Vision

What a client can see, and how a server tells it. A client draws what a server says it sees and nothing else: the fog of war a client draws is only a picture, and what lies inside it is whatever the server has brought into view.

Bringing a unit into view

A server brings a unit into what a client’s side can see with EnterSight.

EnterSight also states the unit’s items.

EnterSight can also carry whole messages of the game family, such as the CreateTurret or CreateNeutral that makes the unit, each taking effect as though it had arrived on its own.

A client does not draw a champion that no EnterSight has placed: given only its CreateChampion, a client shows the champion’s portrait and spells and nothing on the field. One EnterSight after the CreateChampion draws it, with its name and health bar over it.

EnterLocalSight brings a unit into what one client alone can see. EnterTeamSight brings an object into the view of a whole side.

EnterLocalSight states the unit’s health.

Losing sight

LeaveSight and LeaveTeamSight take a unit out of the matching view, and leave it held (see Objects and identifiers). Particles come into and leave a side’s view with ParticleEnterTeamSight and ParticleLeaveTeamSight.

Regions

A region is a patch of ground with sight of its own, which can reveal hidden units within it. A server places one with RegionAdded or fastens one to a unit with RegionAttached, moves it with RegionMoved and takes it away with RegionRemoved; Objects and identifiers says how regions are named and when one ends. A region granting sight has a client clear its map’s cover over it.

A client makes only circular regions.

Drawing the fog

FogSet and FogToggled change how a client draws its fog of war.

A client draws its fog of war, or the map with no darkening, as FogSet and FogToggled say. Neither changes what the client can see.

Who is told what

A client acts on a message about whichever unit it names, its own champion or another, so what a client knows is whatever a server sends it. A server decides, message by message, which clients to tell.

UnitDiedOnMap, InventorySnapshotOnMap, FloatingTextOnMap and SpellSlotChangedForOwner do not exist, so a server sends both audiences of UnitDied, InventorySnapshot, FloatingText and SpellSlotChanged under the one command each.

Messages about a champion’s own state, its gold, its inventory, its spells’ levels, cooldowns and charges, and whether it can shop, are applied to the champion they name on any client that receives them, but a client shows some of them only for its own champion:

• ShopEnabled changes the shop only for the client’s own champion.

ItemAdded and InventorySlot announce a purchase only for the client’s own champion; an ally’s purchase is called out where the message asks for it.

A server SHOULD send SpellCooldown, SpellCharges and GoldGained about a champion only to the client whose champion it is.

A client also acts on what it is told about a unit it holds but cannot see:

• a particle on a hidden unit is created but not drawn until the unit comes into view, unless the particle is bound to a target the client can see;
• floating text over a hidden unit is dropped;
• an animation plays on a hidden unit, which comes into view part way through it.

A server SHOULD NOT send a client what its side cannot see, beyond what keeps its world consistent.

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).