cameraaaaa

engine/camera.go

@@ -0,0 +1,32 @@
+package engine
+
+import (
+	"image"
+
+	"github.com/hajimehoshi/ebiten/v2"
+)
+
+type Camera struct {
+	ID
+	Scene     *Scene
+	Transform GeoMDef
+
+	game *Game
+}
+
+func (c *Camera) Draw(screen *ebiten.Image, geom ebiten.GeoM) {
+	geom.Concat(*c.Transform.GeoM())
+	c.Scene.Draw(screen, geom)
+}
+
+func (c *Camera) Update() error { return c.Scene.Update() }
+
+func (c *Camera) Scan() []interface{} { return []interface{}{c.Scene} }
+
+func (c *Camera) Prepare(game *Game) { c.game = game }
+
+func (c *Camera) Centre(p image.Point) {
+	t := c.Transform.GeoM()
+	t.Reset()
+	t.Translate(float64(c.game.ScreenWidth/2-p.X), float64(c.game.ScreenHeight/2-p.Y))
+}

engine/scene.go

@@ -18,7 +18,6 @@ type Scene struct {
 	Disabled   bool
 	Hidden     bool
 	ID
-	Transform GeoMDef
 	ZPos
 }
 
@@ -27,8 +26,6 @@ func (s *Scene) Draw(screen *ebiten.Image, geom ebiten.GeoM) {
 	if s.Hidden {
 		return
 	}
-	geom.Concat(*s.Transform.GeoM())
-
 	for _, i := range s.Components {
 		if d, ok := i.(Drawer); ok {
 			d.Draw(screen, geom)

engine/tiles.go

@@ -18,11 +18,10 @@ type Tilemap struct {
 	Disabled bool
 	Hidden   bool
 	ID
-	Map       [][]Tile
-	Ersatz    bool // "fake wall"
-	Src       ImageRef
-	TileSize  int
-	Transform GeoMDef
+	Map      [][]Tile
+	Ersatz   bool // "fake wall"
+	Src      ImageRef
+	TileSize int
 	ZPos
 }
 
@@ -59,7 +58,6 @@ func (t *Tilemap) Draw(screen *ebiten.Image, geom ebiten.GeoM) {
 	}
 	src := t.Src.Image()
 	w, _ := src.Size()
-	geom.Concat(*t.Transform.GeoM())
 	for j, row := range t.Map {
 		for i, tile := range row {
 			if tile == nil {

game/aw.go

@@ -16,6 +16,9 @@ func init() {
 type Awakeman struct {
 	engine.Sprite
 
+	CameraID string
+
+	camera      *engine.Camera
 	vx, vy      float64
 	facingLeft  bool
 	coyoteTimer int
@@ -65,10 +68,15 @@ func (aw *Awakeman) Update() error {
 	}
 	aw.MoveX(aw.vx, func() { aw.vx = -aw.vx * bounceDampen })
 	aw.MoveY(aw.vy, func() { aw.vy = -aw.vy * bounceDampen })
+
+	aw.camera.Centre(aw.Pos.Add(aw.Size.Div(2)))
+
 	return aw.Sprite.Update()
 }
 
-func (aw *Awakeman) Prepare(*engine.Game) {
+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.animIdleRight = &engine.Anim{Def: engine.AnimDefs["aw_idle_right"]}
 	aw.animRunLeft = &engine.Anim{Def: engine.AnimDefs["aw_run_left"]}

main.go

@@ -68,6 +68,7 @@ func main() {
 				Rect: image.Rect(320, 0, 321, 240),
 			},
 			&game.Awakeman{
+				CameraID: "level_1_camera",
 				Sprite: engine.Sprite{
 					ID: "awakeman",
 					Actor: engine.Actor{
@@ -93,7 +94,10 @@ func main() {
 				&engine.GobDumper{
 					KeyCombo: []ebiten.Key{ebiten.KeyControl, ebiten.KeyD},
 				},
-				level1,
+				&engine.Camera{
+					ID:    "level_1_camera",
+					Scene: level1,
+				},
 				engine.PerfDisplay{},
 			},
 		},