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module Game.Entities (Entity (..), toSpriteSet, mkPlayer, render) where
import Data.IORef
import qualified Game.Controller as C
import qualified Game.Sprites as S
import qualified SDL
data Dir = DirRight | DirLeft deriving (Eq)
data Type = TypePlayer -- \| TypeEnemy | TypeItem
toSpriteSet :: Dir -> Int
toSpriteSet DirRight = 0
toSpriteSet DirLeft = 1
frameDelay :: Int
frameDelay = 6
jumpFrame :: Int
jumpFrame = 3
gravityOff :: Int
gravityOff = -1
gravityUp :: Int
gravityUp = 0
gravityDown :: Int
gravityDown = 16
gravityTable :: [Int]
gravityTable = [0, 6, 4, 4, 2, 2, 2, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3]
data Entity = Entity
{ eType :: Type,
eX :: Int,
eY :: Int,
eDelay :: Int,
eFrame :: Int,
eFrameLimit :: Int,
eGravity :: Int,
eDir :: Dir,
eSprite :: S.Sprite,
eUpdate :: Entity -> IO Entity,
eBlocked :: Int -> Int -> Bool,
eDestroy :: Bool
}
mkPlayer :: S.SpriteSheet -> Int -> Int -> IORef C.Controls -> (Int -> Int -> Bool) -> IO Entity
mkPlayer sprites x y controls isBlocked = do
s <- S.get sprites "player"
pure $ Entity TypePlayer x y 0 0 3 gravityOff DirRight s (updatePlayer controls) isBlocked False
updateFrame :: Bool -> Entity -> Entity
updateFrame updated e
| isGravityOn = e
| delay > 0 = e {eDelay = delay - 1}
| frame < eFrameLimit e = e {eDelay = frameDelay, eFrame = if updated then frame + 1 else 0}
| otherwise = e {eDelay = frameDelay, eFrame = 0}
where
isGravityOn = eGravity e > gravityOff
frame = eFrame e
delay = eDelay e
updateHorizontal :: Bool -> Bool -> Entity -> Entity
updateHorizontal left right e
-- prevent pressing both directions (keyboard)
| left && right = e
-- change direction first
| left && eDir e /= DirLeft = e {eDir = DirLeft, eDelay = 0}
| right && eDir e /= DirRight = e {eDir = DirRight, eDelay = 0}
| left && isGoingDown = if isBlocked (x - 1) (y + 23) then e else e {eX = x - 1}
| left && not isGoingDown = if isBlocked (x - 1) (y + 23) && isBlocked (x - 1) (y + 17) then e else e {eX = x - 1}
| right && isGoingDown = if isBlocked (x + 17) (y + 23) then e else e {eX = x + 1}
| right && not isGoingDown = if isBlocked (x + 17) (y + 23) && isBlocked (x + 17) (y + 17) then e else e {eX = x + 1}
| otherwise = e
where
x = eX e
y = eY e
isBlocked = eBlocked e
gravity = eGravity e
isGoingDown = gravity == gravityOff || gravity >= gravityDown
updateVertical :: Bool -> Bool -> Entity -> Entity
updateVertical jump down e
| not jump || gravity /= gravityOff = e
| not down = e {eGravity = gravityUp, eFrame = jumpFrame}
-- go down a 8 pixel tall platform; not ideal to have these values hardcoded here
-- but to be fair, the player height/width is hardcoded as well
| down
&& not (isBlocked (x + 2) (y + 24 + 8))
&& not (isBlocked (x + 12) (y + 24 + 8)) =
applyGravity 8 e {eGravity = gravityDown, eFrame = jumpFrame, eY = eY e + 1}
| otherwise = e
where
x = eX e
y = eY e
gravity = eGravity e
isBlocked = eBlocked e
applyGravity :: Int -> Entity -> Entity
applyGravity v e
| v == 0 = e
-- hit the floor
| isGoingDown
&& (isBlocked (x + 2) (y + 24) || isBlocked (x + 12) (y + 24))
&& not (isBlocked (x + 2) (y + 23))
&& not (isBlocked (x + 12) (y + 23)) =
e {eGravity = gravityOff, eDelay = 0, eFrame = 0}
| otherwise = applyGravity (v - 1) e {eY = y + change}
where
gravity = eGravity e
isGoingDown = gravity >= gravityDown
change = if isGoingDown then 1 else -1
x = eX e
y = eY e
isBlocked = eBlocked e
updateGravity :: Entity -> Entity
updateGravity e
| current > gravityOff = applyGravity (gravityTable !! current) e {eGravity = new}
| not (isBlocked (x + 2) (y + 24) || isBlocked (x + 12) (y + 24)) = e {eGravity = gravityDown, eFrame = jumpFrame}
| otherwise = e
where
current = eGravity e
new = if current > gravityOff && current < length gravityTable - 1 then current + 1 else current
x = eX e
y = eY e
isBlocked = eBlocked e
updatePlayer :: IORef C.Controls -> Entity -> IO Entity
updatePlayer controls e = do
ctl <- readIORef controls
pure $
updateGravity $
updateVertical (C.cA ctl) (C.cDown ctl) $
updateHorizontal (C.cLeft ctl) (C.cRight ctl) $
-- left or right, but not both (keyboard)
updateFrame ((C.cLeft ctl || C.cRight ctl) && (C.cLeft ctl /= C.cRight ctl)) e
render :: SDL.Renderer -> Entity -> IO ()
render renderer ent =
S.render renderer sp x y set frame
where
sp = eSprite ent
x = eX ent
y = eY ent
set = toSpriteSet $ eDir ent
frame = eFrame ent
|
