feat: enhance mouse cursor

main.go

@@ -36,17 +36,23 @@ var wantedGopherData []byte
 //go:embed assets/audio/bgm.wav
 var bgmData []byte
 
+//go:embed assets/image/cursor.png
+var cursorData []byte
+
 type Game struct {
 	gameService *service.Game
 	renderer    *view.Renderer
+	cursor      *service.Cursor
 }
 
 func NewGame() *Game {
 	gameService := service.NewGame()
 	renderer := view.NewRenderer(gameService)
+	cursor := service.NewCursor()
 	return &Game{
 		gameService: gameService,
 		renderer:    renderer,
+		cursor:      cursor,
 	}
 }
 
@@ -55,6 +61,13 @@ func (g *Game) Update() error {
 	dt := now.Sub(g.gameService.LastUpdate).Seconds()
 	g.gameService.LastUpdate = now
 
+	// カーソル位置を取得
+	mx, my := ebiten.CursorPosition()
+	isClicking := ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft)
+
+	// カーソルを更新
+	g.cursor.Update(mx, my, isClicking)
+
 	switch g.gameService.State {
 	case service.StateTitle:
 		if inpututil.IsMouseButtonJustPressed(ebiten.MouseButtonLeft) {
@@ -92,6 +105,7 @@ func (g *Game) Update() error {
 
 func (g *Game) Draw(screen *ebiten.Image) {
 	g.renderer.Draw(screen)
+	g.renderer.DrawCursor(screen, g.cursor)
 }
 
 func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
@@ -111,9 +125,16 @@ func main() {
 		bgmData,
 	)
 
+	// Load cursor image
+	if err := service.LoadCursorImage(cursorData); err != nil {
+		log.Printf("Failed to load cursor image: %v", err)
+	}
+
 	// Set window properties
 	ebiten.SetWindowSize(service.ScreenWidth, service.ScreenHeight)
 	ebiten.SetWindowTitle("Find Gopher")
+	// デフォルトカーソルを非表示
+	ebiten.SetCursorMode(ebiten.CursorModeHidden)
 
 	// Create and run game
 	game := NewGame()

service/cursor.go

@@ -0,0 +1,106 @@
+package service
+
+import (
+	"bytes"
+	"image"
+	"time"
+
+	"github.com/hajimehoshi/ebiten/v2"
+)
+
+// Trail はカーソルのトレイル効果の一つの要素を表します
+type Trail struct {
+	X       float64
+	Y       float64
+	Alpha   float64
+	Scale   float64
+	Created time.Time
+}
+
+// Cursor はカスタムカーソルを管理する構造体です
+type Cursor struct {
+	Image        *ebiten.Image
+	X            float64
+	Y            float64
+	LastX        float64
+	LastY        float64
+	Trails       []Trail
+	TrailMaxAge  time.Duration
+	IsClicking   bool
+	ClickScale   float64
+	BaseScale    float64
+	CurrentScale float64
+}
+
+var cursorImage *ebiten.Image
+
+// LoadCursorImage はカーソル画像を読み込みます
+func LoadCursorImage(data []byte) error {
+	img, _, err := image.Decode(bytes.NewReader(data))
+	if err != nil {
+		return err
+	}
+	cursorImage = ebiten.NewImageFromImage(img)
+	return nil
+}
+
+// NewCursor は新しいカーソルインスタンスを作成します
+func NewCursor() *Cursor {
+	return &Cursor{
+		Image:        cursorImage,
+		Trails:       make([]Trail, 0),
+		TrailMaxAge:  500 * time.Millisecond,
+		BaseScale:    1.0,
+		ClickScale:   0.8,
+		CurrentScale: 1.0,
+	}
+}
+
+// Update はカーソルの状態を更新します
+func (c *Cursor) Update(x, y int, isClicking bool) {
+	c.X = float64(x)
+	c.Y = float64(y)
+	c.IsClicking = isClicking
+
+	// カーソルが移動した距離を計算
+	dx := c.X - c.LastX
+	dy := c.Y - c.LastY
+	distance := dx*dx + dy*dy
+
+	now := time.Now()
+
+	// 移動距離が閾値（2ピクセル）以上の場合のみトレイルを追加
+	if distance >= 4.0 { // 2*2 = 4
+		c.Trails = append(c.Trails, Trail{
+			X:       c.X,
+			Y:       c.Y,
+			Alpha:   1.0,
+			Scale:   1.0,
+			Created: now,
+		})
+		// 前回の位置を更新
+		c.LastX = c.X
+		c.LastY = c.Y
+	}
+
+	// 古いトレイルを削除
+	newTrails := make([]Trail, 0)
+	for i := range c.Trails {
+		age := now.Sub(c.Trails[i].Created)
+		if age < c.TrailMaxAge {
+			// アルファ値とスケールを時間経過で減少
+			progress := age.Seconds() / c.TrailMaxAge.Seconds()
+			c.Trails[i].Alpha = 1.0 - progress
+			c.Trails[i].Scale = 1.0 - progress*0.5
+			newTrails = append(newTrails, c.Trails[i])
+		}
+	}
+	c.Trails = newTrails
+
+	// スケールをアニメーション（拡大効果を削除）
+	targetScale := c.BaseScale
+	if isClicking {
+		targetScale = c.ClickScale
+	}
+	c.CurrentScale += (targetScale - c.CurrentScale) * 0.2
+}

view/components/cursor.go

@@ -0,0 +1,72 @@
+package components
+
+import (
+	"image/color"
+
+	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/vector"
+	"github.com/snkrdunk/find-gopher/service"
+)
+
+// DrawCursor はカスタムカーソルとその効果を描画します
+func DrawCursor(screen *ebiten.Image, cursor *service.Cursor) {
+	if cursor == nil || cursor.Image == nil {
+		return
+	}
+
+	// トレイル効果を描画
+	drawCursorTrails(screen, cursor)
+
+	// カーソル本体を描画
+	drawCursorImage(screen, cursor)
+}
+
+// drawCursorTrails はカーソルのトレイル効果を描画します
+func drawCursorTrails(screen *ebiten.Image, cursor *service.Cursor) {
+	for _, trail := range cursor.Trails {
+		if trail.Alpha <= 0 {
+			continue
+		}
+
+		// トレイルの円を描画
+		radius := float32(6 * trail.Scale)
+		alpha := uint8(trail.Alpha * 100)
+		trailColor := color.RGBA{150, 200, 250, alpha}
+
+		vector.DrawFilledCircle(
+			screen,
+			float32(trail.X),
+			float32(trail.Y),
+			radius,
+			trailColor,
+			true,
+		)
+	}
+}
+
+// drawCursorImage はカーソル画像を描画します
+func drawCursorImage(screen *ebiten.Image, cursor *service.Cursor) {
+	if cursor.Image == nil {
+		return
+	}
+
+	opts := &ebiten.DrawImageOptions{}
+
+	// カーソル画像のサイズを取得
+	bounds := cursor.Image.Bounds()
+	w := float64(bounds.Dx())
+	h := float64(bounds.Dy())
+
+	// 中心を基準に変換
+	opts.GeoM.Translate(-w/2, -h/2)
+
+	// 64x64の画像を32x32に縮小（0.5倍）
+	baseScale := 0.5
+	// スケール（baseScale * CurrentScale）
+	opts.GeoM.Scale(baseScale*cursor.CurrentScale, baseScale*cursor.CurrentScale)
+
+	// カーソル位置に移動
+	opts.GeoM.Translate(cursor.X, cursor.Y)
+
+	screen.DrawImage(cursor.Image, opts)
+}

view/renderer.go

@@ -41,3 +41,8 @@ func (r *Renderer) Draw(screen *ebiten.Image) {
 func (r *Renderer) Layout(outsideWidth, outsideHeight int) (int, int) {
 	return service.ScreenWidth, service.ScreenHeight
 }
+
+// DrawCursor はカスタムカーソルを描画します
+func (r *Renderer) DrawCursor(screen *ebiten.Image, cursor *service.Cursor) {
+	components.DrawCursor(screen, cursor)
+}