Split liquid_viscosity to liquid_viscosity and move_resistance (#10810)

9 files changed, 89 insertions, 30 deletions

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: