ansi-terminal-game-1.6.0.2: src/Terminal/Game/Layer/Imperative.hs
-------------------------------------------------------------------------------
-- Layer 1 (imperative), as per
-- https://www.parsonsmatt.org/2018/03/22/three_layer_haskell_cake.html
-- 2019 Francesco Ariis GPLv3
-------------------------------------------------------------------------------
{-# Language ScopedTypeVariables #-}
module Terminal.Game.Layer.Imperative where
import Terminal.Game.Draw
import Terminal.Game.Layer.Object
import qualified Control.Concurrent as CC
import qualified Control.Exception as E
import qualified Control.Monad as CM
import qualified Data.Bool as B
import qualified Data.List as D
import qualified System.IO as SI
import Terminal.Game.Plane
-- | Game environment with current terminal dimensions and current display
-- rate.
data GEnv = GEnv { eTermDims :: Dimensions,
eFPS :: FPS }
-- | General way to create a game. This gives you more control by
-- exposing 'GEnv' (allowing e.g. to adapt to screen resizes, blit
-- FPS, etc.. If you fancy simple, sensible defaults, check 'simpleGame'.
data Game s =
Game { gTPS :: TPS, -- ^ Ticks per second. Since the 2D
-- “char canvas” is coarse, you do not
-- need high values (e.g. 13 TPS is
-- enough for action games).
gInitState :: s, -- ^ Initial state of the game.
gLogicFunction :: GEnv -> s -> Event -> s,
-- ^ Logic function.
gDrawFunction :: GEnv -> s -> Plane,
-- ^ Draw function. Check '***' for
-- centre-blitting.
gQuitFunction :: s -> Bool
-- ^ “Should I quit?” function.
}
-- | Simplest way to create a game. The two most important parameters
-- are the function dealing with logic and the drawing one. Check @alone@
-- (you can compile it with @cabal run -f examples alone@) to see a basic
-- game in action. If you want more control, look at 'Game'.
simpleGame :: Dimensions -- ^ Gamescreen dimensions, in columns and
-- rows. Asks the player to resize their
-- terminal if it is too small.
-- Centre-blits on bigger terminals.
-> TPS -- ^ Ticks per second. Since the 2D “char
-- canvas” is coarse, you do not need
-- high values (e.g. 13 TPS is enough
-- for action games).
-> s -- ^ Initial state of the game.
-> (s -> Event -> s) -- ^ Simple logic function.
-> (s -> Plane) -- ^ Simple draw function.
-> (s -> Bool) -- ^ “Should I quit?” function.
-> Game s
simpleGame (sw, sh) tps s lf df qf = Game tps s lf' df' qf
where
-- lf' :: GEnv -> s -> Event -> s
lf' wen ws we
| isSmaller (eTermDims wen) = ws
| otherwise = lf ws we
-- df' :: GEnv -> s -> Plane
df' wen ws =
let ds = eTermDims wen in
if isSmaller ds
then smallMsg ds
else uncurry blankPlane ds *** df ws
colS ww = ww < sw
rowS wh = wh < sh
isSmaller :: Dimensions -> Bool
isSmaller (ww, wh) = colS ww || rowS wh
smallMsg :: Dimensions -> Plane
smallMsg (ww, wh) =
let cm = show ww ++ " columns"
rm = show wh ++ " rows"
em | colS ww && rowS wh = cm ++ " and " ++ rm
| colS ww = cm
| rowS wh = rm
| otherwise = "smallMsg: passed correct term size!"
in
textBoxLiquid ww $
"This games requires a screen of " ++ show sw ++
" columns and " ++ show sh ++ " rows.\n" ++
"Yours only has " ++ em ++ "!\n\n" ++
"Please resize your terminal now!"
-- | Entry point for the game execution, should be called in @main@.
--
-- You __must__ compile your programs with @-threaded@; if you do not do
-- this the game will crash at start-up. Just add:
--
-- @
-- ghc-options: -threaded
-- @
--
-- in your @.cabal@ file and you will be fine!
playGame :: Game s -> IO ()
playGame g = () <$ runGIO (runGameGeneral g)
-- | As 'playGame', but do not discard state.
playGameS :: Game s -> IO s
playGameS g = runGIO (runGameGeneral g)
-- | Tests a game in a /pure/ environment. You can
-- supply the 'Event's yourself or use 'recordGame' to obtain them.
testGame :: Game s -> [Event] -> s
testGame g es = fst $ runTest (runGameGeneral g) (Env False es)
-- | As 'testGame', but returns 'Game' instead of a bare state.
-- Useful to fast-forward (e.g.: skip menus) before invoking 'playGame'.
setupGame :: Game s -> [Event] -> Game s
setupGame g es = let s' = testGame g es
in g { gInitState = s' }
-- | Similar to 'testGame', runs the game given a list of 'Events'. Unlike
-- 'testGame', the playthrough will be displayed on screen. Useful when a
-- test fails and you want to see how.
--
-- See this in action with @cabal run -f examples alone-playback@.
narrateGame :: Game s -> [Event] -> IO s
narrateGame g e = runReplay (runGameGeneral g) e
-- xxx replaygame is very difficult to test
-- | Play as in 'playGame' and write the session to @file@. Useful to
-- produce input for 'testGame' and 'narrateGame'. Session will be
-- recorded even if an exception happens while playing.
recordGame :: Game s -> FilePath -> IO ()
recordGame g fp =
E.bracket
(CC.newMVar [])
(\ve -> writeMoves fp ve)
(\ve -> () <$ runRecord (runGameGeneral g) ve)
data Config = Config { cMEvents :: CC.MVar [Event],
cTPS :: TPS }
runGameGeneral :: forall s m. MonadGameIO m =>
Game s -> m s
runGameGeneral (Game tps s lf df qf) =
-- init
setupDisplay >>
startEvents tps >>= \(InputHandle ve ts) ->
displaySizeErr >>= \ds ->
-- do it!
let c = Config ve tps in
cleanUpErr (game c ds)
-- this under will be run regardless
(stopEvents ts >>
shutdownDisplay )
where
game :: MonadGameIO m => Config -> Dimensions -> m s
game c wds = gameLoop c s lf df qf
Nothing wds
(creaFPSCalc tps)
-- | Wraps an @IO@ computation so that any 'ATGException' or 'error' gets
-- displayed along with a @\<press any key to quit\>@ prompt.
-- Some terminals shut-down immediately upon program end; adding
-- @errorPress@ to 'playGame' makes it easier to beta-test games on those
-- terminals.
errorPress :: IO a -> IO a
errorPress m = E.catches m [E.Handler errorDisplay,
E.Handler atgDisplay]
where
errorDisplay :: E.ErrorCall -> IO a
errorDisplay (E.ErrorCallWithLocation cs l) = report $
putStrLn (cs ++ "\n\n") >>
putStrLn "Stack trace info:\n" >>
putStrLn l
atgDisplay :: ATGException -> IO a
atgDisplay e = report $ print e
report :: IO () -> IO a
report wm =
putStrLn "ERROR REPORT\n" >>
wm >>
putStrLn "\n\n <Press any key to quit>" >>
SI.hSetBuffering SI.stdin SI.NoBuffering >>
getChar >>
errorWithoutStackTrace "errorPress"
-----------
-- LOGIC --
-----------
-- from http://www.loomsoft.net/resources/alltut/alltut_lesson6.htm
gameLoop :: MonadGameIO m =>
Config -> -- event source
s -> -- state
(GEnv ->
s -> Event -> s) -> -- logic function
(GEnv ->
s -> Plane) -> -- draw function
(s -> Bool) -> -- quit? function
Maybe Plane -> -- last blitted screen
Dimensions -> -- Term dimensions
FPSCalc -> -- calculate fps
m s
gameLoop c s lf df qf opln td fps =
-- quit?
checkQuit qf s >>= \qb ->
if qb
then return s
else
-- fetch events (if any)
pollEvents (cMEvents c) >>= \es ->
-- no events? skip everything
if null es
then sleepABit (cTPS c) >>
gameLoop c s lf df qf opln td fps
else
displaySizeErr >>= \td' ->
-- logic
let ge = GEnv td' (calcFPS fps)
(i, s') = stepsLogic s (lf ge) es in
-- no `Tick` events? You do not need to blit, just update state
if i == 0
then gameLoop c s' lf df qf opln td fps
else
-- FPS calc
let fps' = addFPS i fps in
-- clear screen if resolution changed
let resc = td /= td' in
CM.when resc clearDisplay >>
-- draw
let opln' | resc = Nothing -- res changed? restart double buffering
| otherwise = opln
npln = df ge s' in
blitPlane opln' npln >>
gameLoop c s' lf df qf (Just npln) td' fps'
-- Int = number of `Tick` events
stepsLogic :: s -> (s -> Event -> s) -> [Event] -> (Integer, s)
stepsLogic s lf es = let ies = D.genericLength . filter isTick $ es
in (ies, foldl lf s es)
where
isTick Tick = True
isTick _ = False
-------------------------------------------------------------------------------
-- Frame per Seconds
-- | The number of frames blit to terminal per second. Frames might be
-- dropped, but game speed will remain constant. Check @balls@
-- (@cabal run -f examples balls@) to see how to display FPS.
type FPS = Integer
data FPSCalc = FPSCalc [Integer] TPS
-- list with number of `Ticks` processed at each blit and expected
-- FPS (i.e. TPS)
-- the size of moving average will be TPS (that simplifies calculations)
creaFPSCalc :: TPS -> FPSCalc
creaFPSCalc tps = FPSCalc (D.genericReplicate (tps*1) 1) tps
-- tps*1: size of thw window in **blit actions** (not tick actions!)
-- so keeping it small should be responsive and non flickery
-- at the same time!
-- add ticks
addFPS :: Integer -> FPSCalc -> FPSCalc
addFPS nt (FPSCalc (_:fps) tps) = FPSCalc (fps ++ [nt]) tps
addFPS _ (FPSCalc [] _) = error "addFPS: empty list."
calcFPS :: FPSCalc -> Integer
calcFPS (FPSCalc fps tps) =
let ts = sum fps
ds = D.genericLength fps
in roundQuot (tps * ds) ts
where
roundQuot :: Integer -> Integer -> Integer
roundQuot a b = let (q, r) = quotRem a b
in q + B.bool 0 1 (r > div b 2)