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module Chelleport.AppShell where
import Control.Monad (foldM, unless)
import SDL (($=))
import qualified SDL
import qualified SDL.Font as TTF
data Action act = SysQuit | AppAction act
newtype SysState = SysState {sysExit :: Bool}
data DrawContext = DrawContext
{ ctxWindow :: SDL.Window,
ctxRenderer :: SDL.Renderer,
ctxFont :: TTF.Font
}
createContext :: IO DrawContext
createContext = do
let windowCfg =
SDL.defaultWindow -- SDL.windowMode = SDL.Fullscreen,
{ SDL.windowInputGrabbed = True,
SDL.windowBorder = False
}
window <- SDL.createWindow "My SDL Application" windowCfg
renderer <- SDL.createRenderer window (-1) SDL.defaultRenderer
font <- TTF.load "Inter-Regular.ttf" 16
SDL.windowOpacity window $= 0.6
SDL.rendererDrawBlendMode renderer $= SDL.BlendAlphaBlend
SDL.rendererDrawColor renderer $= SDL.V4 0 0 0 0
pure $ DrawContext {ctxWindow = window, ctxRenderer = renderer, ctxFont = font}
setupAppShell ::
state ->
(state -> DrawContext -> appAction -> IO state) ->
(state -> SDL.Event -> Maybe (Action appAction)) ->
(state -> DrawContext -> IO ()) ->
IO ()
setupAppShell initState update eventHandler draw = do
-- Initialize SDL
SDL.initializeAll
TTF.initialize
ctx <- createContext
appLoop ctx (initState, SysState {sysExit = False})
SDL.destroyRenderer $ ctxRenderer ctx
SDL.destroyWindow $ ctxWindow ctx
where
appLoop drawCtx (state, sysState) = do
events <- SDL.pollEvents
SDL.clear $ ctxRenderer drawCtx
draw state drawCtx
SDL.present $ ctxRenderer drawCtx
(newState, newSysState) <- foldM (evaluateEvent drawCtx) (state, sysState) events
unless (sysExit newSysState) $ appLoop drawCtx (newState, newSysState)
evaluateEvent drawCtx stTup event = maybe (pure stTup) (updateState drawCtx stTup) (eventHandler (fst stTup) event)
updateState _drawCtx (state, sysState) SysQuit = pure (state, sysState {sysExit = True})
updateState drawCtx (state, sysState) (AppAction action) = (,sysState) <$> update state drawCtx action
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