Fix entity rotation in existing worlds (#7989)

diff --git a/src/content_sao.cpp b/src/content_sao.cpp
index f7b193768d0ca886b8e9642223ff91c1b9d6ee9f..cbe19138471aa190fb897261b5b1b6ea63608b50 100644 (file)
--- a/src/content_sao.cpp
+++ b/src/content_sao.cpp
@@ -350,26 +350,43 @@ ServerActiveObject* LuaEntitySAO::create(ServerEnvironment *env, v3f pos,
        s16 hp = 1;
        v3f velocity;
        v3f rotation;
-       if (!data.empty()) {
+
+       while (!data.empty()) { // breakable, run for one iteration
                std::istringstream is(data, std::ios::binary);
-               // read version
+               // 'version' does not allow to incrementally extend the parameter list thus
+               // we need another variable to build on top of 'version=1'. Ugly hack but works™
+               u8 version2 = 0;
                u8 version = readU8(is);
-               // check if version is supported
-               if(version == 0){
-                       name = deSerializeString(is);
-                       state = deSerializeLongString(is);
-               }
-               else if(version == 1){
-                       name = deSerializeString(is);
-                       state = deSerializeLongString(is);
-                       hp = readS16(is);
-                       velocity = readV3F1000(is);
-                       rotation = readV3F1000(is);
-               }
+
+               name = deSerializeString(is);
+               state = deSerializeLongString(is);
+
+               if (version < 1)
+                       break;
+
+               hp = readS16(is);
+               velocity = readV3F1000(is);
+               // yaw must be yaw to be backwards-compatible
+               rotation.Y = readF1000(is);
+
+               if (is.good()) // EOF for old formats
+                       version2 = readU8(is);
+
+               if (version2 < 1) // PROTOCOL_VERSION < 37
+                       break;
+
+               // version2 >= 1
+               rotation.X = readF1000(is);
+               rotation.Z = readF1000(is);
+
+               // if (version2 < 2)
+               //     break;
+               // <read new values>
+               break;
        }
        // create object
-       infostream<<"LuaEntitySAO::create(name=\""<<name<<"\" state=\""
-                       <<state<<"\")"<<std::endl;
+       infostream << "LuaEntitySAO::create(name=\"" << name << "\" state=\""
+                        << state << "\")" << std::endl;
        LuaEntitySAO *sao = new LuaEntitySAO(env, pos, name, state);
        sao->m_hp = hp;
        sao->m_velocity = velocity;
@@ -527,7 +544,7 @@ std::string LuaEntitySAO::getClientInitializationData(u16 protocol_version)
 {
        std::ostringstream os(std::ios::binary);
 
-       // protocol >= 14
+       // PROTOCOL_VERSION >= 37
        writeU8(os, 1); // version
        os << serializeString(""); // name
        writeU8(os, 0); // is_player
@@ -572,7 +589,7 @@ void LuaEntitySAO::getStaticData(std::string *result) const
 {
        verbosestream<<FUNCTION_NAME<<std::endl;
        std::ostringstream os(std::ios::binary);
-       // version
+       // version must be 1 to keep backwards-compatibility. See version2
        writeU8(os, 1);
        // name
        os<<serializeString(m_init_name);
@@ -584,12 +601,18 @@ void LuaEntitySAO::getStaticData(std::string *result) const
        } else {
                os<<serializeLongString(m_init_state);
        }
-       // hp
        writeS16(os, m_hp);
-       // velocity
        writeV3F1000(os, m_velocity);
-       // rotation
-       writeV3F1000(os, m_rotation);
+       // yaw
+       writeF1000(os, m_rotation.Y);
+
+       // version2. Increase this variable for new values
+       writeU8(os, 1); // PROTOCOL_VERSION >= 37
+
+       writeF1000(os, m_rotation.X);
+       writeF1000(os, m_rotation.Z);
+
+       // <write new values>
 
        *result = os.str();
 }