add support for entity linking

src/content_cao_lua.cpp

@@ -19,8 +19,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <list>
 #include "content_cao.h"
 #include "luaentity_common.h"
+#include "clientlinkableobject.h"
 
-class LuaEntityCAO : public ClientActiveObject
+class LuaEntityCAO : public ClientActiveObject, public ClientLinkableObject
 {
 private:
 	core::aabbox3d<f32> m_selection_box;
@@ -223,6 +224,8 @@ public:
 
 	void step(float dtime, ClientEnvironment *env)
 	{
+		//if liked movement is handled by parent entity
+		if(!this->isLinked()) {
 			if(m_prop->physical){
 				core::aabbox3d<f32> box = m_prop->collisionbox;
 				box.MinEdge *= BS;
@@ -251,6 +254,9 @@ public:
 				pos_translator.translate(dtime);
 				updateNodePos();
 			}
+		}
+
+		stepLinkedObjects(this->m_position,dtime);
 
 		m_anim_timer += dtime;
 		if(m_anim_timer >= m_anim_framelength){
@@ -397,7 +403,23 @@ public:
 
 			updateTexturePos();
 		}
+		else if (handleLinkUnlinkMessages(cmd,&is,this->m_env))
+		{
+			//Link unlink already done in handleLinkUnlinkMessages!
 		}
+	}
+
+	void setPosition(v3f toset, float dtime){
+		if (this->isLinked()) {
+			this->m_position = toset + this->m_linkOffset;
+
+			pos_translator.update(m_position, pos_translator.aim_is_end, pos_translator.anim_time);
+			pos_translator.translate(dtime);
+			updateNodePos();
+		}
+	}
+
+	void updateLinkState(bool value) {}
 };
 
 // Prototype

src/content_sao_lua.cpp

@@ -319,5 +319,26 @@ void LuaEntitySAO::sendPosition(bool do_interpolate, bool is_movement_end)
 	m_messages_out.push_back(aom);
 }
 
+bool LuaEntitySAO::sendLinkMsg(ServerActiveObject* parent,v3f offset) {
+	std::ostringstream os(std::ios::binary);
+	writeU8(os, AO_Message_type::Link);
+	// parameters
+	writeU16(os, parent->getId());
+	writeV3F1000(os, offset);
+	// create message and add to list
+	ActiveObjectMessage aom(getId(), false, os.str());
+	m_messages_out.push_back(aom);
+	return true;
+}
+
+bool LuaEntitySAO::sendUnlinkMsg() {
+	std::ostringstream os(std::ios::binary);
+	writeU8(os, AO_Message_type::UnLink);
+	// create message and add to list
+	ActiveObjectMessage aom(getId(), false, os.str());
+	m_messages_out.push_back(aom);
+	return true;
+}
+
 // Prototype
 LuaEntitySAO proto_LuaEntitySAO(NULL, v3f(0,0,0), "_prototype", "");

src/content_sao_lua.h

@@ -25,7 +25,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "scriptapi.h"
 #include "luaentity_common.h"
 
-class LuaEntitySAO : public ServerActiveObject
+class LuaEntitySAO : public ServerActiveObject, public ServerLinkableObject
 {
 public:
 	LuaEntitySAO(ServerEnvironment *env, v3f pos,
@@ -55,6 +55,8 @@ public:
 	void setSprite(v2s16 p, int num_frames, float framelength,
 			bool select_horiz_by_yawpitch);
 	std::string getName();
+	bool sendLinkMsg(ServerActiveObject* parent,v3f offset);
+	bool sendUnlinkMsg();
 
 private:
 	void sendPosition(bool do_interpolate, bool is_movement_end);