},
+		},
+		use_texture_alpha = "blend",
+		paramtype = "light",
+		walkable = false,
+		pointable = false,
+		diggable = false,
+		buildable_to = true,
+		is_ground_content = false,
+		liquidtype = "source",
+		liquid_alternative_flowing = "testnodes:vrliquid_flowing_"..d,
+		liquid_alternative_source = "testnodes:vrliquid_"..d,
+		liquid_viscosity = v,
+		move_resistance = d,
+	})
+
+	minetest.register_node("testnodes:vrliquid_flowing_"..d, {
+		description = "Flowing Test Liquid, Viscosity "..v..", Resistance "..d,
+		drawtype = "flowingliquid",
+		tiles = {"testnodes_liquidflowing_r"..d..".png"..mod},
+		special_tiles = {
+			{name = "testnodes_liquidflowing_r"..d..".png"..mod, backface_culling = false},
+			{name = "testnodes_liquidflowing_r"..d..".png"..mod, backface_culling = false},
+		},
+		use_texture_alpha = "blend",
+		paramtype = "light",
+		paramtype2 = "flowingliquid",
+		walkable = false,
+		pointable = false,
+		diggable = false,
+		buildable_to = true,
+		is_ground_content = false,
+		liquidtype = "flowing",
+		liquid_alternative_flowing = "testnodes:vrliquid_flowing_"..d,
+		liquid_alternative_source = "testnodes:vrliquid_"..d,
+		liquid_viscosity = v,
+		move_resistance = d,
+	})
+
+	end
+
 end
diff --git a/games/devtest/mods/testnodes/properties.lua b/games/devtest/mods/testnodes/properties.lua
index a52cd1d6f..51f703d7c 100644
--- a/games/devtest/mods/testnodes/properties.lua
+++ b/games/devtest/mods/testnodes/properties.lua
@@ -152,6 +152,66 @@ minetest.register_node("testnodes:liquidflowing_nojump", {
 	post_effect_color = {a = 70, r = 255, g = 0, b = 200},
 })
 
+-- A liquid which doesn't have liquid movement physics (source variant)
+minetest.register_node("testnodes:liquid_noswim", {
+	description = S("No-swim Liquid Source Node"),
+	liquidtype = "source",
+	liquid_range = 1,
+	liquid_viscosity = 0,
+	liquid_alternative_flowing = "testnodes:liquidflowing_noswim",
+	liquid_alternative_source = "testnodes:liquid_noswim",
+	liquid_renewable = false,
+	liquid_move_physics = false,
+	groups = {dig_immediate=3},
+	walkable = false,
+
+	drawtype = "liquid",
+	tiles = {"testnodes_liquidsource.png^[colorize:#FF00FF:127"},
+	special_tiles = {
+		{name = "testnodes_liquidsource.png^[colorize:#FF00FF:127", backface_culling = false},
+		{name = "testnodes_liquidsource.png^[colorize:#FF00FF:127", backface_culling = true},
+	},
+	use_texture_alpha = "blend",
+	paramtype = "light",
+	pointable = false,
+	liquids_pointable = true,
+	buildable_to = true,
+	is_ground_content = false,
+	post_effect_color = {a = 70, r = 255, g = 200, b = 200},
+})
+
+-- A liquid which doen't have liquid movement physics (flowing variant)
+minetest.register_node("testnodes:liquidflowing_noswim", {
+	description = S("No-swim Flowing Liquid Node"),
+	liquidtype = "flowing",
+	liquid_range = 1,
+	liquid_viscosity = 0,
+	liquid_alternative_flowing = "testnodes:liquidflowing_noswim",
+	liquid_alternative_source = "testnodes:liquid_noswim",
+	liquid_renewable = false,
+	liquid_move_physics = false,
+	groups = {dig_immediate=3},
+	walkable = false,
+
+
+	drawtype = "flowingliquid",
+	tiles = {"testnodes_liquidflowing.png^[colorize:#FF00FF:127"},
+	special_tiles = {
+		{name = "testnodes_liquidflowing.png^[colorize:#FF00FF:127", backface_culling = false},
+		{name = "testnodes_liquidflowing.png^[colorize:#FF00FF:127", backface_culling = false},
+	},
+	use_texture_alpha = "blend",
+	paramtype = "light",
+	paramtype2 = "flowingliquid",
+	pointable = false,
+	liquids_pointable = true,
+	buildable_to = true,
+	is_ground_content = false,
+	post_effect_color = {a = 70, r = 255, g = 200, b = 200},
+})
+
+
+
 -- Nodes that modify fall damage (various damage modifiers)
 for i=-100, 100, 25 do
 	if i ~= 0 then
@@ -216,6 +276,54 @@ for i=1, 5 do
 	})
 end
 
+-- Move resistance nodes (various resistance levels)
+for r=0, 7 do
+	if r > 0 then
+		minetest.register_node("testnodes:move_resistance"..r, {
+			description = S("Move-resistant Node (@1)", r),
+			walkable = false,
+			move_resistance = r,
+
+			drawtype = "glasslike",
+			paramtype = "light",
+			sunlight_propagates = true,
+			tiles = { "testnodes_move_resistance.png" },
+			is_ground_content = false,
+			groups = { dig_immediate = 3 },
+			color = { b = 0, g = 255, r = math.floor((r/7)*255), a = 255 },
+		})
+	end
+
+	minetest.register_node("testnodes:move_resistance_liquidlike"..r, {
+		description = S("Move-resistant Node, liquidlike (@1)", r),
+		walkable = false,
+		move_resistance = r,
+		liquid_move_physics = true,
+
+		drawtype = "glasslike",
+		paramtype = "light",
+		sunlight_propagates = true,
+		tiles = { "testnodes_move_resistance.png" },
+		is_ground_content = false,
+		groups = { dig_immediate = 3 },
+		color = { b = 255, g = 0, r = math.floor((r/7)*255), a = 255 },
+	})
+end
+
+minetest.register_node("testnodes:climbable_move_resistance_4", {
+	description = S("Climbable Move-resistant Node (4)"),
+	walkable = false,
+	climbable = true,
+	move_resistance = 4,
+
+	drawtype = "glasslike",
+	paramtype = "light",
+	sunlight_propagates = true,
+	tiles = {"testnodes_climbable_resistance_side.png"},
+	is_ground_content = false,
+	groups = { dig_immediate = 3 },
+})
+
 -- By placing something on the node, the node itself will be replaced
 minetest.register_node("testnodes:buildable_to", {
 	description = S("Replacable Node"),
diff --git a/games/devtest/mods/testnodes/textures/testnodes_climbable_resistance_side.png b/games/devtest/mods/testnodes/textures/testnodes_climbable_resistance_side.png
new file mode 100644
index 000000000..be01583e6
--- /dev/null
+++ b/games/devtest/mods/testnodes/textures/testnodes_climbable_resistance_side.png
diff --git a/games/devtest/mods/testnodes/textures/testnodes_move_resistance.png b/games/devtest/mods/testnodes/textures/testnodes_move_resistance.png
new file mode 100644
index 000000000..cac3944bf
--- /dev/null
+++ b/games/devtest/mods/testnodes/textures/testnodes_move_resistance.png
diff --git a/src/client/clientenvironment.cpp b/src/client/clientenvironment.cpp
index 7e3867537..448af36c6 100644
--- a/src/client/clientenvironment.cpp
+++ b/src/client/clientenvironment.cpp
@@ -194,32 +194,41 @@ void ClientEnvironment::step(float dtime)
 		lplayer->applyControl(dtime_part, this);
 
 		// Apply physics
-		if (!free_move && !is_climbing) {
+		if (!free_move) {
 			// Gravity
 			v3f speed = lplayer->getSpeed();
-			if (!lplayer->in_liquid)
+			if (!is_climbing && !lplayer->in_liquid)
 				speed.Y -= lplayer->movement_gravity *
 					lplayer->physics_override_gravity * dtime_part * 2.0f;
 
 			// Liquid floating / sinking
-			if (lplayer->in_liquid && !lplayer->swimming_vertical &&
+			if (!is_climbing && lplayer->in_liquid &&
+					!lplayer->swimming_vertical &&
 					!lplayer->swimming_pitch)
 				speed.Y -= lplayer->movement_liquid_sink * dtime_part * 2.0f;
 
-			// Liquid resistance
-			if (lplayer->in_liquid_stable || lplayer->in_liquid) {
-				// How much the node's viscosity blocks movement, ranges
-				// between 0 and 1. Should match the scale at which viscosity
+			// Movement resistance
+			if (lplayer->move_resistance > 0) {
+				// How much the node's move_resistance blocks movement, ranges
+				// between 0 and 1. Should match the scale at which liquid_viscosity
 				// increase affects other liquid attributes.
-				static const f32 viscosity_factor = 0.3f;
-
-				v3f d_wanted = -speed / lplayer->movement_liquid_fluidity;
+				static const f32 resistance_factor = 0.3f;
+
+				v3f d_wanted;
+				bool in_liquid_stable = lplayer->in_liquid_stable || lplayer->in_liquid;
+				if (in_liquid_stable) {
+					d_wanted = -speed / lplayer->movement_liquid_fluidity;
+				} else {
+					d_wanted = -speed / BS;
+				}
 				f32 dl = d_wanted.getLength();
-				if (dl > lplayer->movement_liquid_fluidity_smooth)
-					dl = lplayer->movement_liquid_fluidity_smooth;
+				if (in_liquid_stable) {
+					if (dl > lplayer->movement_liquid_fluidity_smooth)
+						dl = lplayer->movement_liquid_fluidity_smooth;
+				}
 
-				dl *= (lplayer->liquid_viscosity * viscosity_factor) +
-					(1 - viscosity_factor);
+				dl *= (lplayer->move_resistance * resistance_factor) +
+					(1 - resistance_factor);
 				v3f d = d_wanted.normalize() * (dl * dtime_part * 100.0f);
 				speed += d;
 			}
diff --git a/src/client/localplayer.cpp b/src/client/localplayer.cpp
index 2d4f7305a..3f78d201d 100644
--- a/src/client/localplayer.cpp
+++ b/src/client/localplayer.cpp
@@ -227,8 +227,9 @@ void LocalPlayer::move(f32 dtime, Environment *env, f32 pos_max_d,
 		pp = floatToInt(position + v3f(0.0f, BS * 0.1f, 0.0f), BS);
 		node = map->getNode(pp, &is_valid_position);
 		if (is_valid_position) {
-			in_liquid = nodemgr->get(node.getContent()).isLiquid();
-			liquid_viscosity = nodemgr->get(node.getContent()).liquid_viscosity;
+			const ContentFeatures &cf = nodemgr->get(node.getContent());
+			in_liquid = cf.liquid_move_physics;
+			move_resistance = cf.move_resistance;
 		} else {
 			in_liquid = false;
 		}
@@ -238,8 +239,9 @@ void LocalPlayer::move(f32 dtime, Environment *env, f32 pos_max_d,
 		pp = floatToInt(position + v3f(0.0f, BS * 0.5f, 0.0f), BS);
 		node = map->getNode(pp, &is_valid_position);
 		if (is_valid_position) {
-			in_liquid = nodemgr->get(node.getContent()).isLiquid();
-			liquid_viscosity = nodemgr->get(node.getContent()).liquid_viscosity;
+			const ContentFeatures &cf = nodemgr->get(node.getContent());
+			in_liquid = cf.liquid_move_physics;
+			move_resistance = cf.move_resistance;
 		} else {
 			in_liquid = false;
 		}
@@ -252,7 +254,7 @@ void LocalPlayer::move(f32 dtime, Environment *env, f32 pos_max_d,
 	pp = floatToInt(position + v3f(0.0f), BS);
 	node = map->getNode(pp, &is_valid_position);
 	if (is_valid_position) {
-		in_liquid_stable = nodemgr->get(node.getContent()).isLiquid();
+		in_liquid_stable = nodemgr->get(node.getContent()).liquid_move_physics;
 	} else {
 		in_liquid_stable = false;
 	}
@@ -800,8 +802,9 @@ void LocalPlayer::old_move(f32 dtime, Environment *env, f32 pos_max_d,
 		pp = floatToInt(position + v3f(0.0f, BS * 0.1f, 0.0f), BS);
 		node = map->getNode(pp, &is_valid_position);
 		if (is_valid_position) {
-			in_liquid = nodemgr->get(node.getContent()).isLiquid();
-			liquid_viscosity = nodemgr->get(node.getContent()).liquid_viscosity;
+			const ContentFeatures &cf = nodemgr->get(node.getContent());
+			in_liquid = cf.liquid_move_physics;
+			move_resistance = cf.move_resistance;
 		} else {
 			in_liquid = false;
 		}
@@ -810,8 +813,9 @@ void LocalPlayer::old_move(f32 dtime, Environment *env, f32 pos_max_d,
 		pp = floatToInt(position + v3f(0.0f, BS * 0.5f, 0.0f), BS);
 		node = map->getNode(pp, &is_valid_position);
 		if (is_valid_position) {
-			in_liquid = nodemgr->get(node.getContent()).isLiquid();
-			liquid_viscosity = nodemgr->get(node.getContent()).liquid_viscosity;
+			const ContentFeatures &cf = nodemgr->get(node.getContent());
+			in_liquid = cf.liquid_move_physics;
+			move_resistance = cf.move_resistance;
 		} else {
 			in_liquid = false;
 		}
@@ -823,7 +827,7 @@ void LocalPlayer::old_move(f32 dtime, Environment *env, f32 pos_max_d,
 	pp = floatToInt(position + v3f(0.0f), BS);
 	node = map->getNode(pp, &is_valid_position);
 	if (is_valid_position)
-		in_liquid_stable = nodemgr->get(node.getContent()).isLiquid();
+		in_liquid_stable = nodemgr->get(node.getContent()).liquid_move_physics;
 	else
 		in_liquid_stable = false;
 
diff --git a/src/client/localplayer.h b/src/client/localplayer.h
index 345aec9d9..13b35ae4e 100644
--- a/src/client/localplayer.h
+++ b/src/client/localplayer.h
@@ -55,8 +55,8 @@ public:
 	bool in_liquid = false;
 	// This is more stable and defines the maximum speed of the player
 	bool in_liquid_stable = false;
-	// Gets the viscosity of water to calculate friction
-	u8 liquid_viscosity = 0;
+	// Slows down the player when moving through
+	u8 move_resistance = 0;
 	bool is_climbing = false;
 	bool swimming_vertical = false;
 	bool swimming_pitch = false;
diff --git a/src/nodedef.cpp b/src/nodedef.cpp
index db4043aa1..703df4dee 100644
--- a/src/nodedef.cpp
+++ b/src/nodedef.cpp
@@ -403,6 +403,8 @@ void ContentFeatures::reset()
 	palette_name = "";
 	palette = NULL;
 	node_dig_prediction = "air";
+	move_resistance = 0;
+	liquid_move_physics = false;
 }
 
 void ContentFeatures::setAlphaFromLegacy(u8 legacy_alpha)
@@ -512,9 +514,12 @@ void ContentFeatures::serialize(std::ostream &os, u16 protocol_version) const
 	writeU8(os, legacy_facedir_simple);
 	writeU8(os, legacy_wallmounted);
 
+	// new attributes
 	os << serializeString16(node_dig_prediction);
 	writeU8(os, leveled_max);
 	writeU8(os, alpha);
+	writeU8(os, move_resistance);
+	writeU8(os, liquid_move_physics);
 }
 
 void ContentFeatures::deSerialize(std::istream &is)
@@ -584,9 +589,11 @@ void ContentFeatures::deSerialize(std::istream &is)
 
 	// liquid
 	liquid_type = (enum LiquidType) readU8(is);
+	liquid_move_physics = liquid_type != LIQUID_NONE;
 	liquid_alternative_flowing = deSerializeString16(is);
 	liquid_alternative_source = deSerializeString16(is);
 	liquid_viscosity = readU8(is);
+	move_resistance = liquid_viscosity; // set default move_resistance
 	liquid_renewable = readU8(is);
 	liquid_range = readU8(is);
 	drowning = readU8(is);
@@ -618,6 +625,16 @@ void ContentFeatures::deSerialize(std::istream &is)
 		if (is.eof())
 			throw SerializationError("");
 		alpha = static_cast<enum AlphaMode>(tmp);
+
+		tmp = readU8(is);
+		if (is.eof())
+			throw SerializationError("");
+		move_resistance = tmp;
+
+		tmp = readU8(is);
+		if (is.eof())
+			throw SerializationError("");
+		liquid_move_physics = tmp;
 	} catch(SerializationError &e) {};
 }
 
diff --git a/src/nodedef.h b/src/nodedef.h
index 8a6d88071..ea50d4281 100644
--- a/src/nodedef.h
+++ b/src/nodedef.h
@@ -376,11 +376,15 @@ struct ContentFeatures
 	u32 damage_per_second;
 	// client dig prediction
 	std::string node_dig_prediction;
+	// how slow players move through
+	u8 move_resistance = 0;
 
 	// --- LIQUID PROPERTIES ---
 
 	// Whether the node is non-liquid, source liquid or flowing liquid
 	enum LiquidType liquid_type;
+	// If true, movement (e.g. of players) inside this node is liquid-like.
+	bool liquid_move_physics;
 	// If the content is liquid, this is the flowing version of the liquid.
 	std::string liquid_alternative_flowing;
 	content_t liquid_alternative_flowing_id;
diff --git a/src/script/common/c_content.cpp b/src/script/common/c_content.cpp
index 5a095fd8f..8a5a3fe71 100644
--- a/src/script/common/c_content.cpp
+++ b/src/script/common/c_content.cpp
@@ -719,6 +719,9 @@ void read_content_features(lua_State *L, ContentFeatures &f, int index)
 	// the slowest possible
 	f.liquid_viscosity = getintfield_default(L, index,
 			"liquid_viscosity", f.liquid_viscosity);
+	// If move_resistance is not set explicitly,
+	// move_resistance is equal to liquid_viscosity
+	f.move_resistance = f.liquid_viscosity;
 	f.liquid_range = getintfield_default(L, index,
 			"liquid_range", f.liquid_range);
 	f.leveled = getintfield_default(L, index, "leveled", f.leveled);
@@ -822,6 +825,21 @@ void read_content_features(lua_State *L, ContentFeatures &f, int index)
 	getstringfield(L, index, "node_dig_prediction",
 		f.node_dig_prediction);
 
+	// How much the node slows down players, ranging from 1 to 7,
+	// the higher, the slower.
+	f.move_resistance = getintfield_default(L, index,
+			"move_resistance", f.move_resistance);
+
+	// Whether e.g. players in this node will have liquid movement physics
+	lua_getfield(L, index, "liquid_move_physics");
+	if(lua_isboolean(L, -1)) {
+		f.liquid_move_physics = lua_toboolean(L, -1);
+	} else if(lua_isnil(L, -1)) {
+		f.liquid_move_physics = f.liquid_type != LIQUID_NONE;
+	} else {
+		errorstream << "Field \"liquid_move_physics\": Invalid type!" << std::endl;
+	}
+	lua_pop(L, 1);
 }
 
 void push_content_features(lua_State *L, const ContentFeatures &c)
@@ -949,6 +967,10 @@ void push_content_features(lua_State *L, const ContentFeatures &c)
 	lua_setfield(L, -2, "legacy_wallmounted");
 	lua_pushstring(L, c.node_dig_prediction.c_str());
 	lua_setfield(L, -2, "node_dig_prediction");
+	lua_pushnumber(L, c.move_resistance);
+	lua_setfield(L, -2, "move_resistance");
+	lua_pushboolean(L, c.liquid_move_physics);
+	lua_setfield(L, -2, "liquid_move_physics");
 }
 
 /******************************************************************************/
diff --git a/src/script/cpp_api/s_node.h b/src/script/cpp_api/s_node.h
index 3f771c838..3c6a8445b 100644
--- a/src/script/cpp_api/s_node.h
+++ b/src/script/cpp_api/s_node.h
@@ -53,6 +53,7 @@ public:
 	static struct EnumString es_ContentParamType[];
 	static struct EnumString es_ContentParamType2[];
 	static struct EnumString es_LiquidType[];
+	static struct EnumString es_LiquidMoveType[];
 	static struct EnumString es_NodeBoxType[];
 	static struct EnumString es_TextureAlphaMode[];
 };
diff --git a/src/script/lua_api/l_localplayer.cpp b/src/script/lua_api/l_localplayer.cpp
index 9f3569ecc..bdbe98cb0 100644
--- a/src/script/lua_api/l_localplayer.cpp
+++ b/src/script/lua_api/l_localplayer.cpp
@@ -128,11 +128,11 @@ int LuaLocalPlayer::l_is_in_liquid_stable(lua_State *L)
 	return 1;
 }
 
-int LuaLocalPlayer::l_get_liquid_viscosity(lua_State *L)
+int LuaLocalPlayer::l_get_move_resistance(lua_State *L)
 {
 	LocalPlayer *player = getobject(L, 1);
 
-	lua_pushinteger(L, player->liquid_viscosity);
+	lua_pushinteger(L, player->move_resistance);
 	return 1;
 }
 
@@ -466,7 +466,6 @@ const luaL_Reg LuaLocalPlayer::methods[] = {
 		luamethod(LuaLocalPlayer, is_touching_ground),
 		luamethod(LuaLocalPlayer, is_in_liquid),
 		luamethod(LuaLocalPlayer, is_in_liquid_stable),
-		luamethod(LuaLocalPlayer, get_liquid_viscosity),
 		luamethod(LuaLocalPlayer, is_climbing),
 		luamethod(LuaLocalPlayer, swimming_vertical),
 		luamethod(LuaLocalPlayer, get_physics_override),
@@ -488,5 +487,7 @@ const luaL_Reg LuaLocalPlayer::methods[] = {
 		luamethod(LuaLocalPlayer, hud_change),
 		luamethod(LuaLocalPlayer, hud_get),
 
+		luamethod(LuaLocalPlayer, get_move_resistance),
+
 		{0, 0}
 };
diff --git a/src/script/lua_api/l_localplayer.h b/src/script/lua_api/l_localplayer.h
index 4413f2bdb..041545a49 100644
--- a/src/script/lua_api/l_localplayer.h
+++ b/src/script/lua_api/l_localplayer.h
@@ -51,7 +51,6 @@ private:
 	static int l_is_touching_ground(lua_State *L);
 	static int l_is_in_liquid(lua_State *L);
 	static int l_is_in_liquid_stable(lua_State *L);
-	static int l_get_liquid_viscosity(lua_State *L);
 	static int l_is_climbing(lua_State *L);
 	static int l_swimming_vertical(lua_State *L);
 
@@ -96,6 +95,8 @@ private:
 	// hud_get(self, id)
 	static int l_hud_get(lua_State *L);
 
+	static int l_get_move_resistance(lua_State *L);
+
 	LocalPlayer *m_localplayer = nullptr;
 
 public: