mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-14 06:57:27 +01:00
278 lines
9.3 KiB
HTML
278 lines
9.3 KiB
HTML
<!DOCTYPE html>
|
|
<meta charset="utf-8">
|
|
<meta property="og:image" itemprop="image primaryImageOfPage" content="https://hajimehoshi.github.io/ebiten/images/examples/piano.png">
|
|
<meta name="description" content="Ebiten example - piano">
|
|
<link rel="shortcut icon" href="../favicon.png" type="image/png" >
|
|
<link rel="icon" href="../favicon.png" type="image/png" >
|
|
<title>Ebiten example - piano</title>
|
|
|
|
<link rel="stylesheet" href="../stylesheets/bootstrap.min.css">
|
|
<link rel="stylesheet" href="../stylesheets/highlight-github.css">
|
|
<link rel="stylesheet" href="../stylesheets/ebiten.css">
|
|
<script src="../scripts/googleanalytics.js"></script>
|
|
|
|
<nav class="navbar"><div class="container">
|
|
<nav class="d-flex flex-row" style="width: 100%;">
|
|
<div class="nav mr-auto"><a class="navbar-brand" href="../"><img src="../images/logo_white.svg" alt="EBITEN"></a></div>
|
|
<ul class="nav">
|
|
<li class="nav-item"><a class="nav-link" href="https://github.com/hajimehoshi/ebiten">GitHub</a></li>
|
|
<li class="nav-item"><a class="nav-link" href="https://godoc.org/github.com/hajimehoshi/ebiten">GoDoc</a></li>
|
|
<li class="nav-item"><a class="nav-link" href="https://github.com/hajimehoshi/ebiten/wiki">Wiki</a>
|
|
<li class="nav-item"><a class="nav-link" href="https://ebiten-playground.github.io/">Playground</a>
|
|
</ul>
|
|
</nav>
|
|
</div></nav>
|
|
|
|
<main><div class="container">
|
|
|
|
<h2>Ebiten example - piano</h2>
|
|
<iframe src="piano.content.html" width="640" height="480"></iframe>
|
|
<div class="card"><pre class="card-body"><code class="language-go">// +build example
|
|
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"image/color"
|
|
"io/ioutil"
|
|
"log"
|
|
"math"
|
|
|
|
"github.com/golang/freetype/truetype"
|
|
"golang.org/x/image/font"
|
|
|
|
"github.com/hajimehoshi/ebiten"
|
|
"github.com/hajimehoshi/ebiten/audio"
|
|
"github.com/hajimehoshi/ebiten/ebitenutil"
|
|
"github.com/hajimehoshi/ebiten/inpututil"
|
|
"github.com/hajimehoshi/ebiten/text"
|
|
)
|
|
|
|
var (
|
|
arcadeFont font.Face
|
|
)
|
|
|
|
func init() {
|
|
f, err := ebitenutil.OpenFile("_resources/fonts/arcade_n.ttf")
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
defer f.Close()
|
|
|
|
b, err := ioutil.ReadAll(f)
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
|
|
tt, err := truetype.Parse(b)
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
|
|
const (
|
|
arcadeFontSize = 8
|
|
dpi = 72
|
|
)
|
|
arcadeFont = truetype.NewFace(tt, &truetype.Options{
|
|
Size: arcadeFontSize,
|
|
DPI: dpi,
|
|
Hinting: font.HintingFull,
|
|
})
|
|
}
|
|
|
|
const (
|
|
screenWidth = 320
|
|
screenHeight = 240
|
|
sampleRate = 44100
|
|
baseFreq = 220
|
|
)
|
|
|
|
var audioContext *audio.Context
|
|
|
|
func init() {
|
|
var err error
|
|
audioContext, err = audio.NewContext(sampleRate)
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
}
|
|
|
|
// pianoAt returns an i-th sample of piano with the given frequency.
|
|
func pianoAt(i int, freq float64) float64 {
|
|
// Create piano-like waves with multiple sin waves.
|
|
amp := []float64{1.0, 0.8, 0.6, 0.4, 0.2}
|
|
x := []float64{4.0, 2.0, 1.0, 0.5, 0.25}
|
|
v := 0.0
|
|
for j := 0; j < len(amp); j++ {
|
|
// Decay
|
|
a := amp[j] * math.Exp(-5*float64(i)*freq/baseFreq/(x[j]*sampleRate))
|
|
v += a * math.Sin(2.0*math.Pi*float64(i)*freq*float64(j+1)/sampleRate)
|
|
}
|
|
return v / 5.0
|
|
}
|
|
|
|
// toBytes returns the 2ch little endian 16bit byte sequence with the given left/right sequence.
|
|
func toBytes(l, r []int16) []byte {
|
|
if len(l) != len(r) {
|
|
panic("len(l) must equal to len(r)")
|
|
}
|
|
b := make([]byte, len(l)*4)
|
|
for i := range l {
|
|
b[4*i] = byte(l[i])
|
|
b[4*i+1] = byte(l[i] >> 8)
|
|
b[4*i+2] = byte(r[i])
|
|
b[4*i+3] = byte(r[i] >> 8)
|
|
}
|
|
return b
|
|
}
|
|
|
|
var (
|
|
pianoNoteSamples = map[int][]byte{}
|
|
pianoNoteSamplesInited = false
|
|
pianoNoteSamplesInitCh = make(chan struct{})
|
|
)
|
|
|
|
func init() {
|
|
// Initialize piano data.
|
|
// This takes a little long time (especially on browsers),
|
|
// so run this asynchronously and notice the progress.
|
|
go func() {
|
|
// Create a reference data and use this for other frequency.
|
|
const refFreq = 110
|
|
length := 4 * sampleRate * baseFreq / refFreq
|
|
refData := make([]int16, length)
|
|
for i := 0; i < length; i++ {
|
|
refData[i] = int16(pianoAt(i, refFreq) * math.MaxInt16)
|
|
}
|
|
|
|
for i := range keys {
|
|
freq := baseFreq * math.Exp2(float64(i-1)/12.0)
|
|
|
|
// Clculate the wave data for the freq.
|
|
length := 4 * sampleRate * baseFreq / int(freq)
|
|
l := make([]int16, length)
|
|
r := make([]int16, length)
|
|
for i := 0; i < length; i++ {
|
|
idx := int(float64(i) * freq / refFreq)
|
|
if len(refData) <= idx {
|
|
break
|
|
}
|
|
l[i] = refData[idx]
|
|
}
|
|
copy(r, l)
|
|
n := toBytes(l, r)
|
|
pianoNoteSamples[int(freq)] = n
|
|
}
|
|
close(pianoNoteSamplesInitCh)
|
|
}()
|
|
}
|
|
|
|
// playNote plays piano sound with the given frequency.
|
|
func playNote(freq float64) {
|
|
f := int(freq)
|
|
p, _ := audio.NewPlayerFromBytes(audioContext, pianoNoteSamples[f])
|
|
p.Play()
|
|
}
|
|
|
|
var (
|
|
pianoImage *ebiten.Image
|
|
)
|
|
|
|
func init() {
|
|
pianoImage, _ = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterDefault)
|
|
|
|
const (
|
|
keyWidth = 24
|
|
y = 48
|
|
)
|
|
|
|
whiteKeys := []string{"A", "S", "D", "F", "G", "H", "J", "K", "L"}
|
|
for i, k := range whiteKeys {
|
|
x := i*keyWidth + 36
|
|
height := 112
|
|
ebitenutil.DrawRect(pianoImage, float64(x), float64(y), float64(keyWidth-1), float64(height), color.White)
|
|
text.Draw(pianoImage, k, arcadeFont, x+8, y+height-8, color.Black)
|
|
}
|
|
|
|
blackKeys := []string{"Q", "W", "", "R", "T", "", "U", "I", "O"}
|
|
for i, k := range blackKeys {
|
|
if k == "" {
|
|
continue
|
|
}
|
|
x := i*keyWidth + 24
|
|
height := 64
|
|
ebitenutil.DrawRect(pianoImage, float64(x), float64(y), float64(keyWidth-1), float64(height), color.Black)
|
|
text.Draw(pianoImage, k, arcadeFont, x+8, y+height-8, color.White)
|
|
}
|
|
}
|
|
|
|
var (
|
|
keys = []ebiten.Key{
|
|
ebiten.KeyQ,
|
|
ebiten.KeyA,
|
|
ebiten.KeyW,
|
|
ebiten.KeyS,
|
|
ebiten.KeyD,
|
|
ebiten.KeyR,
|
|
ebiten.KeyF,
|
|
ebiten.KeyT,
|
|
ebiten.KeyG,
|
|
ebiten.KeyH,
|
|
ebiten.KeyU,
|
|
ebiten.KeyJ,
|
|
ebiten.KeyI,
|
|
ebiten.KeyK,
|
|
ebiten.KeyO,
|
|
ebiten.KeyL,
|
|
}
|
|
)
|
|
|
|
func update(screen *ebiten.Image) error {
|
|
// The piano data is still being initialized.
|
|
// Get the progress if available.
|
|
if !pianoNoteSamplesInited {
|
|
select {
|
|
case <-pianoNoteSamplesInitCh:
|
|
pianoNoteSamplesInited = true
|
|
default:
|
|
}
|
|
}
|
|
|
|
if pianoNoteSamplesInited {
|
|
for i, key := range keys {
|
|
if !inpututil.IsKeyJustPressed(key) {
|
|
continue
|
|
}
|
|
playNote(baseFreq * math.Exp2(float64(i-1)/12.0))
|
|
}
|
|
}
|
|
|
|
if ebiten.IsRunningSlowly() {
|
|
return nil
|
|
}
|
|
|
|
screen.Fill(color.RGBA{0x80, 0x80, 0xc0, 0xff})
|
|
screen.DrawImage(pianoImage, nil)
|
|
|
|
ebitenutil.DebugPrint(screen, fmt.Sprintf("FPS: %0.2f", ebiten.CurrentFPS()))
|
|
return nil
|
|
}
|
|
|
|
func main() {
|
|
if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Piano (Ebiten Demo)"); err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
}
|
|
</code></pre></div>
|
|
|
|
</div></main>
|
|
|
|
<footer><div class="container">
|
|
<p>© 2013 Hajime Hoshi</p>
|
|
<p>Code is licensed under <a href="https://github.com/hajimehoshi/ebiten/blob/master/LICENSE">the Apache License 2.0</a>.</p>
|
|
<p>The content of this page is licensed under <a href="https://creativecommons.org/licenses/by/4.0/">the Creative Commons Attribution 4.0 License</a>.</p>
|
|
</div></footer>
|
|
|
|
<script src="../scripts/highlight.pack.js"></script>
|
|
<script>hljs.initHighlightingOnLoad();</script>
|