Split logic up a bit

game/game_context.go

@@ -31,16 +31,18 @@ func CreateGameContext() *GameContext {
 }
 
 func (gc *GameContext) Run() {
+	lastLoop := time.Now()
 	lastTick := time.Now()
 
 	for {
-		deltaTime := 1 + time.Since(lastTick).Microseconds()
+		deltaTime := 1 + time.Since(lastLoop).Microseconds()
-		lastTick = time.Now()
+		lastLoop = time.Now()
 
 		for _, e := range gc.renderContext.CollectInputEvents() {
 			gc.game.Input(e)
 		}
 
+		if time.Since(lastTick).Milliseconds() >= TICK_RATE {
 			stop := !gc.game.Tick(deltaTime)
 
 			if stop {
@@ -49,6 +51,9 @@ func (gc *GameContext) Run() {
 				break
 			}
 
+			lastTick = time.Now()
+		}
+
 		drawables := gc.game.CollectDrawables()
 		gc.renderContext.Draw(deltaTime, drawables)
 	}

game/logic/logic_snippet.go

@@ -0,0 +1,12 @@
+package model
+
+import (
+	"mvvasilev/last_light/game/model"
+
+	"github.com/gdamore/tcell/v2"
+)
+
+type LogicSnippet[T model.Entity] interface {
+	Input(e *tcell.EventKey)
+	Tick(dt int64, entity T)
+}

game/model/dungeon.go

@@ -1,7 +0,0 @@
-package model
-
-type Dungeon struct {
-	player *Player
-
-	levels []Map
-}

game/model/empty_dungeon_level.go

@@ -1,37 +0,0 @@
-package model
-
-import "mvvasilev/last_light/util"
-
-type EmptyDungeonLevel struct {
-	level *BasicMap
-}
-
-func CreateEmptyDungeonLevel(width, height int) *EmptyDungeonLevel {
-	m := new(EmptyDungeonLevel)
-
-	tiles := make([][]Tile, height)
-
-	for h := range height {
-		tiles[h] = make([]Tile, width)
-	}
-
-	m.level = CreateBasicMap(tiles)
-
-	return m
-}
-
-func (edl *EmptyDungeonLevel) Size() util.Size {
-	return edl.level.Size()
-}
-
-func (edl *EmptyDungeonLevel) SetTileAt(x int, y int, t Tile) {
-	edl.level.SetTileAt(x, y, t)
-}
-
-func (edl *EmptyDungeonLevel) TileAt(x int, y int) Tile {
-	return edl.level.TileAt(x, y)
-}
-
-func (edl *EmptyDungeonLevel) Tick() {
-
-}

game/model/entity.go

@@ -40,5 +40,7 @@ type Entity interface {
 
 type MovableEntity interface {
 	Position() util.Position
-	Move(dir Direction)
+	MoveTo(newPosition util.Position)
+
+	Entity
 }

game/model/flat_ground_dungeon_level.go

@@ -1,75 +0,0 @@
-package model
-
-import (
-	"math/rand"
-	"mvvasilev/last_light/util"
-
-	"github.com/gdamore/tcell/v2"
-)
-
-type FlatGroundDungeonLevel struct {
-	tiles [][]Tile
-}
-
-func CreateFlatGroundDungeonLevel(width, height int) *FlatGroundDungeonLevel {
-	level := new(FlatGroundDungeonLevel)
-
-	level.tiles = make([][]Tile, height)
-
-	for h := range height {
-		level.tiles[h] = make([]Tile, width)
-
-		for w := range width {
-			if w == 0 || h == 0 || w >= width-1 || h >= height-1 {
-				level.tiles[h][w] = CreateStaticTile(w, h, TileTypeRock())
-				continue
-			}
-
-			level.tiles[h][w] = genRandomGroundTile(w, h)
-		}
-	}
-
-	return level
-}
-
-func genRandomGroundTile(width, height int) Tile {
-	switch rand.Intn(2) {
-	case 0:
-		return CreateStaticTile(width, height, TileTypeGround())
-	case 1:
-		return CreateStaticTile(width, height, TileTypeGrass())
-	default:
-		return CreateStaticTile(width, height, TileTypeGround())
-	}
-}
-
-func (edl *FlatGroundDungeonLevel) Size() util.Size {
-	return util.SizeOf(len(edl.tiles[0]), len(edl.tiles))
-}
-
-func (edl *FlatGroundDungeonLevel) SetTileAt(x int, y int, t Tile) {
-	if len(edl.tiles) <= y || len(edl.tiles[0]) <= x {
-		return
-	}
-
-	edl.tiles[y][x] = t
-}
-
-func (edl *FlatGroundDungeonLevel) TileAt(x int, y int) Tile {
-	if y < 0 || y >= len(edl.tiles) {
-		return nil
-	}
-
-	if x < 0 || x >= len(edl.tiles[y]) {
-		return nil
-	}
-
-	return edl.tiles[y][x]
-}
-
-func (edl *FlatGroundDungeonLevel) Input(e *tcell.EventKey) {
-
-}
-
-func (edl *FlatGroundDungeonLevel) Tick() {
-}

game/model/player.go

@@ -32,8 +32,8 @@ func (p *Player) Position() util.Position {
 	return p.position
 }
 
-func (p *Player) Move(dir Direction) {
+func (p *Player) MoveTo(newPos util.Position) {
-	p.position = p.Position().WithOffset(MovementDirectionOffset(dir))
+	p.position = newPos
 }
 
 func (p *Player) Presentation() (rune, tcell.Style) {

game/state/look_state.go

@@ -0,0 +1,22 @@
+package state
+
+import (
+	"mvvasilev/last_light/render"
+
+	"github.com/gdamore/tcell/v2"
+)
+
+type LookState struct {
+}
+
+func (ls *LookState) OnInput(e *tcell.EventKey) {
+	panic("not implemented") // TODO: Implement
+}
+
+func (ls *LookState) OnTick(dt int64) GameState {
+	panic("not implemented") // TODO: Implement
+}
+
+func (ls *LookState) CollectDrawables() []render.Drawable {
+	panic("not implemented") // TODO: Implement
+}

game/state/playing_state.go

@@ -3,6 +3,7 @@ package state
 import (
 	"math/rand"
 	"mvvasilev/last_light/game/model"
+	"mvvasilev/last_light/game/world"
 	"mvvasilev/last_light/render"
 	"mvvasilev/last_light/util"
 
@@ -12,7 +13,8 @@ import (
 
 type PlayingState struct {
 	player    *model.Player
-	level  *model.MultilevelMap
+	entityMap *world.EntityMap
+	level     *world.MultilevelMap
 
 	viewport *render.Viewport
 
@@ -27,11 +29,11 @@ func BeginPlayingState() *PlayingState {
 
 	mapSize := util.SizeOf(128, 128)
 
-	dungeonLevel := model.CreateBSPDungeonLevel(mapSize.Width(), mapSize.Height(), 4)
+	dungeonLevel := world.CreateBSPDungeonMap(mapSize.Width(), mapSize.Height(), 4)
 
 	itemTiles := spawnItems(dungeonLevel)
 
-	itemLevel := model.CreateEmptyDungeonLevel(mapSize.Width(), mapSize.Height())
+	itemLevel := world.CreateEmptyDungeonLevel(mapSize.Width(), mapSize.Height())
 
 	for _, it := range itemTiles {
 		itemLevel.SetTileAt(it.Position().X(), it.Position().Y(), it)
@@ -39,13 +41,15 @@ func BeginPlayingState() *PlayingState {
 
 	s.player = model.CreatePlayer(dungeonLevel.PlayerSpawnPoint().XY())
 
-	s.level = model.CreateMultilevelMap(
+	s.entityMap = world.CreateEntityMap(mapSize.WH())
+
+	s.level = world.CreateMultilevelMap(
 		dungeonLevel,
 		itemLevel,
-		model.CreateEmptyDungeonLevel(mapSize.WH()),
+		s.entityMap,
 	)
 
-	s.level.SetTileAtHeight(dungeonLevel.PlayerSpawnPoint().X(), dungeonLevel.PlayerSpawnPoint().Y(), 2, s.player)
+	s.entityMap.AddEntity(s.player, '@', tcell.StyleDefault)
 
 	s.viewport = render.CreateViewport(
 		util.PositionAt(0, 0),
@@ -57,7 +61,7 @@ func BeginPlayingState() *PlayingState {
 	return s
 }
 
-func spawnItems(level *model.BSPDungeonLevel) []model.Tile {
+func spawnItems(level *world.BSPDungeonMap) []world.Tile {
 	rooms := level.Rooms()
 
 	genTable := make(map[float32]*model.ItemType)
@@ -67,7 +71,7 @@ func spawnItems(level *model.BSPDungeonLevel) []model.Tile {
 	genTable[0.051] = model.ItemTypeLongsword()
 	genTable[0.052] = model.ItemTypeKey()
 
-	itemTiles := make([]model.Tile, 0, 10)
+	itemTiles := make([]world.Tile, 0, 10)
 
 	for _, r := range rooms {
 		maxItems := int(0.10 * float64(r.Size().Area()))
@@ -90,7 +94,7 @@ func spawnItems(level *model.BSPDungeonLevel) []model.Tile {
 				util.RandInt(r.Position().Y()+1, r.Position().Y()+r.Size().Height()-1),
 			)
 
-			itemTiles = append(itemTiles, model.CreateItemTile(
+			itemTiles = append(itemTiles, world.CreateItemTile(
 				pos, itemType, 1,
 			))
 		}
@@ -117,14 +121,12 @@ func (ps *PlayingState) MovePlayer() {
 	}
 
 	newPlayerPos := ps.player.Position().WithOffset(model.MovementDirectionOffset(ps.movePlayerDirection))
-
 	tileAtMovePos := ps.level.TileAt(newPlayerPos.XY())
 
 	if tileAtMovePos.Passable() {
-		ps.level.SetTileAtHeight(ps.player.Position().X(), ps.player.Position().Y(), 2, nil)
+		dx, dy := model.MovementDirectionOffset(ps.movePlayerDirection)
-		ps.player.Move(ps.movePlayerDirection)
+		ps.entityMap.MoveEntity(ps.player.UniqueId(), dx, dy)
 		ps.viewport.SetCenter(ps.player.Position())
-		ps.level.SetTileAtHeight(ps.player.Position().X(), ps.player.Position().Y(), 2, ps.player)
 	}
 
 	ps.movePlayerDirection = model.DirectionNone
@@ -134,7 +136,7 @@ func (ps *PlayingState) PickUpItemUnderPlayer() {
 	pos := ps.player.Position()
 	tile := ps.level.TileAtHeight(pos.X(), pos.Y(), 1)
 
-	itemTile, ok := tile.(*model.ItemTile)
+	itemTile, ok := tile.(*world.ItemTile)
 
 	if !ok {
 		return
@@ -178,17 +180,6 @@ func (ps *PlayingState) OnInput(e *tcell.EventKey) {
 		ps.movePlayerDirection = model.DirectionLeft
 	case tcell.KeyRight:
 		ps.movePlayerDirection = model.DirectionRight
-	case tcell.KeyRune:
-		switch e.Rune() {
-		case 'w':
-			ps.movePlayerDirection = model.DirectionUp
-		case 'a':
-			ps.movePlayerDirection = model.DirectionLeft
-		case 's':
-			ps.movePlayerDirection = model.DirectionDown
-		case 'd':
-			ps.movePlayerDirection = model.DirectionRight
-		}
 	}
 }
 

game/world/bsp_map.go

@@ -0,0 +1,35 @@
+package world
+
+import (
+	"mvvasilev/last_light/util"
+)
+
+type BSPDungeonMap struct {
+	level *BasicMap
+
+	playerSpawnPoint util.Position
+	rooms            []util.Room
+}
+
+func (bsp *BSPDungeonMap) PlayerSpawnPoint() util.Position {
+	return bsp.playerSpawnPoint
+}
+
+func (bsp *BSPDungeonMap) Size() util.Size {
+	return bsp.level.Size()
+}
+
+func (bsp *BSPDungeonMap) SetTileAt(x int, y int, t Tile) {
+	bsp.level.SetTileAt(x, y, t)
+}
+
+func (bsp *BSPDungeonMap) TileAt(x int, y int) Tile {
+	return bsp.level.TileAt(x, y)
+}
+
+func (bsp *BSPDungeonMap) Tick(dt int64) {
+}
+
+func (bsp *BSPDungeonMap) Rooms() []util.Room {
+	return bsp.rooms
+}

game/world/dungeon.go

@@ -0,0 +1,15 @@
+package world
+
+import "mvvasilev/last_light/game/model"
+
+type dungeonLevel struct {
+	groundLevel Map
+	entityLevel *EntityMap
+	itemLevel   *Map
+}
+
+type Dungeon struct {
+	player *model.Player
+
+	levels []*dungeonLevel
+}

game/world/empty_map.go

@@ -0,0 +1,23 @@
+package world
+
+import "mvvasilev/last_light/util"
+
+type EmptyDungeonMap struct {
+	level *BasicMap
+}
+
+func (edl *EmptyDungeonMap) Size() util.Size {
+	return edl.level.Size()
+}
+
+func (edl *EmptyDungeonMap) SetTileAt(x int, y int, t Tile) {
+	edl.level.SetTileAt(x, y, t)
+}
+
+func (edl *EmptyDungeonMap) TileAt(x int, y int) Tile {
+	return edl.level.TileAt(x, y)
+}
+
+func (edl *EmptyDungeonMap) Tick(dt int64) {
+
+}

game/world/entity_map.go

@@ -0,0 +1,101 @@
+package world
+
+import (
+	"maps"
+	"mvvasilev/last_light/game/model"
+	"mvvasilev/last_light/util"
+
+	"github.com/gdamore/tcell/v2"
+	"github.com/google/uuid"
+)
+
+type EntityMap struct {
+	entities map[int]EntityTile
+
+	util.Sized
+}
+
+func CreateEntityMap(width, height int) *EntityMap {
+	return &EntityMap{
+		entities: make(map[int]EntityTile, 0),
+		Sized:    util.WithSize(util.SizeOf(width, height)),
+	}
+}
+
+func (em *EntityMap) SetTileAt(x int, y int, t Tile) {
+	// if !em.FitsWithin(x, y) {
+	// 	return
+	// }
+
+	// index := em.Size().AsArrayIndex(x, y)
+
+	// TODO? May not be necessary
+}
+
+func (em *EntityMap) FindEntityByUuid(uuid uuid.UUID) (key int, entity EntityTile) {
+	for i, e := range em.entities {
+		if e.Entity().UniqueId() == uuid {
+			return i, e
+		}
+	}
+
+	return -1, nil
+}
+
+func (em *EntityMap) AddEntity(entity model.MovableEntity, presentation rune, style tcell.Style) {
+	if !em.FitsWithin(entity.Position().XY()) {
+		return
+	}
+
+	key := em.Size().AsArrayIndex(entity.Position().XY())
+	et := CreateBasicEntityTile(entity, presentation, style)
+
+	em.entities[key] = et
+}
+
+func (em *EntityMap) DropEntity(uuid uuid.UUID) {
+	maps.DeleteFunc(em.entities, func(i int, et EntityTile) bool {
+		if et.Entity().UniqueId() == uuid {
+			return true
+		}
+
+		return false
+	})
+}
+
+func (em *EntityMap) MoveEntity(uuid uuid.UUID, dx, dy int) {
+	oldKey, e := em.FindEntityByUuid(uuid)
+
+	if e == nil {
+		return
+	}
+
+	if !em.FitsWithin(e.Entity().Position().WithOffset(dx, dy).XY()) {
+		return
+	}
+
+	delete(em.entities, oldKey)
+
+	newPos := e.Entity().Position().WithOffset(dx, dy)
+	e.Entity().MoveTo(newPos)
+
+	newKey := em.Size().AsArrayIndex(e.Entity().Position().XY())
+
+	em.entities[newKey] = e
+}
+
+func (em *EntityMap) TileAt(x int, y int) Tile {
+	if !em.FitsWithin(x, y) {
+		return CreateStaticTile(x, y, TileTypeVoid())
+	}
+
+	key := em.Size().AsArrayIndex(x, y)
+
+	return em.entities[key]
+}
+
+func (em *EntityMap) Tick(dt int64) {
+	for _, e := range em.entities {
+		e.Entity().Tick(dt)
+	}
+}

game/world/generate_bsp_map.go

@@ -1,4 +1,4 @@
-package model
+package world
 
 import (
 	"math/rand"
@@ -16,7 +16,7 @@ type bspNode struct {
 	origin util.Position
 	size   util.Size
 
-	room    Room
+	room    util.Room
 	hasRoom bool
 
 	left  *bspNode
@@ -25,27 +25,7 @@ type bspNode struct {
 	splitDir splitDirection
 }
 
-type Room struct {
+func CreateBSPDungeonMap(width, height int, numSplits int) *BSPDungeonMap {
-	position util.Position
-	size     util.Size
-}
-
-func (r Room) Size() util.Size {
-	return r.size
-}
-
-func (r Room) Position() util.Position {
-	return r.position
-}
-
-type BSPDungeonLevel struct {
-	level *BasicMap
-
-	playerSpawnPoint util.Position
-	rooms            []Room
-}
-
-func CreateBSPDungeonLevel(width, height int, numSplits int) *BSPDungeonLevel {
 	root := new(bspNode)
 
 	root.origin = util.PositionAt(0, 0)
@@ -59,7 +39,7 @@ func CreateBSPDungeonLevel(width, height int, numSplits int) *BSPDungeonLevel {
 		tiles[h] = make([]Tile, width)
 	}
 
-	rooms := make([]Room, 0, 2^numSplits)
+	rooms := make([]util.Room, 0, 2^numSplits)
 
 	iterateBspLeaves(root, func(leaf *bspNode) {
 		x := util.RandInt(leaf.origin.X(), leaf.origin.X()+leaf.size.Width()/4)
@@ -75,9 +55,9 @@ func CreateBSPDungeonLevel(width, height int, numSplits int) *BSPDungeonLevel {
 			h = h - (y + h - height) - 1
 		}
 
-		room := Room{
+		room := util.Room{
-			position: util.PositionAt(x, y),
+			Positioned: util.WithPosition(util.PositionAt(x, y)),
-			size:     util.SizeOf(w, h),
+			Sized:      util.WithSize(util.SizeOf(w, h)),
 		}
 
 		rooms = append(rooms, room)
@@ -95,36 +75,32 @@ func CreateBSPDungeonLevel(width, height int, numSplits int) *BSPDungeonLevel {
 		zCorridor(
 			tiles,
 			util.PositionAt(
-				roomLeft.position.X()+roomLeft.size.Width()/2,
+				roomLeft.Position().X()+roomLeft.Size().Width()/2,
-				roomLeft.position.Y()+roomLeft.size.Height()/2,
+				roomLeft.Position().Y()+roomLeft.Size().Height()/2,
 			),
 			util.PositionAt(
-				roomRight.position.X()+roomRight.size.Width()/2,
+				roomRight.Position().X()+roomRight.Size().Width()/2,
-				roomRight.position.Y()+roomRight.size.Height()/2,
+				roomRight.Position().Y()+roomRight.Size().Height()/2,
 			),
 			parent.splitDir,
 		)
 	})
 
-	bsp := new(BSPDungeonLevel)
+	bsp := new(BSPDungeonMap)
 
 	spawnRoom := findRoom(root.left)
 
 	bsp.rooms = rooms
 	bsp.level = CreateBasicMap(tiles)
 	bsp.playerSpawnPoint = util.PositionAt(
-		spawnRoom.position.X()+spawnRoom.size.Width()/2,
+		spawnRoom.Position().X()+spawnRoom.Size().Width()/2,
-		spawnRoom.position.Y()+spawnRoom.size.Height()/2,
+		spawnRoom.Position().Y()+spawnRoom.Size().Height()/2,
 	)
 
 	return bsp
 }
 
-func (bsp *BSPDungeonLevel) PlayerSpawnPoint() util.Position {
+func findRoom(parent *bspNode) util.Room {
-	return bsp.playerSpawnPoint
-}
-
-func findRoom(parent *bspNode) Room {
 	if parent.hasRoom {
 		return parent.room
 	}
@@ -280,11 +256,11 @@ func placeWallAtIfNotPassable(tiles [][]Tile, x, y int) {
 	tiles[y][x] = CreateStaticTile(x, y, TileTypeWall())
 }
 
-func makeRoom(tiles [][]Tile, room Room) {
+func makeRoom(tiles [][]Tile, room util.Room) {
-	width := room.size.Width()
+	width := room.Size().Width()
-	height := room.size.Height()
+	height := room.Size().Height()
-	x := room.position.X()
+	x := room.Position().X()
-	y := room.position.Y()
+	y := room.Position().Y()
 
 	for w := x; w < x+width+1; w++ {
 		tiles[y][w] = CreateStaticTile(w, y, TileTypeWall())
@@ -302,22 +278,3 @@ func makeRoom(tiles [][]Tile, room Room) {
 		}
 	}
 }
-
-func (bsp *BSPDungeonLevel) Size() util.Size {
-	return bsp.level.Size()
-}
-
-func (bsp *BSPDungeonLevel) SetTileAt(x int, y int, t Tile) {
-	bsp.level.SetTileAt(x, y, t)
-}
-
-func (bsp *BSPDungeonLevel) TileAt(x int, y int) Tile {
-	return bsp.level.TileAt(x, y)
-}
-
-func (bsp *BSPDungeonLevel) Tick() {
-}
-
-func (bsp *BSPDungeonLevel) Rooms() []Room {
-	return bsp.rooms
-}

game/world/generate_empty_map.go

@@ -0,0 +1,15 @@
+package world
+
+func CreateEmptyDungeonLevel(width, height int) *EmptyDungeonMap {
+	m := new(EmptyDungeonMap)
+
+	tiles := make([][]Tile, height)
+
+	for h := range height {
+		tiles[h] = make([]Tile, width)
+	}
+
+	m.level = CreateBasicMap(tiles)
+
+	return m
+}

game/world/map.go

@@ -1,4 +1,4 @@
-package model
+package world
 
 import (
 	"mvvasilev/last_light/util"
@@ -8,7 +8,17 @@ type Map interface {
 	Size() util.Size
 	SetTileAt(x, y int, t Tile)
 	TileAt(x, y int) Tile
-	Tick()
+	Tick(dt int64)
+}
+
+type WithPlayerSpawnPoint interface {
+	PlayerSpawnPoint() util.Position
+	Map
+}
+
+type WithRooms interface {
+	Rooms() []util.Room
+	Map
 }
 
 type BasicMap struct {

game/world/multilevel_map.go

@@ -1,4 +1,4 @@
-package model
+package world
 
 import "mvvasilev/last_light/util"
 
@@ -102,8 +102,8 @@ func (mm *MultilevelMap) TileAtHeight(x, y, height int) Tile {
 	return mm.layers[height].TileAt(x, y)
 }
 
-func (mm *MultilevelMap) Tick() {
+func (mm *MultilevelMap) Tick(dt int64) {
 	for _, l := range mm.layers {
-		l.Tick()
+		l.Tick(dt)
 	}
 }

game/world/tile.go

@@ -1,6 +1,7 @@
-package model
+package world
 
 import (
+	"mvvasilev/last_light/game/model"
 	"mvvasilev/last_light/util"
 
 	"github.com/gdamore/tcell/v2"
@@ -14,6 +15,8 @@ const (
 	MaterialWall
 	MaterialGrass
 	MaterialVoid
+	MaterialClosedDoor
+	MaterialOpenDoor
 )
 
 type TileType struct {
@@ -74,6 +77,26 @@ func TileTypeWall() TileType {
 	}
 }
 
+func TileTypeClosedDoor() TileType {
+	return TileType{
+		Material:     MaterialClosedDoor,
+		Passable:     false,
+		Transparent:  false,
+		Presentation: '[',
+		Style:        tcell.StyleDefault.Foreground(tcell.ColorLightSteelBlue).Background(tcell.ColorSaddleBrown),
+	}
+}
+
+func TileTypeOpenDoor() TileType {
+	return TileType{
+		Material:     MaterialClosedDoor,
+		Passable:     false,
+		Transparent:  false,
+		Presentation: '_',
+		Style:        tcell.StyleDefault.Foreground(tcell.ColorLightSteelBlue),
+	}
+}
+
 type Tile interface {
 	Position() util.Position
 	Presentation() (rune, tcell.Style)
@@ -117,11 +140,11 @@ func (st *StaticTile) Type() TileType {
 
 type ItemTile struct {
 	position util.Position
-	itemType *ItemType
+	itemType *model.ItemType
 	quantity int
 }
 
-func CreateItemTile(position util.Position, itemType *ItemType, quantity int) *ItemTile {
+func CreateItemTile(position util.Position, itemType *model.ItemType, quantity int) *ItemTile {
 	it := new(ItemTile)
 
 	it.position = position
@@ -131,7 +154,7 @@ func CreateItemTile(position util.Position, itemType *ItemType, quantity int) *I
 	return it
 }
 
-func (it *ItemTile) Type() *ItemType {
+func (it *ItemTile) Type() *model.ItemType {
 	return it.itemType
 }
 
@@ -144,7 +167,7 @@ func (it *ItemTile) Position() util.Position {
 }
 
 func (it *ItemTile) Presentation() (rune, tcell.Style) {
-	return it.itemType.tileIcon, it.itemType.style
+	return it.itemType.TileIcon(), it.itemType.Style()
 }
 
 func (it *ItemTile) Passable() bool {
@@ -154,3 +177,43 @@ func (it *ItemTile) Passable() bool {
 func (it *ItemTile) Transparent() bool {
 	return false
 }
+
+type EntityTile interface {
+	Entity() model.MovableEntity
+	Tile
+}
+
+type BasicEntityTile struct {
+	entity model.MovableEntity
+
+	presentation rune
+	style        tcell.Style
+}
+
+func CreateBasicEntityTile(entity model.MovableEntity, presentation rune, style tcell.Style) *BasicEntityTile {
+	return &BasicEntityTile{
+		entity:       entity,
+		presentation: presentation,
+		style:        style,
+	}
+}
+
+func (bet *BasicEntityTile) Entity() model.MovableEntity {
+	return bet.entity
+}
+
+func (bet *BasicEntityTile) Position() util.Position {
+	return bet.entity.Position()
+}
+
+func (bet *BasicEntityTile) Presentation() (rune, tcell.Style) {
+	return bet.presentation, bet.style
+}
+
+func (bet *BasicEntityTile) Passable() bool {
+	return false
+}
+
+func (bet *BasicEntityTile) Transparent() bool {
+	return false
+}

util/util.go

@@ -2,6 +2,20 @@ package util
 
 import "math/rand"
 
+type Positioned struct {
+	pos Position
+}
+
+func WithPosition(pos Position) Positioned {
+	return Positioned{
+		pos: pos,
+	}
+}
+
+func (wp *Positioned) Position() Position {
+	return wp.pos
+}
+
 type Position struct {
 	x int
 	y int
@@ -29,6 +43,25 @@ func (p Position) WithOffset(xOffset int, yOffset int) Position {
 	return p
 }
 
+type Sized struct {
+	size Size
+}
+
+func WithSize(size Size) Sized {
+	return Sized{
+		size: size,
+	}
+}
+
+// Checks if the provided coordinates fit within the sized struct, [0, N)
+func (ws *Sized) FitsWithin(x, y int) bool {
+	return 0 <= x && x < ws.size.width && 0 <= y && y < ws.size.height
+}
+
+func (ws *Sized) Size() Size {
+	return ws.size
+}
+
 type Size struct {
 	width  int
 	height int
@@ -54,6 +87,10 @@ func (s Size) Area() int {
 	return s.width * s.height
 }
 
+func (s Size) AsArrayIndex(x, y int) int {
+	return y*s.width + x
+}
+
 func LimitIncrement(i int, limit int) int {
 	if (i + 1) > limit {
 		return i
@@ -73,3 +110,8 @@ func LimitDecrement(i int, limit int) int {
 func RandInt(min, max int) int {
 	return min + rand.Intn(max-min)
 }
+
+type Room struct {
+	Positioned
+	Sized
+}