ebiten/exp/audio/audio_windows.go
2016-04-03 02:43:39 +09:00

127 lines
3.1 KiB
Go

// Copyright 2015 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 audio
// #cgo LDFLAGS: -lwinmm
//
// #include <windows.h>
// #include <mmsystem.h>
//
// #define sizeOfWavehdr (sizeof(WAVEHDR))
//
// MMRESULT waveOutOpen2(HWAVEOUT* waveOut, WAVEFORMATEX* format);
import "C"
import (
"fmt"
"io"
"time"
"unsafe"
)
type header struct {
buffer unsafe.Pointer
bufferSize int
waveHdr C.WAVEHDR
}
// TODO: Reduce panics and use errors instead
func newHeader(waveOut C.HWAVEOUT, bufferSize int) header {
// NOTE: This is never freed so far.
buf := C.malloc(C.size_t(bufferSize))
h := header{
buffer: buf,
bufferSize: bufferSize,
waveHdr: C.WAVEHDR{
lpData: C.LPSTR(buf),
dwBufferLength: C.DWORD(bufferSize),
},
}
// TODO: Need to unprepare to avoid memory leak?
if err := C.waveOutPrepareHeader(waveOut, &h.waveHdr, C.sizeOfWavehdr); err != C.MMSYSERR_NOERROR {
panic(fmt.Sprintf("audio: waveOutPrepareHeader error %d", err))
}
return h
}
func (h *header) Write(waveOut C.HWAVEOUT, data []byte) {
if len(data) != h.bufferSize {
panic("audio: len(data) must equal to h.bufferSize")
}
C.memcpy(h.buffer, unsafe.Pointer(&data[0]), C.size_t(h.bufferSize))
if err := C.waveOutWrite(waveOut, &h.waveHdr, C.sizeOfWavehdr); err != C.MMSYSERR_NOERROR {
panic(fmt.Sprintf("audio: waveOutWriter error %d", err))
}
}
const numHeader = 8
var sem = make(chan struct{}, numHeader)
//export releaseSemaphore
func releaseSemaphore() {
<-sem
}
func startPlaying(src io.Reader, sampleRate int) error {
const numBlockAlign = channelNum * bitsPerSample / 8
f := C.WAVEFORMATEX{
wFormatTag: C.WAVE_FORMAT_PCM,
nChannels: channelNum,
nSamplesPerSec: C.DWORD(sampleRate),
nAvgBytesPerSec: C.DWORD(sampleRate) * numBlockAlign,
wBitsPerSample: bitsPerSample,
nBlockAlign: numBlockAlign,
}
var w C.HWAVEOUT
if err := C.waveOutOpen2(&w, &f); err != C.MMSYSERR_NOERROR {
return fmt.Errorf("audio: waveOutOpen error: %d", err)
}
go func() {
const bufferSize = 1024
b := []byte{}
bb := make([]byte, bufferSize)
headers := make([]header, numHeader)
for i := 0; i < numHeader; i++ {
headers[i] = newHeader(w, bufferSize)
}
i := 0
for {
n, err := src.Read(bb)
if 0 < n {
b = append(b, bb[:n]...)
for bufferSize <= len(b) {
sem <- struct{}{}
headers[i].Write(w, b[:bufferSize])
b = b[bufferSize:]
i++
i %= len(headers)
}
}
if err == io.EOF {
break
}
if err != nil {
// TODO: Propagate this error?
panic(err)
}
time.Sleep(1 * time.Millisecond)
}
// TODO: Finalize the wave handler
}()
return nil
}