mirror of
https://github.com/hajimehoshi/ebiten.git
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2aa79e0aa4
Building `syscall/js` itself can be done only under 'js' environment. See also https://travis-ci.org/hajimehoshi/ebiten/builds/526786060
140 lines
3.1 KiB
Go
140 lines
3.1 KiB
Go
// Copyright 2018 The Ebiten Authors
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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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package stb
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import (
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"fmt"
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"io"
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"syscall/js"
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)
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var flatten = js.Global().Get("window").Call("eval", `(function(arr) {
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var ch = arr.length;
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var len = arr[0].length;
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var result = new Float32Array(ch * len);
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for (var j = 0; j < len; j++) {
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for (var i = 0; i < ch; i++) {
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result[j*ch+i] = arr[i][j];
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}
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}
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return result;
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})`)
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func init() {
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// Eval wasm.js first to set the Wasm binary to Module.
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js.Global().Get("window").Call("eval", string(stbvorbis_js))
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}
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type Samples struct {
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samples [][]float32
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channels int
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lengthInSamples int64
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posInSamples int64
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}
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func (s *Samples) Read(buf []float32) (int, error) {
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if s.posInSamples == s.lengthInSamples {
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return 0, io.EOF
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}
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if len(buf) == 0 {
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return 0, nil
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}
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var p int64
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idx := 0
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for idx < len(s.samples) {
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l := int64(len(s.samples[idx])) / int64(s.channels)
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if p+l > s.posInSamples {
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break
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}
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p += l
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idx++
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}
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start := (s.posInSamples - p) * int64(s.channels)
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if start == int64(len(s.samples[idx])) {
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idx++
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start = 0
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}
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if len(s.samples[idx]) == 0 {
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panic(fmt.Sprintf("stb: len(samples[%d]) must be > 0", idx))
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}
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n := copy(buf, s.samples[idx][start:])
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s.posInSamples += int64(n) / int64(s.channels)
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return n, nil
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}
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func (s *Samples) Length() int64 {
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return s.lengthInSamples
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}
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func (s *Samples) SetPosition(pos int64) error {
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s.posInSamples = pos
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return nil
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}
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func DecodeVorbis(buf []byte) (*Samples, int, int, error) {
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ch := make(chan error)
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samples := &Samples{}
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sampleRate := 0
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f := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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r := args[0]
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if e := r.Get("error"); e != js.Null() {
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ch <- fmt.Errorf("audio/vorbis/internal/stb: decode error: %s", e.String())
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close(ch)
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return nil
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}
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if r.Get("eof").Bool() {
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close(ch)
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return nil
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}
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if samples.channels == 0 {
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samples.channels = r.Get("data").Length()
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}
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if sampleRate == 0 {
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sampleRate = r.Get("sampleRate").Int()
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}
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flattened := flatten.Invoke(r.Get("data"))
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if flattened.Length() == 0 {
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return nil
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}
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s := make([]float32, flattened.Length())
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arr := js.TypedArrayOf(s)
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arr.Call("set", flattened)
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arr.Release()
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samples.samples = append(samples.samples, s)
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samples.lengthInSamples += int64(len(s)) / int64(samples.channels)
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return nil
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})
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defer f.Release()
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arr := js.TypedArrayOf(buf)
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js.Global().Get("stbvorbis").Call("decode", arr, f)
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arr.Release()
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if err := <-ch; err != nil {
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return nil, 0, 0, err
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}
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return samples, samples.channels, sampleRate, nil
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}
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