README.md

@@ -57,7 +57,8 @@ These are the keybinds *in* the game. All other keybinds in the menus should be
 | Move left      | `Arrow Left`  | `a`         |
 | Move down      | `Arrow Down`  | `s`         |
 | Move right     | `Arrow Right` | `d`         |
-| Show inventory | `i`           |             |
+| Interaction    | `Space`       | `f`         |
+| Show inventory | `i`           | `Tab`       |
 | Restart level  | `r`           |             |
 | Quit game      | `Esc`         |             |
 

lib/RPGEngine/Data.hs

@@ -19,22 +19,30 @@ data Game = Game {
            -- Main menu
 data State = Menu
            -- Select the level you want to play
-           | LevelSelection { levelList :: [FilePath],
-                              selector  :: ListSelector }
+           | LevelSelection  { levelList :: [FilePath],
+                               selector  :: ListSelector  }
            -- Playing a level
-           | Playing        { levels    :: [Level],
-                              count     :: Int,
-                              level     :: Level,
-                              player    :: Player,
-                              restart   :: State        }
+           | Playing         { levels    :: [Level],
+                               count     :: Int,
+                               level     :: Level,
+                               player    :: Player,
+                               restart   :: State         }
+           -- Selecting an action
+           | ActionSelection { actionList :: [Action],
+                               selector  :: ListSelector,
+                               -- The player of this state will be used to interact
+                               continue  :: State         }
            -- Paused while playing a level
-           | Paused         { continue  :: State        }
+           | Paused          { continue  :: State         }
            -- Won a level
            | Win
            -- Lost a level
-           | Lose           { restart   :: State        }
+           | Lose            { restart   :: State         }
+           | Error Message
            deriving (Eq, Show)
 
+type Message = String
+
 ------------------------------- Level --------------------------------
 
 data Level = Level {

lib/RPGEngine/Data/Level.hs

@@ -5,8 +5,9 @@ where
 import GHC.IO (unsafePerformIO)
 import System.Directory (getDirectoryContents)
 import RPGEngine.Input.Core (ListSelector(..))
-import RPGEngine.Data (Level (..), Physical (..), Direction (..), Entity (..), Game (..), Item (..), Player (..), State (..), X, Y, Layout)
+import RPGEngine.Data (Action(..), Level (..), Physical (..), Direction (..), Entity (..), Game (..), Item (..), Player (..), State (..), X, Y, Layout, Condition (InventoryFull, InventoryContains, Not, AlwaysFalse))
 import RPGEngine.Config (levelFolder)
+import Data.Foldable (find)
 
 ------------------------------ Exported ------------------------------
 
@@ -25,6 +26,17 @@ findAt pos lvl@Level{ index = index } = try
           try     | not (null matches) = head matches
                   | otherwise          = Void
 
+hasAt :: (X, Y) -> Level -> Maybe (Either Item Entity)
+hasAt pos level = match firstItem firstEntity
+    where match :: Maybe Item -> Maybe Entity -> Maybe (Either Item Entity)
+          match (Just a) _ = Just $ Left a
+          match _ (Just a) = Just $ Right a
+          match _ _        = Nothing
+          firstEntity = find ((== pos) . getECoord) $ entities level
+          getECoord e = (entityX e, entityY e)
+          firstItem   = find ((== pos) . getICoord) $ items level
+          getICoord i = (itemX i, itemY i)
+
 directionOffsets :: Direction -> (X, Y)
 directionOffsets North  = ( 0,  1)
 directionOffsets East   = ( 1,  0)
@@ -34,3 +46,28 @@ directionOffsets Stay   = ( 0,  0)
 
 getLevelList :: [FilePath]
 getLevelList = drop 2 $ unsafePerformIO $ getDirectoryContents levelFolder
+
+-- Get the actions of either an entity or an item
+getActions :: Either Item Entity -> [([Condition], Action)]
+getActions (Left item)    = itemActions item
+getActions (Right entity) = entityActions entity
+
+getActionText :: Action -> String
+getActionText Leave            = "Leave"
+getActionText (RetrieveItem _) = "Pick up"
+getActionText (UseItem _)      = "Use item"
+getActionText _ = "ERROR"
+
+-- TODO Check conditions
+-- Filter based on the conditions, keep only the actions of which the
+-- conditions are met.
+filterActions :: [([Condition], Action)] -> [Action]
+filterActions [] = []
+filterActions ((conditions, action):others) = action:filterActions others
+
+-- Check if a condition is met or not.
+meetsCondition :: Condition -> Bool
+meetsCondition InventoryFull          = False -- TODO
+meetsCondition (InventoryContains id) = True -- TODO
+meetsCondition (Not condition)        = not $ meetsCondition condition
+meetsCondition AlwaysFalse            = False

lib/RPGEngine/Input.hs

@@ -13,6 +13,7 @@ import RPGEngine.Input.Playing ( handleInputPlaying )
 import RPGEngine.Input.Paused ( handleInputPaused )
 import RPGEngine.Input.Win ( handleInputWin )
 import RPGEngine.Input.Lose ( handleInputLose )
+import RPGEngine.Input.ActionSelection (handleInputActionSelection)
 
 ------------------------------ Exported ------------------------------
 
@@ -24,3 +25,5 @@ handleAllInput ev g@Game{ state = Playing{}        } = handleInputPlaying ev g
 handleAllInput ev g@Game{ state = Paused{}         } = handleInputPaused ev g
 handleAllInput ev g@Game{ state = Win              } = handleInputWin ev g
 handleAllInput ev g@Game{ state = Lose{}           } = handleInputLose ev g
+handleAllInput ev g@Game{ state = ActionSelection{}} = handleInputActionSelection ev g
+handleAllInput ev g@Game{ state = Error _          } = handleAnyKey (\game -> game{ state = Menu}) ev g

lib/RPGEngine/Input/ActionSelection.hs

@@ -0,0 +1,76 @@
+module RPGEngine.Input.ActionSelection
+( handleInputActionSelection
+) where
+
+import RPGEngine.Input.Core (InputHandler, handleKey, composeInputHandlers, ListSelector (selection))
+
+import RPGEngine.Data (Game (..), State (..), Direction (..), Action (..), ItemId, EntityId)
+import Graphics.Gloss.Interface.IO.Game (Key(SpecialKey), SpecialKey (KeyUp, KeyDown))
+import Graphics.Gloss.Interface.IO.Interact
+    ( SpecialKey(..), KeyState(..) )
+
+------------------------------ Exported ------------------------------
+
+handleInputActionSelection :: InputHandler Game
+handleInputActionSelection = composeInputHandlers [
+    handleKey (SpecialKey KeySpace) Down selectAction,
+
+    handleKey (SpecialKey KeyUp)    Down $ moveSelector North,
+    handleKey (SpecialKey KeyDown)  Down $ moveSelector South
+    ]
+
+----------------------------------------------------------------------
+
+selectAction :: Game -> Game
+selectAction game@Game{ state = ActionSelection list selection continue } = newGame
+    where newGame = game{ state = execute selectedAction continue }
+          selectedAction = Leave
+selectAction g = g
+
+-- TODO Lift this code from LevelSelection
+-- Move the selector either up or down
+moveSelector :: Direction -> Game -> Game
+moveSelector dir game@Game{ state = state@(ActionSelection list selector _) } = newGame
+    where newGame      = game{ state = newState }
+          newState     = state{ selector = newSelector }
+          newSelector  | constraint = selector{ selection = newSelection }
+                       | otherwise = selector
+          constraint   = 0 <= newSelection && newSelection < length list
+          newSelection = selection selector + diff
+          diff         | dir == North = -1
+                       | dir == South =  1
+                       | otherwise    =  0
+moveSelector _ g = g{ state = Error "Something went wrong while moving the selector up or down"}
+
+------------------------------ Actions -------------------------------
+
+execute :: Action -> State -> State
+execute (RetrieveItem id     ) s = pickUpItem id s
+execute (UseItem      id     ) s = useItem id s
+execute (DecreaseHp   eid iid) s = decreaseHp eid iid s
+execute (IncreasePlayerHp iid) s = increasePlayerHp iid s
+execute _ s = s
+
+-- Pick up the item with itemId and put it in the players inventory
+pickUpItem :: ItemId -> State -> State
+pickUpItem _ s = s -- TODO
+
+-- Use an item on the player
+useItem :: ItemId -> State -> State -- TODO
+useItem _ s = s -- TODO
+
+-- Attack an entity using an item
+decreaseHp :: EntityId -> ItemId -> State -> State
+decreaseHp _ _ s = s
+-- TODO DecreaseHp of monster
+-- TODO Check if monster is dead
+-- TODO Entity attack player
+-- TODO Decrease durability of item
+-- TODO Break item if durability below zero
+
+-- Heal a bit
+increasePlayerHp :: ItemId -> State -> State
+increasePlayerHp _ s = s
+-- TODO Increase playerHp
+-- TODO Decrease durability of item
+-- TODO Remove item if durability below zero

lib/RPGEngine/Input/LevelSelection.hs

@@ -24,14 +24,15 @@ handleInputLevelSelection = composeInputHandlers [
 
 -- Select a level and load it in
 selectLevel :: Game -> Game
-selectLevel game@Game{ state = LevelSelection{ levelList = list, selector = selector }} = newGame
+selectLevel game@Game{ state = LevelSelection list selector } = newGame
     where newGame      = parse $ levelFolder ++ (list !! index)
           index        = selection selector
-selectLevel g = g
+selectLevel g = g{ state = Error "Something went wrong while selecting a level"}
 
+-- TODO Lift this code from ActionSelection
 -- Move the selector either up or down
 moveSelector :: Direction -> Game -> Game
-moveSelector dir game@Game{ state = state@LevelSelection{ levelList = list, selector = selector } } = newGame
+moveSelector dir game@Game{ state = state@(LevelSelection list selector) } = newGame
     where newGame      = game{ state = newState }
           newState     = state{ selector = newSelector }
           newSelector  | constraint = selector{ selection = newSelection }
@@ -41,4 +42,4 @@ moveSelector dir game@Game{ state = state@LevelSelection{ levelList = list, sele
           diff         | dir == North = -1
                        | dir == South =  1
                        | otherwise    =  0
-moveSelector _ g = g
+moveSelector _ g = g{ state = Error "Something went wrong while moving the selector up or down"}

lib/RPGEngine/Input/Playing.hs

@@ -5,15 +5,16 @@ module RPGEngine.Input.Playing
 , putCoords
 ) where
 
-import RPGEngine.Input.Core (InputHandler, handle, handleKey, composeInputHandlers)
+import RPGEngine.Input.Core (InputHandler, handle, handleKey, composeInputHandlers, ListSelector (..))
 
-import RPGEngine.Data (Game (..), Layout(..), Level(..), Physical(..), Player(..), State(..), X, Y, Direction (..))
+import RPGEngine.Data (Game (..), Layout(..), Level(..), Physical(..), Player(..), State(..), X, Y, Direction (..), Entity (..), Item (..))
 import RPGEngine.Data.Game (isLegalMove, isPlayerDead, isPlayerAtExit)
-import RPGEngine.Data.Level (directionOffsets, findFirstOf)
+import RPGEngine.Data.Level (directionOffsets, findFirstOf, hasAt, filterActions, getActions)
 
 import Data.Maybe (fromJust, isNothing)
 import Graphics.Gloss.Interface.IO.Game (Key(..))
 import Graphics.Gloss.Interface.IO.Interact (SpecialKey(..), KeyState(..), Event(..), KeyState(..))
+import Prelude hiding (interact)
 
 ------------------------------ Exported ------------------------------
 
@@ -28,15 +29,21 @@ handleInputPlaying = composeInputHandlers [
     handleKey (SpecialKey KeyDown)  Down $ movePlayer South,
     handleKey (SpecialKey KeyLeft)  Down $ movePlayer West,
 
-    handleKey (Char 'w') Down $ movePlayer North,
-    handleKey (Char 'd') Down $ movePlayer East,
-    handleKey (Char 's') Down $ movePlayer South,
-    handleKey (Char 'a') Down $ movePlayer West,
+    handleKey (Char 'w')            Down $ movePlayer North,
+    handleKey (Char 'd')            Down $ movePlayer East,
+    handleKey (Char 's')            Down $ movePlayer South,
+    handleKey (Char 'a')            Down $ movePlayer West,
 
-    handleKey (Char 'r') Down restartGame,
+    -- Interaction with entities and items
+    handleKey (SpecialKey KeySpace) Down checkForInteraction,
+    handleKey (Char 'f')            Down checkForInteraction,
 
-    handleKey (Char 'i') Down $ toggleInventoryShown True,
-    handleKey (Char 'i') Up   $ toggleInventoryShown False
+    handleKey (Char 'i')            Down $ toggleInventoryShown True,
+    handleKey (Char 'i')            Up   $ toggleInventoryShown False,
+    handleKey (SpecialKey KeyTab)   Down $ toggleInventoryShown True,
+    handleKey (SpecialKey KeyTab)   Up   $ toggleInventoryShown False,
+
+    handleKey (Char 'r')            Down restartGame
     ]
 
 ----------------------------------------------------------------------
@@ -63,6 +70,7 @@ pauseGame g = g
 
 restartGame :: Game -> Game
 restartGame g@Game{ state = playing@Playing{ restart = restarted } } = g{ state = restarted }
+restartGame g = g{ state = Error "something went wrong while restarting the level"}
 
 -- Go to next level if there is a next level, otherwise, initialize win state.
 goToNextLevel :: State -> State
@@ -83,16 +91,39 @@ movePlayer dir g@Game{ state = s@Playing{ player = p@Player{ position = (x, y) }
           newCoord  | isLegalMove dir g = (x + xD, y + yD)
                     | otherwise         = (x, y)
           (xD, yD)  = directionOffsets dir
-movePlayer _ g = g
+movePlayer _ g = g{ state = Error "something went wrong while moving the player" }
+
+checkForInteraction :: Game -> Game
+checkForInteraction g@Game{ state = Playing{ level = level, player = player }} = newGame
+    where newGame       | canInteract = interact g
+                        | otherwise   = g
+          canInteract   = not $ null $ hasAt pos level
+          pos           = position player
+checkForInteraction g = g{ state = Error "something went wrong while checking for entities to interact with" }
+
+interact :: Game -> Game
+interact g@Game{ state = s@Playing{ level = level, player = player } } = g{ state = newState }
+    where newState   = ActionSelection actionList selector continue
+          actionList = filterActions $ getActions $ fromJust $ hasAt pos level
+          selector   = ListSelector 0 False
+          pos        = position player
+          continue   = s
+interact g = g{ state = Error "something went wrong while interacting with object"}
 
 toggleInventoryShown :: Bool -> Game -> Game
 toggleInventoryShown shown g@Game{ state = s@Playing{ player = p }}= newGame
     where newGame   = g{ state  = newState     }
           newState  = s{ player = newPlayer    }
           newPlayer = p{ showInventory = shown }
+toggleInventoryShown _ g = g{ state = Error "something went wrong while working inventory" }
 
 -- Map all Physicals onto coordinates
 putCoords :: Level -> [(X, Y, Physical)]
 putCoords l@Level{ layout = lay } = concatMap (\(a, bs) -> map (\(b, c) -> (b, a, c)) bs) numberedList
     where numberedStrips = reverse $ zip [0::Int .. ] $ reverse lay
           numberedList   = map (\(x, strip) -> (x, zip [0::Int ..] strip)) numberedStrips
+
+-- putCoords l = concatMap numberColumns intermediate
+--     where numberColumns (rowIndex, numberedRow) = map (\(colIndex, cell) -> (colIndex, rowIndex, cell)) numberedRow
+--           intermediate                  = zip [0 .. ] numberedRows
+--           numberedRows                  = zip [0::X .. ] $ layout l

lib/RPGEngine/Render.hs

@@ -15,9 +15,11 @@ import RPGEngine.Render.Paused ( renderPaused )
 import RPGEngine.Render.Win ( renderWin )
 import RPGEngine.Render.Lose ( renderLose )
 
-import Graphics.Gloss (Display)
+import Graphics.Gloss ( Display, text, color )
 import Graphics.Gloss.Data.Picture (Picture, blank)
 import Graphics.Gloss.Data.Display (Display(..))
+import RPGEngine.Render.ActionSelection (renderActionSelection)
+import RPGEngine.Config (textColor)
 
 ----------------------------------------------------------------------
 
@@ -33,3 +35,5 @@ render Game{ state = s@Playing{}        } = renderPlaying s
 render Game{ state = s@Paused{}         } = renderPaused s
 render Game{ state = s@Win              } = renderWin s
 render Game{ state = s@Lose{}           } = renderLose s
+render Game{ state = s@ActionSelection{}} = renderActionSelection s
+render Game{ state = Error message      } = color textColor $ text message

lib/RPGEngine/Render/ActionSelection.hs

@@ -0,0 +1,26 @@
+module RPGEngine.Render.ActionSelection
+( renderActionSelection
+) where
+
+import RPGEngine.Data (State (..), Action (..))
+import Graphics.Gloss
+    ( Picture, text, pictures, translate, scale, color )
+import Graphics.Gloss.Data.Picture (blank)
+import RPGEngine.Data.Level (getActionText)
+import RPGEngine.Config (uizoom, selectionColor, textColor)
+import RPGEngine.Input.Core (ListSelector(selection))
+import RPGEngine.Render.Playing (renderPlaying)
+import RPGEngine.Render.Core (overlay)
+
+------------------------------ Exported ------------------------------
+
+renderActionSelection :: State -> Picture
+renderActionSelection (ActionSelection list selector continue) = everything
+    where numberedTexts = zip [0::Int ..] $ map getActionText list
+          sel           = selection selector
+          everything    = pictures $ [renderPlaying continue, overlay] ++ map render numberedTexts
+          render (i, t) | i == sel  = color selectionColor $ make (i, t)
+                        | otherwise = color textColor      $ make (i, t)
+          make (i, t)   = scale uizoom uizoom $ translate 0 (offset i) $ text t
+          offset i      = negate (250 * uizoom * fromIntegral i)
+renderActionSelection _ = blank

lib/RPGEngine/Render/LevelSelection.hs

@@ -21,7 +21,7 @@ renderLevelSelection state = result
 ----------------------------------------------------------------------
 
 renderLevelList :: Renderer State
-renderLevelList LevelSelection{ levelList = list, selector = selector } = everything
+renderLevelList (LevelSelection list selector) = everything
     where everything       = pictures $ map render entries
           sel              = selection selector
           entries          = zip [0::Int .. ] list

lib/RPGEngine/Render/Playing.hs

@@ -42,7 +42,8 @@ focusPlayer _ = id
 renderLevel :: Renderer Level
 renderLevel Level{ layout = l, items = i, entities = e } = level
     where level    = pictures [void, layout, items, entities]
-          void     = createVoid
+        --   void     = createVoid
+          void     = blank
           layout   = renderLayout l
           items    = renderItems i
           entities = renderEntities e

rpg-engine.cabal

@@ -23,6 +23,7 @@ library
 
     RPGEngine.Input
     RPGEngine.Input.Core
+    RPGEngine.Input.ActionSelection
     RPGEngine.Input.Menu
     RPGEngine.Input.LevelSelection
     RPGEngine.Input.Playing
@@ -37,6 +38,7 @@ library
     
     RPGEngine.Render
     RPGEngine.Render.Core
+    RPGEngine.Render.ActionSelection
     RPGEngine.Render.Menu
     RPGEngine.Render.LevelSelection
     RPGEngine.Render.Playing