haskanoid-0.1.6: src/GameState.hs

-- |
-- Copyright  : (c) Ivan Perez & Henrik Nilsson, 2014.
-- License    : See LICENSE file.
-- Maintainer : Ivan Perez <ivan.perez@keera.co.uk>
--
-- The state of the game during execution. It has two parts: general info
-- (level, points, etc.) and the actual gameplay info (objects).
--
-- Because the game is always in some running state (there are no menus, etc.)
-- we assume that there's always some gameplay info, even though it can be
-- empty.
module GameState where

-- Internal imports
import Objects

-- | The running state is given by a bunch of 'Objects' and the current general
-- 'GameInfo'. The latter contains info regarding the current level, the number
-- of points, etc.
--
-- Different parts of the game deal with these data structures.  It is
-- therefore convenient to group them in subtrees, even if there's no
-- substantial difference between them.
data GameState = GameState
  { gameObjects :: Objects
  , gameInfo    :: GameInfo
  }

-- | Initial (default) game state.
neutralGameState :: GameState
neutralGameState = GameState
  { gameObjects = []
  , gameInfo    = neutralGameInfo
  }

-- | The GameInfo tells us the current game state (running, paused, etc.) and
-- general information, in this case, the number of lives, the level and the
-- points.
--
-- Since this info is then presented together to the users in a top panel, it
-- is convenient to give this product of values a proper name.
data GameInfo = GameInfo
  { gameStatus :: GameStatus
  , gameLives  :: Int
  , gameLevel  :: Int
  , gamePoints :: Int
  }

-- | Initial (default) game info (no points, no lives, no level).
neutralGameInfo :: GameInfo
neutralGameInfo = GameInfo
  { gameStatus = GameStarted
  , gameLevel  = 0
  , gameLives  = 0
  , gamePoints = 0
  }

-- | Possible actual game statuses. The game is always in one of these.
-- Interaction and presentation depend on this. Yampa switches are used to jump
-- from one to another, and the display module changes presentation depending
-- on the status.
data GameStatus = GamePlaying
                | GamePaused
                | GameLoading Int
                | GameOver
                | GameFinished
                | GameStarted
  deriving Eq