all: use math/rand/v2

Closes #2746

.github/workflows/test.yml

@@ -7,7 +7,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        go: ['1.19.x', '1.20.x', '1.21.x', '1.22.x', '1.23.x']
+        go: ['1.22.x', '1.23.x']
     name: Test with Go ${{ matrix.go }} on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
     env:

audio/audio.go

@@ -188,14 +188,7 @@ func (c *Context) addPlayingPlayer(p *playerImpl) {
 	defer c.m.Unlock()
 	c.playingPlayers[p] = struct{}{}
 
-	// (reflect.Type).Comparable() is enough here, as reflect.TypeOf should always return a dynamic (non-interface) type.
-	// If reflect.TypeOf returned an interface type, this check would be meaningless.
-	// See these for more details:
-	// * https://pkg.go.dev/reflect#TypeOf
-	// * https://pkg.go.dev/reflect#Type.Comparable
-	//
-	// (*reflect.Value).Comparable() is more intuitive but this was introduced in Go 1.20.
-	if !reflect.TypeOf(p.sourceIdent()).Comparable() {
+	if !reflect.ValueOf(p.sourceIdent()).Comparable() {
 		return
 	}
 

audio/internal/convert/float32.go

@@ -93,10 +93,3 @@ func (r *float32BytesReader) Seek(offset int64, whence int) (int64, error) {
 	}
 	return n / 2 * 4, nil
 }
-
-func min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}

audio/internal/convert/float32_test.go

@@ -17,7 +17,7 @@ package convert_test
 import (
 	"bytes"
 	"io"
-	"math/rand" // TODO: Use math/rand/v2 when the minimum supported version becomes Go 1.22.
+	"math/rand/v2"
 	"testing"
 	"unsafe"
 
@@ -27,7 +27,7 @@ import (
 func randInt16s(n int) []int16 {
 	r := make([]int16, n)
 	for i := range r {
-		r[i] = int16(rand.Intn(1<<16) - (1 << 15))
+		r[i] = int16(rand.IntN(1<<16) - (1 << 15))
 	}
 	return r
 }
@@ -69,15 +69,14 @@ func TestFloat32(t *testing.T) {
 					name = "seek"
 				}
 				t.Run(name, func(t *testing.T) {
-					// Note that unsafe.SliceData is available as of Go 1.20.
 					var in, out []byte
 					if len(c.In) > 0 {
 						outF32 := make([]float32, len(c.In))
 						for i := range c.In {
 							outF32[i] = float32(c.In[i]) / (1 << 15)
 						}
-						in = unsafe.Slice((*byte)(unsafe.Pointer(&c.In[0])), len(c.In)*2)
-						out = unsafe.Slice((*byte)(unsafe.Pointer(&outF32[0])), len(outF32)*4)
+						in = unsafe.Slice((*byte)(unsafe.Pointer(unsafe.SliceData(c.In))), len(c.In)*2)
+						out = unsafe.Slice((*byte)(unsafe.Pointer(unsafe.SliceData(outF32))), len(outF32)*4)
 					}
 					r := convert.NewFloat32BytesReaderFromInt16BytesReader(bytes.NewReader(in)).(io.ReadSeeker)
 					var got []byte

audio/internal/convert/stereof32_test.go

@@ -19,7 +19,7 @@ import (
 	"fmt"
 	"io"
 	"math"
-	"math/rand" // TODO: Use math/rand/v2 when the minimum supported version becomes Go 1.22.
+	"math/rand/v2"
 	"testing"
 
 	"github.com/hajimehoshi/ebiten/v2/audio/internal/convert"

audio/internal/convert/stereoi16_test.go

@@ -17,8 +17,8 @@ package convert_test
 import (
 	"bytes"
 	"fmt"
-	"io" // TODO: Use math/rand/v2 when the minimum supported version becomes Go 1.22.
-	"math/rand"
+	"io"
+	"math/rand/v2"
 	"testing"
 
 	"github.com/hajimehoshi/ebiten/v2/audio/internal/convert"
@@ -101,7 +101,7 @@ func TestStereoI16(t *testing.T) {
 func randBytes(n int) []byte {
 	r := make([]byte, n)
 	for i := range r {
-		r[i] = byte(rand.Intn(256))
+		r[i] = byte(rand.IntN(256))
 	}
 	return r
 }

audio/vorbis/int16.go

@@ -34,13 +34,6 @@ type int16BytesReader struct {
 	fbuf      []float32
 }
 
-func max(a, b int) int {
-	if a < b {
-		return b
-	}
-	return a
-}
-
 func (r *int16BytesReader) Read(buf []byte) (int, error) {
 	if r.eof {
 		return 0, io.EOF

examples/2048/2048/game.go

@@ -15,16 +15,9 @@
 package twenty48
 
 import (
-	"math/rand"
-	"time"
-
 	"github.com/hajimehoshi/ebiten/v2"
 )
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 const (
 	ScreenWidth  = 420
 	ScreenHeight = 600

examples/2048/2048/tile.go

@@ -19,7 +19,7 @@ import (
 	"errors"
 	"image/color"
 	"log"
-	"math/rand"
+	"math/rand/v2"
 	"sort"
 	"strconv"
 
@@ -261,9 +261,9 @@ func addRandomTile(tiles map[*Tile]struct{}, size int) error {
 	if len(availableCells) == 0 {
 		return errors.New("twenty48: there is no space to add a new tile")
 	}
-	c := availableCells[rand.Intn(len(availableCells))]
+	c := availableCells[rand.IntN(len(availableCells))]
 	v := 2
-	if rand.Intn(10) == 0 {
+	if rand.IntN(10) == 0 {
 		v = 4
 	}
 	x := c % size

examples/blend/main.go

@@ -163,19 +163,9 @@ func loadImage(data []byte) (*ebiten.Image, error) {
 }
 
 // max returns the largest of x or y.
-func max(x, y int) int {
-	if x > y {
-		return x
-	}
-	return y
-}
-
 // maxSide returns the largest side of a or b images.
 func maxSide(a, b *ebiten.Image) int {
-	return max(
-		max(a.Bounds().Dx(), b.Bounds().Dx()),
-		max(a.Bounds().Dy(), b.Bounds().Dy()),
-	)
+	return max(a.Bounds().Dx(), b.Bounds().Dx(), a.Bounds().Dy(), b.Bounds().Dy())
 }
 
 // drawCenteredText is a util function for drawing blend mode description.

examples/blocks/blocks/field.go

@@ -187,13 +187,6 @@ func (f *Field) Update() {
 	}
 }
 
-func min(a, b float64) float64 {
-	if a > b {
-		return b
-	}
-	return a
-}
-
 func flushingColor(rate float64) colorm.ColorM {
 	var clr colorm.ColorM
 	alpha := min(1, rate*2)

examples/blocks/blocks/gamescene.go

@@ -20,9 +20,8 @@ import (
 	"image/color"
 	_ "image/jpeg"
 	_ "image/png"
-	"math/rand"
+	"math/rand/v2"
 	"strconv"
-	"time"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/colorm"
@@ -139,10 +138,6 @@ type GameScene struct {
 	gameover           bool
 }
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 func NewGameScene() *GameScene {
 	return &GameScene{
 		field: &Field{},
@@ -194,7 +189,7 @@ const (
 
 func (s *GameScene) choosePiece() *Piece {
 	num := int(BlockTypeMax)
-	blockType := BlockType(rand.Intn(num) + 1)
+	blockType := BlockType(rand.IntN(num) + 1)
 	return Pieces[blockType]
 }
 

examples/chipmunk/main.go

@@ -18,7 +18,7 @@ import (
 	"fmt"
 	"image/color"
 	"log"
-	"math/rand"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"

examples/doomfire/main.go

@@ -17,8 +17,7 @@ package main
 import (
 	"image/color"
 	"log"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 )
@@ -102,7 +101,7 @@ func (g *Game) updateFireIntensityPerPixel(currentPixelIndex int) {
 		return
 	}
 
-	d := rand.Intn(3)
+	d := rand.IntN(3)
 	newI := int(g.indices[below]) - d
 	if newI < 0 {
 		newI = 0
@@ -139,8 +138,6 @@ func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
 }
 
 func main() {
-	rand.Seed(time.Now().UnixNano())
-
 	ebiten.SetWindowSize(screenWidth*6, screenHeight*6)
 	ebiten.SetWindowTitle("Doom Fire (Ebitengine Demo)")
 	if err := ebiten.RunGame(NewGame()); err != nil {

examples/drag/main.go

@@ -20,8 +20,7 @@ import (
 	"image/color"
 	_ "image/png"
 	"log"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
@@ -29,10 +28,6 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/inpututil"
 )
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 const (
 	screenWidth  = 640
 	screenHeight = 480
@@ -196,8 +191,8 @@ func NewGame() *Game {
 		s := &Sprite{
 			image:      ebitenImage,
 			alphaImage: ebitenAlphaImage,
-			x:          rand.Intn(screenWidth - w),
-			y:          rand.Intn(screenHeight - h),
+			x:          rand.IntN(screenWidth - w),
+			y:          rand.IntN(screenHeight - h),
 		}
 		sprites = append(sprites, s)
 	}

examples/flappy/main.go

@@ -24,8 +24,7 @@ import (
 	_ "image/png"
 	"log"
 	"math"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/audio"
@@ -44,10 +43,6 @@ var flagCRT = flag.Bool("crt", false, "enable the CRT effect")
 //go:embed crt.go
 var crtGo []byte
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 func floorDiv(x, y int) int {
 	d := x / y
 	if d*y == x || x >= 0 {
@@ -150,7 +145,7 @@ func (g *Game) init() {
 	g.cameraY = 0
 	g.pipeTileYs = make([]int, 256)
 	for i := range g.pipeTileYs {
-		g.pipeTileYs[i] = rand.Intn(6) + 2
+		g.pipeTileYs[i] = rand.IntN(6) + 2
 	}
 
 	if g.audioContext == nil {

examples/font/main.go

@@ -19,8 +19,7 @@ import (
 	"fmt"
 	"image/color"
 	"log"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/examples/resources/fonts"
@@ -94,10 +93,6 @@ func init() {
 	mplusFaceSource = s
 }
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 type Game struct {
 	counter        int
 	kanjiText      string
@@ -110,14 +105,14 @@ func (g *Game) Update() error {
 		g.kanjiText = ""
 		for j := 0; j < 6; j++ {
 			for i := 0; i < 12; i++ {
-				g.kanjiText += string(jaKanjis[rand.Intn(len(jaKanjis))])
+				g.kanjiText += string(jaKanjis[rand.IntN(len(jaKanjis))])
 			}
 			g.kanjiText += "\n"
 		}
 
-		g.kanjiTextColor.R = 0x80 + uint8(rand.Intn(0x7f))
-		g.kanjiTextColor.G = 0x80 + uint8(rand.Intn(0x7f))
-		g.kanjiTextColor.B = 0x80 + uint8(rand.Intn(0x7f))
+		g.kanjiTextColor.R = 0x80 + uint8(rand.IntN(0x7f))
+		g.kanjiTextColor.G = 0x80 + uint8(rand.IntN(0x7f))
+		g.kanjiTextColor.B = 0x80 + uint8(rand.IntN(0x7f))
 		g.kanjiTextColor.A = 0xff
 	}
 	g.counter++

examples/isometric/level.go

@@ -16,8 +16,7 @@ package main
 
 import (
 	"fmt"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 )
 
 // Level represents a Game level.
@@ -56,9 +55,6 @@ func NewLevel() (*Level, error) {
 		return nil, fmt.Errorf("failed to load embedded spritesheet: %s", err)
 	}
 
-	// Generate a unique permutation each time.
-	r := rand.New(rand.NewSource(time.Now().UTC().UnixNano()))
-
 	// Fill each tile with one or more sprites randomly.
 	l.tiles = make([][]*Tile, l.h)
 	for y := 0; y < l.h; y++ {
@@ -66,7 +62,7 @@ func NewLevel() (*Level, error) {
 		for x := 0; x < l.w; x++ {
 			t := &Tile{}
 			isBorderSpace := x == 0 || y == 0 || x == l.w-1 || y == l.h-1
-			val := r.Intn(1000)
+			val := rand.IntN(1000)
 			switch {
 			case isBorderSpace || val < 275:
 				t.AddSprite(ss.Wall)

examples/life/main.go

@@ -8,16 +8,11 @@ package main
 
 import (
 	"log"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 )
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 // World represents the game state.
 type World struct {
 	area   []bool
@@ -39,8 +34,8 @@ func NewWorld(width, height int, maxInitLiveCells int) *World {
 // init inits world with a random state.
 func (w *World) init(maxLiveCells int) {
 	for i := 0; i < maxLiveCells; i++ {
-		x := rand.Intn(w.width)
-		y := rand.Intn(w.height)
+		x := rand.IntN(w.width)
+		y := rand.IntN(w.height)
 		w.area[y*w.width+x] = true
 	}
 }
@@ -96,20 +91,6 @@ func (w *World) Draw(pix []byte) {
 	}
 }
 
-func max(a, b int) int {
-	if a < b {
-		return b
-	}
-	return a
-}
-
-func min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}
-
 // neighbourCount calculates the Moore neighborhood of (x, y).
 func neighbourCount(a []bool, width, height, x, y int) int {
 	c := 0

examples/lines/main.go

@@ -27,13 +27,6 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/vector"
 )
 
-func min(x, y int) int {
-	if x < y {
-		return x
-	}
-	return y
-}
-
 var (
 	whiteImage = ebiten.NewImage(3, 3)
 

examples/mascot/main.go

@@ -21,8 +21,7 @@ import (
 	"image"
 	_ "image/png"
 	"log"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	rmascot "github.com/hajimehoshi/ebiten/v2/examples/resources/images/mascot"
@@ -60,10 +59,6 @@ func init() {
 	gopher3 = ebiten.NewImageFromImage(img3)
 }
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 type mascot struct {
 	x16  int
 	y16  int
@@ -105,8 +100,8 @@ func (m *mascot) Update() error {
 	}
 
 	// If the mascto is on the ground, cause an action in random.
-	if rand.Intn(60) == 0 && m.y16 == 0 {
-		switch rand.Intn(2) {
+	if rand.IntN(60) == 0 && m.y16 == 0 {
+		switch rand.IntN(2) {
 		case 0:
 			// Jump.
 			m.vy16 = -240

examples/masking/main.go

@@ -145,20 +145,6 @@ func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
 	return screenWidth, screenHeight
 }
 
-func max(a, b int) int {
-	if a < b {
-		return b
-	}
-	return a
-}
-
-func min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}
-
 func main() {
 	ebiten.SetWindowSize(screenWidth*2, screenHeight*2)
 	ebiten.SetWindowTitle("Masking (Ebitengine Demo)")

examples/particles/main.go

@@ -23,18 +23,13 @@ import (
 	_ "image/png"
 	"log"
 	"math"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
 	"github.com/hajimehoshi/ebiten/v2/examples/resources/images"
 )
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 const (
 	screenWidth  = 640
 	screenHeight = 480
@@ -110,7 +105,7 @@ func (s *sprite) draw(screen *ebiten.Image) {
 }
 
 func newSprite(img *ebiten.Image) *sprite {
-	c := rand.Intn(50) + 300
+	c := rand.IntN(50) + 300
 	dir := rand.Float64() * 2 * math.Pi
 	a := rand.Float64() * 2 * math.Pi
 	s := rand.Float64()*0.1 + 0.4
@@ -136,7 +131,7 @@ func (g *Game) Update() error {
 		g.sprites = list.New()
 	}
 
-	if g.sprites.Len() < 500 && rand.Intn(4) < 3 {
+	if g.sprites.Len() < 500 && rand.IntN(4) < 3 {
 		// Emit
 		g.sprites.PushBack(newSprite(smokeImage))
 	}

examples/set/main.go

@@ -18,8 +18,7 @@ import (
 	"fmt"
 	"image/color"
 	"log"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
@@ -30,10 +29,6 @@ const (
 	screenHeight = 240
 )
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 type Game struct {
 	offscreen *ebiten.Image
 }
@@ -46,12 +41,12 @@ func NewGame() *Game {
 
 func (g *Game) Update() error {
 	s := g.offscreen.Bounds().Size()
-	x := rand.Intn(s.X)
-	y := rand.Intn(s.Y)
+	x := rand.IntN(s.X)
+	y := rand.IntN(s.Y)
 	c := color.RGBA{
-		byte(rand.Intn(256)),
-		byte(rand.Intn(256)),
-		byte(rand.Intn(256)),
+		byte(rand.IntN(256)),
+		byte(rand.IntN(256)),
+		byte(rand.IntN(256)),
 		byte(0xff),
 	}
 	g.offscreen.Set(x, y, c)

examples/snake/main.go

@@ -18,8 +18,7 @@ import (
 	"fmt"
 	"image/color"
 	"log"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
@@ -59,10 +58,6 @@ type Game struct {
 	level         int
 }
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 func (g *Game) collidesWithApple() bool {
 	return g.snakeBody[0].X == g.apple.X &&
 		g.snakeBody[0].Y == g.apple.Y
@@ -130,8 +125,8 @@ func (g *Game) Update() error {
 		}
 
 		if g.collidesWithApple() {
-			g.apple.X = rand.Intn(xGridCountInScreen - 1)
-			g.apple.Y = rand.Intn(yGridCountInScreen - 1)
+			g.apple.X = rand.IntN(xGridCountInScreen - 1)
+			g.apple.Y = rand.IntN(yGridCountInScreen - 1)
 			g.snakeBody = append(g.snakeBody, Position{
 				X: g.snakeBody[len(g.snakeBody)-1].X,
 				Y: g.snakeBody[len(g.snakeBody)-1].Y,

examples/sprites/main.go

@@ -21,7 +21,7 @@ import (
 	_ "image/png"
 	"log"
 	"math"
-	"math/rand"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
@@ -119,9 +119,9 @@ func (g *Game) init() {
 	g.sprites.num = 500
 	for i := range g.sprites.sprites {
 		w, h := ebitenImage.Bounds().Dx(), ebitenImage.Bounds().Dy()
-		x, y := rand.Intn(screenWidth-w), rand.Intn(screenHeight-h)
-		vx, vy := 2*rand.Intn(2)-1, 2*rand.Intn(2)-1
-		a := rand.Intn(maxAngle)
+		x, y := rand.IntN(screenWidth-w), rand.IntN(screenHeight-h)
+		vx, vy := 2*rand.IntN(2)-1, 2*rand.IntN(2)-1
+		a := rand.IntN(maxAngle)
 		g.sprites.sprites[i] = &Sprite{
 			imageWidth:  w,
 			imageHeight: h,

examples/spriteshd/main.go

@@ -21,7 +21,7 @@ import (
 	_ "image/png"
 	"log"
 	"math"
-	"math/rand"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
@@ -117,9 +117,9 @@ func (g *Game) init() {
 	g.sprites.num = 500
 	for i := range g.sprites.sprites {
 		w, h := ebitenImage.Bounds().Dx(), ebitenImage.Bounds().Dy()
-		x, y := rand.Intn(screenWidth-w), rand.Intn(screenHeight-h)
-		vx, vy := 2*rand.Intn(2)-1, 2*rand.Intn(2)-1
-		a := rand.Intn(maxAngle)
+		x, y := rand.IntN(screenWidth-w), rand.IntN(screenHeight-h)
+		vx, vy := 2*rand.IntN(2)-1, 2*rand.IntN(2)-1
+		a := rand.IntN(maxAngle)
 		g.sprites.sprites[i] = &Sprite{
 			imageWidth:  w,
 			imageHeight: h,

examples/squiral/main.go

@@ -20,8 +20,7 @@ import (
 	"fmt"
 	"image/color"
 	"log"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
@@ -127,8 +126,8 @@ type squiral struct {
 func (s *squiral) spawn(game *Game) {
 	s.dead = false
 
-	rx := rand.Intn(width-4) + 2
-	ry := rand.Intn(height-4) + 2
+	rx := rand.IntN(width-4) + 2
+	ry := rand.IntN(height-4) + 2
 
 	for dx := -2; dx <= 2; dx++ {
 		for dy := -2; dy <= 2; dy++ {
@@ -140,15 +139,15 @@ func (s *squiral) spawn(game *Game) {
 		}
 	}
 
-	s.speed = rand.Intn(5) + 1
+	s.speed = rand.IntN(5) + 1
 	s.pos.x = rx
 	s.pos.y = ry
-	s.dir = rand.Intn(4)
+	s.dir = rand.IntN(4)
 
 	game.colorCycle = (game.colorCycle + 1) % len(palettes[game.selectedPalette].colors)
 	s.col = palettes[game.selectedPalette].colors[game.colorCycle]
 
-	s.rot = rand.Intn(2)
+	s.rot = rand.IntN(2)
 }
 
 func (s *squiral) step(game *Game) {
@@ -157,7 +156,7 @@ func (s *squiral) step(game *Game) {
 	}
 	x, y := s.pos.x, s.pos.y // shorthands
 
-	change := rand.Intn(1000)
+	change := rand.IntN(1000)
 	if change < 2 {
 		// On 0.2% of iterations, switch rotation direction.
 		s.rot = (s.rot + 1) % 2
@@ -267,10 +266,6 @@ func (a *automaton) step(game *Game) {
 	}
 }
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 type Game struct {
 	selectedPalette int
 	colorCycle      int

examples/stars/main.go

@@ -17,8 +17,7 @@ package main
 import (
 	"image/color"
 	"log"
-	"math/rand"
-	"time"
+	"math/rand/v2"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/vector"
@@ -97,7 +96,6 @@ func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
 }
 
 func main() {
-	rand.Seed(time.Now().UnixNano())
 	ebiten.SetWindowSize(screenWidth, screenHeight)
 	ebiten.SetWindowTitle("Stars (Ebitengine Demo)")
 	if err := ebiten.RunGame(NewGame()); err != nil {

examples/windowsize/main.go

@@ -22,12 +22,11 @@ import (
 	_ "image/jpeg"
 	"log"
 	"math"
-	"math/rand"
+	"math/rand/v2"
 	"regexp"
 	"strconv"
 	"strings"
 	"sync"
-	"time"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
@@ -55,7 +54,6 @@ var (
 
 func init() {
 	flag.Parse()
-	rand.Seed(time.Now().UnixNano())
 }
 
 const (
@@ -71,9 +69,9 @@ var (
 func createRandomIconImage() image.Image {
 	const size = 32
 
-	rf := float64(rand.Intn(0x100))
-	gf := float64(rand.Intn(0x100))
-	bf := float64(rand.Intn(0x100))
+	rf := float64(rand.IntN(0x100))
+	gf := float64(rand.IntN(0x100))
+	bf := float64(rand.IntN(0x100))
 	img := ebiten.NewImage(size, size)
 	pix := make([]byte, 4*size*size)
 	for j := 0; j < size; j++ {

go.mod

@@ -1,9 +1,9 @@
 module github.com/hajimehoshi/ebiten/v2
 
-go 1.19
+go 1.22.0
 
 require (
-	github.com/ebitengine/gomobile v0.0.0-20240911013058-19d2b8b92254
+	github.com/ebitengine/gomobile v0.0.0-20240911145611-4856209ac325
 	github.com/ebitengine/hideconsole v1.0.0
 	github.com/ebitengine/oto/v3 v3.3.0-alpha.4
 	github.com/ebitengine/purego v0.8.0-alpha.5
@@ -15,15 +15,15 @@ require (
 	github.com/jezek/xgb v1.1.1
 	github.com/jfreymuth/oggvorbis v1.0.5
 	github.com/kisielk/errcheck v1.7.0
-	golang.org/x/image v0.19.0
+	golang.org/x/image v0.20.0
 	golang.org/x/sync v0.8.0
 	golang.org/x/sys v0.25.0
-	golang.org/x/text v0.17.0
-	golang.org/x/tools v0.24.0
+	golang.org/x/text v0.18.0
+	golang.org/x/tools v0.25.0
 )
 
 require (
 	github.com/jfreymuth/vorbis v1.0.2 // indirect
 	github.com/pierrec/lz4/v4 v4.1.21 // indirect
-	golang.org/x/mod v0.20.0 // indirect
+	golang.org/x/mod v0.21.0 // indirect
 )

go.sum

@@ -1,5 +1,5 @@
-github.com/ebitengine/gomobile v0.0.0-20240911013058-19d2b8b92254 h1:4gZw/SDMJtxpPh+lMpXLZ63LWWna0mZgtEBuvizRmdo=
-github.com/ebitengine/gomobile v0.0.0-20240911013058-19d2b8b92254/go.mod h1:n2NbB/F4d9wOXFzC7FT1ipERidmYWC5I4YNOYRs5N7I=
+github.com/ebitengine/gomobile v0.0.0-20240911145611-4856209ac325 h1:Gk1XUEttOk0/hb6Tq3WkmutWa0ZLhNn/6fc6XZpM7tM=
+github.com/ebitengine/gomobile v0.0.0-20240911145611-4856209ac325/go.mod h1:ulhSQcbPioQrallSuIzF8l1NKQoD7xmMZc5NxzibUMY=
 github.com/ebitengine/hideconsole v1.0.0 h1:5J4U0kXF+pv/DhiXt5/lTz0eO5ogJ1iXb8Yj1yReDqE=
 github.com/ebitengine/hideconsole v1.0.0/go.mod h1:hTTBTvVYWKBuxPr7peweneWdkUwEuHuB3C1R/ielR1A=
 github.com/ebitengine/oto/v3 v3.3.0-alpha.4 h1:w9SD7kK4GgJULkh5pWVTToMA5Ia1bP7VxD4rIjQqb8M=
@@ -11,6 +11,7 @@ github.com/gen2brain/mpeg v0.3.2-0.20240412154320-a2ac4fc8a46f/go.mod h1:i/ebyRR
 github.com/go-text/typesetting v0.1.1-0.20240522210117-2c045476f496 h1:zgx3rOyOdRoA2GXWpfJkH7Zg248ookseRifdn9VSp5g=
 github.com/go-text/typesetting v0.1.1-0.20240522210117-2c045476f496/go.mod h1:2+owI/sxa73XA581LAzVuEBZ3WEEV2pXeDswCH/3i1I=
 github.com/go-text/typesetting-utils v0.0.0-20240317173224-1986cbe96c66 h1:GUrm65PQPlhFSKjLPGOZNPNxLCybjzjYBzjfoBGaDUY=
+github.com/go-text/typesetting-utils v0.0.0-20240317173224-1986cbe96c66/go.mod h1:DDxDdQEnB70R8owOx3LVpEFvpMK9eeH1o2r0yZhFI9o=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/hajimehoshi/bitmapfont/v3 v3.2.0-alpha.5 h1:gtIcN2INlD2qlfUiECuvbI0moNIoANgIY7MwgW4cFGE=
@@ -37,15 +38,16 @@ golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5y
 golang.org/x/crypto v0.13.0/go.mod h1:y6Z2r+Rw4iayiXXAIxJIDAJ1zMW4yaTpebo8fPOliYc=
 golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDfU=
 golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8=
-golang.org/x/image v0.19.0 h1:D9FX4QWkLfkeqaC62SonffIIuYdOk/UE2XKUBgRIBIQ=
 golang.org/x/image v0.19.0/go.mod h1:y0zrRqlQRWQ5PXaYCOMLTW2fpsxZ8Qh9I/ohnInJEys=
+golang.org/x/image v0.20.0 h1:7cVCUjQwfL18gyBJOmYvptfSHS8Fb3YUDtfLIZ7Nbpw=
+golang.org/x/image v0.20.0/go.mod h1:0a88To4CYVBAHp5FXJm8o7QbUl37Vd85ply1vyD8auM=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
 golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
 golang.org/x/mod v0.15.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/mod v0.17.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
-golang.org/x/mod v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
-golang.org/x/mod v0.20.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/mod v0.21.0 h1:vvrHzRwRfVKSiLrG+d4FMl/Qi4ukBCE6kZlTUkDYRT0=
+golang.org/x/mod v0.21.0/go.mod h1:6SkKJ3Xj0I0BrPOZoBy3bdMptDDU9oJrpohJ3eWZ1fY=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
@@ -92,14 +94,15 @@ golang.org/x/text v0.9.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
 golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
-golang.org/x/text v0.17.0 h1:XtiM5bkSOt+ewxlOE/aE/AKEHibwj/6gvWMl9Rsh0Qc=
 golang.org/x/text v0.17.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
+golang.org/x/text v0.18.0 h1:XvMDiNzPAl0jr17s6W9lcaIhGUfUORdGCNsuLmPG224=
+golang.org/x/text v0.18.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
 golang.org/x/tools v0.13.0/go.mod h1:HvlwmtVNQAhOuCjW7xxvovg8wbNq7LwfXh/k7wXUl58=
 golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
-golang.org/x/tools v0.24.0 h1:J1shsA93PJUEVaUSaay7UXAyE8aimq3GW0pjlolpa24=
-golang.org/x/tools v0.24.0/go.mod h1:YhNqVBIfWHdzvTLs0d8LCuMhkKUgSUKldakyV7W/WDQ=
+golang.org/x/tools v0.25.0 h1:oFU9pkj/iJgs+0DT+VMHrx+oBKs/LJMV+Uvg78sl+fE=
+golang.org/x/tools v0.25.0/go.mod h1:/vtpO8WL1N9cQC3FN5zPqb//fRXskFHbLKk4OW1Q7rg=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

image_test.go

@@ -22,10 +22,9 @@ import (
 	"image/draw"
 	_ "image/png"
 	"math"
-	"math/rand"
+	"math/rand/v2"
 	"runtime"
 	"testing"
-	"time"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/examples/resources/images"
@@ -37,10 +36,6 @@ import (
 // maxImageSize is a maximum image size that should work in almost every environment.
 const maxImageSize = 4096 - 2
 
-func init() {
-	rand.Seed(time.Now().UnixNano())
-}
-
 func skipTooSlowTests(t *testing.T) bool {
 	if testing.Short() {
 		t.Skip("skipping test in short mode")
@@ -348,26 +343,6 @@ func TestImageDeallocate(t *testing.T) {
 	}
 }
 
-type ordered interface {
-	~int | ~int8 | ~int16 | ~int32 | ~int64 | ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr | ~float32 | ~float64 | ~string
-}
-
-// TODO: Use the built-in function min from Go 1.21.
-func min[T ordered](a, b T) T {
-	if a < b {
-		return a
-	}
-	return b
-}
-
-// TODO: Use the built-in function max from Go 1.21.
-func max[T ordered](a, b T) T {
-	if a < b {
-		return b
-	}
-	return a
-}
-
 func TestImageBlendLighter(t *testing.T) {
 	img0, _, err := openEbitenImage()
 	if err != nil {
@@ -4292,7 +4267,7 @@ func TestImageAntiAlias(t *testing.T) {
 		ebiten.BlendXor,
 		ebiten.BlendLighter,
 	} {
-		rnd := rand.New(rand.NewSource(0))
+		rnd := rand.New(rand.NewPCG(0, 0))
 		max := func(x, y, z byte) byte {
 			if x >= y && x >= z {
 				return x

internal/affine/colorm_test.go

@@ -16,7 +16,7 @@ package affine_test
 
 import (
 	"math"
-	"math/rand"
+	"math/rand/v2"
 	"testing"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/affine"

internal/atlas/image.go

@@ -35,13 +35,6 @@ var (
 	maxSize            = 0
 )
 
-func min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}
-
 func appendDeferred(f func()) {
 	deferredM.Lock()
 	defer deferredM.Unlock()

internal/buffered/image.go

@@ -314,8 +314,5 @@ func (i *Image) syncPixelsIfNeeded() {
 	blend := graphicsdriver.BlendCopy
 	i.img.DrawTriangles(srcs, vs, is, blend, dr, [graphics.ShaderSrcImageCount]image.Rectangle{sr}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
-	// TODO: Use clear if Go 1.21 is available.
-	for pos := range i.dotsBuffer {
-		delete(i.dotsBuffer, pos)
-	}
+	clear(i.dotsBuffer)
 }

internal/clock/clock.go

@@ -64,13 +64,6 @@ func ActualTPS() float64 {
 	return actualTPS
 }
 
-func max(a, b int64) int64 {
-	if a < b {
-		return b
-	}
-	return a
-}
-
 func calcCountFromTPS(tps int64, now int64) int {
 	if tps == 0 {
 		return 0

internal/glfw/context_windows.go

@@ -616,6 +616,5 @@ func bytePtrToString(p *byte) string {
 		ptr = unsafe.Add(ptr, 1)
 	}
 
-	// unsafe.String(p, n) is available as of Go 1.20.
-	return string(unsafe.Slice(p, n))
+	return unsafe.String(p, n)
 }

internal/graphicscommand/commandqueue.go

@@ -507,13 +507,6 @@ func roundUpPower2(x int) int {
 	return p2
 }
 
-func max(a, b int) int {
-	if a < b {
-		return b
-	}
-	return a
-}
-
 func (b *uint32sBuffer) alloc(n int) []uint32 {
 	buf := b.buf
 	if len(buf)+n > cap(buf) {

internal/graphicsdriver/opengl/gl/procaddr_darwin.go

@@ -38,8 +38,7 @@ func (c *defaultContext) init() error {
 		return nil
 	}
 
-	// TODO: Use multiple %w-s as of Go 1.20
-	return fmt.Errorf("gl: failed to load: OpenGL.framework: %v, OpenGLES.framework: %v", errGL, errGLES)
+	return fmt.Errorf("gl: failed to load: OpenGL.framework: %w, OpenGLES.framework: %w", errGL, errGLES)
 }
 
 func (c *defaultContext) getProcAddress(name string) (uintptr, error) {

internal/graphicsdriver/opengl/gl/procaddr_linbsd.go

@@ -17,8 +17,8 @@
 package gl
 
 import (
+	"errors"
 	"fmt"
-	"strings"
 
 	"github.com/ebitengine/purego"
 )
@@ -29,8 +29,7 @@ var (
 )
 
 func (c *defaultContext) init() error {
-	// TODO: Use multiple %w-s as of Go 1.20.
-	var errors []string
+	var errs []error
 
 	// Try OpenGL ES first. Some machines like Android and Raspberry Pi might work only with OpenGL ES.
 	for _, name := range []string{"libGLESv2.so", "libGLESv2.so.2", "libGLESv2.so.1", "libGLESv2.so.0"} {
@@ -40,7 +39,7 @@ func (c *defaultContext) init() error {
 			c.isES = true
 			return nil
 		}
-		errors = append(errors, fmt.Sprintf("%s: %v", name, err))
+		errs = append(errs, fmt.Errorf("gl: Dlopen failed: name: %s: %w", name, err))
 	}
 
 	// Try OpenGL next.
@@ -54,10 +53,11 @@ func (c *defaultContext) init() error {
 			libGL = lib
 			return nil
 		}
-		errors = append(errors, fmt.Sprintf("%s: %v", name, err))
+		errs = append(errs, fmt.Errorf("gl: Dlopen failed: name: %s: %w", name, err))
 	}
 
-	return fmt.Errorf("gl: failed to load libGL.so and libGLESv2.so: %s", strings.Join(errors, ", "))
+	errs = append([]error{fmt.Errorf("gl: failed to load libGL.so and libGLESv2.so: ")}, errs...)
+	return errors.Join(errs...)
 }
 
 func (c *defaultContext) getProcAddress(name string) (uintptr, error) {

internal/png/gen.go

@@ -136,18 +136,6 @@ func run() error {
 		fmt.Fprintln(w)
 		format.Node(w, fset, tree)
 
-		if f == "reader.go" {
-			// The min function was removed as of Go 1.22, but this is needed for old Go.
-			// TODO: Remove this when Go 1.21 is the minimum supported version.
-			fmt.Fprintln(w, `
-func min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}`)
-		}
-
 		if err := w.Flush(); err != nil {
 			return err
 		}

internal/png/stdlibreader.go

@@ -1054,10 +1054,3 @@ func DecodeConfig(r io.Reader) (image.Config, error) {
 func init() {
 
 }
-
-func min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}