Slippery physics override setting

Allows mods to change a player's slip factor (e.g. wearing boots could
reduce this)

Note: Require assistance on implementing needed changed protocol version
check in I_object!

src/content_cao.cpp

@@ -1661,6 +1661,8 @@ void GenericCAO::processMessage(const std::string &data)
 		float override_speed = readF1000(is);
 		float override_jump = readF1000(is);
 		float override_gravity = readF1000(is);
+///TODO: detect protocol VERSION!
+		float override_slip = readF1000(is);
 		// these are sent inverted so we get true when the server sends nothing
 		bool sneak = !readU8(is);
 		bool sneak_glitch = !readU8(is);
@@ -1672,6 +1674,7 @@ void GenericCAO::processMessage(const std::string &data)
 			player->physics_override_speed = override_speed;
 			player->physics_override_jump = override_jump;
 			player->physics_override_gravity = override_gravity;
+			player->physics_override_slip = override_slip;
 			player->physics_override_sneak = sneak;
 			player->physics_override_sneak_glitch = sneak_glitch;
 		}

src/content_sao.cpp

@@ -773,6 +773,7 @@ PlayerSAO::PlayerSAO(ServerEnvironment *env_, Player *player_, u16 peer_id_,
 	m_physics_override_speed(1),
 	m_physics_override_jump(1),
 	m_physics_override_gravity(1),
+	m_physics_override_slip(1),
 	m_physics_override_sneak(true),
 	m_physics_override_sneak_glitch(true),
 	m_physics_override_sent(false)
@@ -865,7 +866,7 @@ std::string PlayerSAO::getClientInitializationData(u16 protocol_version)
 		}
 		os<<serializeLongString(gob_cmd_update_attachment(m_attachment_parent_id, m_attachment_bone, m_attachment_position, m_attachment_rotation)); // 4
 		os<<serializeLongString(gob_cmd_update_physics_override(m_physics_override_speed,
-				m_physics_override_jump, m_physics_override_gravity, m_physics_override_sneak,
+				m_physics_override_jump, m_physics_override_gravity, m_physics_override_slip, m_physics_override_sneak,
 				m_physics_override_sneak_glitch)); // 5
 		os << serializeLongString(gob_cmd_update_nametag_attributes(m_prop.nametag_color)); // 6 (GENERIC_CMD_UPDATE_NAMETAG_ATTRIBUTES) : Deprecated, for backwards compatibility only.
 	}
@@ -989,7 +990,7 @@ void PlayerSAO::step(float dtime, bool send_recommended)
 	if(m_physics_override_sent == false){
 		m_physics_override_sent = true;
 		std::string str = gob_cmd_update_physics_override(m_physics_override_speed,
-				m_physics_override_jump, m_physics_override_gravity,
+				m_physics_override_jump, m_physics_override_gravity, m_physics_override_slip,
 				m_physics_override_sneak, m_physics_override_sneak_glitch);
 		// create message and add to list
 		ActiveObjectMessage aom(getId(), true, str);

src/content_sao.h

@@ -336,6 +336,7 @@ public:
 	float m_physics_override_speed;
 	float m_physics_override_jump;
 	float m_physics_override_gravity;
+	float m_physics_override_slip;
 	bool m_physics_override_sneak;
 	bool m_physics_override_sneak_glitch;
 	bool m_physics_override_sent;

src/genericobject.cpp

@@ -118,7 +118,7 @@ std::string gob_cmd_update_armor_groups(const ItemGroupList &armor_groups)
 }
 
 std::string gob_cmd_update_physics_override(float physics_override_speed, float physics_override_jump,
-		float physics_override_gravity, bool sneak, bool sneak_glitch)
+		float physics_override_gravity, float physics_override_slip, bool sneak, bool sneak_glitch)
 {
 	std::ostringstream os(std::ios::binary);
 	// command 
@@ -127,6 +127,7 @@ std::string gob_cmd_update_physics_override(float physics_override_speed, float
 	writeF1000(os, physics_override_speed);
 	writeF1000(os, physics_override_jump);
 	writeF1000(os, physics_override_gravity);
+	writeF1000(os, physics_override_slip);
 	// these are sent inverted so we get true when the server sends nothing
 	writeU8(os, !sneak);
 	writeU8(os, !sneak_glitch);

src/genericobject.h

@@ -67,7 +67,7 @@ std::string gob_cmd_punched(s16 damage, s16 result_hp);
 std::string gob_cmd_update_armor_groups(const ItemGroupList &armor_groups);
 
 std::string gob_cmd_update_physics_override(float physics_override_speed,
-		float physics_override_jump, float physics_override_gravity, bool sneak, bool sneak_glitch);
+		float physics_override_jump, float physics_override_gravity, float physics_override_slip, bool sneak, bool sneak_glitch);
 
 std::string gob_cmd_update_animation(v2f frames, float frame_speed, float frame_blend, bool frame_loop);
 

src/localplayer.cpp

@@ -610,19 +610,25 @@ void LocalPlayer::applyControl(float dtime, Environment *env)
 	else
 		incH = incV = movement_acceleration_default * BS * dtime;
 
-	// Accelerate to target speed with maximum increment
+	int slippery;
+	if (!free_move && !control.sneak && !is_climbing)
+	{
 	INodeDefManager *nodemgr = m_gamedef->ndef();
 	Map *map = &env->getMap();
-	v3s16 p = floatToInt(getPosition() - v3f(0,BS/2,0), BS);
+		v3s16 position = floatToInt(getPosition() - v3f(0,BS/2,0), BS);
-	ContentFeatures node = nodemgr->get(map->getNodeNoEx(p));
+		ContentFeatures node = nodemgr->get(map->getNodeNoEx(position));
-	int slippery = itemgroup_get(node.groups, "slippery");
-	// Sliding onto a non-walkable node, set a default to allow sliding off edges
-	if (slippery==0 && node.walkable==false && !free_move && !is_climbing && !control.sneak)
-	{
-		slippery = 10;
-	}
 
-	accelerateHorizontal(speedH * physics_override_speed, incH * physics_override_speed, slippery);
+		slippery = itemgroup_get(node.groups, "slippery");
+
+		// Sliding onto a non-walkable node that you should fall through?
+		if (slippery==0 && !node.walkable)
+			slippery = 100; // override to allow sliding off edges into
+	}
+	else
+		slippery = 0;
+
+	// Accelerate to target speed with maximum increment
+	accelerateHorizontal(speedH * physics_override_speed, incH * physics_override_speed, slippery * physics_override_slip);
 	accelerateVertical(speedV * physics_override_speed, incV * physics_override_speed);
 }
 

src/network/networkprotocol.h

@@ -132,9 +132,11 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 		Rename GENERIC_CMD_SET_ATTACHMENT to GENERIC_CMD_ATTACH_TO
 	PROTOCOL_VERSION 26:
 		Add TileDef tileable_horizontal, tileable_vertical flags
+	PROTOCOL_VERSION 27:
+		Add physics_override_slip
 */
 
-#define LATEST_PROTOCOL_VERSION 26
+#define LATEST_PROTOCOL_VERSION 27
 
 // Server's supported network protocol range
 #define SERVER_PROTOCOL_VERSION_MIN 13

src/player.cpp

@@ -95,6 +95,7 @@ Player::Player(IGameDef *gamedef, const char *name):
 	physics_override_speed        = 1;
 	physics_override_jump         = 1;
 	physics_override_gravity      = 1;
+	physics_override_slip		  = 1;
 	physics_override_sneak        = true;
 	physics_override_sneak_glitch = true;
 
@@ -121,9 +122,9 @@ void Player::accelerateHorizontal(v3f target_speed, f32 max_increase, int slippe
 	if (slippery)
 	{
 		if (target_speed == v3f(0))
-			d_wanted = -m_speed*.5/slippery;
+			d_wanted = -m_speed * 5 / slippery;
 		else
-			d_wanted = target_speed*.1 - m_speed*.1;
+			d_wanted = target_speed * .1 - m_speed * .1;
 	}
 	d_wanted.Y = 0;
 	f32 dl = d_wanted.getLength();

src/player.h

@@ -352,6 +352,7 @@ public:
 	float physics_override_speed;
 	float physics_override_jump;
 	float physics_override_gravity;
+	float physics_override_slip;
 	bool physics_override_sneak;
 	bool physics_override_sneak_glitch;
 

src/script/lua_api/l_object.cpp

@@ -401,7 +401,7 @@ int ObjectRef::l_get_armor_groups(lua_State *L)
 }
 
 // set_physics_override(self, physics_override_speed, physics_override_jump,
-//                      physics_override_gravity, sneak, sneak_glitch)
+//                      physics_override_gravity, physics_override_slip, sneak, sneak_glitch)
 int ObjectRef::l_set_physics_override(lua_State *L)
 {
 	NO_MAP_LOCK_REQUIRED;
@@ -413,6 +413,7 @@ int ObjectRef::l_set_physics_override(lua_State *L)
 		co->m_physics_override_speed = getfloatfield_default(L, 2, "speed", co->m_physics_override_speed);
 		co->m_physics_override_jump = getfloatfield_default(L, 2, "jump", co->m_physics_override_jump);
 		co->m_physics_override_gravity = getfloatfield_default(L, 2, "gravity", co->m_physics_override_gravity);
+		co->m_physics_override_slip = getfloatfield_default(L, 2, "slip", co->m_physics_override_slip);
 		co->m_physics_override_sneak = getboolfield_default(L, 2, "sneak", co->m_physics_override_sneak);
 		co->m_physics_override_sneak_glitch = getboolfield_default(L, 2, "sneak_glitch", co->m_physics_override_sneak_glitch);
 		co->m_physics_override_sent = false;
@@ -450,6 +451,8 @@ int ObjectRef::l_get_physics_override(lua_State *L)
 	lua_setfield(L, -2, "jump");
 	lua_pushnumber(L, co->m_physics_override_gravity);
 	lua_setfield(L, -2, "gravity");
+	lua_pushnumber(L, co->m_physics_override_slip);
+	lua_setfield(L, -2, "slip");
 	lua_pushboolean(L, co->m_physics_override_sneak);
 	lua_setfield(L, -2, "sneak");
 	lua_pushboolean(L, co->m_physics_override_sneak_glitch);

src/script/lua_api/l_object.h

@@ -105,7 +105,7 @@ private:
 	static int l_get_armor_groups(lua_State *L);
 
 	// set_physics_override(self, physics_override_speed, physics_override_jump,
-	//                      physics_override_gravity, sneak, sneak_glitch)
+	//                      physics_override_gravity, physics_override_slip, sneak, sneak_glitch)
 	static int l_set_physics_override(lua_State *L);
 
 	// get_physics_override(self)

src/serverobject.h

@@ -149,7 +149,7 @@ public:
 	{}
 	virtual ItemGroupList getArmorGroups()
 	{ return ItemGroupList(); }
-	virtual void setPhysicsOverride(float physics_override_speed, float physics_override_jump, float physics_override_gravity)
+	virtual void setPhysicsOverride(float physics_override_speed, float physics_override_jump, float physics_override_gravity, float physics_override_slip)
 	{}
 	virtual void setAnimation(v2f frames, float frame_speed, float frame_blend, bool frame_loop)
 	{}