LambdaHack-0.9.4.1: A game engine library for tactical squad ASCII roguelike dungeon crawlers

Game.LambdaHack.Atomic

Description

Atomic game state transformations, their representation and semantics.

Synopsis

# Re-exported from Game.LambdaHack.Atomic.CmdAtomic

data CmdAtomic Source #

Abstract syntax of atomic commands, that is, atomic game state transformations.

Constructors

 UpdAtomic UpdAtomic atomic updates SfxAtomic SfxAtomic atomic special effects
Instances
 Source # Instance detailsDefined in Game.LambdaHack.Atomic.CmdAtomic MethodsshowList :: [CmdAtomic] -> ShowS #

data UpdAtomic Source #

Abstract syntax of atomic updates, that is, atomic commands that really change the State. Most of them are an encoding of a game state diff, though they also carry some intentional hints that help clients determine whether and how to communicate it to players.

Instances
 Source # Instance detailsDefined in Game.LambdaHack.Atomic.CmdAtomic MethodsshowList :: [UpdAtomic] -> ShowS #

data HearMsg Source #

Symbolic representation of text messages about heard noises, sent by server to clients and shown to players and used by AI.

Constructors

 HearUpd Bool UpdAtomic HearStrike (ContentId ItemKind) HearSummon Bool (GroupName ItemKind) Dice HearTaunt Text
Instances
 Source # Instance detailsDefined in Game.LambdaHack.Atomic.CmdAtomic MethodsshowList :: [HearMsg] -> ShowS #

data SfxAtomic Source #

Abstract syntax of atomic special effects, that is, atomic commands that only display special effects and don't change State nor client state.

Instances
 Source # Instance detailsDefined in Game.LambdaHack.Atomic.CmdAtomic MethodsshowList :: [SfxAtomic] -> ShowS #

data SfxMsg Source #

Symbolic representation of text messages sent by server to clients and shown to players.

Instances
 Source # Instance detailsDefined in Game.LambdaHack.Atomic.CmdAtomic MethodsshowsPrec :: Int -> SfxMsg -> ShowS #showList :: [SfxMsg] -> ShowS #

# Re-exported from Game.LambdaHack.Atomic.HandleAtomicWrite

handleUpdAtomic :: MonadStateWrite m => UpdAtomic -> m () Source #

The game-state semantics of atomic game commands. There is no corresponding definition for special effects (SfxAtomic), because they don't modify State.

For each of the commands, we are guaranteed that the client, the command is addressed to, perceives all the positions the command affects (as computed by posUpdAtomic). In the code for each semantic function we additonally verify the client is aware of any relevant items and/or actors and we throw the AtomicFail exception if it's not. The server keeps copies of all clients' states and, before sending a command to a client, applies it to the client's state copy. If AtomicFail is signalled, the command is ignored for that client. This enables simpler server code that addresses commands to all clients that can see it, even though not all are able to process it.

data PosAtomic Source #

The type representing visibility of atomic commands to factions, based on the position of the command, etc. Note that the server sees and smells all positions. Also note that hearing is not covered because it gives very restricted information, so hearing doesn't equal seeing (and we assume smelling actors get lots of data from smells).

Constructors

 PosSight LevelId [Point] whomever sees all the positions, notices PosFidAndSight [FactionId] LevelId [Point] observers and the faction notice PosSmell LevelId [Point] whomever smells all the positions, notices PosFid FactionId only the faction notices, server doesn't PosFidAndSer (Maybe LevelId) FactionId faction and server notices PosSer only the server notices PosAll everybody notices PosNone never broadcasted, but sent manually
Instances
 Source # Instance detailsDefined in Game.LambdaHack.Atomic.PosAtomicRead Methods Source # Instance detailsDefined in Game.LambdaHack.Atomic.PosAtomicRead MethodsshowList :: [PosAtomic] -> ShowS #

Produce the positions where the atomic update takes place or, more generally, the conditions under which the update can be noticed by a client.

The goal of this mechanics is to ensure that atomic commands involving some positions visible by a client convey similar information as the client would get by directly observing the changes of the portion of server state limited to the visible positions. Consequently, when the visible commands are later applied to the client's state, the state stays consistent --- in sync with the server state and correctly limited by visiblity. There is some wiggle room both in what "in sync" and "visible" means and how they propagate through time.

E.g., UpdDisplaceActor in a black room between two enemy actors, with only one actor carrying a 0-radius light would not be distinguishable by looking at the state (or the screen) from UpdMoveActor of the illuminated actor, hence such UpdDisplaceActor should not be observable, but UpdMoveActor in similar cotext would be (or the former should be perceived as the latter). However, to simplify, we assign as strict visibility requirements to UpdMoveActor as to UpdDisplaceActor and fall back to UpdSpotActor (which provides minimal information that does not contradict state) if the visibility is lower.

Produce the positions where the atomic special effect takes place.

Decompose an atomic action that is outside a client's visiblity. The decomposed actions give less information that the original command, but some of them may fall within the visibility range of the client. The original action may give more information than even the total sum of all actions it's broken into. E.g., UpdMoveActor informs about the continued existence of the actor between moves vs popping out of existence and then back in.

This is computed in server's State from before performing the command.

Given the client, its perception and an atomic command, determine if the client notices the command.

Determine whether the server would see a command that has the given visibilty conditions.

The monad for writing to the main game state. Atomic updates (UpdAtomic) are given semantics in this monad.

Methods

modifyState :: (State -> State) -> m () Source #

putState :: State -> m () Source #

Instances
 Source # Instance detailsDefined in Implementation.MonadClientImplementation MethodsmodifyState :: (State -> State) -> CliImplementation () Source # Source # Instance detailsDefined in Implementation.MonadServerImplementation MethodsmodifyState :: (State -> State) -> SerImplementation () Source #

newtype AtomicFail Source #

Exception signifying that atomic action failed because the information it carries is inconsistent with the client's state, (e.g., because the client knows too little to understand the command or already deduced the state change from earlier commands or is confused, amnesiac or sees illusory actors or tiles). Whenever we know the failure is logically impossible, we don't throw the AtomicFail exception, but insert a normal assertion or error call, which are never caught nor handled.

Constructors

 AtomicFail String
Instances
 Source # Instance detailsDefined in Game.LambdaHack.Atomic.MonadStateWrite MethodsshowList :: [AtomicFail] -> ShowS # Source # Instance detailsDefined in Game.LambdaHack.Atomic.MonadStateWrite Methods