Brought in screen manager, minor refactor.

.vscode/launch.json

@@ -0,0 +1,15 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "survive",
+            "type": "go",
+            "request": "launch",
+            "mode": "auto",
+            "program": "main.go"
+        }        
+    ]
+}

assets/imagebank.go

@@ -0,0 +1,76 @@
+package assets
+
+import (
+	"bytes"
+	"image"
+	"log"
+
+	_ "embed"
+
+	"github.com/hajimehoshi/ebiten/v2"
+)
+
+type AssetName string
+
+const (
+	FlyEyeNormal  AssetName = "FlyEyeNormal"
+	FlyEyeDamaged AssetName = "FlyEyeDamaged"
+	FlyEyeDying   AssetName = "FlyEyeDying"
+	FlyEyeShadow  AssetName = "FlyEyeShadow"
+	HeroNormal    AssetName = "HeroNormal"
+	HeroDying     AssetName = "HeroDying"
+	TileSet       AssetName = "TileSet"
+	Altar         AssetName = "Altar"
+	Weapon        AssetName = "Weapon"
+)
+
+var (
+	ImageBank map[AssetName]*ebiten.Image
+
+	flyeyeImage  *ebiten.Image
+	flyeyeImage2 *ebiten.Image
+	flyeyeImage3 *ebiten.Image
+	shadow       *ebiten.Image
+
+	//go:embed fly-eye.png
+	flyeye_img []byte
+	//go:embed fly-eye2.png
+	flyeye_img2 []byte
+	//go:embed fly-eye3.png
+	flyeye_img3 []byte
+	//go:embed shadow.png
+	shadow_img []byte
+	//go:embed hero.png
+	hero_img []byte
+	//go:embed herodeath.png
+	herodeath_img []byte
+	//go:embed grasstile.png
+	tileset_img []byte
+	//go:embed altar.png
+	altar_img []byte
+	//go:embed weapon.png
+	weapon_img []byte
+)
+
+func LoadImages() {
+	ImageBank = make(map[AssetName]*ebiten.Image)
+
+	ImageBank[FlyEyeNormal] = LoadImagesFatal(flyeye_img)
+	ImageBank[FlyEyeDamaged] = LoadImagesFatal(flyeye_img2)
+	ImageBank[FlyEyeDying] = LoadImagesFatal(flyeye_img3)
+	ImageBank[FlyEyeShadow] = LoadImagesFatal(shadow_img)
+	ImageBank[HeroNormal] = LoadImagesFatal(hero_img)
+	ImageBank[HeroDying] = LoadImagesFatal(herodeath_img)
+	ImageBank[TileSet] = LoadImagesFatal(tileset_img)
+	ImageBank[Altar] = LoadImagesFatal(altar_img)
+	ImageBank[Weapon] = LoadImagesFatal(weapon_img)
+
+}
+
+func LoadImagesFatal(b []byte) *ebiten.Image {
+	img, _, err := image.Decode(bytes.NewReader(b))
+	if err != nil {
+		log.Fatal(err)
+	}
+	return ebiten.NewImageFromImage(img)
+}

elements/explosion.go

@@ -1,8 +1,10 @@
-package main
+package elements
+
+import "mover/gamedata"
 
 type Explosion struct {
 	Radius float64
-	Origin Coordinates
+	Origin gamedata.Coordinates
 	cycle  int
 	Active bool
 }
@@ -27,7 +29,7 @@ func (e *Explosion) Update() {
 
 }
 
-func (e *Explosion) SetOrigin(origin Coordinates) {
+func (e *Explosion) SetOrigin(origin gamedata.Coordinates) {
 	e.Origin = origin
 }
 

elements/hero.go

@@ -1,9 +1,9 @@
-package main
+package elements
 
 import (
-	"bytes"
 	"image"
-	"log"
+	"mover/assets"
+	"mover/gamedata"
 
 	_ "embed"
 	"image/color"
@@ -12,15 +12,9 @@ import (
 	"github.com/hajimehoshi/ebiten/v2"
 )
 
-var (
+const (
-	heroImage *ebiten.Image
+	MOVER_WIDTH  = 48
-	heroDeath *ebiten.Image
+	MOVER_HEIGHT = 48
-
-	//go:embed hero.png
-	hero_img []byte
-
-	//go:embed herodeath.png
-	herodeath_img []byte
 )
 
 const (
@@ -34,28 +28,14 @@ const (
 
 type HeroAction uint
 
-func init() {
-	img, _, err := image.Decode(bytes.NewReader(hero_img))
-	if err != nil {
-		log.Fatal(err)
-	}
-	heroImage = ebiten.NewImageFromImage(img)
-
-	img, _, err = image.Decode(bytes.NewReader(herodeath_img))
-	if err != nil {
-		log.Fatal(err)
-	}
-	heroDeath = ebiten.NewImageFromImage(img)
-}
-
 type Hero struct {
 	Sprite     *ebiten.Image
 	Maks       *ebiten.Image
 	MaksDest   *ebiten.Image
 	Angle      float64
-	Pos        Coordinates
+	Pos        gamedata.Coordinates
-	Origin     Coordinates
+	Origin     gamedata.Coordinates
-	Lastpos    Coordinates
+	Lastpos    gamedata.Coordinates
 	Action     HeroAction
 	cycles     int
 	Upgrade    bool
@@ -93,7 +73,7 @@ func (m *Hero) SetAngle(a float64) {
 	m.Angle = a
 }
 
-func (m *Hero) SetOrigin(coords Coordinates) {
+func (m *Hero) SetOrigin(coords gamedata.Coordinates) {
 	m.Origin = coords
 	m.Pos = coords
 }
@@ -117,16 +97,16 @@ func (m *Hero) Draw() {
 
 	switch m.Action {
 	case HeroActionDefault:
-		m.Sprite.DrawImage(heroImage.SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), op)
+		m.Sprite.DrawImage(assets.ImageBank[assets.HeroNormal].SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), op)
 	case HeroActionDying:
-		m.Sprite.DrawImage(heroDeath.SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), op)
+		m.Sprite.DrawImage(assets.ImageBank[assets.HeroDying].SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), op)
 
 		if m.dyingcount >= 31 {
 			m.cycles = 0
 			m.Action++
 		}
 	case HeroActionExploding:
-		m.Sprite.DrawImage(heroDeath.SubImage(image.Rect(48*3, 0, 48*4, 48)).(*ebiten.Image), op)
+		m.Sprite.DrawImage(assets.ImageBank[assets.HeroDying].SubImage(image.Rect(48*3, 0, 48*4, 48)).(*ebiten.Image), op)
 	default:
 	}
 }

elements/mover.go

@@ -1,9 +1,9 @@
-package main
+package elements
 
 import (
-	"bytes"
 	"image"
-	"log"
+	"mover/assets"
+	"mover/gamedata"
 
 	_ "embed"
 	"image/color"
@@ -12,22 +12,6 @@ import (
 	"github.com/hajimehoshi/ebiten/v2"
 )
 
-var (
-	flyeyeImage  *ebiten.Image
-	flyeyeImage2 *ebiten.Image
-	flyeyeImage3 *ebiten.Image
-	shadow       *ebiten.Image
-
-	//go:embed fly-eye.png
-	flyeye_img []byte
-	//go:embed fly-eye2.png
-	flyeye_img2 []byte
-	//go:embed fly-eye3.png
-	flyeye_img3 []byte
-	//go:embed shadow.png
-	shadow_img []byte
-)
-
 const (
 	MoverActionDefault = iota
 	MoverActionDamaged
@@ -39,39 +23,13 @@ const (
 
 type MoverAction uint
 
-func init() {
-	img, _, err := image.Decode(bytes.NewReader(flyeye_img))
-	if err != nil {
-		log.Fatal(err)
-	}
-	flyeyeImage = ebiten.NewImageFromImage(img)
-
-	img, _, err = image.Decode(bytes.NewReader(flyeye_img2))
-	if err != nil {
-		log.Fatal(err)
-	}
-	flyeyeImage2 = ebiten.NewImageFromImage(img)
-
-	img, _, err = image.Decode(bytes.NewReader(flyeye_img3))
-	if err != nil {
-		log.Fatal(err)
-	}
-	flyeyeImage3 = ebiten.NewImageFromImage(img)
-
-	img, _, err = image.Decode(bytes.NewReader(shadow_img))
-	if err != nil {
-		log.Fatal(err)
-	}
-	shadow = ebiten.NewImageFromImage(img)
-}
-
 type Mover struct {
 	Sprite     *ebiten.Image
 	Maks       *ebiten.Image
 	MaksDest   *ebiten.Image
 	Angle      float64
-	Pos        Coordinates
+	Pos        gamedata.Coordinates
-	Origin     Coordinates
+	Origin     gamedata.Coordinates
 	Action     MoverAction
 	cycles     int
 	rotating   bool
@@ -106,7 +64,7 @@ func (m *Mover) SetAngle(a float64) {
 	m.Angle = a
 }
 
-func (m *Mover) SetOrigin(coords Coordinates) {
+func (m *Mover) SetOrigin(coords gamedata.Coordinates) {
 	m.Origin = coords
 	m.Pos = coords
 }
@@ -126,18 +84,18 @@ func (m *Mover) Draw() {
 	case MoverActionDefault:
 		op := &ebiten.DrawImageOptions{}
 		op.GeoM.Translate(14, 40)
-		m.Sprite.DrawImage(shadow, op)
+		m.Sprite.DrawImage(assets.ImageBank[assets.FlyEyeShadow], op)
-		m.Sprite.DrawImage(flyeyeImage.SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), nil)
+		m.Sprite.DrawImage(assets.ImageBank[assets.FlyEyeNormal].SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), nil)
 	case MoverActionDamaged:
 		op := &ebiten.DrawImageOptions{}
 		op.GeoM.Translate(14, 40)
-		m.Sprite.DrawImage(shadow, op)
+		m.Sprite.DrawImage(assets.ImageBank[assets.FlyEyeShadow], op)
-		m.Sprite.DrawImage(flyeyeImage2.SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), nil)
+		m.Sprite.DrawImage(assets.ImageBank[assets.FlyEyeDamaged].SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), nil)
 	case MoverActionDying:
 
 		if (m.cycles/5)%2 == 0 {
 
-			m.MaksDest.DrawImage(flyeyeImage2.SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), nil)
+			m.MaksDest.DrawImage(assets.ImageBank[assets.FlyEyeDamaged].SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), nil)
 			op := &ebiten.DrawImageOptions{}
 			op.GeoM.Reset()
 			op.Blend = ebiten.BlendSourceAtop
@@ -145,14 +103,14 @@ func (m *Mover) Draw() {
 			m.Sprite.DrawImage(m.MaksDest, nil)
 
 		} else {
-			m.Sprite.DrawImage(flyeyeImage2.SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), nil)
+			m.Sprite.DrawImage(assets.ImageBank[assets.FlyEyeDamaged].SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), nil)
 		}
 		if m.dyingcount >= 31 {
 			m.cycles = 0
 			m.SetHit()
 		}
 	case MoverActionExploding:
-		m.Sprite.DrawImage(flyeyeImage3.SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), nil)
+		m.Sprite.DrawImage(assets.ImageBank[assets.FlyEyeDying].SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), nil)
 		if idx == 3 {
 			m.SetHit()
 		}

elements/projectile.go

@@ -1,14 +1,17 @@
-package main
+package elements
 
-import "math"
+import (
+	"math"
+	"mover/gamedata"
+)
 
 type Projectile struct {
-	Pos      Coordinates
+	Pos      gamedata.Coordinates
 	Velocity float64
 	a        float64
 }
 
-func NewProjectile(origin Coordinates, angle, velocity float64) *Projectile {
+func NewProjectile(origin gamedata.Coordinates, angle, velocity float64) *Projectile {
 	return &Projectile{
 		Velocity: velocity,
 		a:        angle,

gamedata/coordinates.go

@@ -1,4 +1,4 @@
-package main
+package gamedata
 
 type Coordinates struct {
 	X float64

gamedata/gameinfo.go

@@ -0,0 +1,16 @@
+package gamedata
+
+type Area struct {
+	Width  int
+	Height int
+}
+
+func (a *Area) Area() int {
+	return a.Height * a.Width
+}
+
+type GameInfo struct {
+	Name       string
+	Version    string
+	Dimensions Area
+}

main.go

@@ -1,8 +1,11 @@
 package main
 
 import (
-	"fmt"
 	"log"
+	"mover/assets"
+	"mover/gamedata"
+	"mover/screenmanager"
+	"mover/screens"
 
 	"github.com/hajimehoshi/ebiten/v2"
 )
@@ -13,17 +16,23 @@ const (
 )
 
 func main() {
-	ver := "survive v0.10"
+	//moverGame := &Game{}
-
+	moverGame := screenmanager.NewManager()
-	fmt.Println(ver)
+	moverGame.SetDimensions(gamedata.Area{Width: screenWidth, Height: screenHeight})
-
-	moverGame := &Game{}
 
 	ebiten.SetWindowSize(screenWidth*1.5, screenHeight*1.5)
-	ebiten.SetWindowTitle(ver)
+	ebiten.SetWindowTitle(moverGame.Info.Name + ": v" + moverGame.Info.Version)
 
-	if err := ebiten.RunGame(moverGame); err != nil {
+	loadScreens(&moverGame)
+
+	if err := ebiten.RunGame(&moverGame); err != nil {
 		log.Fatal(err)
 	}
 
 }
+
+func loadScreens(m *screenmanager.Manager) {
+	assets.LoadImages()
+	m.AddScene(&screens.Game{})
+	m.ResetScenes()
+}

screenmanager/manager.go

@@ -0,0 +1,136 @@
+package screenmanager
+
+import (
+	"mover/gamedata"
+	"mover/screens"
+
+	"github.com/hajimehoshi/ebiten/v2"
+)
+
+const (
+	defaultWidth  = 1024
+	defaultHeight = 768
+)
+
+type Manager struct {
+	Info           gamedata.GameInfo
+	currentScene   screens.Screen
+	currentSceneId uint
+	nextSceneId    uint
+	screens        []screens.Screen
+	internalerr    error
+}
+
+// can be used to create default manager instance
+func NewManager() Manager {
+	return Manager{
+		Info: gamedata.GameInfo{
+			Name:    "survive",
+			Version: "0.12",
+			Dimensions: gamedata.Area{
+				Width:  defaultWidth,
+				Height: defaultHeight,
+			},
+		},
+		currentSceneId: 0,
+		nextSceneId:    1,
+		internalerr:    nil,
+	}
+}
+
+// ebitengine update proxy on behalf of current scene
+func (m *Manager) Update() error {
+	if m.currentScene == nil {
+		return nil
+	}
+
+	err := m.currentScene.Update()
+	if err != nil {
+		return err
+	}
+
+	return m.internalerr
+}
+
+// shutdown application
+func (m *Manager) Quit() {
+	m.internalerr = ebiten.Termination
+}
+
+// calls current scene's draw method if the currentscene is valid
+func (m *Manager) Draw(screen *ebiten.Image) {
+	if m.currentScene != nil {
+		m.currentScene.Draw(screen)
+	}
+}
+
+// ebitengine proxy for layout
+func (m *Manager) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int) {
+	return m.Info.Dimensions.Width, m.Info.Dimensions.Height
+}
+
+// appends scene to the managed screens
+func (m *Manager) AddScene(s screens.Screen) {
+	setDefaultHandlers(m, s)
+	s.SetDimensions(m.Info.Dimensions)
+	m.screens = append(m.screens, s)
+}
+
+// sets the default callback handlers for a given scene within manager
+// Default Handling behaviours:
+//
+//	reset: sets (scene, nextscene) to {0, 1}
+//	scene completion: sets (scene, nextscene) to {nextscene, nextscene+1}
+//	end game: shutdown groovy
+//
+//	note: NOOP and RELOAD are purposefully not mapped; they are scene
+//	specific and should be mapped to by user of groovy
+func setDefaultHandlers(m *Manager, s screens.Screen) {
+	s.SetEventHandler(screens.EventReset, func() { m.ResetScenes() })
+	s.SetEventHandler(screens.EventCompleted, func() { m.TransitionScene() })
+	s.SetEventHandler(screens.EventEndgame, func() { m.Quit() })
+}
+
+// we're going to reset the scene to the first one
+func (m *Manager) ResetScenes() {
+	m.currentSceneId = 0
+	m.nextSceneId = 1
+	m.SetCurrentScene(0)
+}
+
+// sets the current scene, based on sceneindex n
+// n > scenelist, quit
+// otherwise, scene = n
+func (m *Manager) SetCurrentScene(sceneId uint) {
+	if sceneId >= uint(len(m.screens)) {
+		m.Quit()
+	} else {
+		m.currentSceneId = sceneId
+		m.currentScene = m.screens[sceneId]
+		m.nextSceneId = m.currentSceneId + 1
+	}
+}
+
+// handle scene transition
+func (m *Manager) TransitionScene() {
+	m.SetCurrentScene(m.nextSceneId)
+}
+
+// set new sceneId as the successor
+func (m *Manager) SetNextScene(sceneId uint) {
+	m.nextSceneId = sceneId
+}
+
+// sets sene dimensions
+func (m *Manager) SetDimensions(a gamedata.Area) {
+	m.Info.Dimensions = a
+}
+
+// report number of total screens
+func (m *Manager) SceneCount() uint {
+	return uint(len(m.screens))
+}
+
+func (m *Manager) GetScene(sceneId uint) screens.Screen {
+	return m.screens[sceneId]
+}

screens/game.go

@@ -1,14 +1,16 @@
-package main
+package screens
 
 import (
-	"bytes"
 	"fmt"
 	"image"
 	"image/color"
 	"log"
 	"math"
 	"math/rand/v2"
+	"mover/assets"
+	"mover/elements"
 	"mover/fonts"
+	"mover/gamedata"
 
 	_ "embed"
 
@@ -23,19 +25,6 @@ const (
 	MOVER_HEIGHT = 48
 )
 
-var (
-	weaponImage  *ebiten.Image
-	tilesetImage *ebiten.Image
-	altarImage   *ebiten.Image
-
-	//go:embed grasstile.png
-	tileset_img []byte
-	//go:embed altar.png
-	altar_img []byte
-	//go:embed weapon.png
-	weapon_img []byte
-)
-
 type Game struct {
 	background        *ebiten.Image
 	collisionMask     *ebiten.Image
@@ -43,20 +32,21 @@ type Game struct {
 	heroCollisionMask *ebiten.Image
 	heroCollisionCpy  *ebiten.Image
 
-	Pos         Coordinates
+	dimensions  gamedata.Area
+	Pos         gamedata.Coordinates
 	Paused      bool
 	initialized bool
 	gameover    bool
 	reset       bool
 	runtime     float64
-	hero        *Hero
+	hero        *elements.Hero
-	projectiles map[int]*Projectile
+	projectiles map[int]*elements.Projectile
-	explosion   *Explosion
+	explosion   *elements.Explosion
 
 	score   int
 	counter int
 	timer   int
-	targets []*Mover
+	targets []*elements.Mover
 
 	gamepadIDsBuf []ebiten.GamepadID
 	gamepadIDs    map[ebiten.GamepadID]struct{}
@@ -64,43 +54,23 @@ type Game struct {
 	//pressedButtons map[ebiten.GamepadID][]string
 }
 
-func init() {
-	img, _, err := image.Decode(bytes.NewReader(tileset_img))
-	if err != nil {
-		log.Fatal(err)
-	}
-	tilesetImage = ebiten.NewImageFromImage(img)
-
-	img, _, err = image.Decode(bytes.NewReader(altar_img))
-	if err != nil {
-		log.Fatal(err)
-	}
-	altarImage = ebiten.NewImageFromImage(img)
-
-	img, _, err = image.Decode(bytes.NewReader(weapon_img))
-	if err != nil {
-		log.Fatal(err)
-	}
-	weaponImage = ebiten.NewImageFromImage(img)
-}
-
 func (g *Game) Initialize() {
 
-	origin := Coordinates{X: 640 / 2, Y: 480 / 2}
+	origin := gamedata.Coordinates{X: 640 / 2, Y: 480 / 2}
 
 	g.ConstructBackground()
-	g.hero = NewHero()
+	g.hero = elements.NewHero()
 	g.hero.SetOrigin(origin)
 	g.hero.ToggleRotate()
 
 	g.gameover = false
 
-	g.collisionMask = ebiten.NewImage(screenWidth, screenHeight)
+	g.collisionMask = ebiten.NewImage(g.dimensions.Width, g.dimensions.Height)
-	g.projectileMask = ebiten.NewImage(screenWidth, screenHeight)
+	g.projectileMask = ebiten.NewImage(g.dimensions.Width, g.dimensions.Height)
 	g.heroCollisionMask = ebiten.NewImage(MOVER_WIDTH, MOVER_HEIGHT)
 	g.heroCollisionCpy = ebiten.NewImage(MOVER_WIDTH, MOVER_HEIGHT)
 
-	g.explosion = NewExplosion()
+	g.explosion = elements.NewExplosion()
 	g.explosion.SetOrigin(origin)
 	g.score = 0
 	g.reset = false
@@ -116,7 +86,7 @@ func (g *Game) Initialize() {
 	g.timer = 0
 	g.runtime = 0.
 
-	g.projectiles = make(map[int]*Projectile)
+	g.projectiles = make(map[int]*elements.Projectile)
 	g.initialized = true
 	g.reset = false
 
@@ -184,7 +154,7 @@ func (g *Game) Draw(screen *ebiten.Image) {
 	op.GeoM.Translate(0, -16)
 	op.GeoM.Rotate(g.hero.Angle)
 	op.GeoM.Translate(g.hero.Pos.X, g.hero.Pos.Y)
-	screen.DrawImage(weaponImage, op)
+	screen.DrawImage(assets.ImageBank[assets.Weapon], op)
 
 	//secondary/upgraded weapon sprite; in testing proves sort of distracting
 	/*
@@ -226,7 +196,7 @@ func (g *Game) Draw(screen *ebiten.Image) {
 }
 
 func (g *Game) Layout(width, height int) (int, int) {
-	return screenWidth, screenHeight
+	return g.dimensions.Width, g.dimensions.Height
 }
 
 func (g *Game) CleanupTargets() {
@@ -234,7 +204,7 @@ func (g *Game) CleanupTargets() {
 	i := 0
 	for _, target := range g.targets {
 		//moving valid targets to the front of the slice
-		if target.Action < MoverActionDead {
+		if target.Action < elements.MoverActionDead {
 			g.targets[i] = target
 			i++
 		}
@@ -282,7 +252,7 @@ func (g *Game) StepGame() {
 func (g *Game) SpawnEnemies() {
 	f := 40000 / (g.counter + 1)
 	if g.counter%f == 0 {
-		g.targets = append(g.targets, NewMover())
+		g.targets = append(g.targets, elements.NewMover())
 
 		x0 := rand.Float64() * 640
 		y0 := rand.Float64() * 480
@@ -290,15 +260,15 @@ func (g *Game) SpawnEnemies() {
 
 		switch quadrant {
 		case 0:
-			g.targets[len(g.targets)-1].SetOrigin(Coordinates{X: x0, Y: -MOVER_HEIGHT})
+			g.targets[len(g.targets)-1].SetOrigin(gamedata.Coordinates{X: x0, Y: -MOVER_HEIGHT})
 		case 1:
-			g.targets[len(g.targets)-1].SetOrigin(Coordinates{X: x0, Y: screenHeight + MOVER_HEIGHT})
+			g.targets[len(g.targets)-1].SetOrigin(gamedata.Coordinates{X: x0, Y: float64(g.dimensions.Height) + MOVER_HEIGHT})
 		case 2:
-			g.targets[len(g.targets)-1].SetOrigin(Coordinates{X: -MOVER_WIDTH, Y: y0})
+			g.targets[len(g.targets)-1].SetOrigin(gamedata.Coordinates{X: -MOVER_WIDTH, Y: y0})
 		case 3:
-			g.targets[len(g.targets)-1].SetOrigin(Coordinates{X: screenWidth + x0, Y: y0})
+			g.targets[len(g.targets)-1].SetOrigin(gamedata.Coordinates{X: float64(g.dimensions.Width) + x0, Y: y0})
 		default:
-			g.targets[len(g.targets)-1].SetOrigin(Coordinates{X: x0, Y: y0})
+			g.targets[len(g.targets)-1].SetOrigin(gamedata.Coordinates{X: x0, Y: y0})
 			fmt.Println("WTF " + string(quadrant))
 		}
 
@@ -319,7 +289,8 @@ func (g *Game) HandlePulseWaveUpdate() {
 			dy := target.Pos.Y - g.hero.Pos.Y
 			r := math.Sqrt(dx*dx + dy*dy)
 
-			if r >= g.explosion.Radius-5 && r <= g.explosion.Radius+5 && target.Action <= MoverActionDamaged && !target.Touched {
+			if r >= g.explosion.Radius-5 && r <= g.explosion.Radius+5 &&
+				target.Action <= elements.MoverActionDamaged && !target.Touched {
 				target.ToggleColor()
 				target.Touched = true
 				//target.SetHit()
@@ -344,7 +315,9 @@ func (g *Game) UpdateProjectiles() {
 		//compute projectile collisions
 		for _, target := range g.targets {
 			//first, boundary check
-			if p.Pos.X >= target.Pos.X-MOVER_WIDTH/2 && p.Pos.X <= target.Pos.X+MOVER_WIDTH/2 && p.Pos.Y >= target.Pos.Y-MOVER_HEIGHT/2 && p.Pos.Y <= target.Pos.Y+MOVER_HEIGHT/2 && target.Action == MoverActionDamaged {
+			if p.Pos.X >= target.Pos.X-MOVER_WIDTH/2 && p.Pos.X <= target.Pos.X+MOVER_WIDTH/2 &&
+				p.Pos.Y >= target.Pos.Y-MOVER_HEIGHT/2 && p.Pos.Y <= target.Pos.Y+MOVER_HEIGHT/2 &&
+				target.Action == elements.MoverActionDamaged {
 				//fmt.Println("potential collision")
 
 				//the following computes total collisions in the image using a projectile mask that is a duplicate of what is on screen
@@ -359,7 +332,7 @@ func (g *Game) UpdateProjectiles() {
 				g.collisionMask.DrawImage(target.Sprite, op)
 
 				//var pixels []byte = make([]byte, MOVER_WIDTH*MOVER_HEIGHT*4)
-				var pixels []byte = make([]byte, screenWidth*screenHeight*4)
+				var pixels []byte = make([]byte, g.dimensions.Width*g.dimensions.Height*4)
 				g.collisionMask.ReadPixels(pixels)
 				for i := 0; i < len(pixels); i = i + 4 {
 					if pixels[i+3] != 0 {
@@ -367,7 +340,7 @@ func (g *Game) UpdateProjectiles() {
 						delete(g.projectiles, k)
 						//target.ToggleColor()
 						target.SetHit()
-						//target.SetOrigin(Coordinates{X: rand.Float64() * 640, Y: rand.Float64() * 480})
+						//target.SetOrigin(gamedata.Coordinates{X: rand.Float64() * 640, Y: rand.Float64() * 480})
 						target.Hit = true
 						break
 					}
@@ -380,7 +353,7 @@ func (g *Game) UpdateProjectiles() {
 func (g *Game) UpdateTargets() {
 	for _, target := range g.targets {
 
-		if !target.Hit && g.hero.Action < HeroActionDying {
+		if !target.Hit && g.hero.Action < elements.HeroActionDying {
 			dx := g.hero.Pos.X - target.Pos.X
 			dy := g.hero.Pos.Y - target.Pos.Y
 			angle := math.Atan2(dy, dx)
@@ -392,7 +365,9 @@ func (g *Game) UpdateTargets() {
 		}
 
 		//compute collision with hero
-		if g.hero.Pos.X >= target.Pos.X-MOVER_WIDTH/2 && g.hero.Pos.X <= target.Pos.X+MOVER_WIDTH/2 && g.hero.Pos.Y >= target.Pos.Y-MOVER_HEIGHT/2 && g.hero.Pos.Y <= target.Pos.Y+MOVER_HEIGHT/2 && target.Action < MoverActionDying && g.hero.Action < HeroActionDying {
+		if g.hero.Pos.X >= target.Pos.X-MOVER_WIDTH/2 && g.hero.Pos.X <= target.Pos.X+MOVER_WIDTH/2 &&
+			g.hero.Pos.Y >= target.Pos.Y-MOVER_HEIGHT/2 && g.hero.Pos.Y <= target.Pos.Y+MOVER_HEIGHT/2 &&
+			target.Action < elements.MoverActionDying && g.hero.Action < elements.HeroActionDying {
 			g.heroCollisionMask.Clear()
 			g.heroCollisionMask.DrawImage(g.hero.Sprite, nil)
 
@@ -428,10 +403,10 @@ func (g *Game) ResetTargetTouches() {
 func (g *Game) AppendProjectiles() {
 	if g.counter%14 == 0 && ebiten.IsStandardGamepadButtonPressed(0, ebiten.StandardGamepadButtonFrontBottomRight) {
 
-		g.projectiles[g.counter] = NewProjectile(Coordinates{X: g.hero.Pos.X, Y: g.hero.Pos.Y}, g.hero.Angle, 5.)
+		g.projectiles[g.counter] = elements.NewProjectile(gamedata.Coordinates{X: g.hero.Pos.X, Y: g.hero.Pos.Y}, g.hero.Angle, 5.)
 
 		if g.hero.Upgrade {
-			g.projectiles[g.counter+1] = NewProjectile(Coordinates{X: g.hero.Pos.X, Y: g.hero.Pos.Y}, g.hero.Angle+math.Pi, 5.)
+			g.projectiles[g.counter+1] = elements.NewProjectile(gamedata.Coordinates{X: g.hero.Pos.X, Y: g.hero.Pos.Y}, g.hero.Angle+math.Pi, 5.)
 		}
 	}
 }
@@ -487,7 +462,7 @@ func (g *Game) UpdateHeroPosition() {
 }
 
 func (g *Game) ConstructBackground() {
-	g.background = ebiten.NewImage(screenWidth, screenHeight)
+	g.background = ebiten.NewImage(g.dimensions.Width, g.dimensions.Height)
 	BLOCK_SIZE := 32
 
 	for i := 0; i < 640/16; i++ {
@@ -505,7 +480,7 @@ func (g *Game) ConstructBackground() {
 			//translate for grid element we're painting
 			op := &ebiten.DrawImageOptions{}
 			op.GeoM.Translate(float64(i)*16, float64(j)*16)
-			g.background.DrawImage(tilesetImage.SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), op)
+			g.background.DrawImage(assets.ImageBank[assets.TileSet].SubImage(image.Rect(x0, y0, x1, y1)).(*ebiten.Image), op)
 		}
 	}
 
@@ -514,5 +489,13 @@ func (g *Game) ConstructBackground() {
 
 	op := &ebiten.DrawImageOptions{}
 	op.GeoM.Translate(ax, ay)
-	g.background.DrawImage(altarImage, op)
+	g.background.DrawImage(assets.ImageBank[assets.Altar], op)
+}
+
+func (g *Game) SetDimensions(a gamedata.Area) {
+	g.dimensions = a
+}
+
+func (g *Game) SetEventHandler(e ScreenManagerEvent, f func()) {
+
 }

screens/scene.go

@@ -0,0 +1,25 @@
+package screens
+
+import (
+	"mover/gamedata"
+
+	"github.com/hajimehoshi/ebiten/v2"
+)
+
+type ScreenManagerEvent int
+
+const (
+	EventNoop      ScreenManagerEvent = iota
+	EventReset                        // reset to initial scene
+	EventLoad                         // loading elements
+	EventReload                       // reload current scene
+	EventCompleted                    // current scene has completed
+	EventEndgame                      // shutdown all scenes
+)
+
+type Screen interface {
+	Update() error
+	Draw(screen *ebiten.Image)
+	SetEventHandler(e ScreenManagerEvent, f func())
+	SetDimensions(a gamedata.Area)
+}