From d264de084cde43ee84816a036457b08d6bcbba67 Mon Sep 17 00:00:00 2001
From: placki <f4meatball@gmail.com>
Date: Sat, 29 Oct 2011 00:14:40 +0200
Subject: [PATCH] crafted_teleports, teleport pairs/loops, working "0,0,0"

---
 minetest.conf.example   |   4 ++
 src/defaultsettings.cpp |   1 +
 src/player.cpp          |   5 +-
 src/player.h            |   2 +
 src/server.cpp          | 104 +++++++++++++++++++++++++++++++---------
 5 files changed, 92 insertions(+), 24 deletions(-)

diff --git a/minetest.conf.example b/minetest.conf.example
index 30adc5e..2cf4c6c 100644
--- a/minetest.conf.example
+++ b/minetest.conf.example
@@ -154,4 +154,8 @@
 # Set to true to enable experimental features or stuff that is tested
 # (varies from version to version, usually not useful at all)
 #enable_experimental = false
+# 0 - disables crafted teleports. 1 - teleport work if target area exists and there are 2 air/water (clear) tiles
+# 2 - teleport A works iff it points to clear area containing teleport B, and teleport B points back to teleport A
+# 3 or more - just like 2 but there can be 3 of more teleports in loop (warning - high value is bad for server performance)
+#crafted_teleports = 4
 
diff --git a/src/defaultsettings.cpp b/src/defaultsettings.cpp
index 7f0d46a..ccacd37 100644
--- a/src/defaultsettings.cpp
+++ b/src/defaultsettings.cpp
@@ -109,5 +109,6 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("server_map_save_interval", "10");
 	settings->setDefault("full_block_send_enable_min_time_from_building", "2.0");
 	settings->setDefault("enable_experimental", "false");
+	settings->setDefault("crafted_teleports", "4");
 }
 
diff --git a/src/player.cpp b/src/player.cpp
index e2d1f49..c104a8d 100644
--- a/src/player.cpp
+++ b/src/player.cpp
@@ -40,13 +40,14 @@ Player::Player():
 	craftresult_is_preview(true),
 	hp(20),
 	peer_id(PEER_ID_INEXISTENT),
+	clanOwner(0),
 	m_selected_item(0),
 	m_pitch(0),
 	m_yaw(0),
 	m_speed(0,0,0),
-	m_position(0,0,0),
-	clanOwner(0)
+	m_position(0,0,0)
 {
+	lastTeleportPos.X=FLT_MAX;
 	updateName("<not set>");
 	resetInventory();
 }
diff --git a/src/player.h b/src/player.h
index 7818853..ad89487 100644
--- a/src/player.h
+++ b/src/player.h
@@ -171,6 +171,8 @@ public:
 	std::set<int> clans;
 	u16 clanOwner;
 	bool canModify(const ClansManager* clansManager, Map* map, MapBlock* block, MapNode* node, v3s16* nodepos) const;
+	v3f lastTeleportPos;	//server: remember position player teleported to, to let him move away.
+
 
 protected:
 	char m_name[PLAYERNAME_SIZE];
diff --git a/src/server.cpp b/src/server.cpp
index 2239341..03b7161 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -1816,6 +1816,38 @@ void Server::Receive()
 	}
 }
 
+bool getTeleportTarget(/*const*/ ServerEnvironment *m_env,/*in+out*/ v3s16 &where,/*out*/v3f &tgt)
+{
+	// actionstream<<"Is Teleport at: "<<"("<<where.X<<","<<where.Y<<","<<where.Z<<")     "<<std::endl;
+	SignNodeMetadata* meta=NULL;
+	if(m_env->getMap().getNodeNoEx(where).getContent() == CONTENT_TELEPORT)
+		meta = (SignNodeMetadata*)m_env->getMap().getNodeMetadata(where);
+	else {
+		where.Y++;
+		if(where.Y<MAP_GENERATION_LIMIT-1)
+			if(m_env->getMap().getNodeNoEx(where).getContent() == CONTENT_TELEPORT)
+				meta = (SignNodeMetadata*)m_env->getMap().getNodeMetadata(where);
+	}
+
+	if(meta){
+		std::string text = meta->getText();
+		if(text == "")
+			return false;
+		str_replace_char(text,',',' ');
+		std::istringstream is(text);
+		is >> tgt.X >> tgt.Y >> tgt.Z;
+
+		if(	tgt.X >= MAP_GENERATION_LIMIT || tgt.X <= -MAP_GENERATION_LIMIT ||
+			tgt.Y >= MAP_GENERATION_LIMIT || tgt.Y <= -MAP_GENERATION_LIMIT ||
+			tgt.Z >= MAP_GENERATION_LIMIT || tgt.Z <= -MAP_GENERATION_LIMIT ||
+			( tgt.X == 0 && tgt.Y == 0 && tgt.Z == 0 && text.substr(0,5) != "0 0 0" )
+		) return false;
+		// actionstream<<"It points to: "<<"("<<tgt.X<<","<<tgt.Y<<","<<tgt.Z<<")     "<<std::endl;
+		return true;
+	}
+	return false;
+}
+
 void Server::ProcessData(u8 *data, u32 datasize, u16 peer_id)
 {
 	DSTACK(__FUNCTION_NAME);
@@ -2174,30 +2206,58 @@ void Server::ProcessData(u8 *data, u32 datasize, u16 peer_id)
 				<<"("<<position.X<<","<<position.Y<<","<<position.Z<<")"
 				<<" pitch="<<pitch<<" yaw="<<yaw<<std::endl;*/
 
-		//j
-		v3s16 pos = floatToInt(position, BS);
-		MapNode n = m_env.getMap().getNodeNoEx(pos);
-		if(n.getContent() == CONTENT_TELEPORT){
-			SignNodeMetadata* meta = (SignNodeMetadata*)m_env.getMap().getNodeMetadata(pos);
-			if(meta){
-				v3f t;
-				std::string text = meta->getText();
-				str_replace_char(text,',',' ');
-				std::istringstream is(text);
-				is >> t.X >> t.Y >> t.Z;
+		//j,placki
+		int teleport_option=g_settings->getU16("crafted_teleports");
+		if(teleport_option) {
+			v3s16 tele_posi = floatToInt(position, BS);
 
-				//TODO: map limits!
-				if(	t.X > 32000 || t.X < -32000 ||
-					t.Y > 32000 || t.Y < -32000 ||
-					t.Z > 32000 || t.Z < -32000 ||
-					(t.X == 0 && t.Y == 0 && t.Z == 0)
-				) return;
-
-				dout_server << "Teleporting: " << text << std::endl;
-				player->setPosition(t*BS);
-				SendMovePlayer(player);
+			if(player->lastTeleportPos.X != FLT_MAX){
+				if(player->getPosition().getDistanceFrom(player->lastTeleportPos) <= BS*3/2) //1 tile away
+					return; //allow player to leave teleport destination
+				else
+					player->lastTeleportPos.X=FLT_MAX;	//player left previous teleport destination
 			}
-		}
+
+			v3f tgtf;
+			if(getTeleportTarget(&m_env,tele_posi,tgtf)){
+				if(player->lastTeleportPos == tgtf*BS)
+					return;	//already checked... and failed, so skip checks.
+				player->lastTeleportPos=tgtf*BS;
+
+				// check: is there known and empty place to teleport to?
+				v3s16 tgti=floatToInt(tgtf, 1);
+				content_t c1,c2;
+				c1=m_env.getMap().getNodeNoEx(tgti).getContent();
+				tgti.Y++;
+				c2=m_env.getMap().getNodeNoEx(tgti).getContent();
+				if((c1==CONTENT_IGNORE)||(c2==CONTENT_IGNORE))	//teleporting to unknown space?
+					return;
+				if(content_features(c1).walkable || content_features(c2).walkable)
+					return;
+
+				if(teleport_option > 1){
+					tgti=floatToInt(tgtf, 1);
+					bool loop=false;
+					while(!loop && teleport_option>1)
+					{	//check if there is teleport at primary teleport target, and it loops back.
+						v3f tgtfnext;
+						if(getTeleportTarget(&m_env,tgti,tgtfnext)){
+							tgti=floatToInt(tgtfnext, 1);
+							loop=(tele_posi.getDistanceFrom(tgti)<=1);	// tile away
+							//actionstream<<" D:"<<tele_posi.getDistanceFrom(tgti)<<" from="<<"("<<tgtf.X<<","<<tgtf.Y<<","<<tgtf.Z<<")"<<
+							//"  to="<<"("<<tgtfnext.X<<","<<tgtfnext.Y<<","<<tgtfnext.Z<<")     "<< std::endl;
+						}	else return;	//no teleport at destination
+						teleport_option--;
+					}
+					if(!loop)
+						return;
+				}
+
+				dout_server << "Teleporting: " << tgtf.X << " " << tgtf.Y << " " << tgtf.Z << std::endl;
+				player->setPosition(tgtf*BS);
+				SendMovePlayer(player);
+			}	//teleport exists
+		}	//teleport_option
 	}
 	else if(command == TOSERVER_GOTBLOCKS)
 	{