mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 13:22:19 +02:00
106 lines
2.5 KiB
Go
106 lines
2.5 KiB
Go
// Copyright 2016 Hajime Hoshi
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// +build !js
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package vorbis
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import (
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"bytes"
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"errors"
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"fmt"
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"io"
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"math"
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"github.com/hajimehoshi/ebiten/audio"
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"github.com/jfreymuth/go-vorbis/ogg/vorbis"
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)
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// Stream is a decoded audio stream.
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type Stream struct {
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buf *bytes.Reader
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}
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func newStream(v *vorbis.Vorbis) (*Stream, error) {
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data := []byte{}
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// TODO: We can delay decoding.
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for {
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out, err := v.DecodePacket()
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if err == io.EOF {
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break
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}
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if err != nil {
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return nil, err
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}
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const channelNum = 2
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b := make([]byte, len(out[0])*2*channelNum)
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for i := 0; i < len(out[0]); i++ {
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vv := int16(out[0][i] * math.MaxInt16)
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b[4*i] = byte(vv)
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b[4*i+1] = byte(vv >> 8)
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vv = int16(out[1][i] * math.MaxInt16)
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b[4*i+2] = byte(vv)
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b[4*i+3] = byte(vv >> 8)
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}
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data = append(data, b...)
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}
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s := &Stream{
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buf: bytes.NewReader(data),
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}
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return s, nil
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}
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// Read is implementation of io.Reader's Read.
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func (s *Stream) Read(p []byte) (int, error) {
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return s.buf.Read(p)
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}
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// Seek is implementation of io.Seeker's Seek.
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func (s *Stream) Seek(offset int64, whence int) (int64, error) {
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return s.buf.Seek(offset, whence)
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}
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// Read is implementation of io.Closer's Close.
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func (s *Stream) Close() error {
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s.buf = nil
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return nil
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}
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// Size returns the size of decoded stream in bytes.
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func (s *Stream) Size() int64 {
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return s.buf.Size()
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}
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// Decode decodes Ogg/Vorbis data to playable stream.
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//
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// The sample rate must be same as that of audio context.
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func Decode(context *audio.Context, src audio.ReadSeekCloser) (*Stream, error) {
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v, err := vorbis.Open(src)
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if err != nil {
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return nil, err
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}
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// TODO: Remove this magic number
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if v.Channels() != 2 {
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return nil, errors.New("vorbis: number of channels must be 2")
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}
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if v.SampleRate() != context.SampleRate() {
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return nil, fmt.Errorf("vorbis: sample rate must be %d but %d", context.SampleRate(), v.SampleRate())
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}
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s, err := newStream(v)
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if err != nil {
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return nil, err
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}
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return s, nil
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}
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