Added solver & optimized state.

Positions are kept by index only.
Added path finder & visualization (F5).
2020-01-16 07:33:04 +01:00 · 2020-01-15 21:49:01 +01:00 · 2020-01-15 21:25:32 +01:00 · 2020-01-15 19:51:57 +01:00 · 2020-01-15 19:06:06 +01:00 · 2020-01-15 19:03:52 +01:00
48 changed files with 1901 additions and 498 deletions
--- a/README.md
+++ b/README.md
@ -0,0 +1,356 @@
+# Sokodragon
+
+This game was made for RmBeer, his wishlist:
+```
+1) DRAGONS!!! HUNDREDS AND HUNDREDS, NO, THOUSANDS OF DRAGONS!!!!!! I LOVE DRAGONS AND I WANT SEE ALL!!!!! I WANT A DRAGON LIKE THE MAIN CHARACTER!!!!! \o/
+2) Include morbid scenes, gores or bloody, where humans are destroyed as part of the game. ^^
+3) Make a good story for the game! :D
+4) That is an action game, strategy, or logical problem, can be any of the 3 or all the 3. I like games to think and solve, because they are more challenging. :) (no like puzzle with part of images and no like questions games)
+
+It may be difficult to create 1000 dragons, I settle for one or some if it's difficult for you. :)
+```
+
+Safe to say I failed miserably to meet the requirements. The game features a single dragon and it is a puzzle game which satifies rules 1) and 4). The idea was to let the dragon have to get to a human/villain type (instead of the egg now) but drawing this was too challenging. Didn't think about a good story yet. Nevertheless: I hope you enjoy solving the 4 puzzles added.
+
+## Building
+Prerequisites:
+- [Allegro](https://liballeg.org/) 5.2 (development libraries).
+- [Go](https://golang.org/dl/) 1.12 or later.
+- GCC.
+- Git.
+
+With all prequisites installed you can run:
+```
+go get -u opslag.de/schobers/krampus19/cmd/krampus19
+```
+
+The generated binary can be found in `$GOPATH/bin` and will depend on the dynamic runtimes and the resources found in `$GOPATH/src/opslag.de/schobers/krampus19/cmd/krampus19/res`.
+
+### Sources
+Can be found at https://opslag.de/schobers/krampus19 (Git repository).
+
+### Embedding resources
+```
+go get -u github.com/GeertJohan/go.rice/rice
+go get -u opslag.de/schobers/krampus19/cmd/krampus19
+go generate opslag.de/schobers/krampus19/cmd/krampus19
+go install opslag.de/schobers/krampus19/cmd/krampus19
+```
+
+Note that `go get` of the `rice` tool is only required once.
+
+### Usefull flags
+`go install` can be executed with the following flags (on Windows):
+- `-tags "static"`: to link against Allegro statically.
+- `-tags "console"`: to show the console output in stdout.
+- `-ldflags "-s -w"`: to reduce the binary size.
+
+Example:
+```
+go install -tags "static console" -ldflags "-s -w" opslag.de/schobers/krampus19/cmd/krampus19
+```
+
+## Settings
+
+- Video settings are only taken into account when the game is restarted. The resolution only applies to fullscreen mode (the "Windowed" setting must be unchecked).
+
+## Licenses
+### Fira Mono font
+
+Copyright (c) 2012-2013, The Mozilla Corporation and Telefonica S.A.
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.
+
+### Open Sans font
+
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--- a/cmd/krampus19/animations.go
+++ b/cmd/krampus19/animations.go
@ -14,9 +14,8 @@ type moveAnimation struct {
 	pos      geom.PointF32
 }

-func newMoveAnimation(e *entity, to geom.Point) *moveAnimation {
-	ani := &moveAnimation{e: e, from: e.pos, to: to, pos: e.pos.ToF32()}
-	ani.e.pos = to
+func newMoveAnimation(e *entity, from, to geom.Point) *moveAnimation {
+	ani := &moveAnimation{e: e, from: from, to: to, pos: from.ToF32()}
 	return ani
 }

--- a/cmd/krampus19/changesettings.go
+++ b/cmd/krampus19/changesettings.go
@ -280,7 +280,8 @@ func (s *changeSettings) Enter(ctx *Context) error {
 	)
 	buttons := &alui.StackPanel{Orientation: alui.OrientationHorizontal}
 	buttons.AddChild(
-		newWideButton("Apply", func() {
+		newWideButton("Cancel", func() { s.ctx.Navigation.ShowMainMenu() }),
+		newWideButton("OK", func() {
 			var controls = controls{MoveLeft: keyLeft.Key, MoveUp: keyUp.Key, MoveRight: keyRight.Key, MoveDown: keyDown.Key}
 			var video = video{Windowed: windowed.Selected, DisplayMode: displayMode.Mode()}
 			s.ctx.Settings = settings{Controls: controls, Video: video}
@ -293,11 +294,22 @@ func (s *changeSettings) Enter(ctx *Context) error {

 			s.ctx.Navigation.ShowMainMenu()
 		}),
-		newWideButton("Cancel", func() { s.ctx.Navigation.ShowMainMenu() }),
 	)
 	s.AddChild(alui.Center(buttons))
 	return nil
 }

+func (s *changeSettings) Handle(e allg5.Event) {
+	s.Column.Handle(e)
+
+	switch e := e.(type) {
+	case *allg5.KeyDownEvent:
+		switch e.KeyCode {
+		case allg5.KeyEscape:
+			s.ctx.Navigation.ShowMainMenu()
+		}
+	}
+}
+
 func (s *changeSettings) Leave() {
 }
--- a/cmd/krampus19/console.go
+++ b/cmd/krampus19/console.go
@ -63,7 +63,7 @@ func (c *console) Render(ctx *alui.Context, bounds geom.RectangleF32) {
 		}
 		messageTop := size.Y - totalHeight - c.offset
 		for _, m := range messages {
-			if messageTop <= size.Y || (messageTop+lineHeight) >= 0 {
+			if messageTop <= size.Y && (messageTop+lineHeight) >= 0 {
 				ctx.Fonts.DrawFont(font, 0, messageTop, ctx.Palette.Text, m)
 			}
 			messageTop += lineHeight
--- a/cmd/krampus19/context.go
+++ b/cmd/krampus19/context.go
@ -3,6 +3,7 @@ package main
 import (
 	"time"

+	"github.com/spf13/afero"
 	"opslag.de/schobers/geom"
 	"opslag.de/schobers/krampus19/alui"

@ -23,9 +24,10 @@ func newTexture(bmp *allg5.Bitmap) texture {
 type Context struct {
 	DisplaySize  geom.Point
 	Resources    vfs.CopyDir
+	ResourcesFs  afero.Fs
 	Textures     map[string]texture
 	Sprites      map[string]sprite
-	Levels       map[string]levelPack
+	Levels       *levelPacks
 	Progress     progress
 	SpriteDrawer SpriteDrawer
 	Settings     settings
--- a/cmd/krampus19/entity.go
+++ b/cmd/krampus19/entity.go
@ -2,11 +2,12 @@ package main

 import (
 	"opslag.de/schobers/geom"
+	"opslag.de/schobers/krampus19/soko"
 )

 type entity struct {
-	typ entityType
-	pos geom.Point
+	id  int
+	typ soko.EntityType
 	scr entityLoc
 }

@ -15,6 +16,6 @@ type entityLoc struct {
 	z   float32
 }

-func newEntity(typ entityType, pos geom.Point) *entity {
-	return &entity{typ, pos, entityLoc{pos.ToF32(), 0}}
+func newEntity(e soko.Entity, pos geom.Point) *entity {
+	return &entity{e.ID, e.Typ, entityLoc{pos.ToF32(), 0}}
 }
--- a/cmd/krampus19/entitylist.go
+++ b/cmd/krampus19/entitylist.go
@ -1,35 +0,0 @@
-package main
-
-import "opslag.de/schobers/geom"
-
-type entityList []*entity
-
-func (l entityList) Add(e *entity) entityList {
-	return append(l, e)
-}
-
-func (l entityList) AddList(list entityList) entityList {
-	return append(l, list...)
-}
-
-func (l entityList) Find(pos geom.Point) int {
-	for i, e := range l {
-		if e.pos == pos {
-			return i
-		}
-	}
-	return -1
-}
-
-func (l entityList) FindEntity(pos geom.Point) *entity {
-	idx := l.Find(pos)
-	if idx == -1 {
-		return nil
-	}
-	return l[idx]
-}
-
-func (l entityList) Remove(pos geom.Point) entityList {
-	idx := l.Find(pos)
-	return append(l[:idx], l[idx+1:]...)
-}
--- a/cmd/krampus19/entitymap.go
+++ b/cmd/krampus19/entitymap.go
@ -0,0 +1,25 @@
+package main
+
+import "sort"
+
+type entityMap map[int]*entity
+
+func (m entityMap) RenderOrder() []*entity {
+	entities := make([]*entity, 0, len(m))
+	for _, e := range m {
+		entities = append(entities, e)
+	}
+
+	sort.Slice(entities, func(i, j int) bool {
+		var posI, posJ = entities[i].scr.pos, entities[j].scr.pos
+		if posI.Y == posJ.Y {
+			if posI.X == posJ.X {
+				return entities[i].id < entities[j].id
+			}
+			return posI.X < posJ.X
+		}
+		return posI.Y < posJ.Y
+	})
+
+	return entities
+}
--- a/cmd/krampus19/game.go
+++ b/cmd/krampus19/game.go
@ -6,7 +6,11 @@ import (
 	"image/png"
 	"io"
 	"log"
+	"os"
+	"path/filepath"
+	"strings"

+	"github.com/spf13/afero"
 	"opslag.de/schobers/allg5"
 	"opslag.de/schobers/fs/vfs"
 	"opslag.de/schobers/geom"
@ -25,7 +29,7 @@ type game struct {
 }

 func (g *game) initUI(disp *allg5.Display, cons *gut.Console, fps *gut.FPS) error {
-	disp.SetWindowTitle("Krampushack '19 - Title TBD - by Tharro")
+	disp.SetWindowTitle("Krampushack '19 - Sokodragon - by Tharro")
 	ui := alui.NewUI(disp, &g.main)
 	ui.SetPalette(alui.Palette{
 		Icon:    allg5.NewColor(0x21, 0x21, 0x21),
@ -98,24 +102,57 @@ func (g *game) loadTextures(pathToName map[string]string) error {
 	return nil
 }

-func (g *game) loadLevelPack(ids ...string) error {
-	g.ctx.Levels = map[string]levelPack{}
-	for _, id := range ids {
-		fileName := fmt.Sprintf("levels/pack%s.txt", id)
-		f, err := g.ctx.Resources.Open(fileName)
+func (g *game) loadLevelPacks() error {
+	g.ctx.Levels = newLevelPacks()
+
+	var ids []string
+	const root = "levels"
+	err := afero.Walk(g.ctx.ResourcesFs, root, func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
-		defer f.Close()
-		pack, err := parseLevelPackAsset(f, func(levelID string) (io.ReadCloser, error) {
-			fileName := fmt.Sprintf("levels/pack%s_level%s.txt", id, levelID)
-			return g.ctx.Resources.Open(fileName)
-		})
-		if err != nil {
-			return err
+		if !info.IsDir() {
+			return nil
 		}
-		g.ctx.Levels[id] = pack
+		name := filepath.Base(path)
+		if name == root {
+			return nil
+		}
+
+		if !strings.HasPrefix(name, "pack") {
+			return filepath.SkipDir
+		}
+		ids = append(ids, name[4:])
+		return filepath.SkipDir
+	})
+	if err != nil {
+		return err
 	}
+
+	for _, id := range ids {
+		err := g.loadLevelPack(id)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (g *game) loadLevelPack(id string) error {
+	fileName := fmt.Sprintf("levels/pack%s/info.txt", id)
+	f, err := g.ctx.Resources.Open(fileName)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	pack, err := parseLevelPackAsset(f, func(levelID string) (io.ReadCloser, error) {
+		fileName := fmt.Sprintf("levels/pack%s/level%s.txt", id, levelID)
+		return g.ctx.Resources.Open(fileName)
+	})
+	if err != nil {
+		return err
+	}
+	g.ctx.Levels.Add(id, pack)
 	return nil
 }

@ -149,9 +186,9 @@ func (g *game) loadSprites(names ...string) error {
 func (g *game) loadAssets() error {
 	log.Println("Loading textures...")
 	err := g.loadTextures(map[string]string{
-		"entity_brick.png":   "brick",
-		"entity_dragon.png":  "dragon",
-		"entity_villain.png": "villain",
+		"entity_brick.png":  "brick",
+		"entity_dragon.png": "dragon",
+		"entity_egg.png":    "egg",

 		"tile_lava_brick.png": "lava_brick",
 		"tile_magma.png":      "magma",
@ -164,12 +201,12 @@ func (g *game) loadAssets() error {
 	}
 	log.Printf("Loaded %d textures.\n", len(g.ctx.Textures))

-	log.Println("Loading levels...")
-	err = g.loadLevelPack("1")
+	log.Println("Loading level packs...")
+	err = g.loadLevelPacks()
 	if err != nil {
 		return err
 	}
-	log.Printf("Loaded %d levels.\n", len(g.ctx.Levels))
+	log.Printf("Loaded %d levels packs (%d levels).\n", g.ctx.Levels.Len(), g.ctx.Levels.LenLevels())

 	log.Println("Loading fonts...")
 	err = g.loadFonts()
@ -179,7 +216,7 @@ func (g *game) loadAssets() error {
 	log.Printf("Loaded %d fonts.\n", g.ui.Fonts().Len())

 	log.Println("Loading sprites")
-	err = g.loadSprites("brick", "dragon", "lava_brick", "magma", "particles", "ui", "villain")
+	err = g.loadSprites("brick", "dragon", "egg", "lava_brick", "magma", "particles", "ui")
 	if err != nil {
 		return err
 	}
@ -192,9 +229,9 @@ func (g *game) Destroy() {
 	g.ctx.Destroy()
 }

-func (g *game) Init(disp *allg5.Display, settings settings, res vfs.CopyDir, cons *gut.Console, fps *gut.FPS) error {
+func (g *game) Init(disp *allg5.Display, settings settings, res vfs.CopyDir, resFs afero.Fs, cons *gut.Console, fps *gut.FPS) error {
 	log.Print("Initializing game...")
-	g.ctx = &Context{Resources: res, Textures: map[string]texture{}, Settings: settings, Navigation: navigation{game: g}}
+	g.ctx = &Context{Resources: res, ResourcesFs: resFs, Textures: map[string]texture{}, Settings: settings, Navigation: navigation{game: g}}
 	g.ctx.DisplaySize = geom.Pt(disp.Width(), disp.Height())
 	g.ctx.SpriteDrawer.ctx = g.ctx
 	err := g.ctx.Progress.load()
--- a/cmd/krampus19/io.go
+++ b/cmd/krampus19/io.go
@ -34,7 +34,7 @@ func userDir() (string, error) {
 		return "", err
 	}
 	dir := filepath.Join(config, "krampus19")
-	err = os.MkdirAll(dir, 0600)
+	err = os.MkdirAll(dir, 0777)
 	if err != nil {
 		return "", err
 	}
--- a/cmd/krampus19/krampus19.go
+++ b/cmd/krampus19/krampus19.go
@ -24,10 +24,15 @@ func main() {
 	}
 }

-func resources() (vfs.CopyDir, error) {
+func resources() (vfs.CopyDir, afero.Fs, error) {
 	var embeddedFs = ricefs.NewFs(rice.MustFindBox("res"))
 	var osFs = afero.NewBasePathFs(afero.NewOsFs(), "./res")
-	return vfs.NewCopyDir(vfs.NewFallbackFs(osFs, embeddedFs))
+	var fs = vfs.NewFallbackFs(osFs, embeddedFs)
+	copy, err := vfs.NewCopyDir(fs)
+	if err != nil {
+		return nil, nil, err
+	}
+	return copy, fs, nil
 }

 func run() error {
@ -35,7 +40,7 @@ func run() error {
 	cons := &gut.Console{}
 	log.SetOutput(io.MultiWriter(log.Writer(), cons))

-	res, err := resources()
+	res, resFs, err := resources()
 	if err != nil {
 		return err
 	}
@ -52,7 +57,9 @@ func run() error {
 	}

 	log.Printf("Initializing Allegro.")
-	err = allg5.Init(allg5.InitAll)
+	var init = allg5.InitAll
+	init.Audio = false
+	err = allg5.Init(init)
 	if err != nil {
 		return err
 	}
@ -105,7 +112,7 @@ func run() error {
 	defer fps.Destroy()

 	game := &game{}
-	err = game.Init(disp, settings, res, cons, fps)
+	err = game.Init(disp, settings, res, resFs, cons, fps)
 	if err != nil {
 		return err
 	}
--- a/cmd/krampus19/level.go
+++ b/cmd/krampus19/level.go
@ -1,142 +0,0 @@
-package main
-
-import (
-	"errors"
-	"fmt"
-	"io"
-
-	"opslag.de/schobers/geom"
-)
-
-type entityType byte
-type tile byte
-
-const (
-	entityTypeInvalid   entityType = entityType(0)
-	entityTypeNone                 = '_'
-	entityTypeCharacter            = '@'
-	entityTypeVillain              = 'X'
-	entityTypeBrick                = 'B'
-)
-
-func (e entityType) IsValid() bool {
-	switch e {
-	case entityTypeNone:
-	case entityTypeCharacter:
-	case entityTypeVillain:
-	case entityTypeBrick:
-	default:
-		return false
-	}
-	return true
-}
-
-const (
-	tileInvalid tile = tile(0)
-	tileNothing      = '.'
-	tileBasic        = '#'
-	tileMagma        = '~'
-)
-
-func (t tile) IsValid() bool {
-	switch t {
-	case tileNothing:
-	case tileBasic:
-	case tileMagma:
-	default:
-		return false
-	}
-	return true
-}
-
-type level struct {
-	width    int
-	height   int
-	tiles    []tile
-	entities []entityType
-}
-
-func (l level) idxToPos(i int) geom.Point { return geom.Pt(i%l.width, i/l.width) }
-
-func (l level) posToIdx(p geom.Point) int {
-	if p.X < 0 || p.Y < 0 || p.X >= l.width || p.Y >= l.height {
-		return -1
-	}
-	return p.Y*l.width + p.X
-}
-
-func parseLevelAsset(r io.Reader) (level, error) {
-	var l level
-	ctx := levelContext{&l}
-	err := parseLines(r, ctx.parse)
-	if err != nil {
-		return level{}, err
-	}
-	return l, nil
-}
-
-type levelContext struct {
-	level *level
-}
-
-func (c *levelContext) parse(p *lineParser) parseLineFn {
-	if p.eof() {
-		return nil
-	}
-	switch p.peek() {
-	case "level:":
-		return c.parseContent
-	case "":
-		p.next() // skip
-		return c.parse
-	default:
-		return nil
-	}
-}
-
-func (c *levelContext) parseContent(p *lineParser) parseLineFn {
-	if p.next() != "level:" {
-		return p.emitErr(errors.New("expected level start"))
-	}
-	return c.parseRow
-}
-
-func (c *levelContext) parseRow(p *lineParser) parseLineFn {
-	if p.eof() {
-		return p.emitErr(errors.New("unexpected end of file"))
-	}
-	line := p.next()
-	if line == ":level" {
-		return c.parse
-	}
-	if c.level.height == 0 {
-		c.level.width = len(line) / 2
-	}
-	return c.addRow(p, line)
-}
-
-func (c *levelContext) addRow(p *lineParser, line string) parseLineFn {
-	var tiles []tile
-	var entities []entityType
-	for i := 0; i < len(line); i += 2 {
-		tiles = append(tiles, tile(line[i]))
-		entities = append(entities, entityType(line[i+1]))
-	}
-
-	for i, t := range tiles {
-		if !t.IsValid() {
-			return p.emitErr(fmt.Errorf("level contains invalid tile at (%d, %d)", i, c.level.height))
-		}
-	}
-	for i, e := range entities {
-		if !e.IsValid() {
-			return p.emitErr(fmt.Errorf("level contains invalid entity type at (%d, %d)", i, c.level.height))
-		}
-	}
-
-	c.level.height++
-	c.level.tiles = append(c.level.tiles, tiles...)
-	c.level.entities = append(c.level.entities, entities...)
-
-	return c.parseRow
-}
--- a/cmd/krampus19/levelpack.go
+++ b/cmd/krampus19/levelpack.go
@ -4,12 +4,16 @@ import (
 	"errors"
 	"io"
 	"strings"
+
+	"opslag.de/schobers/krampus19/gut"
+
+	"opslag.de/schobers/krampus19/soko"
 )

 type levelPack struct {
 	name   string
 	order  []string
-	levels map[string]level
+	levels map[string]soko.Level
 }

 func (p levelPack) find(level string) int {
@ -29,6 +33,8 @@ func (p levelPack) FindNext(level string) (string, bool) {
 	return p.order[idx+1], true
 }

+func (p levelPack) Len() int { return len(p.order) }
+
 type parseLevelPackContext struct {
 	name   string
 	levels []string
@ -36,19 +42,19 @@ type parseLevelPackContext struct {

 func parseLevelPackAsset(r io.Reader, openLevelFn func(id string) (io.ReadCloser, error)) (levelPack, error) {
 	ctx := &parseLevelPackContext{}
-	err := parseLines(r, ctx.Parse)
+	err := gut.ParseLines(r, ctx.Parse)
 	if err != nil {
 		return levelPack{}, err
 	}

-	pack := levelPack{name: ctx.name, levels: map[string]level{}}
+	pack := levelPack{name: ctx.name, levels: map[string]soko.Level{}}
 	for _, id := range ctx.levels {
 		rc, err := openLevelFn(id)
 		if err != nil {
 			return levelPack{}, err
 		}
 		defer rc.Close()
-		level, err := parseLevelAsset(rc)
+		level, err := soko.ParseLevel(rc)
 		if err != nil {
 			return levelPack{}, err
 		}
@ -59,65 +65,65 @@ func parseLevelPackAsset(r io.Reader, openLevelFn func(id string) (io.ReadCloser
 	return pack, nil
 }

-func (c *parseLevelPackContext) Parse(p *lineParser) parseLineFn {
-	if p.skipSpaceEOF() {
-		return p.emitErr(errors.New("empty level pack"))
+func (c *parseLevelPackContext) Parse(p *gut.LineParser) gut.ParseLineFn {
+	if p.SkipSpaceEOF() {
+		return p.EmitErr(errors.New("empty level pack"))
 	}
 	return c.parse
 }

-func (c *parseLevelPackContext) parse(p *lineParser) parseLineFn {
+func (c *parseLevelPackContext) parse(p *gut.LineParser) gut.ParseLineFn {
 	const levelsTag = "levels:"
 	const nameTag = "name:"

-	if p.skipSpaceEOF() {
+	if p.SkipSpaceEOF() {
 		return nil
 	}

-	line := p.next()
+	line := p.Next()
 	switch {
 	case strings.HasPrefix(line, nameTag):
 		c.name = strings.TrimSpace(line[len(nameTag):])
 		return c.parse
 	case strings.HasPrefix(line, levelsTag):
-		return skipSpaceBeforeContent(c.parseLevels)
+		return gut.SkipSpaceBeforeContent(c.parseLevels)
 	}
-	return p.emitErr(errors.New("tag not allowed"))
+	return p.EmitErr(errors.New("tag not allowed"))
 }

-func (c *parseLevelPackContext) parseLevels(p *lineParser) parseLineFn {
+func (c *parseLevelPackContext) parseLevels(p *gut.LineParser) gut.ParseLineFn {
 	const levelTag = "level:"
 	const levelsEndTag = ":levels"

-	line := p.next()
+	line := p.Next()
 	switch line {
 	case levelTag:
-		return skipSpaceBeforeContent(c.parseLevel)
+		return gut.SkipSpaceBeforeContent(c.parseLevel)
 	case levelsEndTag:
 		return c.parse
 	}
-	return p.emitErr(errors.New("tag not allowed"))
+	return p.EmitErr(errors.New("tag not allowed"))
 }

-func (c *parseLevelPackContext) parseLevel(p *lineParser) parseLineFn {
+func (c *parseLevelPackContext) parseLevel(p *gut.LineParser) gut.ParseLineFn {
 	const idTag = "id:"

-	line := p.next()
+	line := p.Next()
 	switch {
 	case strings.HasPrefix(line, idTag):
 		c.levels = append(c.levels, strings.TrimSpace(line[len(idTag):]))
-		return skipSpaceBeforeContent(c.parseLevelEnd)
+		return gut.SkipSpaceBeforeContent(c.parseLevelEnd)
 	}
-	return p.emitErr(errors.New("must have an id tag"))
+	return p.EmitErr(errors.New("must have an id tag"))
 }

-func (c *parseLevelPackContext) parseLevelEnd(p *lineParser) parseLineFn {
+func (c *parseLevelPackContext) parseLevelEnd(p *gut.LineParser) gut.ParseLineFn {
 	const levelEndTag = ":level"

-	line := p.next()
+	line := p.Next()
 	switch {
 	case strings.HasPrefix(line, levelEndTag):
-		return skipSpaceBeforeContent(c.parseLevels)
+		return gut.SkipSpaceBeforeContent(c.parseLevels)
 	}
-	return p.emitErr(errors.New("tag not allowed"))
+	return p.EmitErr(errors.New("tag not allowed"))
 }
--- a/cmd/krampus19/levelpacks.go
+++ b/cmd/krampus19/levelpacks.go
@ -0,0 +1,36 @@
+package main
+
+type levelPacks struct {
+	packs map[string]levelPack
+	order []string
+}
+
+func newLevelPacks() *levelPacks {
+	return &levelPacks{map[string]levelPack{}, nil}
+}
+
+func (p *levelPacks) Add(id string, pack levelPack) {
+	p.order = append(p.order, id)
+	p.packs[id] = pack
+}
+
+func (p *levelPacks) ByID(id string) levelPack { return p.packs[id] }
+
+func (p *levelPacks) FirstPackID() string {
+	if p.Len() == 0 {
+		return ""
+	}
+	return p.order[0]
+}
+
+func (p *levelPacks) Len() int { return len(p.order) }
+
+func (p *levelPacks) LenLevels() int {
+	var cnt int
+	for _, pack := range p.packs {
+		cnt += pack.Len()
+	}
+	return cnt
+}
+
+func (p *levelPacks) MustSelect() bool { return p.Len() != 1 }
--- a/cmd/krampus19/levelpackselect.go
+++ b/cmd/krampus19/levelpackselect.go
@ -0,0 +1,40 @@
+package main
+
+import (
+	"opslag.de/schobers/allg5"
+
+	"opslag.de/schobers/krampus19/alui"
+)
+
+type levelPackSelect struct {
+	alui.Menu
+
+	ctx *Context
+}
+
+func (s *levelPackSelect) Enter(ctx *Context) error {
+	s.ctx = ctx
+	s.Init()
+	s.AddChild(newHeader("Select a level pack"))
+	for _, id := range s.ctx.Levels.order {
+		var copy = id
+		s.Add(s.ctx.Levels.ByID(id).name, func() {
+			s.ctx.Navigation.SelectLevel(copy)
+		})
+	}
+	s.Add("Back to main menu", func() { s.ctx.Navigation.ShowMainMenu() })
+	return nil
+}
+
+func (s *levelPackSelect) Handle(e allg5.Event) {
+	switch e := e.(type) {
+	case *allg5.KeyDownEvent:
+		switch e.KeyCode {
+		case allg5.KeyEscape:
+			s.ctx.Navigation.ShowMainMenu()
+		}
+	}
+	s.Menu.Handle(e)
+}
+
+func (s *levelPackSelect) Leave() {}
--- a/cmd/krampus19/levelselect.go
+++ b/cmd/krampus19/levelselect.go
@ -3,6 +3,8 @@ package main
 import (
 	"fmt"

+	"opslag.de/schobers/allg5"
+
 	"opslag.de/schobers/krampus19/alui"
 )

@ -17,7 +19,7 @@ type levelSelect struct {

 func (s *levelSelect) Enter(ctx *Context) error {
 	s.ctx = ctx
-	s.pack = s.ctx.Levels[s.packID]
+	s.pack = s.ctx.Levels.ByID(s.packID)
 	s.Init()
 	name := func(i int, steps int) string {
 		if steps == 0 {
@ -25,14 +27,33 @@ func (s *levelSelect) Enter(ctx *Context) error {
 		}
 		return fmt.Sprintf("Level %d (%d)", i, steps)
 	}
+	if s.ctx.Levels.MustSelect() {
+		s.AddChild(newHeader(fmt.Sprintf("Select a '%s' level", s.pack.name)))
+	} else {
+		s.AddChild(newHeader("Select a level"))
+	}
 	for i, id := range s.pack.order {
 		levelID := id
 		s.Add(name(i+1, s.ctx.Progress.Level(s.packID, levelID).Steps), func() {
 			s.ctx.Navigation.PlayLevel(s.packID, levelID)
 		})
 	}
+	if s.ctx.Levels.MustSelect() {
+		s.Add("Select level pack", func() { s.ctx.Navigation.SelectPack() })
+	}
 	s.Add("Back to main menu", func() { s.ctx.Navigation.ShowMainMenu() })
 	return nil
 }

+func (s *levelSelect) Handle(e allg5.Event) {
+	switch e := e.(type) {
+	case *allg5.KeyDownEvent:
+		switch e.KeyCode {
+		case allg5.KeyEscape:
+			s.ctx.Navigation.ShowMainMenu()
+		}
+	}
+	s.Menu.Handle(e)
+}
+
 func (s *levelSelect) Leave() {}
--- a/cmd/krampus19/lineparser.go
+++ b/cmd/krampus19/lineparser.go
@ -1,64 +0,0 @@
-package main
-
-import (
-	"errors"
-	"io"
-	"io/ioutil"
-	"strings"
-)
-
-type lineParser struct {
-	lines []string
-	i     int
-	err   error
-}
-
-var errUnexpectedEnd = errors.New("unexpected end of file")
-
-func (p *lineParser) eof() bool    { return p.i == len(p.lines) }
-func (p *lineParser) peek() string { return p.lines[p.i] }
-func (p *lineParser) next() string {
-	i := p.i
-	p.i++
-	return p.lines[i]
-}
-
-func (p *lineParser) emitErr(err error) parseLineFn {
-	p.err = err
-	return nil
-}
-
-func (p *lineParser) skipSpaceEOF() bool {
-	for !p.eof() && len(strings.TrimSpace(p.peek())) == 0 {
-		p.next()
-	}
-	return p.eof()
-}
-
-func skipSpaceBeforeContent(next parseLineFn) parseLineFn {
-	return func(p *lineParser) parseLineFn {
-		if p.skipSpaceEOF() {
-			return p.emitErr(errUnexpectedEnd)
-		}
-		return next
-	}
-}
-
-type parseLineFn func(p *lineParser) parseLineFn
-
-func parseLines(r io.Reader, fn parseLineFn) error {
-	content, err := ioutil.ReadAll(r)
-	if err != nil {
-		return err
-	}
-	lines := strings.Split(string(content), "\n")
-	for i, line := range lines {
-		lines[i] = strings.TrimRight(line, "\r\n")
-	}
-
-	parser := &lineParser{lines: lines}
-	for fn != nil {
-		fn = fn(parser)
-	}
-	return parser.err
-}
--- a/cmd/krampus19/mainmenu.go
+++ b/cmd/krampus19/mainmenu.go
@ -1,6 +1,7 @@
 package main

 import (
+	"opslag.de/schobers/allg5"
 	"opslag.de/schobers/krampus19/alui"
 )

@ -10,10 +11,15 @@ type mainMenu struct {
 	ctx *Context
 }

+func newHeader(label string) alui.Control {
+	return alui.NewMargins(&alui.Label{ControlBase: alui.ControlBase{Font: "header"}, Text: label, TextAlign: allg5.AlignCenter}, 3*margin)
+}
+
 func (m *mainMenu) Enter(ctx *Context) error {
 	m.ctx = ctx
 	m.Init()
-	m.Add("Play", func() { m.ctx.Navigation.SelectLevel("1") })
+	m.AddChild(newHeader("Sokodragon"))
+	m.Add("Play", func() { m.ctx.Navigation.SelectPack() })
 	m.Add("Settings", func() { m.ctx.Navigation.ChangeSettings() })
 	m.Add("Quit", func() { m.ctx.Navigation.Quit() })
 	return nil
--- a/cmd/krampus19/navigation.go
+++ b/cmd/krampus19/navigation.go
@ -28,6 +28,15 @@ func (n *navigation) SelectLevel(packID string) {
 	n.switchTo(&levelSelect{packID: packID})
 }

+func (n *navigation) SelectPack() {
+	if n.game.ctx.Levels.MustSelect() {
+		n.switchTo(&levelPackSelect{})
+	} else {
+		packID := n.game.ctx.Levels.FirstPackID()
+		n.SelectLevel(packID)
+	}
+}
+
 func (n *navigation) ShowMainMenu() {
 	n.switchTo(&mainMenu{})
 }
--- a/cmd/krampus19/playlevel.go
+++ b/cmd/krampus19/playlevel.go
@ -3,11 +3,12 @@ package main
 import (
 	"fmt"
 	"log"
-	"sort"
+	"strconv"

 	"opslag.de/schobers/allg5"
 	"opslag.de/schobers/geom"
 	"opslag.de/schobers/krampus19/alui"
+	"opslag.de/schobers/krampus19/soko"
 )

 type playLevel struct {
@ -25,21 +26,24 @@ type playLevel struct {
 	offset  geom.PointF32
 	scale   float32

-	state playLevelState
+	state       playLevelState
+	pathFinding bool
 }

 type keyPressedState map[allg5.Key]bool

-func (s keyPressedState) CountPressed(keys ...allg5.Key) int {
-	var cnt int
+func (s keyPressedState) ArePressed(keys ...allg5.Key) []allg5.Key {
+	pressed := make([]allg5.Key, 0, len(keys))
 	for _, k := range keys {
 		if s[k] {
-			cnt++
+			pressed = append(pressed, k)
 		}
 	}
-	return cnt
+	return pressed
 }

+func (s keyPressedState) CountPressed(keys ...allg5.Key) int { return len(s.ArePressed(keys...)) }
+
 func (l *playLevel) Enter(ctx *Context) error {
 	l.ctx = ctx

@ -82,6 +86,9 @@ func (l *playLevel) onComplete() {
 	if ok {
 		menu.Add("Continue with next", func() { l.ctx.Navigation.PlayLevel(l.packID, nextID) })
 	}
+	if l.ctx.Levels.MustSelect() {
+		menu.Add("Select level pack", func() { l.ctx.Navigation.SelectPack() })
+	}
 	menu.Add("Select level", func() { l.ctx.Navigation.SelectLevel(l.packID) })
 	menu.Add("Go to main menu", func() { l.ctx.Navigation.ShowMainMenu() })

@ -116,13 +123,13 @@ func (l *playLevel) Layout(ctx *alui.Context, bounds geom.RectangleF32) {
 		l.offset = geom.PointF32{}

 		level := l.state.Level()
-		var contentCenter = l.posToScreenF32(geom.PtF32(.5*float32(level.width), .5*float32(level.height)), 0)
+		var contentCenter = l.posToScreenF32(geom.PtF32(.5*float32(level.Width), .5*float32(level.Height)), 0)
 		var content = geom.RectF32(contentCenter.X, contentCenter.Y, contentCenter.X, contentCenter.Y)
-		for idx, tile := range l.state.Level().tiles {
-			if tile == tileNothing || tile == tileInvalid {
+		for idx, tile := range l.state.Level().Tiles {
+			if tile == soko.TileTypeNothing || tile == soko.TileTypeInvalid {
 				continue
 			}
-			pos := level.idxToPos(idx).ToF32()
+			pos := level.IdxToPos(idx).ToF32()
 			bottomLeft := l.posToScreenF32(pos.Add2D(-1.5, 1.5), 100)
 			content.Min = geom.MinPtF32(content.Min, bottomLeft)
 			content.Max = geom.MaxPtF32(content.Max, bottomLeft)
@ -161,15 +168,10 @@ func (l *playLevel) Handle(e allg5.Event) {
 			case allg5.KeyEscape:
 				l.showMenu = true
 				l.menu.Activate(0)
-			case l.ctx.Settings.Controls.MoveUp:
-				l.state.TryPlayerMove(geom.Pt(0, -1), e.KeyCode)
-			case l.ctx.Settings.Controls.MoveRight:
-				l.state.TryPlayerMove(geom.Pt(1, 0), e.KeyCode)
-			case l.ctx.Settings.Controls.MoveDown:
-				l.state.TryPlayerMove(geom.Pt(0, 1), e.KeyCode)
-			case l.ctx.Settings.Controls.MoveLeft:
-				l.state.TryPlayerMove(geom.Pt(-1, 0), e.KeyCode)
+			case allg5.KeyF5:
+				l.pathFinding = !l.pathFinding
 			}
+			l.state.TryPlayerMove(e.KeyCode)
 		}
 	}
 }
@ -193,19 +195,19 @@ func (l *playLevel) Render(ctx *alui.Context, bounds geom.RectangleF32) {
 		}
 	}

-	for i, t := range level.tiles {
-		pos := geom.Pt(i%level.width, i/level.width)
+	for i, t := range level.Tiles {
+		pos := geom.Pt(i%level.Width, i/level.Width)
 		scr := entityLoc{pos.ToF32(), 0}
 		switch t {
-		case tileBasic:
+		case soko.TileTypeBasic:
 			if l.state.IsNextToMagma(pos) {
 				l.drawSprite("lava_brick", "magma", scr)
 			} else {
 				l.drawSprite("lava_brick", "lava_brick", scr)
 			}
-		case tileMagma:
+		case soko.TileTypeMagma:
 			l.drawSprite("magma", "magma", scr)
-			brick := l.state.FindSunkenBrick(pos)
+			brick := l.state.FindSunkenBrickEntity(pos)
 			if brick != nil {
 				behind, front := splitParticles(scr.pos.Y, l.state.Particles(pos))
 				drawParticles(behind)
@ -216,26 +218,30 @@ func (l *playLevel) Render(ctx *alui.Context, bounds geom.RectangleF32) {
 		}
 	}

-	entities := l.state.Entities()
-	sort.Slice(entities, func(i, j int) bool {
-		if entities[i].scr.pos.Y == entities[j].scr.pos.Y {
-			return entities[i].scr.pos.X < entities[j].scr.pos.X
-		}
-		return entities[i].scr.pos.Y < entities[j].scr.pos.Y
-	})
-
+	entities := l.state.Entities().RenderOrder()
 	for _, e := range entities {
 		switch e.typ {
-		case entityTypeBrick:
+		case soko.EntityTypeBrick:
 			l.drawSprite("brick", "brick", e.scr)
-		case entityTypeCharacter:
+		case soko.EntityTypePlayer:
 			l.drawSprite("dragon", "dragon", e.scr)
-		case entityTypeVillain:
-			l.drawSprite("villain", "villain", e.scr)
+		case soko.EntityTypeTarget:
+			l.drawSprite("egg", "egg", e.scr)
 		}
 	}

 	font := ctx.Fonts.Get("default")
+
+	if l.pathFinding {
+		dists := soko.NewPathFinder(&l.state.state).FindDistances()
+		for i := range level.Tiles {
+			pos := geom.Pt(i%level.Width, i/level.Width)
+			scr := entityLoc{pos.ToF32(), 0}
+			posDist := l.posToScreenF32(scr.pos, -20)
+			ctx.Fonts.DrawAlignFont(font, posDist.X, posDist.Y, posDist.X, ctx.Palette.Text, allg5.AlignCenter, strconv.Itoa(dists[i]))
+		}
+	}
+
 	steps := fmt.Sprintf("STEPS: %d", l.state.Steps())
 	ctx.Fonts.DrawAlignFont(font, bounds.Min.X, 24, bounds.Max.X, ctx.Palette.Text, allg5.AlignCenter, steps)

--- a/cmd/krampus19/playlevelstate.go
+++ b/cmd/krampus19/playlevelstate.go
@ -7,18 +7,20 @@ import (
 	"opslag.de/schobers/allg5"
 	"opslag.de/schobers/geom"
 	"opslag.de/schobers/krampus19/gut"
+	"opslag.de/schobers/krampus19/soko"
 )

 type playLevelState struct {
 	ctx *Context

-	pack    levelPack
-	level   level
-	player  *entity
-	villain *entity
-	bricks  entityList
-	sunken  entityList
-	splash  map[geom.Point]*splashAnimation
+	pack   levelPack
+	level  soko.Level
+	state  soko.State
+	player *entity
+	egg    *entity
+	bricks entityMap
+	sunken entityMap
+	splash map[geom.Point]*splashAnimation

 	steps      int
 	complete   bool
@ -29,9 +31,14 @@ type playLevelState struct {
 	keysDown keyPressedState
 }

-func (s *playLevelState) Entities() entityList {
-	var entities entityList
-	return entities.Add(s.player).Add(s.villain).AddList(s.bricks)
+func (s *playLevelState) Entities() entityMap {
+	entities := entityMap{}
+	entities[s.player.id] = s.player
+	entities[s.egg.id] = s.egg
+	for id, e := range s.bricks {
+		entities[id] = e
+	}
+	return entities
 }

 func (s *playLevelState) Particles(at geom.Point) []particle {
@ -48,39 +55,48 @@ func (s *playLevelState) Particles(at geom.Point) []particle {
 	return particles
 }

-func (s *playLevelState) FindSunkenBrick(pos geom.Point) *entity {
-	return s.sunken.FindEntity(pos)
+func (s *playLevelState) FindSunkenBrickEntity(pos geom.Point) *entity {
+	idx := s.level.PosToIdx(pos)
+	if idx == -1 {
+		return nil
+	}
+	id := s.state.SunkenBricks[idx]
+	if id != -1 {
+		return s.sunken[id]
+	}
+	return nil
 }

 func (s *playLevelState) IsNextToMagma(pos geom.Point) bool {
-	return s.checkTile(pos.Add2D(1, 0), s.isMagma) ||
-		s.checkTile(pos.Add2D(-1, 0), s.isMagma) ||
-		s.checkTile(pos.Add2D(0, -1), s.isMagma) ||
-		s.checkTile(pos.Add2D(0, 1), s.isMagma)
+	return s.state.Any(soko.IsMagma, soko.Neighbours(pos)...)
 }

 func (s *playLevelState) Init(ctx *Context, pack, level string, onComplete func()) {
 	s.ctx = ctx
-	s.pack = ctx.Levels[pack]
+	s.pack = ctx.Levels.ByID(pack)
 	s.level = s.pack.levels[level]
+	s.state = s.level.State()
 	s.bricks = nil
 	s.sunken = nil
 	s.splash = map[geom.Point]*splashAnimation{}
-	for i, e := range s.level.entities {
-		switch e {
-		case entityTypeBrick:
-			s.bricks = append(s.bricks, newEntity(e, s.level.idxToPos(i)))
-		case entityTypeCharacter:
-			s.player = newEntity(e, s.level.idxToPos(i))
-		case entityTypeVillain:
-			s.villain = newEntity(e, s.level.idxToPos(i))
+
+	newEntity := func(e soko.Entity) *entity { return newEntity(e, s.state.IdxToPos[e.Pos]) }
+
+	s.player = newEntity(s.state.Player)
+	s.egg = newEntity(s.state.Target)
+	s.bricks = entityMap{}
+	for _, e := range s.state.Entities {
+		if e.Typ != soko.EntityTypeBrick {
+			continue
 		}
+		s.bricks[e.ID] = newEntity(soko.Entity{ID: e.ID, Pos: e.Pos, Typ: soko.EntityTypeBrick})
 	}
+	s.sunken = entityMap{}
 	s.keysDown = keyPressedState{}
 	s.onComplete = onComplete
 }

-func (s *playLevelState) Level() level { return s.level }
+func (s *playLevelState) Level() soko.Level { return s.level }

 func (s *playLevelState) PressKey(key allg5.Key) {
 	s.keysDown[key] = true
@ -96,114 +112,77 @@ func (s *playLevelState) Tick(now time.Duration) {
 	s.ani.Animate(now)
 }

-func (s *playLevelState) TryPlayerMove(dir geom.Point, key allg5.Key) {
-	if s.player.scr.pos != s.player.pos.ToF32() {
+func (s *playLevelState) TryPlayerMove(key allg5.Key) {
+	var dir soko.Direction
+	switch key {
+	case s.ctx.Settings.Controls.MoveUp:
+		dir = soko.DirectionUp
+	case s.ctx.Settings.Controls.MoveRight:
+		dir = soko.DirectionRight
+	case s.ctx.Settings.Controls.MoveDown:
+		dir = soko.DirectionDown
+	case s.ctx.Settings.Controls.MoveLeft:
+		dir = soko.DirectionLeft
+	default:
+		return
+	}
+	s.tryPlayerMove(dir)
+}
+
+func (s *playLevelState) tryPlayerMove(dir soko.Direction) {
+	playerPt := s.state.IdxToPos[s.state.Player.Pos]
+	if s.player.scr.pos != playerPt.ToF32() {
 		return
 	}

-	to := s.player.pos.Add(dir)
-	if !s.canMove(s.player.pos, dir) {
-		log.Printf("Move is not allowed (tried out move to %s after key '%s' was pressed)", to, gut.KeyToString(key))
+	state, ok := s.state.MovePlayer(dir)
+	if !ok {
+		log.Printf("Move is not allowed (tried out move %s)", dir.String())
 		return
 	}

-	s.steps++
-	log.Printf("Moving player to %s", to)
-	s.ani.StartFn(s.ctx.Tick, newMoveAnimation(s.player, to), func() {
-		log.Printf("Player movement finished")
-		if s.player.pos == s.villain.pos {
-			s.complete = true
-			if onComplete := s.onComplete; onComplete != nil {
-				onComplete()
-			}
-		} else if s.keysDown[key] && s.keysDown.CountPressed(s.ctx.Settings.Controls.MovementKeys()...) == 1 {
-			log.Printf("Key %s is still down, moving further", gut.KeyToString(key))
-			s.TryPlayerMove(dir, key)
-		}
-	})
+	to := state.Player.Pos
+	toPt := state.IdxToPos[to]

-	if brick := s.bricks.FindEntity(to); brick != nil {
-		log.Printf("Pushing brick at %s", to)
-		brickTo := to.Add(dir)
-		s.ani.StartFn(s.ctx.Tick, newMoveAnimation(brick, brickTo), func() {
+	if brickID := s.state.Bricks[to]; brickID != -1 {
+		log.Printf("Brick %d moved", brickID)
+		brick := s.bricks[brickID]
+		brickTo := state.Entities.ByID(brickID).Pos
+		brickToPt := state.IdxToPos[brickTo]
+		s.ani.StartFn(s.ctx.Tick, newMoveAnimation(brick, toPt, brickToPt), func() {
 			log.Printf("Brick movement finished")
-			if s.checkTile(brickTo, s.wouldBrickSink) {
-				log.Printf("Sinking brick at %s", brickTo)
-				s.bricks = s.bricks.Remove(brickTo)
-				s.sunken = s.sunken.Add(brick)
+			if sunkenBrickID := state.SunkenBricks[brickTo]; sunkenBrickID == brickID {
+				log.Printf("Sinking brick %d", brickID)
+				delete(s.bricks, brickID)
+				s.sunken[brickID] = brick
 				s.ani.Start(s.ctx.Tick, newSinkAnimation(brick))

-				splash := newSplashAnimation(brickTo)
-				s.splash[brickTo] = splash
+				splash := newSplashAnimation(brickToPt)
+				s.splash[brickToPt] = splash
 				s.ani.StartFn(s.ctx.Tick, splash, func() {
-					delete(s.splash, brickTo)
+					delete(s.splash, brickToPt)
 				})
 			}
 		})
 	}
-}

-func (s *playLevelState) canMove(from, dir geom.Point) bool {
-	to := from.Add(dir)
-	if !s.checkTile(to, s.isSolidTile) {
-		return false
-	}
-	brick := s.bricks.FindEntity(to)
-	if brick != nil {
-		brickTo := to.Add(dir)
-		return !s.checkTileNotFound(brickTo, s.isObstructed, true)
-	}
-	return true
-}
-
-func (s *playLevelState) checkTile(pos geom.Point, check func(pos geom.Point, idx int, t tile) bool) bool {
-	return s.checkTileNotFound(pos, check, false)
-}
-
-func (s *playLevelState) checkTileNotFound(pos geom.Point, check func(pos geom.Point, idx int, t tile) bool, notFound bool) bool {
-	idx := s.level.posToIdx(pos)
-	if idx == -1 {
-		return notFound
-	}
-	return check(pos, idx, s.level.tiles[idx])
-}
-
-func (s *playLevelState) findEntityAt(pos geom.Point) *entity {
-	if s.player.pos == pos {
-		return s.player
-	}
-	brick := s.bricks.FindEntity(pos)
-	if brick != nil {
-		return brick
-	}
-	return s.sunken.FindEntity(pos)
-}
-
-func (s *playLevelState) isObstructed(pos geom.Point, idx int, t tile) bool {
-	if s.bricks.FindEntity(pos) != nil {
-		return true // brick
-	}
-	switch s.level.tiles[idx] {
-	case tileMagma:
-		return false
-	case tileBasic:
-		return false
-	}
-	return true
-}
-
-func (s *playLevelState) isMagma(pos geom.Point, idx int, t tile) bool { return t == tileMagma }
-
-func (s *playLevelState) isSolidTile(pos geom.Point, idx int, t tile) bool {
-	switch t {
-	case tileBasic:
-		return true
-	case tileMagma:
-		return s.sunken.FindEntity(pos) != nil
-	}
-	return false
-}
-
-func (s *playLevelState) wouldBrickSink(pos geom.Point, idx int, t tile) bool {
-	return t == tileMagma && s.sunken.FindEntity(pos) == nil
+	s.steps++
+	log.Printf("Moving player to %s", toPt)
+	s.ani.StartFn(s.ctx.Tick, newMoveAnimation(s.player, playerPt, toPt), func() {
+		log.Printf("Player movement finished")
+		if to == state.Target.Pos {
+			s.complete = true
+			if onComplete := s.onComplete; onComplete != nil {
+				onComplete()
+			}
+		} else {
+			pressed := s.keysDown.ArePressed(s.ctx.Settings.Controls.MovementKeys()...)
+			if len(pressed) == 1 {
+				key := pressed[0]
+				log.Printf("Movement key %s is down, moving further", gut.KeyToString(key))
+				s.TryPlayerMove(key)
+			}
+		}
+	})
+	s.state = state
 }
--- a/cmd/krampus19/res/entity_dragon.png
+++ b/cmd/krampus19/res/entity_dragon.png
--- a/cmd/krampus19/res/entity_egg.png
+++ b/cmd/krampus19/res/entity_egg.png
--- a/cmd/krampus19/res/entity_villain.png
+++ b/cmd/krampus19/res/entity_villain.png
--- a/cmd/krampus19/res/levels/pack1/info.txt
+++ b/cmd/krampus19/res/levels/pack1/info.txt
--- a/cmd/krampus19/res/levels/pack1/level1.txt
+++ b/cmd/krampus19/res/levels/pack1/level1.txt
--- a/cmd/krampus19/res/levels/pack1/level2.txt
+++ b/cmd/krampus19/res/levels/pack1/level2.txt
--- a/cmd/krampus19/res/levels/pack1/level3.txt
+++ b/cmd/krampus19/res/levels/pack1/level3.txt
--- a/cmd/krampus19/res/levels/pack1/level4.txt
+++ b/cmd/krampus19/res/levels/pack1/level4.txt
--- a/cmd/krampus19/res/sprites/dragon.txt
+++ b/cmd/krampus19/res/sprites/dragon.txt
@ -3,9 +3,9 @@ texture: dragon

 part:
 name: dragon
-sub_texture: 0,0,200,400
-anchor: 100,350
-scale: 2
+sub_texture: 0,0,1140,1980
+anchor: 570,1920
+scale: 5
 :part

 :sprite
--- a/cmd/krampus19/res/sprites/egg.txt
+++ b/cmd/krampus19/res/sprites/egg.txt
@ -0,0 +1,11 @@
+sprite:
+texture: egg
+
+part:
+name: egg
+sub_texture: 0,0,1140,1980
+anchor: 570,1860
+scale: 6
+:part
+
+:sprite
--- a/cmd/krampus19/res/sprites/villain.txt
+++ b/cmd/krampus19/res/sprites/villain.txt
@ -1,11 +0,0 @@
-sprite:
-texture: villain
-
-part:
-name: villain
-sub_texture: 0,0,200,400
-anchor: 100,350
-scale: 2
-:part
-
-:sprite
--- a/cmd/krampus19/sprite.go
+++ b/cmd/krampus19/sprite.go
@ -7,6 +7,7 @@ import (
 	"strings"

 	"opslag.de/schobers/geom"
+	"opslag.de/schobers/krampus19/gut"
 )

 type sprite struct {
@ -33,7 +34,7 @@ type spritePart struct {
 func loadSpriteAsset(r io.Reader) (sprite, error) {
 	var l sprite
 	ctx := spriteContext{&l, nil}
-	err := parseLines(r, ctx.parse)
+	err := gut.ParseLines(r, ctx.parse)
 	if err != nil {
 		return sprite{}, err
 	}
@ -45,44 +46,44 @@ type spriteContext struct {
 	part   *spritePart
 }

-func (c *spriteContext) parse(p *lineParser) parseLineFn {
-	if p.skipSpaceEOF() {
+func (c *spriteContext) parse(p *gut.LineParser) gut.ParseLineFn {
+	if p.SkipSpaceEOF() {
 		return nil
 	}
-	line := p.peek()
+	line := p.Peek()
 	switch {
 	case strings.HasPrefix(line, "sprite:"):
-		p.next()
+		p.Next()
 		return c.parseContent
 	default:
 		return nil
 	}
 }

-func (c *spriteContext) parseContent(p *lineParser) parseLineFn {
+func (c *spriteContext) parseContent(p *gut.LineParser) gut.ParseLineFn {
 	const partTag = "part:"
 	const textureTag = "texture:"
 	const spriteEndTag = ":sprite"
-	if p.skipSpaceEOF() {
-		return p.emitErr(errUnexpectedEnd)
+	if p.SkipSpaceEOF() {
+		return p.EmitErr(gut.ErrUnexpectedEnd)
 	}
-	line := p.peek()
+	line := p.Peek()
 	switch {
 	case strings.HasPrefix(line, textureTag):
 		c.sprite.texture = strings.TrimSpace(line[len(textureTag):])
-		p.next()
+		p.Next()
 		return c.parseContent
 	case line == partTag:
-		p.next()
+		p.Next()
 		c.part = &spritePart{}
 		return c.parsePart
 	case line == spriteEndTag:
 		return nil
 	}
-	return p.emitErr(errors.New("unexpected content of sprite"))
+	return p.EmitErr(errors.New("unexpected content of sprite"))
 }

-func (c *spriteContext) parsePart(p *lineParser) parseLineFn {
+func (c *spriteContext) parsePart(p *gut.LineParser) gut.ParseLineFn {
 	mustAtois := func(s ...string) []int {
 		res := make([]int, len(s))
 		var err error
@ -110,14 +111,14 @@ func (c *spriteContext) parsePart(p *lineParser) parseLineFn {
 	const anchorTag = "anchor:"
 	const scaleTag = "scale:"
 	const partEndTag = ":part"
-	if p.skipSpaceEOF() {
-		return p.emitErr(errUnexpectedEnd)
+	if p.SkipSpaceEOF() {
+		return p.EmitErr(gut.ErrUnexpectedEnd)
 	}
-	line := p.peek()
+	line := p.Peek()
 	switch {
 	case strings.HasPrefix(line, nameTag):
 		c.part.name = strings.TrimSpace(line[len(nameTag):])
-		p.next()
+		p.Next()
 		return c.parsePart
 	case strings.HasPrefix(line, subTextureTag):
 		var coords = mustCoords(line[len(subTextureTag):])
@ -125,7 +126,7 @@ func (c *spriteContext) parsePart(p *lineParser) parseLineFn {
 			panic("expected four coordinates (min x, min y, size x, size y)")
 		}
 		c.part.sub = geom.Rect(coords[0], coords[1], coords[0]+coords[2], coords[1]+coords[3])
-		p.next()
+		p.Next()
 		return c.parsePart
 	case strings.HasPrefix(line, anchorTag):
 		var coords = mustCoords(line[len(anchorTag):])
@ -133,16 +134,16 @@ func (c *spriteContext) parsePart(p *lineParser) parseLineFn {
 			panic("expected two coordinates (min x, min y)")
 		}
 		c.part.anchor = geom.Pt(coords[0], coords[1])
-		p.next()
+		p.Next()
 		return c.parsePart
 	case strings.HasPrefix(line, scaleTag):
 		c.part.scale = mustAtof(line[len(scaleTag):])
-		p.next()
+		p.Next()
 		return c.parsePart
 	case line == partEndTag:
 		c.sprite.parts = append(c.sprite.parts, *c.part)
-		p.next()
+		p.Next()
 		return c.parseContent
 	}
-	return p.emitErr(errors.New("unexpected content of part"))
+	return p.EmitErr(errors.New("unexpected content of part"))
 }
--- a/gut/lineparser.go
+++ b/gut/lineparser.go
@ -0,0 +1,66 @@
+package gut
+
+import (
+	"errors"
+	"io"
+	"io/ioutil"
+	"strings"
+)
+
+type LineParser struct {
+	lines []string
+	i     int
+	err   error
+}
+
+var ErrUnexpectedEnd = errors.New("unexpected end of file")
+
+func (p *LineParser) EOF() bool { return p.i == len(p.lines) }
+
+func (p *LineParser) EmitErr(err error) ParseLineFn {
+	p.err = err
+	return nil
+}
+
+func (p *LineParser) Next() string {
+	i := p.i
+	p.i++
+	return p.lines[i]
+}
+
+func (p *LineParser) Peek() string { return p.lines[p.i] }
+
+func (p *LineParser) SkipSpaceEOF() bool {
+	for !p.EOF() && len(strings.TrimSpace(p.Peek())) == 0 {
+		p.Next()
+	}
+	return p.EOF()
+}
+
+func SkipSpaceBeforeContent(next ParseLineFn) ParseLineFn {
+	return func(p *LineParser) ParseLineFn {
+		if p.SkipSpaceEOF() {
+			return p.EmitErr(ErrUnexpectedEnd)
+		}
+		return next
+	}
+}
+
+type ParseLineFn func(p *LineParser) ParseLineFn
+
+func ParseLines(r io.Reader, fn ParseLineFn) error {
+	content, err := ioutil.ReadAll(r)
+	if err != nil {
+		return err
+	}
+	lines := strings.Split(string(content), "\n")
+	for i, line := range lines {
+		lines[i] = strings.TrimRight(line, "\r\n")
+	}
+
+	parser := &LineParser{lines: lines}
+	for fn != nil {
+		fn = fn(parser)
+	}
+	return parser.err
+}
--- a/soko/direction.go
+++ b/soko/direction.go
@ -0,0 +1,64 @@
+package soko
+
+import "opslag.de/schobers/geom"
+
+type Direction int
+
+const (
+	DirectionUp Direction = iota
+	DirectionRight
+	DirectionDown
+	DirectionLeft
+)
+
+var Directions = [4]Direction{DirectionUp, DirectionRight, DirectionDown, DirectionLeft}
+
+func (d Direction) Invert() Direction {
+	switch d {
+	case DirectionUp:
+		return DirectionDown
+	case DirectionRight:
+		return DirectionLeft
+	case DirectionDown:
+		return DirectionUp
+	case DirectionLeft:
+		return DirectionRight
+	}
+	panic("invalid direction")
+}
+
+func (d Direction) String() string {
+	switch d {
+	case DirectionUp:
+		return "up"
+	case DirectionRight:
+		return "right"
+	case DirectionDown:
+		return "down"
+	case DirectionLeft:
+		return "left"
+	}
+	return "invalid"
+}
+
+func (d Direction) ToPoint() geom.Point {
+	switch d {
+	case DirectionUp:
+		return geom.Pt(0, -1)
+	case DirectionRight:
+		return geom.Pt(1, 0)
+	case DirectionDown:
+		return geom.Pt(0, 1)
+	case DirectionLeft:
+		return geom.Pt(-1, 0)
+	}
+	return geom.Point{}
+}
+
+func Neighbours(p geom.Point) []geom.Point {
+	neighbours := make([]geom.Point, 4)
+	for i, dir := range Directions {
+		neighbours[i] = p.Add(dir.ToPoint())
+	}
+	return neighbours
+}
--- a/soko/entity.go
+++ b/soko/entity.go
@ -0,0 +1,48 @@
+package soko
+
+type Entity struct {
+	ID  int
+	Pos int
+	Typ EntityType
+}
+
+type Entities []Entity
+
+func (e Entities) ByID(id int) Entity {
+	idx := e.IdxById(id)
+	if idx == -1 {
+		return Entity{ID: -1}
+	}
+	return e[idx]
+}
+
+func (e Entities) Clone() Entities {
+	clone := make(Entities, len(e))
+	copy(clone, e)
+	return clone
+}
+
+func (e Entities) IdxById(id int) int {
+	for i, e := range e {
+		if e.ID == id {
+			return i
+		}
+	}
+	return -1
+}
+
+type Ints []int
+
+func NewInts(n int) Ints {
+	ids := make(Ints, n)
+	for i := range ids {
+		ids[i] = -1
+	}
+	return ids
+}
+
+func (e Ints) Clone() Ints {
+	clone := make(Ints, len(e))
+	copy(clone, e)
+	return clone
+}
--- a/soko/entitylocations.go
+++ b/soko/entitylocations.go
@ -0,0 +1,31 @@
+package soko
+
+import "opslag.de/schobers/geom"
+
+type EntityLocations map[geom.Point]int
+
+func (l EntityLocations) Add(p geom.Point, id int) { l[p] = id }
+
+func (l EntityLocations) Clone() EntityLocations {
+	clone := EntityLocations{}
+	for p, id := range l {
+		clone[p] = id
+	}
+	return clone
+}
+
+func (l EntityLocations) Has(p geom.Point) bool {
+	_, ok := l[p]
+	return ok
+}
+
+func (l EntityLocations) Move(from, to geom.Point) {
+	id, ok := l[from]
+	if !ok {
+		panic("no entitiy at position")
+	}
+	l.Remove(from)
+	l.Add(to, id)
+}
+
+func (l EntityLocations) Remove(p geom.Point) { delete(l, p) }
--- a/soko/entitytype.go
+++ b/soko/entitytype.go
@ -0,0 +1,23 @@
+package soko
+
+type EntityType byte
+
+const (
+	EntityTypeInvalid EntityType = EntityType(0)
+	EntityTypeNone               = '_'
+	EntityTypePlayer             = '@'
+	EntityTypeTarget             = 'X'
+	EntityTypeBrick              = 'B'
+)
+
+func (e EntityType) IsValid() bool {
+	switch e {
+	case EntityTypeNone:
+	case EntityTypePlayer:
+	case EntityTypeTarget:
+	case EntityTypeBrick:
+	default:
+		return false
+	}
+	return true
+}
--- a/soko/level.go
+++ b/soko/level.go
@ -0,0 +1,91 @@
+package soko
+
+import (
+	"opslag.de/schobers/geom"
+)
+
+type Level struct {
+	Width  int
+	Height int
+
+	Tiles    []TileType
+	Entities []EntityType
+}
+
+func (l Level) IdxToPos(i int) geom.Point { return geom.Pt(i%l.Width, i/l.Width) }
+
+func (l Level) PosToIdx(p geom.Point) int {
+	if p.X < 0 || p.Y < 0 || p.X >= l.Width || p.Y >= l.Height {
+		return -1
+	}
+	return p.Y*l.Width + p.X
+}
+
+func (l Level) Moves() []Moves {
+	moves := make([]Moves, len(l.Tiles))
+	w := l.Width
+	for y := 0; y < l.Height; y++ {
+		for x := 0; x < w; x++ {
+			var m Moves
+			idx := y*w + x
+			if y > 0 {
+				m.Valid = append(m.Valid, idx-w)
+				m.All[DirectionUp] = idx - w
+			} else {
+				m.All[DirectionUp] = -1
+			}
+			if y < (l.Height - 1) {
+				m.Valid = append(m.Valid, idx+w)
+				m.All[DirectionDown] = idx + w
+			} else {
+				m.All[DirectionDown] = -1
+			}
+			if x > 0 {
+				m.Valid = append(m.Valid, idx-1)
+				m.All[DirectionLeft] = idx - 1
+			} else {
+				m.All[DirectionLeft] = idx - 1
+			}
+			if x < (w - 1) {
+				m.Valid = append(m.Valid, idx+1)
+				m.All[DirectionRight] = idx + 1
+			} else {
+				m.All[DirectionRight] = idx + 1
+			}
+			moves[idx] = m
+		}
+	}
+	return moves
+}
+
+func (l Level) MoveIdx(idx int, dir Direction) int {
+	switch dir {
+	case DirectionUp:
+		if idx < l.Width {
+			return -1
+		}
+		return idx - l.Width
+	case DirectionRight:
+		if (idx+1)%l.Width == 0 {
+			return -1
+		}
+		return idx + 1
+	case DirectionDown:
+		if idx >= (l.Width*l.Height)-l.Width {
+			return -1
+		}
+		return idx + l.Width
+	case DirectionLeft:
+		if idx%l.Width == 0 {
+			return -1
+		}
+		return idx - 1
+	}
+	return -1
+}
+
+func (l Level) Size() int { return l.Width * l.Height }
+
+func (l Level) State() State {
+	return NewState(l)
+}
--- a/soko/levelparser.go
+++ b/soko/levelparser.go
@ -0,0 +1,85 @@
+package soko
+
+import (
+	"errors"
+	"fmt"
+	"io"
+
+	"opslag.de/schobers/krampus19/gut"
+)
+
+func ParseLevel(r io.Reader) (Level, error) {
+	var l Level
+	ctx := levelContext{&l}
+	err := gut.ParseLines(r, ctx.parse)
+	if err != nil {
+		return Level{}, err
+	}
+	return l, nil
+}
+
+type levelContext struct {
+	level *Level
+}
+
+func (c *levelContext) parse(p *gut.LineParser) gut.ParseLineFn {
+	if p.EOF() {
+		return nil
+	}
+	switch p.Peek() {
+	case "level:":
+		return c.parseContent
+	case "":
+		p.Next() // skip
+		return c.parse
+	default:
+		return nil
+	}
+}
+
+func (c *levelContext) parseContent(p *gut.LineParser) gut.ParseLineFn {
+	if p.Next() != "level:" {
+		return p.EmitErr(errors.New("expected level start"))
+	}
+	return c.parseRow
+}
+
+func (c *levelContext) parseRow(p *gut.LineParser) gut.ParseLineFn {
+	if p.EOF() {
+		return p.EmitErr(errors.New("unexpected end of file"))
+	}
+	line := p.Next()
+	if line == ":level" {
+		return c.parse
+	}
+	if c.level.Height == 0 {
+		c.level.Width = len(line) / 2
+	}
+	return c.addRow(p, line)
+}
+
+func (c *levelContext) addRow(p *gut.LineParser, line string) gut.ParseLineFn {
+	var tiles []TileType
+	var entities []EntityType
+	for i := 0; i < len(line); i += 2 {
+		tiles = append(tiles, TileType(line[i]))
+		entities = append(entities, EntityType(line[i+1]))
+	}
+
+	for i, t := range tiles {
+		if !t.IsValid() {
+			return p.EmitErr(fmt.Errorf("level contains invalid TileType at (%d, %d)", i, c.level.Height))
+		}
+	}
+	for i, e := range entities {
+		if !e.IsValid() {
+			return p.EmitErr(fmt.Errorf("level contains invalid entity type at (%d, %d)", i, c.level.Height))
+		}
+	}
+
+	c.level.Height++
+	c.level.Tiles = append(c.level.Tiles, tiles...)
+	c.level.Entities = append(c.level.Entities, entities...)
+
+	return c.parseRow
+}
--- a/soko/locations.go
+++ b/soko/locations.go
@ -0,0 +1,17 @@
+package soko
+
+import "opslag.de/schobers/geom"
+
+type Locations map[geom.Point]bool
+
+func (l Locations) Add(p geom.Point) { l[p] = true }
+
+func (l Locations) Clone() Locations {
+	clone := Locations{}
+	for p := range l {
+		clone[p] = true
+	}
+	return clone
+}
+
+func (l Locations) Remove(p geom.Point) { delete(l, p) }
--- a/soko/moves.go
+++ b/soko/moves.go
@ -0,0 +1,6 @@
+package soko
+
+type Moves struct {
+	All   [4]int
+	Valid []int
+}
--- a/soko/pathfinder.go
+++ b/soko/pathfinder.go
@ -0,0 +1,133 @@
+package soko
+
+import (
+	"sort"
+)
+
+type PathFinder struct {
+	state *State
+	moves []Moves
+}
+
+func NewPathFinder(s *State) PathFinder {
+	return PathFinder{s, nil}
+}
+
+func NewPathFinderMoves(s *State, moves []Moves) PathFinder {
+	return PathFinder{s, moves}
+}
+
+func (p PathFinder) Find(target int) []int {
+	source := p.state.Player.Pos
+	level := p.state.Level
+	size := level.Size()
+	distances := NewInts(size)
+	distances[source] = 0
+	moves := NewInts(size)
+	moves[source] = source
+	state := p.newPathFinderState(source)
+
+	heuristic := func(i int) int {
+		idx := state.frontier[i]
+		return distances[idx] + p.state.IdxToPos[idx].DistInt(p.state.IdxToPos[target])
+	}
+	for {
+		curr := state.frontier[0]
+		if curr == target {
+			break
+		}
+		state.frontier = state.frontier[1:]
+
+		state.findBetterNeighbours(distances, curr, func(nextIdx, newDistance int) {
+			moves[nextIdx] = curr
+		})
+
+		if len(state.frontier) == 0 {
+			return nil // no path
+		}
+
+		// apply heuristic to frontier (favor points closer to target)
+		sort.Slice(state.frontier, func(i, j int) bool { return heuristic(i) < heuristic(j) })
+	}
+
+	// build reverse path
+	curr := target
+	path := []int{curr}
+	for {
+		curr = moves[curr]
+		if curr == source {
+			break
+		}
+		path = append(path, curr)
+	}
+	// reverse path
+	n := len(path)
+	for i := 0; i < n/2; i++ {
+		path[i], path[n-i-1] = path[n-i-1], path[i]
+	}
+	return path
+}
+
+func (p PathFinder) FindDistances() Ints {
+	source := p.state.Player.Pos
+	level := p.state.Level
+	size := level.Size()
+	distances := NewInts(size)
+	distances[source] = 0
+	state := p.newPathFinderState(source)
+
+	for {
+		curr := state.frontier[0]
+		state.frontier = state.frontier[1:]
+
+		state.findBetterNeighbours(distances, curr, nil)
+
+		if len(state.frontier) == 0 {
+			return distances
+		}
+	}
+}
+
+func (p PathFinder) newPathFinderState(source int) *pathFinderState {
+	return &pathFinderState{p.state, append(make([]int, 0, p.state.Level.Size()), source), p.moves}
+}
+
+type pathFinderState struct {
+	state    *State
+	frontier []int
+	moves    []Moves
+}
+
+type betterNeighbourFn func(int, int)
+
+func (s *pathFinderState) findBetterNeighbours(distances []int, curr int, better betterNeighbourFn) {
+	currDistance := distances[curr]
+	newDistance := currDistance + 1
+
+	var moves []int
+	if s.moves == nil {
+		for _, dir := range Directions {
+			nextIdx := s.state.Level.MoveIdx(curr, dir)
+			if nextIdx == -1 {
+				continue
+			}
+			moves = append(moves, nextIdx)
+		}
+	} else {
+		moves = s.moves[curr].Valid
+	}
+	for _, nextIdx := range moves {
+		if distance := distances[nextIdx]; distance != -1 && distance <= newDistance { // skip when shorter path exists
+			continue
+		}
+		if !s.state.Walkable[nextIdx] || s.state.Bricks[nextIdx] != -1 { // filter neighbours
+			continue
+		}
+		distances[nextIdx] = newDistance
+		s.frontier = append(s.frontier, nextIdx)
+		if better == nil {
+			continue
+		}
+		better(nextIdx, newDistance)
+	}
+}
--- a/soko/solver.go
+++ b/soko/solver.go
@ -0,0 +1,94 @@
+package soko
+
+func Solve(l Level) int {
+	state := l.State()
+	return solve(state)
+}
+
+func solve(state State) int {
+	level := state.Level
+	target := state.Target.Pos
+	costs := &stateCostQueue{}
+	costs.Put(&stateCost{&state, 0, nil})
+	costsByPlayerIdx := make([][]*stateCost, level.Size())
+	findCost := func(s *State) *stateCost {
+		costs := costsByPlayerIdx[s.Player.Pos]
+		for i := 0; i < len(costs); i++ {
+			if !costs[i].state.Equal(s) {
+				continue
+			}
+			return costs[i]
+		}
+		return nil
+	}
+	addCost := func(next *State, nextCost int) {
+		cost := findCost(next)
+		if cost == nil {
+			newCost := &stateCost{next, nextCost, nil}
+			costs.Put(newCost)
+			player := next.Player.Pos
+			costsByPlayerIdx[player] = append(costsByPlayerIdx[player], newCost)
+		} else if nextCost < cost.cost {
+			cost.cost = nextCost
+			costs.Update(cost)
+		}
+	}
+	moves := level.Moves()
+	type direction struct {
+		dir     Direction
+		inverse Direction
+	}
+	dirs := make([]direction, 4)
+	for _, dir := range Directions {
+		dirs[dir] = direction{dir, dir.Invert()}
+	}
+	for {
+		curr := costs.Get()
+		currPlayerPos := curr.state.Player.Pos
+		if currPlayerPos == target {
+			return curr.cost
+		}
+
+		if curr.distances == nil {
+			curr.distances = NewPathFinderMoves(curr.state, moves).FindDistances()
+		}
+		distances := curr.distances
+		for _, e := range curr.state.Entities {
+			idx := e.Pos
+			if e.Typ != EntityTypeBrick || curr.state.SunkenBricks[idx] == e.ID {
+				continue
+			}
+			for i := 0; i < 4; i++ {
+				player := moves[e.Pos].All[dirs[i].inverse]
+				if player == -1 {
+					continue
+				}
+				walk := distances[player]
+				if walk == -1 {
+					continue
+				}
+				if !curr.state.IsOpenForBrick(curr.state.IdxToPos[moves[e.Pos].All[i]]) {
+					continue
+				}
+				curr.state.Player.Pos = player
+				next, ok := curr.state.MovePlayer(dirs[i].dir)
+				if !ok {
+					panic("should be a valid move")
+				}
+				nextCost := curr.cost + walk + 1
+				addCost(&next, nextCost)
+			}
+		}
+		curr.state.Player.Pos = currPlayerPos
+		if walk := distances[target]; walk != -1 {
+			next := curr.state.Clone()
+			next.Player.Pos = target
+			nextCost := curr.cost + walk
+			addCost(&next, nextCost)
+		}
+
+		if costs.Empty() {
+			return -1
+		}
+	}
+}
--- a/soko/solver_test.go
+++ b/soko/solver_test.go
@ -0,0 +1,111 @@
+package soko
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var levelBenchmark = `level:
+._._._._._._._._._._._._._._._._._._._._
+._._._._._#_#_#_._._._._._._._._._._._._
+._._._._._#_#_#_._._._._._._._._._._._._
+._._._._._#_#_#_._._._._._._._._._._._._
+._._._#_#_#_#_#_#_._._._._._._._._._._._
+._._._#_._#_._._#_._._._._#X#_#_~_#_#_._
+._#_#_#_._#_._._#_._._._._._._._~_#_#_._
+._#_#B#_#_#B#_#_#_#_#_#_#_#_#_#_#_#_#_._
+._._._._._#_._._._#_._#@._._._._#_#_._._
+._._._._._#_#_#_#_#_._._._._._._._._._._
+._._._._._._._._._._._._._._._._._._._._
+:level`
+
+var levelEasy = `level:
+._._._._._._._._._._
+._#@#_#_#B#_~_#_#X._
+._._._._._._._._._._
+:level`
+
+var level1 = `level:
+._._._._._._._._._._
+._#_#_#_#_~_~_~_#_._
+._#_#_._#B~_~_#_#_._
+._#_#_#_#_~_~_~_#_._
+._#_#_._#B~_~_#_#_._
+._#@#_#_#_~_~_#_#X._
+._#_#_~_~_~_#_#_#_._
+._#_#_~_~_~_#_#_#_._
+._._._._._._._._._._
+:level`
+
+var level2 = `level:
+._._._._._._._._._._._._._._._._._._._._
+._._._._._#_#_#_._._._._._._._._._._._._
+._._._._._#B#_#_._._._._._._._._._._._._
+._._._._._#_#_#B._._._._._._._._._._._._
+._._._#_#_#B#_#B#_._._._._._._._._._._._
+._._._#_._#_._._#_._._._._#X#_~_~_~_#_._
+._#_#_#_._#_._._#_._._._._._._._~_~_#_._
+._#_#B#_#_#B#_#_#_#_#_#_#_#_#_#_~_#_#_._
+._._._._._#_._._._#_._#@._._._._#_#_._._
+._._._._._#_#_#_#_#_._._._._._._._._._._
+._._._._._._._._._._._._._._._._._._._._
+:level`
+
+var level3 = `level:
+._._._._._._._._._._
+._._._._._._._._._._
+._~_#_#_#_#B#_._._._
+._~_#B#_#_._#_._._._
+._~_._#_~_#_#_._._._
+._#X._#_~_#_._._._._
+._._#_#B#_#_._._._._
+._._#@#_._._._._._._
+._._._._._._._._._._
+:level`
+
+var level4 = `level:
+._._._._._._._._._._._._
+._._#_#_._._._._._._._._
+._._#_#B#_#B#@#_#_._._._
+._._#_#_#_#_#B#_#_._._._
+._._._._._._#_._._._._._
+._._._._._._#_._._._._._
+._._._._._._#B._._._._._
+._._._#_#_._#_._#_#_._._
+._#_#_#_#_~_#_#_#_#_#_._
+._#_._._#_._#_._#_._#_._
+._#_._#X~_._~_._~_._#_._
+._#_._._#_._#_._#_._#_._
+._#_#_#_#_#_~_#_#_#_#_._
+._._._._._._._._._._._._
+:level`
+
+func mustParseLevel(s string) Level {
+	l, err := ParseLevel(bytes.NewBufferString(s))
+	if err != nil {
+		panic("couldn't parse level")
+	}
+	return l
+}
+
+func TestSolver(t *testing.T) {
+	solve := func(s string) int {
+		l := mustParseLevel(s)
+		steps := Solve(l)
+		return steps
+	}
+	assert.Equal(t, 7, solve(levelEasy))
+	assert.Equal(t, 35, solve(level1))
+	// assert.Equal(t, -1, solve(level2))
+	assert.Equal(t, 49, solve(level3))
+	// assert.Equal(t, -1, solve(level4))
+}
+
+func BenchmarkSolver(b *testing.B) {
+	l := mustParseLevel(levelBenchmark)
+	for n := 0; n < b.N; n++ {
+		Solve(l)
+	}
+}
--- a/soko/state.go
+++ b/soko/state.go
@ -0,0 +1,240 @@
+package soko
+
+import "opslag.de/schobers/geom"
+
+type State struct {
+	Player Entity
+	Target Entity
+
+	Entities Entities
+
+	Level        Level
+	IdxToPos     []geom.Point
+	Bricks       Ints
+	SunkenBricks Ints
+	Walkable     []bool
+
+	nextEntityID int
+}
+
+func NewState(l Level) State {
+	size := l.Size()
+	s := State{
+		Entities:     Entities{},
+		Level:        l,
+		IdxToPos:     make([]geom.Point, size),
+		Bricks:       NewInts(size),
+		SunkenBricks: NewInts(size),
+		Walkable:     make([]bool, size),
+	}
+
+	for idx, t := range l.Tiles {
+		switch t {
+		case TileTypeBasic:
+			s.Walkable[idx] = true
+		}
+		s.IdxToPos[idx] = s.Level.IdxToPos(idx)
+	}
+
+	for idx, e := range l.Entities {
+		pos := s.IdxToPos[idx]
+		switch e {
+		case EntityTypeBrick:
+			s.addBrick(pos)
+		case EntityTypePlayer:
+			s.initPlayer(pos)
+		case EntityTypeTarget:
+			s.initTarget(pos)
+		}
+	}
+	return s
+}
+
+// Clone creates and returns a clone of the state.
+func (s State) Clone() State {
+	return State{
+		Player:       s.Player,
+		Target:       s.Target,
+		Entities:     s.Entities.Clone(),
+		Level:        s.Level,
+		IdxToPos:     s.IdxToPos,
+		Bricks:       s.Bricks.Clone(),
+		SunkenBricks: s.SunkenBricks.Clone(),
+		Walkable:     append(s.Walkable[:0:0], s.Walkable...),
+		nextEntityID: s.nextEntityID,
+	}
+}
+
+func (s State) All(pred func(State, geom.Point) bool, p ...geom.Point) bool {
+	for _, p := range p {
+		if !pred(s, p) {
+			return false
+		}
+	}
+	return true
+}
+
+func (s State) Any(pred func(State, geom.Point) bool, p ...geom.Point) bool {
+	for _, p := range p {
+		if pred(s, p) {
+			return true
+		}
+	}
+	return false
+}
+
+func (s *State) Equal(other *State) bool {
+	for i := 0; i < len(s.Entities); i++ {
+		if other.Entities[i].Pos != s.Entities[i].Pos {
+			return false
+		}
+	}
+	return true
+}
+
+func (s State) IsOpenForBrick(p geom.Point) bool {
+	idx := s.Level.PosToIdx(p)
+	if idx == -1 {
+		return false
+	}
+	return s.isOpenForBrick(idx)
+}
+
+// IsWalkable indicates that a player could walk over this tile regardless of any Bricks that might be there.
+func (s State) IsWalkable(p geom.Point) bool {
+	idx := s.Level.PosToIdx(p)
+	if idx == -1 {
+		return false
+	}
+	return s.Walkable[idx]
+}
+
+// IsWalkableAndFree indicates that a player can walk over this tile (no brick is at the tile).
+func (s State) IsWalkableAndFree(p geom.Point) bool {
+	idx := s.Level.PosToIdx(p)
+	if idx == -1 {
+		return false
+	}
+	return s.Walkable[idx] && s.Bricks[idx] == -1
+}
+
+// MovePlayer tries to move the player in the specified direction. Returns the new state and true if the move is valid. Returns the current state and false is the move was invalid.
+func (s State) MovePlayer(dir Direction) (State, bool) {
+	to := s.Level.MoveIdx(s.Player.Pos, dir)
+	if to == -1 {
+		return s, false
+	}
+
+	if !s.Walkable[to] {
+		return s, false
+	}
+
+	brickID := s.Bricks[to]
+	if brickID == -1 {
+		return s.Mutate(func(s *State) {
+			s.movePlayer(to)
+		}), true
+	}
+
+	brickTo := s.Level.MoveIdx(to, dir)
+	if brickTo == -1 {
+		return s, false
+	}
+	if !s.isOpenForBrick(brickTo) {
+		return s, false
+	}
+	return s.Mutate(func(s *State) {
+		s.movePlayer(to)
+
+		if s.Level.Tiles[brickTo] == TileTypeMagma && s.SunkenBricks[brickTo] == -1 {
+			s.SunkenBricks[brickTo] = brickID
+			s.Walkable[brickTo] = true
+			s.Bricks[to] = -1
+		} else {
+			s.Bricks[brickTo] = brickID
+			s.Bricks[to] = -1
+		}
+		s.updateEntity(brickID, Entity{brickID, brickTo, EntityTypeBrick})
+	}), true
+}
+
+func (s State) SetPlayer(to geom.Point) (State, bool) {
+	toIdx := s.Level.PosToIdx(to)
+	if toIdx == -1 {
+		return s, false
+	}
+	if !s.Walkable[toIdx] {
+		return s, false
+	}
+	if s.Bricks[toIdx] != -1 {
+		return s, false
+	}
+	return s.Mutate(func(s *State) {
+		s.movePlayer(toIdx)
+	}), true
+
+}
+
+// Mutate clones the state, applies the mutation on the clone and returns the clone.
+func (s State) Mutate(fn func(s *State)) State {
+	clone := s.Clone()
+	fn(&clone)
+	return clone
+}
+
+func (s *State) addBrick(pos geom.Point) {
+	s.addEntity(pos, EntityTypeBrick, func(e Entity) {
+		idx := s.Level.PosToIdx(pos)
+		if idx != -1 {
+			s.Bricks[idx] = e.ID
+		}
+	})
+}
+
+func (s *State) addEntity(pos geom.Point, typ EntityType, add func(Entity)) {
+	id := s.nextEntityID
+	e := Entity{id, s.Level.PosToIdx(pos), typ}
+	add(e)
+	s.Entities = append(s.Entities, e)
+	s.nextEntityID++
+}
+
+func (s *State) initPlayer(pos geom.Point) {
+	s.addEntity(pos, EntityTypePlayer, func(e Entity) {
+		s.Player = e
+	})
+}
+
+func (s *State) initTarget(pos geom.Point) {
+	s.addEntity(pos, EntityTypeTarget, func(e Entity) {
+		s.Target = e
+	})
+}
+
+func (s State) isOpenForBrick(idx int) bool {
+	if s.Walkable[idx] {
+		return s.Bricks[idx] == -1
+	}
+	return s.Level.Tiles[idx] == TileTypeMagma
+}
+
+func (s *State) updateEntity(id int, e Entity) {
+	idx := s.Entities.IdxById(id)
+	if idx == -1 {
+		return
+	}
+	s.Entities[idx] = e
+}
+
+func (s *State) movePlayer(to int) {
+	s.Player.Pos = to
+	s.updateEntity(s.Player.ID, Entity{s.Player.ID, to, EntityTypePlayer})
+}
+
+func IsMagma(s State, p geom.Point) bool {
+	idx := s.Level.PosToIdx(p)
+	if idx == -1 {
+		return false
+	}
+	return s.Level.Tiles[idx] == TileTypeMagma
+}
--- a/soko/statecost.go
+++ b/soko/statecost.go
@ -0,0 +1,71 @@
+package soko
+
+type stateCost struct {
+	state     *State
+	cost      int
+	distances Ints
+}
+
+type stateCostQueue struct {
+	first *stateCostQueueItem
+}
+
+type stateCostQueueItem struct {
+	Value *stateCost
+	Next  *stateCostQueueItem
+}
+
+func (q *stateCostQueue) Empty() bool {
+	return q.first == nil
+}
+
+func (q *stateCostQueue) Get() *stateCost {
+	if q.Empty() {
+		panic("nothing in queue")
+	}
+	first := q.first
+	q.first = first.Next
+	return first.Value
+}
+
+func (q *stateCostQueue) Put(value *stateCost) {
+	priority := value.cost
+	item := &stateCostQueueItem{value, nil}
+	if q.Empty() {
+		q.first = item
+		return
+	}
+	if priority < q.first.Value.cost {
+		item.Next = q.first
+		q.first = item
+		return
+	}
+	curr := q.first
+	for curr.Next != nil {
+		if priority < curr.Next.Value.cost {
+			item.Next = curr.Next
+			curr.Next = item
+			return
+		}
+		curr = curr.Next
+	}
+	curr.Next = item
+}
+
+func (q *stateCostQueue) Update(value *stateCost) {
+	var prev *stateCostQueueItem
+	curr := q.first
+	for curr.Value != value {
+		prev = curr
+		curr = curr.Next
+		if curr == nil {
+			panic("not in queue")
+		}
+	}
+	if prev == nil {
+		q.first = curr.Next
+	} else {
+		prev.Next = curr.Next
+	}
+	q.Put(value)
+}
--- a/soko/tiletype.go
+++ b/soko/tiletype.go
@ -0,0 +1,21 @@
+package soko
+
+type TileType byte
+
+const (
+	TileTypeInvalid TileType = TileType(0)
+	TileTypeNothing          = '.'
+	TileTypeBasic            = '#'
+	TileTypeMagma            = '~'
+)
+
+func (t TileType) IsValid() bool {
+	switch t {
+	case TileTypeNothing:
+	case TileTypeBasic:
+	case TileTypeMagma:
+	default:
+		return false
+	}
+	return true
+}
Author	SHA1	Message	Date
Sander Schobers	365e9dbbbb	Added solver & optimized state. Positions are kept by index only.	2020-01-16 07:33:04 +01:00
Sander Schobers	8fc459e1d6	Added path finder & visualization (F5).	2020-01-15 21:49:01 +01:00
Sander Schobers	93be82bdbd	Moved level state to soko package. Renamed entity type character and egg to player and target respectively.	2020-01-15 21:25:32 +01:00
Sander Schobers	1e9d3e9089	Renamed Tile to TileType.	2020-01-15 19:51:57 +01:00
Sander Schobers	cb81ced655	Moved tile & entity type to separate code unit.	2020-01-15 19:06:06 +01:00
Sander Schobers	a4058df9c8	Moved level to separate package (soko). Moved lineparser to gut package.	2020-01-15 19:03:52 +01:00
Sander Schobers	a19d33cb9f	Changed behaviour of player after brick has been sunken. - Previously the player would stop on the current tile even if the correct key was pressed. Now the movement continues without interruption.	2020-01-14 19:35:52 +01:00
Sander Schobers	041cdccc3f	Changed behaviour of movement. - Every movement key at any moment is valid if it is the only movement key pressed (when the previous move is finished).	2020-01-14 19:34:02 +01:00
Sander Schobers	cdb581d0f6	Added level pack selection.	2020-01-14 19:12:43 +01:00
Sander Schobers	0203539201	Can load more than a single level pack (but not play yet).	2020-01-14 18:53:15 +01:00
Sander Schobers	fd92207400	Changed structure of levels/packs.	2020-01-14 18:38:42 +01:00
Sander Schobers	46e3ac060a	Changed Mkdir command to give more rights.	2019-12-31 13:38:10 +01:00
Sander Schobers	2b58bf1d7f	Fixed bug where you weren't able to get past level select menu.	2019-12-31 12:22:57 +01:00
Sander Schobers	3dbb74ac77	Updated README.	2019-12-31 12:11:54 +01:00
Sander Schobers	cbf18822be	Updated README.	2019-12-31 11:51:25 +01:00
Sander Schobers	c61f074465	Escape will go back to main menu in the level selection menu.	2019-12-31 11:43:42 +01:00
Sander Schobers	449873f6b8	Added title on main menu. Changed "Apply" button into "OK" (settings menu).	2019-12-31 11:27:55 +01:00
Sander Schobers	4b393610e2	Fixed bug in rendering of console. - All messages were rendered (outside bounds of the bitmap). Now only rendering (partially) visible messages.	2019-12-31 11:22:18 +01:00
Sander Schobers	30999c944a	Updated dragon sprite & changed villain into an egg.	2019-12-31 11:21:31 +01:00
Sander Schobers	70ce0da074	Added README.	2019-12-29 23:34:28 +01:00
Sander Schobers	72aab5509e	Added title.	2019-12-29 23:29:34 +01:00
Sander Schobers	88a02f0f9b	Disabled initialization of audio.	2019-12-29 22:29:18 +01:00
Sander Schobers	03685f9a33	Changed order of apply/cancel in settings view. Escape now exits settings directly.	2019-12-29 22:06:38 +01:00