Particle spawner: Fix missing parameters

The changes done to clientpackethandler.cpp and server.cpp move the
compatibility code into a protocol version check so that older code
parts can easily be removed in the future (e.g. bump of minimal version).

src/network/clientpackethandler.cpp

@@ -994,14 +994,22 @@ void Client::handleCommand_AddParticleSpawner(NetworkPacket* pkt)
 	p.amount             = readU16(is);
 	p.time               = readF32(is);
 
-	// older protocols do not support tweening, and send only
-	// static ranges, so we can't just use the normal serialization
-	// functions for the older values.
-	p.pos.start.legacyDeSerialize(is);
-	p.vel.start.legacyDeSerialize(is);
-	p.acc.start.legacyDeSerialize(is);
-	p.exptime.start.legacyDeSerialize(is);
-	p.size.start.legacyDeSerialize(is);
+	bool missing_end_values = false;
+	if (m_proto_ver >= 42) {
+		// All tweenable parameters
+		p.pos.deSerialize(is);
+		p.vel.deSerialize(is);
+		p.acc.deSerialize(is);
+		p.exptime.deSerialize(is);
+		p.size.deSerialize(is);
+	} else {
+		p.pos.start.legacyDeSerialize(is);
+		p.vel.start.legacyDeSerialize(is);
+		p.acc.start.legacyDeSerialize(is);
+		p.exptime.start.legacyDeSerialize(is);
+		p.size.start.legacyDeSerialize(is);
+		missing_end_values = true;
+	}
 
 	p.collisiondetection = readU8(is);
 	p.texture.string     = deSerializeString32(is);
@@ -1017,8 +1025,6 @@ void Client::handleCommand_AddParticleSpawner(NetworkPacket* pkt)
 	p.glow = readU8(is);
 	p.object_collision = readU8(is);
 
-	bool legacy_format = true;
-
 	// This is kinda awful
 	do {
 		u16 tmp_param0 = readU16(is);
@@ -1028,25 +1034,30 @@ void Client::handleCommand_AddParticleSpawner(NetworkPacket* pkt)
 		p.node.param2 = readU8(is);
 		p.node_tile   = readU8(is);
 
-		// v >= 5.6.0
-		f32 tmp_sbias = readF32(is);
-		if (is.eof())
-			break;
+		if (m_proto_ver < 42) {
+			// v >= 5.6.0
+			f32 tmp_sbias = readF32(is);
+			if (is.eof())
+				break;
 
-		// initial bias must be stored separately in the stream to preserve
-		// backwards compatibility with older clients, which do not support
-		// a bias field in their range "format"
-		p.pos.start.bias = tmp_sbias;
-		p.vel.start.bias = readF32(is);
-		p.acc.start.bias = readF32(is);
-		p.exptime.start.bias = readF32(is);
-		p.size.start.bias = readF32(is);
+			// initial bias must be stored separately in the stream to preserve
+			// backwards compatibility with older clients, which do not support
+			// a bias field in their range "format"
+			p.pos.start.bias = tmp_sbias;
+			p.vel.start.bias = readF32(is);
+			p.acc.start.bias = readF32(is);
+			p.exptime.start.bias = readF32(is);
+			p.size.start.bias = readF32(is);
 
-		p.pos.end.deSerialize(is);
-		p.vel.end.deSerialize(is);
-		p.acc.end.deSerialize(is);
-		p.exptime.end.deSerialize(is);
-		p.size.end.deSerialize(is);
+			p.pos.end.deSerialize(is);
+			p.vel.end.deSerialize(is);
+			p.acc.end.deSerialize(is);
+			p.exptime.end.deSerialize(is);
+			p.size.end.deSerialize(is);
+
+			missing_end_values = false;
+		}
+		// else: fields are already read by deSerialize() very early
 
 		// properties for legacy texture field
 		p.texture.deSerialize(is, m_proto_ver, true);
@@ -1077,11 +1088,9 @@ void Client::handleCommand_AddParticleSpawner(NetworkPacket* pkt)
 			newtex.deSerialize(is, m_proto_ver);
 			p.texpool.push_back(newtex);
 		}
-
-		legacy_format = false;
 	} while(0);
 
-	if (legacy_format) {
+	if (missing_end_values) {
 		// there's no tweening data to be had, so we need to set the
 		// legacy params to constant values, otherwise everything old
 		// will tween to zero

src/network/networkprotocol.h

@@ -213,6 +213,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 	PROTOCOL VERSION 42:
 		TOSERVER_UPDATE_CLIENT_INFO added
 		new fields for TOCLIENT_SET_LIGHTING and TOCLIENT_SET_SKY
+		Send forgotten TweenedParameter properties
 		[scheduled bump for 5.7.0]
 */
 
@@ -538,20 +539,33 @@ enum ToClientCommand
 
 	TOCLIENT_ADD_PARTICLESPAWNER = 0x47,
 	/*
-		-- struct range<T> { T min, T max, f32 bias };
-		-- struct tween<T> { T start, T end };
+		using range<T> = RangedParameter<T> {
+			T min, max
+			f32 bias
+		}
+		using tween<T> = TweenedParameter<T> {
+			u8 style
+			u16 reps
+			f32 beginning
+			T start, end
+		}
+
 		u16 amount
 		f32 spawntime
-		v3f minpos
-		v3f maxpos
-		v3f minvel
-		v3f maxvel
-		v3f minacc
-		v3f maxacc
-		f32 minexptime
-		f32 maxexptime
-		f32 minsize
-		f32 maxsize
+		if PROTOCOL_VERSION >= 42 {
+			tween<T> pos, vel, acc, exptime, size
+		} else {
+			v3f minpos
+			v3f maxpos
+			v3f minvel
+			v3f maxvel
+			v3f minacc
+			v3f maxacc
+			f32 minexptime
+			f32 maxexptime
+			f32 minsize
+			f32 maxsize
+		}
 		u8 bool collisiondetection
 		u32 len
 		u8[len] texture
@@ -562,18 +576,20 @@ enum ToClientCommand
 		u8 glow
 		u8 object_collision
 
-		f32 pos_start_bias
-		f32 vel_start_bias
-		f32 acc_start_bias
-		f32 exptime_start_bias
-		f32 size_start_bias
+		if PROTOCOL_VERSION < 42 {
+			f32 pos_start_bias
+			f32 vel_start_bias
+			f32 acc_start_bias
+			f32 exptime_start_bias
+			f32 size_start_bias
 
-		range<v3f> pos_end
-		-- i.e v3f pos_end_min
-		--     v3f pos_end_max
-		--     f32 pos_end_bias
-		range<v3f> vel_end
-		range<v3f> acc_end
+			range<v3f> pos_end
+			-- i.e v3f pos_end_min
+			--     v3f pos_end_max
+			--     f32 pos_end_bias
+			range<v3f> vel_end
+			range<v3f> acc_end
+		}
 
 		tween<range<v3f>> drag
 		-- i.e. v3f drag_start_min

src/server.cpp

@@ -1649,7 +1649,18 @@ void Server::SendAddParticleSpawner(session_t peer_id, u16 protocol_version,
 	NetworkPacket pkt(TOCLIENT_ADD_PARTICLESPAWNER, 100, peer_id);
 
 	pkt << p.amount << p.time;
-	{ // serialize legacy fields
+
+	if (protocol_version >= 42) {
+		// Serialize entire thing
+		std::ostringstream os(std::ios_base::binary);
+		p.pos.serialize(os);
+		p.vel.serialize(os);
+		p.acc.serialize(os);
+		p.exptime.serialize(os);
+		p.size.serialize(os);
+		pkt.putRawString(os.str());
+	} else {
+		// serialize legacy fields only (compatibility)
 		std::ostringstream os(std::ios_base::binary);
 		p.pos.start.legacySerialize(os);
 		p.vel.start.legacySerialize(os);
@@ -1672,21 +1683,23 @@ void Server::SendAddParticleSpawner(session_t peer_id, u16 protocol_version,
 	pkt << p.node.param0 << p.node.param2 << p.node_tile;
 
 	{ // serialize new fields
-		// initial bias for older properties
-		pkt << p.pos.start.bias
-			<< p.vel.start.bias
-			<< p.acc.start.bias
-			<< p.exptime.start.bias
-			<< p.size.start.bias;
-
 		std::ostringstream os(std::ios_base::binary);
+		if (protocol_version < 42) {
+			// initial bias for older properties
+			pkt << p.pos.start.bias
+				<< p.vel.start.bias
+				<< p.acc.start.bias
+				<< p.exptime.start.bias
+				<< p.size.start.bias;
 
-		// final tween frames of older properties
-		p.pos.end.serialize(os);
-		p.vel.end.serialize(os);
-		p.acc.end.serialize(os);
-		p.exptime.end.serialize(os);
-		p.size.end.serialize(os);
+			// final tween frames of older properties
+			p.pos.end.serialize(os);
+			p.vel.end.serialize(os);
+			p.acc.end.serialize(os);
+			p.exptime.end.serialize(os);
+			p.size.end.serialize(os);
+		}
+		// else: fields are already written by serialize() very early
 
 		// properties for legacy texture field
 		p.texture.serialize(os, protocol_version, true);