Complete the attachment framework.

The child ID can now be checked against the parent ID in content_cao.cpp so the parent can be detected. Actual attachment code to come

Divide attachment system between server attachments and client attachments, neither coded right now. As explained in the code comment:

// Attachments need to be handled on both the server and client.
// If we attach only on the server, models (which are client-side)
// can't be read so we don't know the origin and orientation of bones.
// If we attach only on the client, the real position of attachments is
// not updated and you can't click them for example.

1 files changed, 146 insertions, 82 deletions

diff --git a/src/content_sao.cpp b/src/content_sao.cpp
index b23d287f4..7787e33fb 100644
--- a/src/content_sao.cpp
+++ b/src/content_sao.cpp
@@ -218,6 +218,7 @@ public:
 
 		if(pos_f.getDistanceFrom(m_last_sent_position) > 0.05*BS)
 		{
+			// TODO: We shouldn't be sending this when the object is attached, but we can't check m_parent here
 			setBasePosition(pos_f);
 			m_last_sent_position = pos_f;
 
@@ -383,6 +384,7 @@ void LuaEntitySAO::addedToEnvironment(u32 dtime_s)
 	// Create entity from name
 	lua_State *L = m_env->getLua();
 	m_registered = scriptapi_luaentity_add(L, m_id, m_init_name.c_str());
+	m_parent = NULL;
 	
 	if(m_registered){
 		// Get properties
@@ -442,28 +444,39 @@ void LuaEntitySAO::step(float dtime, bool send_recommended)
 
 	m_last_sent_position_timer += dtime;
 	
-	if(m_prop.physical){
-		core::aabbox3d<f32> box = m_prop.collisionbox;
-		box.MinEdge *= BS;
-		box.MaxEdge *= BS;
-		collisionMoveResult moveresult;
-		f32 pos_max_d = BS*0.25; // Distance per iteration
-		f32 stepheight = 0; // Maximum climbable step height
-		v3f p_pos = m_base_position;
-		v3f p_velocity = m_velocity;
-		v3f p_acceleration = m_acceleration;
-		IGameDef *gamedef = m_env->getGameDef();
-		moveresult = collisionMoveSimple(&m_env->getMap(), gamedef,
-				pos_max_d, box, stepheight, dtime,
-				p_pos, p_velocity, p_acceleration);
-		// Apply results
-		m_base_position = p_pos;
-		m_velocity = p_velocity;
-		m_acceleration = p_acceleration;
-	} else {
-		m_base_position += dtime * m_velocity + 0.5 * dtime
-				* dtime * m_acceleration;
-		m_velocity += dtime * m_acceleration;
+	if(m_parent != NULL)
+	{
+		// REMAINING ATTACHMENT ISSUES:
+		// This is causing a segmentation fault, investigate why!
+		//m_base_position = m_parent->getBasePosition();
+		m_velocity = v3f(0,0,0);
+		m_acceleration = v3f(0,0,0);
+	}
+	else
+	{
+		if(m_prop.physical){
+			core::aabbox3d<f32> box = m_prop.collisionbox;
+			box.MinEdge *= BS;
+			box.MaxEdge *= BS;
+			collisionMoveResult moveresult;
+			f32 pos_max_d = BS*0.25; // Distance per iteration
+			f32 stepheight = 0; // Maximum climbable step height
+			v3f p_pos = m_base_position;
+			v3f p_velocity = m_velocity;
+			v3f p_acceleration = m_acceleration;
+			IGameDef *gamedef = m_env->getGameDef();
+			moveresult = collisionMoveSimple(&m_env->getMap(), gamedef,
+					pos_max_d, box, stepheight, dtime,
+					p_pos, p_velocity, p_acceleration);
+			// Apply results
+			m_base_position = p_pos;
+			m_velocity = p_velocity;
+			m_acceleration = p_acceleration;
+		} else {
+			m_base_position += dtime * m_velocity + 0.5 * dtime
+					* dtime * m_acceleration;
+			m_velocity += dtime * m_acceleration;
+		}
 	}
 
 	if(m_registered){
@@ -551,6 +564,10 @@ int LuaEntitySAO::punch(v3f dir,
 		m_removed = true;
 		return 0;
 	}
+
+	// It's best that attachments cannot be punched 
+	if(m_parent != NULL)
+		return 0;
 	
 	ItemStack *punchitem = NULL;
 	ItemStack punchitem_static;
@@ -601,12 +618,16 @@ void LuaEntitySAO::rightClick(ServerActiveObject *clicker)
 
 void LuaEntitySAO::setPos(v3f pos)
 {
+	if(m_parent != NULL)
+		return;
 	m_base_position = pos;
 	sendPosition(false, true);
 }
 
 void LuaEntitySAO::moveTo(v3f pos, bool continuous)
 {
+	if(m_parent != NULL)
+		return;
 	m_base_position = pos;
 	if(!continuous)
 		sendPosition(true, true);
@@ -661,14 +682,21 @@ void LuaEntitySAO::setBonePosRot(std::string bone, v3f position, v3f rotation)
 	m_messages_out.push_back(aom);
 }
 
-// Part of the attachment structure, not used yet!
 void LuaEntitySAO::setAttachment(ServerActiveObject *parent, std::string bone, v3f position, v3f rotation)
 {
-	// Parent should be translated from a ServerActiveObject into something
-	// the client will recognize (as a ClientActiveObject) then sent in
-	// gob_cmd_set_attachment that way.
+	// Attachments need to be handled on both the server and client.
+	// If we just attach on the server, we can only copy the position of the parent. Attachments
+	// are still sent to clients at an interval so players would see them following the parent
+	// instead of sticking to it, plus we can't read and attach to skeletal bones.
+	// If we just attach on the client, the server still sees the child at its original location.
+	// This can break some things, so we also give the server the most accurate representation
+	// even if players will only see the client changes since they override server-sent position.
 
-	std::string str = gob_cmd_set_attachment(); // <- parameters here
+	// Server attachment:
+	m_parent = parent;
+
+	// Client attachment:
+	std::string str = gob_cmd_set_attachment(parent->getId(), bone, position, rotation);
 	// create message and add to list
 	ActiveObjectMessage aom(getId(), true, str);
 	m_messages_out.push_back(aom);
@@ -748,6 +776,9 @@ std::string LuaEntitySAO::getPropertyPacket()
 
 void LuaEntitySAO::sendPosition(bool do_interpolate, bool is_movement_end)
 {
+	if(m_parent != NULL)
+		return;
+	
 	m_last_sent_move_precision = m_base_position.getDistanceFrom(
 			m_last_sent_position);
 	m_last_sent_position_timer = 0;
@@ -843,6 +874,7 @@ void PlayerSAO::addedToEnvironment(u32 dtime_s)
 {
 	ServerActiveObject::addedToEnvironment(dtime_s);
 	ServerActiveObject::setBasePosition(m_player->getPosition());
+	m_parent = NULL;
 	m_player->setPlayerSAO(this);
 	m_player->peer_id = m_peer_id;
 	m_last_good_position = m_player->getPosition();
@@ -893,7 +925,7 @@ std::string PlayerSAO::getStaticData()
 }
 
 void PlayerSAO::step(float dtime, bool send_recommended)
-{
+{	
 	if(!m_properties_sent)
 	{
 		m_properties_sent = true;
@@ -905,71 +937,82 @@ void PlayerSAO::step(float dtime, bool send_recommended)
 
 	m_time_from_last_punch += dtime;
 	m_nocheat_dig_time += dtime;
-	
-	if(m_is_singleplayer || g_settings->getBool("disable_anticheat"))
-	{
-		m_last_good_position = m_player->getPosition();
-		m_last_good_position_age = 0;
-	}
-	else
+
+	if(m_parent == NULL)
 	{
-		/*
-			Check player movements
-
-			NOTE: Actually the server should handle player physics like the
-			client does and compare player's position to what is calculated
-			on our side. This is required when eg. players fly due to an
-			explosion. Altough a node-based alternative might be possible
-			too, and much more lightweight.
-		*/
-
-		float player_max_speed = 0;
-		float player_max_speed_up = 0;
-		if(m_privs.count("fast") != 0){
-			// Fast speed
-			player_max_speed = BS * 20;
-			player_max_speed_up = BS * 20;
-		} else {
-			// Normal speed
-			player_max_speed = BS * 4.0;
-			player_max_speed_up = BS * 4.0;
+		if(m_is_singleplayer || g_settings->getBool("disable_anticheat"))
+		{
+			m_last_good_position = m_player->getPosition();
+			m_last_good_position_age = 0;
 		}
-		// Tolerance
-		player_max_speed *= 2.5;
-		player_max_speed_up *= 2.5;
-
-		m_last_good_position_age += dtime;
-		if(m_last_good_position_age >= 1.0){
-			float age = m_last_good_position_age;
-			v3f diff = (m_player->getPosition() - m_last_good_position);
-			float d_vert = diff.Y;
-			diff.Y = 0;
-			float d_horiz = diff.getLength();
-			/*infostream<<m_player->getName()<<"'s horizontal speed is "
-					<<(d_horiz/age)<<std::endl;*/
-			if(d_horiz <= age * player_max_speed &&
-					(d_vert < 0 || d_vert < age * player_max_speed_up)){
-				m_last_good_position = m_player->getPosition();
+		else
+		{
+			/*
+				Check player movements
+
+				NOTE: Actually the server should handle player physics like the
+				client does and compare player's position to what is calculated
+				on our side. This is required when eg. players fly due to an
+				explosion. Altough a node-based alternative might be possible
+				too, and much more lightweight.
+			*/
+
+			float player_max_speed = 0;
+			float player_max_speed_up = 0;
+			if(m_privs.count("fast") != 0){
+				// Fast speed
+				player_max_speed = BS * 20;
+				player_max_speed_up = BS * 20;
 			} else {
-				actionstream<<"Player "<<m_player->getName()
-						<<" moved too fast; resetting position"
-						<<std::endl;
-				m_player->setPosition(m_last_good_position);
-				m_teleported = true;
+				// Normal speed
+				player_max_speed = BS * 4.0;
+				player_max_speed_up = BS * 4.0;
+			}
+			// Tolerance
+			player_max_speed *= 2.5;
+			player_max_speed_up *= 2.5;
+
+			m_last_good_position_age += dtime;
+			if(m_last_good_position_age >= 1.0){
+				float age = m_last_good_position_age;
+				v3f diff = (m_player->getPosition() - m_last_good_position);
+				float d_vert = diff.Y;
+				diff.Y = 0;
+				float d_horiz = diff.getLength();
+				/*infostream<<m_player->getName()<<"'s horizontal speed is "
+						<<(d_horiz/age)<<std::endl;*/
+				if(d_horiz <= age * player_max_speed &&
+						(d_vert < 0 || d_vert < age * player_max_speed_up)){
+					m_last_good_position = m_player->getPosition();
+				} else {
+					actionstream<<"Player "<<m_player->getName()
+							<<" moved too fast; resetting position"
+							<<std::endl;
+					m_player->setPosition(m_last_good_position);
+					m_teleported = true;
+				}
+				m_last_good_position_age = 0;
 			}
-			m_last_good_position_age = 0;
 		}
 	}
 
 	if(send_recommended == false)
 		return;
 
-	if(m_position_not_sent)
+	// If the object is attached client-side, don't waste bandwidth and send its position to clients
+	if(m_position_not_sent && m_parent == NULL)
 	{
 		m_position_not_sent = false;
 		float update_interval = m_env->getSendRecommendedInterval();
+		v3f pos;
+		// REMAINING ATTACHMENT ISSUES:
+		// This is causing a segmentation fault, investigate why!
+		if(m_parent != NULL)
+			pos = m_parent->getBasePosition();
+		else
+			pos = m_player->getPosition() + v3f(0,BS*1,0);
 		std::string str = gob_cmd_update_position(
-			m_player->getPosition() + v3f(0,BS*1,0),
+			pos,
 			v3f(0,0,0),
 			v3f(0,0,0),
 			m_player->getYaw(),
@@ -1000,12 +1043,16 @@ void PlayerSAO::step(float dtime, bool send_recommended)
 
 void PlayerSAO::setBasePosition(const v3f &position)
 {
+	if(m_parent != NULL)
+		return;
 	ServerActiveObject::setBasePosition(position);
 	m_position_not_sent = true;
 }
 
 void PlayerSAO::setPos(v3f pos)
 {
+	if(m_parent != NULL)
+		return;
 	m_player->setPosition(pos);
 	// Movement caused by this command is always valid
 	m_last_good_position = pos;
@@ -1016,6 +1063,8 @@ void PlayerSAO::setPos(v3f pos)
 
 void PlayerSAO::moveTo(v3f pos, bool continuous)
 {
+	if(m_parent != NULL)
+		return;
 	m_player->setPosition(pos);
 	// Movement caused by this command is always valid
 	m_last_good_position = pos;
@@ -1029,6 +1078,10 @@ int PlayerSAO::punch(v3f dir,
 	ServerActiveObject *puncher,
 	float time_from_last_punch)
 {
+	// It's best that attachments cannot be punched 
+	if(m_parent != NULL)
+		return 0;
+
 	if(!toolcap)
 		return 0;
 
@@ -1126,10 +1179,21 @@ void PlayerSAO::setBonePosRot(std::string bone, v3f position, v3f rotation)
 	m_messages_out.push_back(aom);
 }
 
-// Part of the attachment structure, not used yet!
 void PlayerSAO::setAttachment(ServerActiveObject *parent, std::string bone, v3f position, v3f rotation)
-{	
-	std::string str = gob_cmd_set_attachment(); // <- parameters here
+{
+	// Attachments need to be handled on both the server and client.
+	// If we just attach on the server, we can only copy the position of the parent. Attachments
+	// are still sent to clients at an interval so players would see them following the parent
+	// instead of sticking to it, plus we can't read and attach to skeletal bones.
+	// If we just attach on the client, the server still sees the child at its original location.
+	// This can break some things, so we also give the server the most accurate representation
+	// even if players will only see the client changes since they override server-sent position.
+
+	// Server attachment:
+	m_parent = parent;
+
+	// Client attachment:
+	std::string str = gob_cmd_set_attachment(parent->getId(), bone, position, rotation);
 	// create message and add to list
 	ActiveObjectMessage aom(getId(), true, str);
 	m_messages_out.push_back(aom);