Replication

With Replication a server states what has changed about the units a client can see: for each unit, the groups of values it carries and which values of each follow. What the values are follows from the unit.

The groups follow in the order 0, 1, 2, 3, 5 and then 4: group 4 comes last, each behind the length of its run. A sending end MUST write each group’s length as the number of bytes its run takes.

Each value takes one of two shapes, and the table row naming it says which. Nothing on the wire carries a table, a field name, a width or a shape, so an end that does not already hold the table cannot read a run.

A value that counts is a thirty two bit unsigned integer, and a value with a sign travels as the same thirty two bits. It takes seven bits from each byte, lowest seven first, and the top bit of a byte is set while another byte follows. Five bytes therefore carry anything it holds.

A value that measures takes one of three forms: a single byte of 255 meaning zero; a byte of 254 followed by four bytes; or four bytes on their own. The four bytes are the measure itself, a thirty two bit float, lowest byte first. A sending end MUST write the byte of 254 before a measure whose lowest byte is 254 or 255, and MUST NOT write it before any other. A measure written plain therefore never begins with either, so its first byte says which form it takes.

What settles a reading

A run is a sequence of values with nothing between them, in the order the set bits name them, lowest first.

The bit that names a value means different things for different units. Champions, turrets, minions and units belonging to no side, and buildings each answer to a table of their own, so the same bit in the same group is one value on one unit and another on the next. A sending end MUST write the table the unit it names answers to.

Props answer to a table of their own as well.

Which table a unit answers to follows from the message that put it on the field (see Units). A building, which no message creates, answers to the building table.

A building answers to the building table of the map loaded.

Which batches a client takes

A client answers a batch with TransientAck where it holds every unit the batch names, whether or not it took the values. Ordering says which batches a client takes, and what that requires of a server.

Reading the tables

Each row gives the group and bits that name a value and what the value is.

Each row also gives the shape a sending end writes the value in.

A champion

Bit 2 holds which of slots 0 to 3 can be cast from, one bit for each slot, set as a champion learns the spell in it, and bit 4 holds which summoner spells can be cast from, as a mask in which a server sets its bits 4 and 5, one for each summoner slot. Bits 3 and 5 of the group carry zero. Sides and slots numbers the slots.

Bits 8 to 11 carry what the spells in slots 0 to 3 cost. A server sets bits 8 to 27 together and writes zero in bits 12 to 27. It leaves bits 6 and 7, and group 1 bit 31, clear.

A server writes 0x800007 in group 1 bit 0.

What a client shows from this table

A client shows, for a champion:

• its health and resource bars, as they stand (group 3 bits 0 and 1) out of their greatest (bits 2 and 3);
• its level (group 3 bit 13), on the portrait and over the health bar, together with the spell points that level brings;
• its gold (group 0 bit 0);
• in the panel under its portrait, ability power (group 1 bit 6), armour (bit 9), spell resistance (bit 10), movement speed (group 3 bit 10), and attack speed as the champion’s own base attack speed times group 1 bit 19;
• in its panel of statistics, group 1 bit 21 as cooldown reduction, its size as a percent whatever its sign; bits 28 and 29 as life steal and spell vamp, and bit 30 as tenacity, each a fraction shown as a percent; and bits 24 and 26 as flat penetration of armour and of spell resistance.

The attack damage the panel under the portrait shows is the client’s own figure for the champion’s level, with group 1 bit 14 added to it and drawn as a bonus.

Until a champion’s first batch arrives, the panel shows figures the client holds for that champion. Once one arrives, it shows the values batches carry, and armour, spell resistance, ability power and movement speed read 0 where no batch has carried them.

Each percent penetration field carries the share of armour or spell resistance left standing, 1 where nothing is cut through. The panel shows what two of them cut through together, as 200 percent less both shares in percent: bit 25 of group 1 with bit 0 of group 2 for armour, and bit 27 of group 1 with bit 1 of group 2 for spell resistance.

A spell’s cooldown lasts its base length times one plus the modifier at bit 21, so a reduction is carried as a negative fraction and the panel shows its size.

Bit 22 sets the countdown a client shows on the champion’s passive. It is a moment on the match clock (see Time), in seconds, on the same clock as the time a ClockSync carries, and not the time left: 120 at the opening of a match starts the countdown from 2:00. Once that moment has passed, the passive shows ready. Bit 23 is how long the whole cooldown lasts, in seconds, and a client shades the passive’s icon by the time left over that length; the countdown itself follows bit 22 alone.

A turret

Where a server raises a turret’s health at its greatest, it raises health as it stands to the same value.

A minion, and a unit belonging to no side

Both answer to one table.

A building

Inhibitors and nexuses, each named by the identifier Objects and identifiers gives its name. Where a server replicates a map’s buildings, it sends these two groups and nothing else. On map 8 it replicates none.

The health figure does not follow the building’s health. A server SHOULD send an inhibitor’s as 4000 on maps 1 and 11 and 3000 on map 10, a nexus’s as 5500 on those three, and every building’s as 0 on map 12. A server SHOULD NOT change it, even as a building is destroyed. A server first names a building in the EnterSight that brings it into a side’s sight.

A prop

A server need not replicate a prop’s values. Where it does, they follow the table below.

Values stated outside a batch

Besides its batches, a server states some values with messages of their own.

A server grants experience with ExperienceGained and gold with GoldGained.

A server can send the gold a unit earns to another with GoldRedirect. A level gained is LevelUp, which on its own is enough for a client to show the new level on its champion’s portrait. A server sets a champion’s tallies for the scoreboard with ChampionStats. A server can also add to a unit’s shield (ShieldAdded), change how its health bar or resource bar is shown (HealthBar, ResourceDisplay), change the sort of resource it has (ResourceKindChanged), set the highest level a champion reaches (LevelCap), and count minions killed, scores and deeds (MinionKillCount, ScoreAdded, StatisticIncremented).

Messages

Each message of this system in this book, with each layout it has across the book’s patches and every note its definition carries. A layout is the message’s body, after the header its channel’s family puts in front (see Messages).