✨ Slide and collide!

pkg/internal/land/object.go

@@ -8,7 +8,7 @@ type Object interface {
 }
 
 type DrawableObject interface {
-	Draw(*sdl.Renderer)
+	Draw(pen *sdl.Renderer)
 }
 
 type BaseObject struct {

pkg/internal/land/object_collision.go

@@ -0,0 +1,18 @@
+package land
+
+type CollidableObject interface {
+	GetPosition() Vector2D
+	GetSize() Vector2D
+	OnCollide(other CollidableObject)
+}
+
+func checkCollisionBetweenObject(a, b CollidableObject) bool {
+	aPos := a.GetPosition()
+	aSize := a.GetSize()
+	bPos := b.GetPosition()
+	bSize := b.GetSize()
+	return aPos.X < bPos.X+bSize.X &&
+		aPos.X+aSize.X > bPos.X &&
+		aPos.Y < bPos.Y+bSize.Y &&
+		aPos.Y+aSize.Y > bPos.Y
+}

pkg/internal/land/object_movable.go

@@ -0,0 +1,6 @@
+package land
+
+type MoveableObject interface {
+	Move(deltaX int64, deltaY int64)
+	SlideByVelocity()
+}

pkg/internal/land/prof.go

@@ -19,7 +19,7 @@ func (p *PerformanceAnalyzer) Draw() {
 	atomic.AddInt64(&p.drawCount, 1)
 }
 
-func (p *PerformanceAnalyzer) KeepResetting(duration time.Duration) {
+func (p *PerformanceAnalyzer) RunResetter(duration time.Duration) {
 	ticker := time.NewTicker(duration)
 	defer ticker.Stop()
 	for {

pkg/internal/land/root.go

@@ -16,7 +16,7 @@ func NewRootObject() *RootObject {
 		Analyzer: &PerformanceAnalyzer{},
 	}
 
-	go in.Analyzer.KeepResetting(1 * time.Second)
+	go in.Analyzer.RunResetter(1 * time.Second)
 
 	return in
 }
@@ -38,6 +38,24 @@ func (p *RootObject) RunEventLoop(tickDuration time.Duration) {
 func (p *RootObject) Update() {
 	p.BaseObject.Update()
 
+	// Check collision
+	for _, child := range p.Children {
+		for _, other := range p.Children {
+			collidableChild, ok := child.(CollidableObject)
+			if !ok {
+				continue
+			}
+			collidableOther, ok := other.(CollidableObject)
+			if !ok {
+				continue
+			}
+			if child != other && checkCollisionBetweenObject(collidableChild, collidableOther) {
+				collidableChild.OnCollide(collidableOther)
+				collidableOther.OnCollide(collidableChild)
+			}
+		}
+	}
+
 	p.Analyzer.Tick()
 }
 

pkg/internal/land/vector2d.go

@@ -3,3 +3,7 @@ package land
 type Vector2D struct {
 	X, Y float64
 }
+
+func (p Vector2D) IsZero() bool {
+	return p.X == 0 && p.Y == 0
+}