Slimes hit enemies

3 files changed, 54 insertions, 24 deletions

diff --git a/src/Game.hs b/src/Game.hs
index bc604ad..1e0245b 100644
--- a/src/Game.hs
+++ b/src/Game.hs
@@ -82,7 +82,8 @@ main = do
         { batteries = 0,
           totalBatteries = M.totalBatteries map',
           lives = maxLives,
-          totalLives = maxLives
+          totalLives = maxLives,
+          hitDelay = 0
         }
   hud <- H.mkHud sprites state
   entities <- newIORef =<< E.mkEntities sprites map' controls state
diff --git a/src/Game/Entities.hs b/src/Game/Entities.hs
index 8decf07..cfdfcd0 100644
--- a/src/Game/Entities.hs
+++ b/src/Game/Entities.hs
@@ -13,12 +13,15 @@ import qualified SDL
 
 data Dir = DirRight | DirLeft deriving (Eq)
 
-data Type = TypePlayer | TypePickup | TypeEffect
+data Type = TypePlayer | TypePickup | TypeEffect | TypeEnemy
 
 toSpriteSet :: Dir -> Int
 toSpriteSet DirRight = 0
 toSpriteSet DirLeft = 1
 
+hitDelay :: Int
+hitDelay = 72
+
 frameDelay :: Int
 frameDelay = 6
 
@@ -45,6 +48,7 @@ type IsBlocked = Int -> Int -> Bool
 data Entities = Entities
   { sprites :: S.SpriteSheet,
     player :: IORef Entity,
+    state :: IORef GS.State,
     entities :: [Entity]
   }
 
@@ -83,6 +87,19 @@ collision playerRef other = do
       && player.y + 12 < other.y + 16
       && other.y + 4 < player.y + 24
 
+-- | Update game state to reflect that the player was hit by an enemy.
+hitPlayer :: IORef GS.State -> IO ()
+hitPlayer stateRef =
+  stateRef $~ updatePlayerHit
+  where
+    updatePlayerHit :: GS.State -> GS.State
+    updatePlayerHit s = s {GS.lives = s.lives - 1, GS.hitDelay = hitDelay}
+
+-- | Update game state to reflect that the player picked up a battery.
+collectedBattery :: IORef GS.State -> IO ()
+collectedBattery stateRef =
+  stateRef $~ (\s -> s {GS.batteries = s.batteries + 1})
+
 mkEntities :: S.SpriteSheet -> M.Map -> IORef C.Controls -> IORef GS.State -> IO Entities
 mkEntities sprites m controls stateRef = do
   player <- case find M.isPlayer (M.objects m) of
@@ -91,11 +108,11 @@ mkEntities sprites m controls stateRef = do
   playerRef <- newIORef player
   entities <- traverse (toEntity playerRef) $ sort $ filter (not . M.isPlayer) (M.objects m)
   -- the entities list has always player first
-  pure $ Entities sprites playerRef (player : entities)
+  pure $ Entities sprites playerRef stateRef (player : entities)
   where
     toEntity :: IORef Entity -> M.Object -> IO Entity
-    toEntity playerRef (M.SlimeEntity x y) = mkSlime sprites x y playerRef (M.isBlocked m)
-    toEntity playerRef (M.BatteryEntity x y) = mkBattery sprites x y playerRef stateRef
+    toEntity playerRef (M.SlimeEntity x y) = mkSlime sprites x y playerRef (M.isBlocked m) (hitPlayer stateRef)
+    toEntity playerRef (M.BatteryEntity x y) = mkBattery sprites x y playerRef (collectedBattery stateRef)
     toEntity _ (M.PlayerEntity _ _) = error "Player already processed"
 
 processSpawn :: S.SpriteSheet -> Spawn -> IO Entity
@@ -106,8 +123,16 @@ updateAll es = do
   -- update the player first (including the reference)
   updatedPlayer <- player.update player
   _ <- writeIORef es.player updatedPlayer
+  state <- readIORef es.state
   -- then the other entities
-  updated <- (updatedPlayer :) <$> traverse (\e -> e.update e) others
+  updated <-
+    if state.hitDelay > 0
+      then do
+        -- if the player was hit, update state and don't update the enemies
+        _ <- writeIORef es.state state {GS.hitDelay = state.hitDelay - 1}
+        (updatedPlayer :) <$> traverse (\e -> if notEnemy e then e.update e else pure e) others
+      else -- otherwise update all
+        (updatedPlayer :) <$> traverse (\e -> e.update e) others
   -- collect new entities
   new <- traverse (processSpawn es.sprites) (concatMap (\e -> e.spawns) updated)
   -- clear spawns (new entities), filter out destroyed entities, and add the new ones
@@ -116,11 +141,18 @@ updateAll es = do
     player = head es.entities
     others = tail es.entities
 
+    notEnemy :: Entity -> Bool
+    notEnemy ent = case ent.typ of
+      TypeEnemy -> False
+      _ -> True
+
 render :: SDL.Renderer -> Entities -> IO ()
 render renderer es = do
+  state <- readIORef es.state
   -- always render player last
   traverse_ renderOne others
-  renderOne player
+  -- won't draw all the frames if the player was hit
+  if testBit state.hitDelay 2 then pure () else renderOne player
   where
     player = head es.entities
     others = tail es.entities
@@ -156,8 +188,8 @@ updateEffect e
   | e.frame + 1 < frameLimit e = e {delay = frameDelay, frame = e.frame + 1}
   | otherwise = e {destroy = True}
 
-mkBattery :: S.SpriteSheet -> Int -> Int -> IORef Entity -> IORef GS.State -> IO Entity
-mkBattery sprites x y playerRef stateRef = do
+mkBattery :: S.SpriteSheet -> Int -> Int -> IORef Entity -> IO () -> IO Entity
+mkBattery sprites x y playerRef collectedBattery' = do
   s <- S.get sprites "battery"
   pure
     Entity
@@ -170,19 +202,15 @@ mkBattery sprites x y playerRef stateRef = do
         gravity = gravityOff,
         dir = DirRight,
         sprite = s,
-        update = updateBattery (collision playerRef) collectedBattery,
+        update = updateBattery (collision playerRef) collectedBattery',
         destroy = False,
         spawns = []
       }
-  where
-    collectedBattery :: IO ()
-    collectedBattery = do
-      stateRef $~ (\s -> s {GS.batteries = s.batteries + 1})
 
 updateBattery :: Collision -> IO () -> Entity -> IO Entity
-updateBattery touchedPlayer collectedBattery e = do
+updateBattery touchedPlayer collectedBattery' e = do
   touched <- touchedPlayer e
-  if touched then e {destroy = True} <$ collectedBattery else pure updateBatteryFrame
+  if touched then e {destroy = True} <$ collectedBattery' else pure updateBatteryFrame
   where
     updateBatteryFrame :: Entity
     updateBatteryFrame
@@ -190,12 +218,12 @@ updateBattery touchedPlayer collectedBattery e = do
       | e.frame + 1 < frameLimit e = e {delay = frameDelay, frame = e.frame + 1}
       | otherwise = e {delay = frameDelay, frame = 0}
 
-mkSlime :: S.SpriteSheet -> Int -> Int -> IORef Entity -> IsBlocked -> IO Entity
-mkSlime sprites x y playerRef isBlocked = do
+mkSlime :: S.SpriteSheet -> Int -> Int -> IORef Entity -> IsBlocked -> IO () -> IO Entity
+mkSlime sprites x y playerRef isBlocked hitPlayer' = do
   s <- S.get sprites "slime"
   pure
     Entity
-      { typ = TypePickup,
+      { typ = TypeEnemy,
         x = x,
         y = y,
         delay = frameDelay,
@@ -204,16 +232,16 @@ mkSlime sprites x y playerRef isBlocked = do
         gravity = gravityOff,
         dir = DirRight,
         sprite = s,
-        update = updateSlime (collision playerRef) isBlocked,
+        update = updateSlime (collision playerRef) isBlocked hitPlayer',
         destroy = False,
         spawns = []
       }
 
-updateSlime :: Collision -> IsBlocked -> Entity -> IO Entity
-updateSlime touchedPlayer isBlocked e = do
+updateSlime :: Collision -> IsBlocked -> IO () -> Entity -> IO Entity
+updateSlime touchedPlayer isBlocked hitPlayer' e = do
   touched <- touchedPlayer e
   let updated = updateSlimeFrame
-  pure $ if touched then e {destroy = True} else updateMovement updated
+  if touched then fmap (const e) hitPlayer' else pure $ updateMovement updated
   where
     updateMovement :: Entity -> Entity
     updateMovement ent
diff --git a/src/Game/State.hs b/src/Game/State.hs
index 2223434..d943ac0 100644
--- a/src/Game/State.hs
+++ b/src/Game/State.hs
@@ -4,5 +4,6 @@ data State = State
   { batteries :: Int,
     totalBatteries :: Int,
     lives :: Int,
-    totalLives :: Int
+    totalLives :: Int,
+    hitDelay :: Int
   }