mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 05:12:18 +02:00
125 lines
2.9 KiB
Go
125 lines
2.9 KiB
Go
// Copyright 2016 Hajime Hoshi
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"log"
|
|
"math"
|
|
|
|
"github.com/hajimehoshi/ebiten/v2"
|
|
"github.com/hajimehoshi/ebiten/v2/audio"
|
|
"github.com/hajimehoshi/ebiten/v2/ebitenutil"
|
|
)
|
|
|
|
const (
|
|
screenWidth = 640
|
|
screenHeight = 480
|
|
sampleRate = 48000
|
|
frequency = 440
|
|
)
|
|
|
|
// stream is an infinite stream of 440 Hz sine wave.
|
|
type stream struct {
|
|
position int64
|
|
remaining []byte
|
|
}
|
|
|
|
// Read is io.Reader's Read.
|
|
//
|
|
// Read fills the data with sine wave samples.
|
|
func (s *stream) Read(buf []byte) (int, error) {
|
|
if len(s.remaining) > 0 {
|
|
n := copy(buf, s.remaining)
|
|
s.remaining = s.remaining[n:]
|
|
return n, nil
|
|
}
|
|
|
|
var origBuf []byte
|
|
if len(buf)%8 > 0 {
|
|
origBuf = buf
|
|
buf = make([]byte, len(origBuf)+8-len(origBuf)%8)
|
|
}
|
|
|
|
const length = int64(sampleRate / frequency)
|
|
p := s.position / 8
|
|
for i := 0; i < len(buf)/8; i++ {
|
|
v := math.Float32bits(float32(math.Sin(2 * math.Pi * float64(p) / float64(length))))
|
|
buf[8*i] = byte(v)
|
|
buf[8*i+1] = byte(v >> 8)
|
|
buf[8*i+2] = byte(v >> 16)
|
|
buf[8*i+3] = byte(v >> 24)
|
|
buf[8*i+4] = byte(v)
|
|
buf[8*i+5] = byte(v >> 8)
|
|
buf[8*i+6] = byte(v >> 16)
|
|
buf[8*i+7] = byte(v >> 24)
|
|
p++
|
|
}
|
|
|
|
s.position += int64(len(buf))
|
|
s.position %= length * 8
|
|
|
|
if origBuf != nil {
|
|
n := copy(origBuf, buf)
|
|
s.remaining = buf[n:]
|
|
return n, nil
|
|
}
|
|
return len(buf), nil
|
|
}
|
|
|
|
// Close is io.Closer's Close.
|
|
func (s *stream) Close() error {
|
|
return nil
|
|
}
|
|
|
|
type Game struct {
|
|
audioContext *audio.Context
|
|
player *audio.Player
|
|
}
|
|
|
|
func (g *Game) Update() error {
|
|
if g.audioContext == nil {
|
|
g.audioContext = audio.NewContext(sampleRate)
|
|
}
|
|
if g.player == nil {
|
|
// Pass the (infinite) stream to NewPlayer.
|
|
// After calling Play, the stream never ends as long as the player object lives.
|
|
var err error
|
|
g.player, err = g.audioContext.NewPlayerF32(&stream{})
|
|
if err != nil {
|
|
return err
|
|
}
|
|
g.player.Play()
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (g *Game) Draw(screen *ebiten.Image) {
|
|
msg := fmt.Sprintf("TPS: %0.2f\nThis is an example using infinite audio stream.", ebiten.ActualTPS())
|
|
ebitenutil.DebugPrint(screen, msg)
|
|
}
|
|
|
|
func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
|
|
return screenWidth, screenHeight
|
|
}
|
|
|
|
func main() {
|
|
ebiten.SetWindowSize(screenWidth, screenHeight)
|
|
ebiten.SetWindowTitle("Sine Wave (Ebitengine Demo)")
|
|
if err := ebiten.RunGame(&Game{}); err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
}
|