Revert "examples/audiopanning: Bug fix: Out of range at reading bytes"

This reverts commit cf2fc7a998.

Reason: Calling UnreadByte twice is illegal

Updates #1598
This commit is contained in:
Hajime Hoshi 2021-04-20 00:21:27 +09:00
parent cf2fc7a998
commit e5c70f8ae6

View File

@ -17,7 +17,6 @@
package main
import (
"bufio"
"bytes"
"fmt"
"image"
@ -144,28 +143,16 @@ func main() {
// StereoPanStream is an audio buffer that changes the stereo channel's signal
// based on the Panning.
type StereoPanStream struct {
src *bufio.Reader
io.ReadSeeker
pan float64 // -1: left; 0: center; 1: right
}
func (s *StereoPanStream) Read(p []byte) (n int, err error) {
n, err = s.src.Read(p)
if err != nil && err != io.EOF {
n, err = s.ReadSeeker.Read(p)
if err != nil {
return
}
// Align the read size to multiples of 4.
extra := n - n/4*4
for i := 0; i < extra; i++ {
if err := s.src.UnreadByte(); err != nil {
return 0, err
}
if err == io.EOF {
err = nil
}
}
n -= extra
// This implementation uses a linear scale, ranging from -1 to 1, for stereo or mono sounds.
// If pan = 0.0, the balance for the sound in each speaker is at 100% left and 100% right.
// When pan is -1.0, only the left channel of the stereo sound is audible, when pan is 1.0,
@ -173,7 +160,7 @@ func (s *StereoPanStream) Read(p []byte) (n int, err error) {
// https://docs.unity3d.com/ScriptReference/AudioSource-panStereo.html
ls := math.Min(s.pan*-1+1, 1)
rs := math.Min(s.pan+1, 1)
for i := 0; i < n; i += 4 {
for i := 0; i < len(p); i += 4 {
lc := int16(float64(int16(p[i])|int16(p[i+1])<<8) * ls)
rc := int16(float64(int16(p[i+2])|int16(p[i+3])<<8) * rs)
@ -198,8 +185,8 @@ func (s *StereoPanStream) Pan() float64 {
// The src's format must be linear PCM (16bits little endian, 2 channel stereo)
// without a header (e.g. RIFF header). The sample rate must be same as that
// of the audio context.
func NewStereoPanStreamFromReader(src io.Reader) *StereoPanStream {
func NewStereoPanStreamFromReader(src io.ReadSeeker) *StereoPanStream {
return &StereoPanStream{
src: bufio.NewReader(src),
ReadSeeker: src,
}
}