1 files changed, 215 insertions, 0 deletions
diff --git a/pongo.go b/pongo.go
new file mode 100644
index 0000000..f4dc038
--- /dev/null
+++ b/pongo.go
@@ -0,0 +1,215 @@
+package main
+
+import (
+	_ "embed"
+	"github.com/gen2brain/raylib-go/raylib"
+	"math"
+	"strconv"
+)
+
+const (
+	screenWidth  = 1920
+	screenHeight = 1080
+
+	ballSpeed = 5
+
+	paddleSpeed = 5
+)
+
+func printCenter(text string, size int32, color rl.Color) {
+	rl.DrawText(text, screenWidth/2-rl.MeasureText(text, size), screenHeight/2, size, color)
+}
+
+type rect rl.Rectangle
+
+func (r rect) bottom() float32 {
+	return r.Y + r.Height
+}
+
+func (r rect) right() float32 {
+	return r.X + r.Width
+}
+
+func (r rect) collides(s rect) bool {
+	return rl.CheckCollisionRecs(rl.Rectangle(r), rl.Rectangle(s))
+}
+
+func (r rect) draw(color rl.Color) {
+	rl.DrawRectangleRec(rl.Rectangle(r), color)
+}
+
+type ball struct {
+	pos      rl.Vector2
+	velocity rl.Vector2
+}
+
+func (b *ball) bounds() rect {
+	const ballSize = 30
+	return rect{
+		X:      b.pos.X,
+		Y:      b.pos.Y,
+		Width:  ballSize,
+		Height: ballSize,
+	}
+}
+
+func (b *ball) predictIntersection(targetX float32) (float32, bool) {
+	if b.velocity.X <= 0 {
+		return 0, false
+	}
+	x := b.pos.X
+	y := b.pos.Y
+	velocity := b.velocity
+	dist := targetX - x
+	prediction := y + velocity.Y*dist/velocity.X
+	if prediction < 0 {
+		bounces := int(-prediction / screenHeight)
+		if bounces%2 == 0 {
+			return -prediction - float32(screenHeight*bounces), true
+		}
+		return prediction + float32(screenHeight*(bounces+1)), true
+	}
+	if prediction > screenHeight {
+		bounces := int(prediction / screenHeight)
+		if bounces%2 == 0 {
+			return prediction - float32(screenHeight*bounces), true
+		}
+		return -prediction + float32(screenHeight*(bounces+1)), true
+	}
+	return prediction, true
+}
+
+type side int
+
+const (
+	left side = iota
+	right
+)
+
+func (b *ball) reset(side side) {
+	b.pos = rl.Vector2{X: screenWidth / 2, Y: screenHeight / 2}
+	b.velocity = rl.Vector2{X: ballSpeed}
+	if side == left {
+		b.velocity.X = -b.velocity.X
+	}
+}
+
+type paddle struct {
+	pos  float32
+	side side
+}
+
+func (p *paddle) bounds() rect {
+	const (
+		paddleHeight = 200
+		thickness    = 10
+		padding      = 100
+	)
+	r := rect{
+		X:      padding - thickness/2,
+		Y:      p.pos - paddleHeight/2,
+		Width:  thickness,
+		Height: paddleHeight,
+	}
+	if p.side == right {
+		r.X = screenWidth - padding - thickness/2
+	}
+	return r
+}
+
+//go:embed ping.mp3
+var pingMP3 []byte
+
+func main() {
+	rl.InitWindow(screenWidth, screenHeight, "pongo")
+	defer rl.CloseWindow()
+	rl.SetTargetFPS(120)
+
+	rl.InitAudioDevice()
+	defer rl.CloseAudioDevice()
+
+	pingWave := rl.LoadWaveFromMemory(".mp3", pingMP3, int32(len(pingMP3)))
+	defer rl.UnloadWave(pingWave)
+	ping := rl.LoadSoundFromWave(pingWave)
+	defer rl.UnloadSound(ping)
+
+	playerScore := 0
+	aiScore := 0
+
+	var ball ball
+	ball.reset(left)
+
+	paddle1 := paddle{pos: screenHeight / 2, side: left}
+	paddle2 := paddle{pos: screenHeight / 2, side: right}
+
+	for !rl.WindowShouldClose() {
+		switch {
+		case rl.IsKeyDown(rl.KeyUp) && paddle1.bounds().Y >= 0:
+			paddle1.pos -= paddleSpeed
+		case rl.IsKeyDown(rl.KeyDown) && paddle1.bounds().bottom() <= screenHeight:
+			paddle1.pos += paddleSpeed
+		}
+
+		if prediction, ok := ball.predictIntersection(paddle2.bounds().X); ok {
+			switch {
+			case paddle2.pos < prediction && paddle2.bounds().bottom() <= screenHeight:
+				paddle2.pos += paddleSpeed
+			case paddle2.pos > prediction && paddle2.bounds().Y >= 0:
+				paddle2.pos -= paddleSpeed
+			}
+		}
+
+		ball.pos = rl.Vector2Add(ball.pos, ball.velocity)
+		switch {
+		case ball.bounds().collides(paddle1.bounds()):
+			rl.PlaySound(ping)
+			d := ball.pos.Y - paddle1.pos
+			if d < 0 {
+				d = -d
+			}
+			angle := d / (paddle1.bounds().Height/2 + ball.bounds().Height) * (75 * 2 * math.Pi / 360)
+			if ball.pos.Y < paddle1.pos {
+				angle = -angle
+			}
+			speed := ballSpeed * (1 + 4*d/(paddle1.bounds().Height/2+ball.bounds().Height))
+			ball.velocity = rl.Vector2{X: speed * float32(math.Cos(float64(angle))), Y: speed * float32(math.Sin(float64(angle)))}
+		case ball.bounds().collides(paddle2.bounds()):
+			rl.PlaySound(ping)
+			d := ball.pos.Y - paddle2.pos
+			if d < 0 {
+				d = -d
+			}
+			angle := d / (paddle2.bounds().Height/2 + ball.bounds().Height) * (75 * 2 * math.Pi / 360)
+			if ball.pos.Y < paddle2.pos {
+				angle = -angle
+			}
+			angle += math.Pi
+			speed := ballSpeed * (1 + 4*d/(paddle2.bounds().Height/2+ball.bounds().Height))
+			ball.velocity = rl.Vector2{X: speed * float32(math.Cos(float64(angle))), Y: speed * float32(math.Sin(float64(angle)))}
+		case ball.bounds().right() <= paddle1.bounds().X:
+			aiScore++
+			ball.reset(right)
+		case ball.bounds().X >= paddle2.bounds().X:
+			playerScore++
+			ball.reset(left)
+		case ball.bounds().Y <= 0 || ball.bounds().bottom() >= screenHeight:
+			ball.velocity.Y = -ball.velocity.Y
+			rl.PlaySound(ping)
+		}
+
+		rl.BeginDrawing()
+
+		rl.ClearBackground(rl.Black)
+		rl.DrawLine(screenWidth/2, 0, screenWidth/2, screenHeight, rl.Gray)
+
+		paddle1.bounds().draw(rl.RayWhite)
+		paddle2.bounds().draw(rl.RayWhite)
+		ball.bounds().draw(rl.RayWhite)
+
+		const fontSize = 120
+		rl.DrawText(strconv.Itoa(playerScore), int32(paddle1.bounds().X)+20, 30, fontSize, rl.RayWhite)
+		rl.DrawText(strconv.Itoa(aiScore), int32(paddle2.bounds().X)-rl.MeasureText("9999", fontSize), 30, fontSize, rl.RayWhite)
+
+		rl.EndDrawing()
+	}
+}