change how anim works

engine/anim.go

@@ -1,42 +1,47 @@
 package engine
 
-// Anim is an "instance" of an AnimDef: an animation being displayed,
+// Ensure Anim satisfies Animer.
-// together with the current state.
+var _ Animer = &Anim{}
-type Anim struct {
-	Def   *AnimDef
-	Index int
-	Ticks int
-}
-
-func (a *Anim) CurrentFrame() int { return a.Def.Frames[a.Index].Frame }
-
-func (a *Anim) Reset() { a.Index, a.Ticks = 0, 0 }
-
-// Update increments the tick count and advances the frame if necessary.
-func (a *Anim) Update() error {
-	a.Ticks++
-	if a.Def.OneShot && a.Index == len(a.Def.Frames)-1 {
-		// on the last frame of a one shot so remain on final frame
-		return nil
-	}
-	if a.Ticks >= a.Def.Frames[a.Index].Duration {
-		a.Ticks = 0
-		a.Index++
-	}
-	if !a.Def.OneShot && a.Index >= len(a.Def.Frames) {
-		a.Index = 0
-	}
-	return nil
-}
-
-// AnimDef describes an animation (sequence of frames and timings).
-type AnimDef struct {
-	Frames  []AnimFrame
-	OneShot bool
-}
 
 // AnimFrame describes a frame in an animation.
 type AnimFrame struct {
 	Frame    int // show this frame
 	Duration int // for this long, in ticks
 }
+
+// Anim is n animation being displayed, together with the current state.
+type Anim struct {
+	Frames  []AnimFrame
+	OneShot bool
+	Index   int
+	Ticks   int
+}
+
+// Copy makes a shallow copy of the anim.
+func (a *Anim) Copy() *Anim {
+	a2 := *a
+	return &a2
+}
+
+// CurrentFrame returns the frame number for the current index.
+func (a *Anim) CurrentFrame() int { return a.Frames[a.Index].Frame }
+
+// Reset resets both Index and Ticks to 0.
+func (a *Anim) Reset() { a.Index, a.Ticks = 0, 0 }
+
+// Update increments the tick count and advances the frame if necessary.
+func (a *Anim) Update() error {
+	a.Ticks++
+	if a.OneShot && a.Index == len(a.Frames)-1 {
+		// on the last frame of a one shot so remain on final frame
+		return nil
+	}
+	if a.Ticks >= a.Frames[a.Index].Duration {
+		a.Ticks = 0
+		a.Index++
+	}
+	if !a.OneShot && a.Index >= len(a.Frames) {
+		a.Index = 0
+	}
+	return nil
+}

engine/animref.go

@@ -0,0 +1,48 @@
+package engine
+
+import (
+	"encoding/gob"
+	"io/fs"
+)
+
+var (
+	animCache = make(map[assetKey]Anim)
+
+	_ Animer = &AnimRef{}
+	_ Loader = &AnimRef{}
+)
+
+func init() {
+	gob.Register(AnimRef{})
+}
+
+// AnimRef manages an Anim using a premade AnimDef from the cache.
+type AnimRef struct {
+	Path string
+
+	anim Anim
+}
+
+func (r *AnimRef) Load(assets fs.FS) error {
+	// Fast path: set r.anim to a copy
+	anim, found := animCache[assetKey{assets, r.Path}]
+	if found {
+		r.anim = anim
+		return nil
+	}
+	// Slow path: load from gobz file
+	if err := loadGobz(&r.anim, assets, r.Path); err != nil {
+		return err
+	}
+	animCache[assetKey{assets, r.Path}] = r.anim
+	return nil
+}
+
+// CurrentFrame returns the value of CurrentFrame from r.anim.
+func (r *AnimRef) CurrentFrame() int { return r.anim.CurrentFrame() }
+
+// Reset calls Reset on r.anim.
+func (r *AnimRef) Reset() { r.anim.Reset() }
+
+// Update calls Update on r.anim.
+func (r *AnimRef) Update() error { return r.anim.Update() }

engine/asset.go

@@ -1,28 +1,22 @@
 package engine
 
 import (
+	"compress/gzip"
 	"encoding/gob"
 	"image"
 	"io/fs"
-	"log"
 
 	"github.com/hajimehoshi/ebiten/v2"
 )
 
 var (
-	// AnimDefs are easier to write as Go expressions -
-	// so just set this.
-	// TODO: put in Game
-	AnimDefs map[string]*AnimDef
-
 	imageCache = make(map[assetKey]*ebiten.Image)
 
-	// Ensure ImageRef satisfies interfaces.
+	// Ensure types satisfy interfaces.
 	_ Loader = &ImageRef{}
 )
 
 func init() {
-	gob.Register(AnimRef{})
 	gob.Register(ImageRef{})
 }
 
@@ -31,24 +25,17 @@ type assetKey struct {
 	path   string
 }
 
-// AnimRef manages an Anim using a premade AnimDef from the cache.
+func loadGobz(dst interface{}, assets fs.FS, path string) error {
-type AnimRef struct {
+	f, err := assets.Open(path)
-	Key string
+	if err != nil {
-
+		return err
-	anim *Anim
-}
-
-func (r *AnimRef) Anim() *Anim {
-	if r.anim != nil {
-		return r.anim
 	}
-	ad := AnimDefs[r.Key]
+	defer f.Close()
-	if ad == nil {
+	gz, err := gzip.NewReader(f)
-		log.Fatalf("Unknown AnimDef %q", r.Key)
+	if err != nil {
-		return nil
+		return err
 	}
-	r.anim = &Anim{Def: ad}
+	return gob.NewDecoder(gz).Decode(dst)
-	return r.anim
 }
 
 // ImageRef loads images from the AssetFS into *ebiten.Image form.

engine/interface.go

@@ -7,6 +7,14 @@ import (
 	"github.com/hajimehoshi/ebiten/v2"
 )
 
+// Animer components have a current frame index.
+type Animer interface {
+	Updater
+
+	CurrentFrame() int
+	Reset()
+}
+
 // Bounder components have a bounding rectangle.
 type Bounder interface {
 	BoundingRect() image.Rectangle

engine/sceneref.go

@@ -1,7 +1,6 @@
 package engine
 
 import (
-	"compress/gzip"
 	"encoding/gob"
 	"image"
 	"io/fs"
@@ -36,18 +35,8 @@ type SceneRef struct {
 
 // Load loads the scene from the file.
 func (r *SceneRef) Load(assets fs.FS) error {
-	f, err := assets.Open(r.Path)
-	if err != nil {
-		return err
-	}
-	defer f.Close()
-
-	gz, err := gzip.NewReader(f)
-	if err != nil {
-		return err
-	}
 	sc := new(Scene)
-	if err := gob.NewDecoder(gz).Decode(sc); err != nil {
+	if err := loadGobz(sc, assets, r.Path); err != nil {
 		return err
 	}
 	r.scene = sc

engine/tiles.go

@@ -141,9 +141,7 @@ func (s StaticTile) TileIndex() int { return int(s) }
 
 // AnimatedTile uses an Anim to choose a tile index.
 type AnimatedTile struct {
-	AnimRef
+	Animer
 }
 
-func (a *AnimatedTile) TileIndex() int { return a.Anim().CurrentFrame() }
+func (a *AnimatedTile) TileIndex() int { return a.CurrentFrame() }
-
-func (a *AnimatedTile) Update() error { return a.Anim().Update() }

game/anims.go

@@ -1,65 +0,0 @@
-package game
-
-import "drjosh.dev/gurgle/engine"
-
-func init() {
-	engine.AnimDefs = map[string]*engine.AnimDef{
-		"green_tiles": {
-			Frames: []engine.AnimFrame{
-				{Frame: 0, Duration: 16},
-				{Frame: 1, Duration: 16},
-				{Frame: 2, Duration: 16},
-			},
-		},
-		"red_tiles": {
-			Frames: []engine.AnimFrame{
-				{Frame: 3, Duration: 12},
-				{Frame: 4, Duration: 12},
-				{Frame: 5, Duration: 12},
-				{Frame: 6, Duration: 12},
-			},
-		},
-		"aw_idle_right": {
-			Frames: []engine.AnimFrame{
-				{Frame: 0, Duration: 60},
-			},
-		},
-		"aw_idle_left": {
-			Frames: []engine.AnimFrame{
-				{Frame: 1, Duration: 60},
-			},
-		},
-		"aw_walk_right": {
-			Frames: []engine.AnimFrame{
-				{Frame: 2, Duration: 6},
-				{Frame: 3, Duration: 6},
-				{Frame: 4, Duration: 6},
-				{Frame: 5, Duration: 6},
-			},
-		},
-		"aw_walk_left": {
-			Frames: []engine.AnimFrame{
-				{Frame: 6, Duration: 6},
-				{Frame: 7, Duration: 6},
-				{Frame: 8, Duration: 6},
-				{Frame: 9, Duration: 6},
-			},
-		},
-		"aw_run_right": {
-			Frames: []engine.AnimFrame{
-				{Frame: 10, Duration: 3},
-				{Frame: 11, Duration: 5},
-				{Frame: 12, Duration: 3},
-				{Frame: 13, Duration: 3},
-			},
-		},
-		"aw_run_left": {
-			Frames: []engine.AnimFrame{
-				{Frame: 14, Duration: 3},
-				{Frame: 15, Duration: 5},
-				{Frame: 16, Duration: 3},
-				{Frame: 17, Duration: 3},
-			},
-		},
-	}
-}

game/aw.go

@@ -26,7 +26,7 @@ type Awakeman struct {
 	jumpBuffer  int
 	noclip      bool
 
-	animIdleLeft, animIdleRight, animRunLeft, animRunRight *engine.Anim
+	animIdleLeft, animIdleRight, animRunLeft, animRunRight, animWalkLeft, animWalkRight *engine.Anim
 }
 
 func (aw *Awakeman) Update() error {
@@ -163,10 +163,40 @@ func (aw *Awakeman) realUpdate() error {
 func (aw *Awakeman) Prepare(game *engine.Game) {
 	aw.camera = game.Component(aw.CameraID).(*engine.Camera)
 
-	aw.animIdleLeft = &engine.Anim{Def: engine.AnimDefs["aw_idle_left"]}
+	aw.animIdleLeft = &engine.Anim{Frames: []engine.AnimFrame{
-	aw.animIdleRight = &engine.Anim{Def: engine.AnimDefs["aw_idle_right"]}
+		{Frame: 1, Duration: 60},
-	aw.animRunLeft = &engine.Anim{Def: engine.AnimDefs["aw_run_left"]}
+	}}
-	aw.animRunRight = &engine.Anim{Def: engine.AnimDefs["aw_run_right"]}
+	aw.animIdleRight = &engine.Anim{Frames: []engine.AnimFrame{
+		{Frame: 0, Duration: 60},
+	}}
+	aw.animRunLeft = &engine.Anim{Frames: []engine.AnimFrame{
+		{Frame: 14, Duration: 3},
+		{Frame: 15, Duration: 5},
+		{Frame: 16, Duration: 3},
+		{Frame: 17, Duration: 3},
+	}}
+	aw.animRunRight = &engine.Anim{Frames: []engine.AnimFrame{
+		{Frame: 10, Duration: 3},
+		{Frame: 11, Duration: 5},
+		{Frame: 12, Duration: 3},
+		{Frame: 13, Duration: 3},
+	}}
+	aw.animWalkRight = &engine.Anim{
+		Frames: []engine.AnimFrame{
+			{Frame: 2, Duration: 6},
+			{Frame: 3, Duration: 6},
+			{Frame: 4, Duration: 6},
+			{Frame: 5, Duration: 6},
+		},
+	}
+	aw.animWalkLeft = &engine.Anim{
+		Frames: []engine.AnimFrame{
+			{Frame: 6, Duration: 6},
+			{Frame: 7, Duration: 6},
+			{Frame: 8, Duration: 6},
+			{Frame: 9, Duration: 6},
+		},
+	}
 }
 
 func (aw *Awakeman) Scan() []interface{} { return []interface{}{&aw.Sprite} }

main.go

@@ -20,23 +20,32 @@ func main() {
 	ebiten.SetWindowSize(640, 480)
 	ebiten.SetWindowTitle("TODO")
 
-	// engine.AnimDefs set in game/anims.go
+	redTileAnim := &engine.Anim{Frames: []engine.AnimFrame{
-
+		{Frame: 3, Duration: 12},
+		{Frame: 4, Duration: 12},
+		{Frame: 5, Duration: 12},
+		{Frame: 6, Duration: 12},
+	}}
+	greenTileAnim := &engine.Anim{Frames: []engine.AnimFrame{
+		{Frame: 0, Duration: 16},
+		{Frame: 1, Duration: 16},
+		{Frame: 2, Duration: 16},
+	}}
 	denseTiles := [][]engine.Tile{
 		{engine.StaticTile(9), nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, engine.StaticTile(9)},
-		{nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "red_tiles"}}, nil, nil, nil, nil, nil, nil, nil, nil, nil},
+		{nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, &engine.AnimatedTile{Animer: redTileAnim.Copy()}, nil, nil, nil, nil, nil, nil, nil, nil, nil},
-		{nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "red_tiles"}}, nil, nil, nil},
+		{nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, &engine.AnimatedTile{Animer: redTileAnim.Copy()}, nil, nil, nil},
 		{nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil},
-		{nil, nil, &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "green_tiles"}}, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil},
+		{nil, nil, &engine.AnimatedTile{Animer: greenTileAnim.Copy()}, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil},
-		{nil, nil, nil, nil, nil, &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "red_tiles"}}, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil},
+		{nil, nil, nil, nil, nil, &engine.AnimatedTile{Animer: redTileAnim.Copy()}, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil},
-		{nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "green_tiles"}}, nil, nil, nil, nil, nil, nil},
+		{nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, &engine.AnimatedTile{Animer: greenTileAnim.Copy()}, nil, nil, nil, nil, nil, nil},
-		{nil, nil, nil, nil, &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "green_tiles"}}, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil},
+		{nil, nil, nil, nil, &engine.AnimatedTile{Animer: greenTileAnim.Copy()}, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil},
-		{nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "green_tiles"}}, nil, nil, nil, nil, nil, nil, nil, nil, nil},
+		{nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, &engine.AnimatedTile{Animer: greenTileAnim.Copy()}, nil, nil, nil, nil, nil, nil, nil, nil, nil},
-		{nil, &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "red_tiles"}}, nil, nil, nil, nil, nil, nil, engine.StaticTile(9), nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil},
+		{nil, &engine.AnimatedTile{Animer: redTileAnim.Copy()}, nil, nil, nil, nil, nil, nil, engine.StaticTile(9), nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil},
 		{nil, nil, nil, nil, nil, engine.StaticTile(9), nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, engine.StaticTile(9), nil, nil, nil},
 		{nil, nil, nil, nil, engine.StaticTile(9), engine.StaticTile(9), engine.StaticTile(9), nil, nil, nil, engine.StaticTile(9), nil, nil, nil, nil, nil, nil, nil, nil, nil},
-		{engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "red_tiles"}}, engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8)},
+		{engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), &engine.AnimatedTile{Animer: redTileAnim.Copy()}, engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8), engine.StaticTile(8)},
-		{engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "red_tiles"}}, engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), &engine.AnimatedTile{AnimRef: engine.AnimRef{Key: "green_tiles"}}, engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7)},
+		{engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), &engine.AnimatedTile{Animer: redTileAnim.Copy()}, engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), &engine.AnimatedTile{Animer: greenTileAnim.Copy()}, engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7)},
 		{engine.StaticTile(9), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(7), engine.StaticTile(9)},
 	}
 	tiles := make(map[image.Point]engine.Tile)