18/8/21 7:45 PM

builtInComponentsAndSystems/animator.go

@@ -0,0 +1,55 @@
+package builtInComponentsAndSystems
+
+
+import (
+	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/eboatwright/pearl"
+)
+
+
+type Animation struct {
+	Frames []int
+	Speed  int
+}
+
+type Animator struct {
+	Animations            []Animation
+	CurrentAnimation      int
+	CurrentAnimationIndex int
+	AnimationTimer        int
+}
+func (a *Animator) ID() string { return "animator" }
+
+func (a *Animator) ChangeAnimation(index int) {
+	if a.CurrentAnimation != index {
+		a.CurrentAnimation = index
+		a.CurrentAnimationIndex = 0
+		a.AnimationTimer = 0
+	}
+}
+
+
+type AnimationSystem struct {}
+
+func (as *AnimationSystem) Update(entity *pearl.Entity, scene *pearl.Scene) {
+	a := entity.GetComponent("animator").(*Animator)
+	i := entity.GetComponent("image").(*Image)
+
+	a.AnimationTimer--
+	if a.AnimationTimer <= 0 {
+		a.AnimationTimer = a.Animations[a.CurrentAnimation].Speed
+		a.CurrentAnimationIndex++
+
+		if a.CurrentAnimationIndex >= len(a.Animations[a.CurrentAnimation].Frames) {
+			a.CurrentAnimationIndex = 0
+		}
+
+		i.SourcePos.X = float64(a.Animations[a.CurrentAnimation].Frames[a.CurrentAnimationIndex]) * i.Size.X
+	}
+}
+
+func (as *AnimationSystem) Draw(entity *pearl.Entity, scene *pearl.Scene, screen *ebiten.Image, options *ebiten.DrawImageOptions) {}
+
+func (as *AnimationSystem) GetRequirements() []string {
+	return []string { "animator", "image" }
+}

examples/2-platformer/main.go

@@ -61,6 +61,18 @@ func onStart() {
 			Image: pearl.LoadImage("data/img/wizard.png"),
 			Size:  pearl.Vector2 { 16, 16 },
 		},
+		&bicas.Animator {
+			Animations: []bicas.Animation {
+				bicas.Animation {
+					Frames: []int { 0 },
+					Speed:  1,
+				},
+				bicas.Animation {
+					Frames: []int { 0, 1 },
+					Speed:  8,
+				},
+			},
+		},
 		&bicas.Rigidbody {
 			Friction:      pearl.Vector2 { 0.8, 1 },
 			Gravity:       pearl.Vector2 { 0, 0.4 },
@@ -89,6 +101,7 @@ func onStart() {
 
 		&bicas.LevelRenderer {  },
 		&bicas.ImageRenderer {  },
+		&bicas.AnimationSystem {  },
 	})
 }
 

examples/2-platformer/player.go

@@ -22,6 +22,7 @@ func (ps *PlayerSystem) Update(entity *pearl.Entity, scene *pearl.Scene) {
 	t := entity.GetComponent("transform").(*bicas.Transform)
 	rb := entity.GetComponent("rigidbody").(*bicas.Rigidbody)
 	p := entity.GetComponent("player").(*Player)
+	anim := entity.GetComponent("animator").(*bicas.Animator)
 
 	xInput := pearl.GetInputAxis(
 		[]ebiten.Key { ebiten.KeyA, ebiten.KeyLeft },
@@ -30,6 +31,9 @@ func (ps *PlayerSystem) Update(entity *pearl.Entity, scene *pearl.Scene) {
 
 	if xInput != 0 {
 		t.Scale.X = float64(xInput)
+		anim.ChangeAnimation(1)
+	} else {
+		anim.ChangeAnimation(0)
 	}
 
 	rb.Velocity.X += float64(xInput) * p.MoveSpeed
@@ -46,5 +50,5 @@ func (ps *PlayerSystem) Update(entity *pearl.Entity, scene *pearl.Scene) {
 func (ps *PlayerSystem) Draw(entity *pearl.Entity, scene *pearl.Scene, screen *ebiten.Image, options *ebiten.DrawImageOptions) {}
 
 func (ps *PlayerSystem) GetRequirements() []string {
-	return []string { "transform", "rigidbody", "player" }
+	return []string { "transform", "rigidbody", "animator", "player" }
 }