Do not advance state in render (#269)

* Do not advance state in render

* Update advance logic for sprite and region

d2asset/archive_manager.go

@@ -1,7 +1,7 @@
 package d2asset
 
 import (
-	"fmt"
+	"errors"
 	"path"
 	"sync"
 
@@ -25,7 +25,7 @@ func createArchiveManager(config *d2corecommon.Configuration) *archiveManager {
 	return &archiveManager{cache: createCache(ArchiveBudget), config: config}
 }
 
-func (am *archiveManager) loadArchiveForFilePath(filePath string) (*d2mpq.MPQ, error) {
+func (am *archiveManager) loadArchiveForFile(filePath string) (*d2mpq.MPQ, error) {
 	am.mutex.Lock()
 	defer am.mutex.Unlock()
 
@@ -39,7 +39,24 @@ func (am *archiveManager) loadArchiveForFilePath(filePath string) (*d2mpq.MPQ, e
 		}
 	}
 
-	return nil, fmt.Errorf("file not found: %s", filePath)
+	return nil, errors.New("file not found")
+}
+
+func (am *archiveManager) fileExistsInArchive(filePath string) (bool, error) {
+	am.mutex.Lock()
+	defer am.mutex.Unlock()
+
+	if err := am.cacheArchiveEntries(); err != nil {
+		return false, err
+	}
+
+	for _, archiveEntry := range am.entries {
+		if archiveEntry.hashEntryMap.Contains(filePath) {
+			return true, nil
+		}
+	}
+
+	return false, nil
 }
 
 func (am *archiveManager) loadArchive(archivePath string) (*d2mpq.MPQ, error) {

d2asset/asset_manager.go

@@ -2,6 +2,7 @@ package d2asset
 
 import (
 	"errors"
+	"log"
 
 	"github.com/OpenDiablo2/D2Shared/d2data/d2cof"
 	"github.com/OpenDiablo2/D2Shared/d2data/d2datadict"
@@ -102,7 +103,20 @@ func LoadFile(filePath string) ([]byte, error) {
 		return nil, ErrNoInit
 	}
 
-	return singleton.fileManager.loadFile(filePath)
+	data, err := singleton.fileManager.loadFile(filePath)
+	if err != nil {
+		log.Printf("error loading file %s (%v)", filePath, err.Error())
+	}
+
+	return data, err
+}
+
+func FileExists(filePath string) (bool, error) {
+	if singleton == nil {
+		return false, ErrNoInit
+	}
+
+	return singleton.fileManager.fileExists(filePath)
 }
 
 func LoadAnimation(animationPath, palettePath string) (*Animation, error) {

d2asset/composite.go

@@ -115,7 +115,12 @@ type compositeMode struct {
 }
 
 func (c *Composite) createMode(animationMode, weaponClass string, direction int) (*compositeMode, error) {
-	cof, err := loadCOF(fmt.Sprintf("%s/%s/COF/%s%s%s.COF", c.object.Base, c.object.Token, c.object.Token, animationMode, weaponClass))
+	cofPath := fmt.Sprintf("%s/%s/COF/%s%s%s.COF", c.object.Base, c.object.Token, c.object.Token, animationMode, weaponClass)
+	if exists, _ := FileExists(cofPath); !exists {
+		return nil, errors.New("composite not found")
+	}
+
+	cof, err := loadCOF(cofPath)
 	if err != nil {
 		return nil, err
 	}
@@ -249,9 +254,11 @@ func loadCompositeLayer(object *d2datadict.ObjectLookupRecord, layerKey, layerVa
 	}
 
 	for _, animationPath := range animationPaths {
-		animation, err := LoadAnimationWithTransparency(animationPath, palettePath, transparency)
-		if err == nil {
-			return animation, nil
+		if exists, _ := FileExists(animationPath); exists {
+			animation, err := LoadAnimationWithTransparency(animationPath, palettePath, transparency)
+			if err == nil {
+				return animation, nil
+			}
 		}
 	}
 

d2asset/file_manager.go

@@ -23,7 +23,7 @@ func (fm *fileManager) loadFile(filePath string) ([]byte, error) {
 		return value.([]byte), nil
 	}
 
-	archive, err := fm.archiveManager.loadArchiveForFilePath(filePath)
+	archive, err := fm.archiveManager.loadArchiveForFile(filePath)
 	if err != nil {
 		return nil, err
 	}
@@ -40,6 +40,11 @@ func (fm *fileManager) loadFile(filePath string) ([]byte, error) {
 	return data, nil
 }
 
+func (fm *fileManager) fileExists(filePath string) (bool, error) {
+	filePath = fm.fixupFilePath(filePath)
+	return fm.archiveManager.fileExistsInArchive(filePath)
+}
+
 func (fm *fileManager) fixupFilePath(filePath string) string {
 	filePath = strings.ReplaceAll(filePath, "{LANG}", fm.config.Language)
 	if strings.ToUpper(d2resource.LanguageCode) == "CHI" {

d2core/d2scene/character_select.go

@@ -232,7 +232,7 @@ func (v *CharacterSelect) moveSelectionBox() {
 	v.d2HeroTitle.SetText(v.gameStates[v.selectedCharacter].HeroName)
 }
 
-func (v *CharacterSelect) Update(tickTime float64) {
+func (v *CharacterSelect) Advance(tickTime float64) {
 	if !v.showDeleteConfirmation {
 		if ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
 			if !v.mouseButtonPressed {

d2core/d2scene/credits.go

@@ -120,7 +120,7 @@ func (v *Credits) Render(screen *d2surface.Surface) {
 const secondsPerCycle = float64(0.02)
 
 // Update runs the update logic on the credits scene
-func (v *Credits) Update(tickTime float64) {
+func (v *Credits) Advance(tickTime float64) {
 	v.cycleTime += tickTime
 	for v.cycleTime >= secondsPerCycle {
 		v.cycleTime -= secondsPerCycle

d2core/d2scene/game.go

@@ -93,7 +93,7 @@ func (v Game) Render(screen *d2surface.Surface) {
 	v.gameControls.Render(screen)
 }
 
-func (v *Game) Update(tickTime float64) {
+func (v *Game) Advance(tickTime float64) {
 	v.mapEngine.Advance(tickTime)
 
 	rx, ry := v.mapEngine.WorldToOrtho(v.hero.AnimatedEntity.LocationX/5, v.hero.AnimatedEntity.LocationY/5)

d2core/d2scene/main_menu.go

@@ -244,7 +244,12 @@ func (v *MainMenu) Render(screen *d2surface.Surface) {
 }
 
 // Update runs the update logic on the main menu
-func (v *MainMenu) Update(tickTime float64) {
+func (v *MainMenu) Advance(tickTime float64) {
+	v.diabloLogoLeftBack.Advance(tickTime)
+	v.diabloLogoRightBack.Advance(tickTime)
+	v.diabloLogoLeft.Advance(tickTime)
+	v.diabloLogoRight.Advance(tickTime)
+
 	if v.ShowTrademarkScreen {
 		if v.uiManager.CursorButtonPressed(d2ui.CursorButtonLeft) {
 			if v.leftButtonHeld {

d2core/d2scene/map_engine_testing.go

@@ -206,7 +206,7 @@ func (v *MapEngineTest) Render(screen *d2surface.Surface) {
 	screen.PopN(6)
 }
 
-func (v *MapEngineTest) Update(tickTime float64) {
+func (v *MapEngineTest) Advance(tickTime float64) {
 	v.mapEngine.Advance(tickTime)
 
 	ctrlPressed := v.uiManager.KeyPressed(ebiten.KeyControl)

d2core/d2scene/select_hero_class.go

@@ -35,6 +35,17 @@ type HeroRenderInfo struct {
 	DeselectSfx              *d2audio.SoundEffect
 }
 
+func (hri *HeroRenderInfo) Advance(elapsed float64) {
+	advanceSprite(hri.IdleSprite, elapsed)
+	advanceSprite(hri.IdleSelectedSprite, elapsed)
+	advanceSprite(hri.ForwardWalkSprite, elapsed)
+	advanceSprite(hri.ForwardWalkSpriteOverlay, elapsed)
+	advanceSprite(hri.SelectedSprite, elapsed)
+	advanceSprite(hri.SelectedSpriteOverlay, elapsed)
+	advanceSprite(hri.BackWalkSprite, elapsed)
+	advanceSprite(hri.BackWalkSpriteOverlay, elapsed)
+}
+
 type SelectHeroClass struct {
 	uiManager          *d2ui.Manager
 	soundManager       *d2audio.Manager
@@ -471,12 +482,12 @@ func (v *SelectHeroClass) Render(screen *d2surface.Surface) {
 	}
 }
 
-func (v *SelectHeroClass) Update(tickTime float64) {
+func (v *SelectHeroClass) Advance(tickTime float64) {
 	canSelect := true
 	for _, info := range v.heroRenderInfo {
+		info.Advance(tickTime)
 		if info.Stance != d2enum.HeroStanceIdle && info.Stance != d2enum.HeroStanceIdleSelected && info.Stance != d2enum.HeroStanceSelected {
 			canSelect = false
-			break
 		}
 	}
 	allIdle := true
@@ -652,3 +663,9 @@ func drawSprite(sprite *d2render.Sprite, target *d2surface.Surface) {
 		sprite.Render(target)
 	}
 }
+
+func advanceSprite(sprite *d2render.Sprite, elapsed float64) {
+	if sprite != nil {
+		sprite.Advance(elapsed)
+	}
+}

d2core/engine.go

@@ -52,7 +52,10 @@ type Engine struct {
 
 // CreateEngine creates and instance of the OpenDiablo2 engine
 func CreateEngine() *Engine {
-	result := &Engine{timeScale: 1.0}
+	result := &Engine{
+		lastTime:  d2helper.Now(),
+		timeScale: 1.0,
+	}
 
 	result.Settings = d2corecommon.LoadConfiguration()
 	if err := result.Settings.Save(); err != nil {
@@ -137,8 +140,8 @@ func (v *Engine) updateScene() {
 	v.ResetLoading()
 }
 
-// Update updates the internal state of the engine
-func (v *Engine) Update() {
+// Advance updates the internal state of the engine
+func (v *Engine) Advance() {
 	if ebiten.IsKeyPressed(ebiten.KeyAlt) && ebiten.IsKeyPressed(ebiten.KeyEnter) {
 		if !v.fullscreenKey {
 			ebiten.SetFullscreen(!ebiten.IsFullscreen())
@@ -169,13 +172,13 @@ func (v *Engine) Update() {
 	deltaTime := (currentTime - v.lastTime) * v.timeScale
 	v.lastTime = currentTime
 
-	v.CurrentScene.Update(deltaTime)
-	v.UIManager.Update()
+	v.CurrentScene.Advance(deltaTime)
+	v.UIManager.Advance(deltaTime)
 	d2term.Advance(deltaTime)
 }
 
 // Draw draws the game
-func (v Engine) Draw(target *d2surface.Surface) {
+func (v Engine) Render(target *d2surface.Surface) {
 	if v.loadingProgress < 1.0 {
 		v.LoadingSprite.SetCurrentFrame(int(d2helper.Max(0, d2helper.Min(uint32(v.LoadingSprite.GetFrameCount()-1), uint32(float64(v.LoadingSprite.GetFrameCount()-1)*v.loadingProgress)))))
 		v.LoadingSprite.Render(target)

d2corecommon/d2coreinterface/drawable.go

@@ -5,6 +5,7 @@ import "github.com/OpenDiablo2/OpenDiablo2/d2render/d2surface"
 // Drawable represents an instance that can be drawn
 type Drawable interface {
 	Render(target *d2surface.Surface)
+	Advance(elapsed float64)
 	GetSize() (width, height int)
 	SetPosition(x, y int)
 	GetPosition() (x, y int)

d2corecommon/d2coreinterface/scene.go

@@ -7,5 +7,5 @@ type Scene interface {
 	Load() []func()
 	Unload()
 	Render(target *d2surface.Surface)
-	Update(tickTime float64)
+	Advance(tickTime float64)
 }

d2render/d2mapengine/region.go

@@ -34,7 +34,7 @@ type MapRegion struct {
 	startY            float64
 	imageCacheRecords map[uint32]*ebiten.Image
 	seed              int64
-	currentFrame      byte
+	currentFrame      int
 	lastFrameTime     float64
 }
 
@@ -154,18 +154,6 @@ func (mr *MapRegion) loadEntities() []MapEntity {
 	return entities
 }
 
-func (mr *MapRegion) updateAnimations() {
-	now := d2helper.Now()
-	framesToAdd := math.Floor((now - mr.lastFrameTime) / 0.1)
-	if framesToAdd > 0 {
-		mr.lastFrameTime += 0.1 * framesToAdd
-		mr.currentFrame += byte(math.Floor(framesToAdd))
-		if mr.currentFrame > 9 {
-			mr.currentFrame = 0
-		}
-	}
-}
-
 func (mr *MapRegion) getStartTilePosition() (float64, float64) {
 	return float64(mr.tileRect.Left) + mr.startX, float64(mr.tileRect.Top) + mr.startY
 }
@@ -224,8 +212,17 @@ func (mr *MapRegion) isVisbile(viewport *Viewport) bool {
 	return viewport.IsTileRectVisible(mr.tileRect)
 }
 
-func (mr *MapRegion) advance(tickTime float64) {
-	mr.updateAnimations()
+func (mr *MapRegion) advance(elapsed float64) {
+	frameLength := 0.1
+
+	mr.lastFrameTime += elapsed
+	framesAdvanced := int(mr.lastFrameTime / frameLength)
+	mr.lastFrameTime -= float64(framesAdvanced) * frameLength
+
+	mr.currentFrame += framesAdvanced
+	if mr.currentFrame > 9 {
+		mr.currentFrame = 0
+	}
 }
 
 func (mr *MapRegion) getTileWorldPosition(tileX, tileY int) (float64, float64) {
@@ -322,7 +319,7 @@ func (mr *MapRegion) renderFloor(tile d2ds1.FloorShadowRecord, viewport *Viewpor
 	if !tile.Animated {
 		img = mr.getImageCacheRecord(tile.Style, tile.Sequence, 0, tile.RandomIndex)
 	} else {
-		img = mr.getImageCacheRecord(tile.Style, tile.Sequence, 0, mr.currentFrame)
+		img = mr.getImageCacheRecord(tile.Style, tile.Sequence, 0, byte(mr.currentFrame))
 	}
 	if img == nil {
 		log.Printf("Render called on uncached floor {%v,%v}", tile.Style, tile.Sequence)

d2render/d2ui/button.go

@@ -178,7 +178,7 @@ func (v *Button) Activate() {
 }
 
 // Render renders the button
-func (v Button) Render(target *d2surface.Surface) {
+func (v *Button) Render(target *d2surface.Surface) {
 	target.PushCompositeMode(ebiten.CompositeModeSourceAtop)
 	target.PushFilter(ebiten.FilterNearest)
 	target.PushTranslation(v.x, v.y)
@@ -199,8 +199,12 @@ func (v Button) Render(target *d2surface.Surface) {
 	}
 }
 
+func (v *Button) Advance(elapsed float64) {
+
+}
+
 // GetEnabled returns the enabled state
-func (v Button) GetEnabled() bool {
+func (v *Button) GetEnabled() bool {
 	return v.enabled
 }
 
@@ -210,7 +214,7 @@ func (v *Button) SetEnabled(enabled bool) {
 }
 
 // GetSize returns the size of the button
-func (v Button) GetSize() (int, int) {
+func (v *Button) GetSize() (int, int) {
 	return v.width, v.height
 }
 
@@ -221,12 +225,12 @@ func (v *Button) SetPosition(x, y int) {
 }
 
 // GetPosition returns the location of the button
-func (v Button) GetPosition() (x, y int) {
+func (v *Button) GetPosition() (x, y int) {
 	return v.x, v.y
 }
 
 // GetVisible returns the visibility of the button
-func (v Button) GetVisible() bool {
+func (v *Button) GetVisible() bool {
 	return v.visible
 }
 
@@ -236,7 +240,7 @@ func (v *Button) SetVisible(visible bool) {
 }
 
 // GetPressed returns the pressed state of the button
-func (v Button) GetPressed() bool {
+func (v *Button) GetPressed() bool {
 	return v.pressed
 }
 

d2render/d2ui/checkbox.go

@@ -40,7 +40,7 @@ func CreateCheckbox(checkState bool) Checkbox {
 	return result
 }
 
-func (v Checkbox) Render(target *d2surface.Surface) {
+func (v *Checkbox) Render(target *d2surface.Surface) {
 	target.PushCompositeMode(ebiten.CompositeModeSourceAtop)
 	target.PushTranslation(v.x, v.y)
 	target.PushFilter(ebiten.FilterNearest)
@@ -52,7 +52,12 @@ func (v Checkbox) Render(target *d2surface.Surface) {
 		target.Render(v.Image)
 	}
 }
-func (v Checkbox) GetEnabled() bool {
+
+func (v *Checkbox) Advance(elapsed float64) {
+
+}
+
+func (v *Checkbox) GetEnabled() bool {
 	return v.enabled
 }
 
@@ -60,18 +65,18 @@ func (v *Checkbox) SetEnabled(enabled bool) {
 	v.enabled = enabled
 }
 
-func (v Checkbox) SetPressed(pressed bool) {
+func (v *Checkbox) SetPressed(pressed bool) {
 }
 
 func (v *Checkbox) SetCheckState(checkState bool) {
 	v.checkState = checkState
 }
 
-func (v Checkbox) GetCheckState() bool {
+func (v *Checkbox) GetCheckState() bool {
 	return v.checkState
 }
 
-func (v Checkbox) GetPressed() bool {
+func (v *Checkbox) GetPressed() bool {
 	return v.checkState
 }
 
@@ -87,15 +92,15 @@ func (v *Checkbox) Activate() {
 	v.onClick()
 }
 
-func (v Checkbox) GetPosition() (int, int) {
+func (v *Checkbox) GetPosition() (int, int) {
 	return v.x, v.y
 }
 
-func (v Checkbox) GetSize() (int, int) {
+func (v *Checkbox) GetSize() (int, int) {
 	return v.width, v.height
 }
 
-func (v Checkbox) GetVisible() bool {
+func (v *Checkbox) GetVisible() bool {
 	return v.visible
 }
 

d2render/d2ui/manager.go

@@ -72,7 +72,13 @@ func (v *Manager) Render(target *d2surface.Surface) {
 }
 
 // Update updates all of the UI elements
-func (v *Manager) Update() {
+func (v *Manager) Advance(elapsed float64) {
+	for _, widget := range v.widgets {
+		if widget.GetVisible() {
+			widget.Advance(elapsed)
+		}
+	}
+
 	v.cursorButtons = 0
 	if ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
 		if !v.waitForLeftMouseUp {

d2render/d2ui/scrollbar.go

@@ -69,7 +69,7 @@ func (v *Scrollbar) Activate() {
 	}
 }
 
-func (v Scrollbar) GetLastDirChange() int {
+func (v *Scrollbar) GetLastDirChange() int {
 	return v.lastDirChange
 }
 
@@ -96,6 +96,10 @@ func (v *Scrollbar) Render(target *d2surface.Surface) {
 	v.scrollbarSprite.RenderSegmented(target, 1, 1, 4+offset)
 }
 
+func (v *Scrollbar) Advance(elapsed float64) {
+	v.scrollbarSprite.Advance(elapsed)
+}
+
 func (v *Scrollbar) GetSize() (width, height int) {
 	return 10, int(v.height)
 }
@@ -134,10 +138,10 @@ func (v *Scrollbar) SetCurrentOffset(currentOffset int) {
 	v.currentOffset = currentOffset
 }
 
-func (v Scrollbar) GetMaxOffset() int {
+func (v *Scrollbar) GetMaxOffset() int {
 	return v.maxOffset
 }
 
-func (v Scrollbar) GetCurrentOffset() int {
+func (v *Scrollbar) GetCurrentOffset() int {
 	return v.currentOffset
 }

d2render/d2ui/textbox.go

@@ -52,7 +52,7 @@ func repeatingKeyPressed(key ebiten.Key) bool {
 	return false
 }
 
-func (v TextBox) Render(target *d2surface.Surface) {
+func (v *TextBox) Render(target *d2surface.Surface) {
 	if !v.visible {
 		return
 	}
@@ -63,6 +63,10 @@ func (v TextBox) Render(target *d2surface.Surface) {
 	}
 }
 
+func (v *TextBox) Advance(elapsed float64) {
+
+}
+
 func (v *TextBox) Update() {
 	if !v.visible || !v.enabled {
 		return
@@ -80,7 +84,7 @@ func (v *TextBox) Update() {
 	}
 }
 
-func (v TextBox) GetText() string {
+func (v *TextBox) GetText() string {
 	return v.text
 }
 
@@ -108,7 +112,7 @@ func (v *TextBox) SetText(newText string) {
 	}
 }
 
-func (v TextBox) GetSize() (width, height int) {
+func (v *TextBox) GetSize() (width, height int) {
 	return v.bgSprite.GetCurrentFrameSize()
 }
 
@@ -120,11 +124,11 @@ func (v *TextBox) SetPosition(x, y int) {
 	v.bgSprite.SetPosition(v.x, v.y+26)
 }
 
-func (v TextBox) GetPosition() (x, y int) {
+func (v *TextBox) GetPosition() (x, y int) {
 	return v.x, v.y
 }
 
-func (v TextBox) GetVisible() bool {
+func (v *TextBox) GetVisible() bool {
 	return v.visible
 }
 
@@ -132,7 +136,7 @@ func (v *TextBox) SetVisible(visible bool) {
 	v.visible = visible
 }
 
-func (v TextBox) GetEnabled() bool {
+func (v *TextBox) GetEnabled() bool {
 	return v.enabled
 }
 
@@ -144,7 +148,7 @@ func (v *TextBox) SetPressed(pressed bool) {
 	// no op
 }
 
-func (v TextBox) GetPressed() bool {
+func (v *TextBox) GetPressed() bool {
 	return false
 }
 
@@ -152,6 +156,6 @@ func (v *TextBox) OnActivated(callback func()) {
 	// no op
 }
 
-func (v TextBox) Activate() {
+func (v *TextBox) Activate() {
 	//no op
 }

d2render/sprite.go

@@ -9,10 +9,9 @@ import (
 )
 
 type Sprite struct {
-	x             int
-	y             int
-	lastFrameTime float64
-	animation     *d2asset.Animation
+	x         int
+	y         int
+	animation *d2asset.Animation
 }
 
 func LoadSprite(animationPath, palettePath string) (*Sprite, error) {
@@ -21,7 +20,7 @@ func LoadSprite(animationPath, palettePath string) (*Sprite, error) {
 		return nil, err
 	}
 
-	return &Sprite{lastFrameTime: d2helper.Now(), animation: animation}, nil
+	return &Sprite{animation: animation}, nil
 }
 
 func MustLoadSprite(animationPath, palettePath string) *Sprite {
@@ -34,10 +33,6 @@ func MustLoadSprite(animationPath, palettePath string) *Sprite {
 }
 
 func (s *Sprite) Render(target *d2surface.Surface) error {
-	if err := s.advance(); err != nil {
-		return err
-	}
-
 	_, frameHeight := s.animation.GetCurrentFrameSize()
 
 	target.PushTranslation(s.x, s.y-frameHeight)
@@ -46,10 +41,6 @@ func (s *Sprite) Render(target *d2surface.Surface) error {
 }
 
 func (s *Sprite) RenderSegmented(target *d2surface.Surface, segmentsX, segmentsY, frameOffset int) error {
-	if err := s.advance(); err != nil {
-		return err
-	}
-
 	var currentY int
 	for y := 0; y < segmentsY; y++ {
 		var currentX int
@@ -127,22 +118,18 @@ func (s *Sprite) GetDirection() int {
 }
 
 func (s *Sprite) SetCurrentFrame(frameIndex int) error {
-	s.lastFrameTime = d2helper.Now()
 	return s.animation.SetCurrentFrame(frameIndex)
 }
 
 func (s *Sprite) Rewind() {
-	s.lastFrameTime = d2helper.Now()
 	s.animation.SetCurrentFrame(0)
 }
 
 func (s *Sprite) PlayForward() {
-	s.lastFrameTime = d2helper.Now()
 	s.animation.PlayForward()
 }
 
 func (s *Sprite) PlayBackward() {
-	s.lastFrameTime = d2helper.Now()
 	s.animation.PlayBackward()
 }
 
@@ -170,11 +157,6 @@ func (s *Sprite) SetBlend(blend bool) {
 	s.animation.SetBlend(blend)
 }
 
-func (s *Sprite) advance() error {
-	lastFrameTime := d2helper.Now()
-	if err := s.animation.Advance(lastFrameTime - s.lastFrameTime); err != nil {
-		return err
-	}
-	s.lastFrameTime = lastFrameTime
-	return nil
+func (s *Sprite) Advance(elapsed float64) error {
+	return s.animation.Advance(elapsed)
 }

main.go

@@ -67,10 +67,10 @@ func main() {
 }
 
 func update(screen *ebiten.Image) error {
-	d2Engine.Update()
+	d2Engine.Advance()
 	if !ebiten.IsDrawingSkipped() {
 		surface := d2surface.CreateSurface(screen)
-		d2Engine.Draw(surface)
+		d2Engine.Render(surface)
 		if surface.GetDepth() > 0 {
 			panic("detected surface stack leak")
 		}