audio/vorbis: Use stb_vorbis.c on browsers

This change adds a Ogg/Vorbis decoder stb_vorbis.c usage that is
compiled by Emscripten as WebAssembly.

Fixes #623

audio/vorbis/internal/stb/.gitignore

@@ -0,0 +1,4 @@
+*.wasm
+*.wasm.map
+*.wast
+

audio/vorbis/internal/stb/build.sh

@@ -0,0 +1,2 @@
+emcc -Os -o stbvorbis.js -g -DSTB_VORBIS_NO_STDIO -s WASM=1 -s EXPORTED_FUNCTIONS='["_stb_vorbis_decode_memory"]' -s EXTRA_EXPORTED_RUNTIME_METHODS='["ccall","cwrap"]' -s ALLOW_MEMORY_GROWTH=1 stb_vorbis.c
+go run genwasmjs.go < stbvorbis.wasm > wasm.js

audio/vorbis/internal/stb/decode.go

@@ -0,0 +1,47 @@
+// Copyright 2018 The Ebiten Authors
+//
+// 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 stb
+
+import (
+	"fmt"
+
+	"github.com/gopherjs/gopherwasm/js"
+)
+
+func init() {
+	// Eval wasm.js first to set the Wasm binary to Module.
+	js.Global().Get("window").Call("eval", string(wasm_js))
+
+	js.Global().Get("window").Call("eval", string(stbvorbis_js))
+	js.Global().Get("window").Call("eval", string(decode_js))
+
+	ch := make(chan struct{})
+	js.Global().Get("_ebiten").Call("initializeVorbisDecoder", js.NewCallback(func([]js.Value) {
+		close(ch)
+	}))
+	<-ch
+}
+
+func DecodeVorbis(buf []byte) ([]int16, int, int, error) {
+	r := js.Global().Get("_ebiten").Call("decodeVorbis", buf)
+	if r == js.Null() {
+		return nil, 0, 0, fmt.Errorf("audio/vorbis/internal/stb: decode failed")
+	}
+	data := make([]int16, r.Get("data").Get("length").Int())
+	// TODO: Use js.TypeArrayOf
+	arr := js.ValueOf(data)
+	arr.Call("set", r.Get("data"))
+	return data, r.Get("channels").Int(), r.Get("sampleRate").Int(), nil
+}

audio/vorbis/internal/stb/decode.js

@@ -0,0 +1,80 @@
+// Copyright 2018 The Ebiten Authors
+//
+// 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.
+
+var _ebiten = {};
+
+(() => {
+  var decodeMemory = null;
+  var vorbisDecoderInitialized = null;
+
+  _ebiten.initializeVorbisDecoder = (callback) => {
+    Module.run();
+    vorbisDecoderInitialized = callback;
+  };
+
+  Module.onRuntimeInitialized = () => {
+    decodeMemory = Module.cwrap('stb_vorbis_decode_memory', 'number', ['number', 'number', 'number', 'number', 'number']);
+    if (vorbisDecoderInitialized) {
+      vorbisDecoderInitialized();
+    }
+  }
+
+  function arrayToHeap(typedArray){
+    const ptr = Module._malloc(typedArray.byteLength);
+    const heapBytes = new Uint8Array(Module.HEAPU8.buffer, ptr, typedArray.byteLength);
+    heapBytes.set(new Uint8Array(typedArray.buffer, typedArray.byteOffset, typedArray.byteLength));
+    return heapBytes;
+  }
+
+  function ptrToInt32(ptr) {
+    const a = new Int32Array(Module.HEAPU8.buffer, ptr, 1);
+    return a[0];
+  }
+
+  function ptrToFloat32(ptr) {
+    const a = new Float32Array(Module.HEAPU8.buffer, ptr, 1);
+    return a[0];
+  }
+
+  function ptrToInt16s(ptr, length) {
+    const buf = new ArrayBuffer(length * Int16Array.BYTES_PER_ELEMENT);
+    const copied = new Int16Array(buf);
+    copied.set(new Int16Array(Module.HEAPU8.buffer, ptr, length));
+    return copied;
+  }
+
+  _ebiten.decodeVorbis = (buf) => {
+    const copiedBuf = arrayToHeap(buf);
+    const channelsPtr = Module._malloc(4);
+    const sampleRatePtr = Module._malloc(4);
+    const outputPtr = Module._malloc(4);
+    const length = decodeMemory(copiedBuf.byteOffset, copiedBuf.length, channelsPtr, sampleRatePtr, outputPtr);
+    if (length < 0) {
+      return null;
+    }
+    const channels = ptrToInt32(channelsPtr);
+    const result = {
+      data:       ptrToInt16s(ptrToInt32(outputPtr), length * channels),
+      channels:   channels,
+      sampleRate: ptrToInt32(sampleRatePtr),
+    };
+
+    Module._free(copiedBuf.byteOffset);
+    Module._free(channelsPtr);
+    Module._free(sampleRatePtr);
+    Module._free(ptrToInt32(outputPtr));
+    Module._free(outputPtr);
+    return result;
+  };
+})();

audio/vorbis/internal/stb/decodejs_file_js.go

@@ -0,0 +1,6 @@
+// Code generated by file2byteslice. DO NOT EDIT.
+// (gofmt is fine after generating)
+
+package stb
+
+var decode_js = []byte("// Copyright 2018 The Ebiten Authors\n//\n// Licensed under the Apache License, Version 2.0 (the \"License\");\n// you may not use this file except in compliance with the License.\n// You may obtain a copy of the License at\n//\n//     http://www.apache.org/licenses/LICENSE-2.0\n//\n// Unless required by applicable law or agreed to in writing, software\n// distributed under the License is distributed on an \"AS IS\" BASIS,\n// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n// See the License for the specific language governing permissions and\n// limitations under the License.\n\nvar _ebiten = {};\n\n(() => {\n  var decodeMemory = null;\n  var vorbisDecoderInitialized = null;\n\n  _ebiten.initializeVorbisDecoder = (callback) => {\n    Module.run();\n    vorbisDecoderInitialized = callback;\n  };\n\n  Module.onRuntimeInitialized = () => {\n    decodeMemory = Module.cwrap('stb_vorbis_decode_memory', 'number', ['number', 'number', 'number', 'number', 'number']);\n    if (vorbisDecoderInitialized) {\n      vorbisDecoderInitialized();\n    }\n  }\n\n  function arrayToHeap(typedArray){\n    const ptr = Module._malloc(typedArray.byteLength);\n    const heapBytes = new Uint8Array(Module.HEAPU8.buffer, ptr, typedArray.byteLength);\n    heapBytes.set(new Uint8Array(typedArray.buffer, typedArray.byteOffset, typedArray.byteLength));\n    return heapBytes;\n  }\n\n  function ptrToInt32(ptr) {\n    const a = new Int32Array(Module.HEAPU8.buffer, ptr, 1);\n    return a[0];\n  }\n\n  function ptrToFloat32(ptr) {\n    const a = new Float32Array(Module.HEAPU8.buffer, ptr, 1);\n    return a[0];\n  }\n\n  function ptrToInt16s(ptr, length) {\n    const buf = new ArrayBuffer(length * Int16Array.BYTES_PER_ELEMENT);\n    const copied = new Int16Array(buf);\n    copied.set(new Int16Array(Module.HEAPU8.buffer, ptr, length));\n    return copied;\n  }\n\n  _ebiten.decodeVorbis = (buf) => {\n    const copiedBuf = arrayToHeap(buf);\n    const channelsPtr = Module._malloc(4);\n    const sampleRatePtr = Module._malloc(4);\n    const outputPtr = Module._malloc(4);\n    const length = decodeMemory(copiedBuf.byteOffset, copiedBuf.length, channelsPtr, sampleRatePtr, outputPtr);\n    if (length < 0) {\n      return null;\n    }\n    const channels = ptrToInt32(channelsPtr);\n    const result = {\n      data:       ptrToInt16s(ptrToInt32(outputPtr), length * channels),\n      channels:   channels,\n      sampleRate: ptrToInt32(sampleRatePtr),\n    };\n\n    Module._free(copiedBuf.byteOffset);\n    Module._free(channelsPtr);\n    Module._free(sampleRatePtr);\n    Module._free(ptrToInt32(outputPtr));\n    Module._free(outputPtr);\n    return result;\n  };\n})();\n")

audio/vorbis/internal/stb/generate.go

@@ -0,0 +1,20 @@
+// Copyright 2018 The Ebiten Authors
+//
+// 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 stb
+
+//go:generate bash build.sh
+//go:generate file2byteslice -package=stb -input=decode.js -output=decodejs_file_js.go -var=decode_js
+//go:generate file2byteslice -package=stb -input=stbvorbis.js -output=stbvorbisjs_file_js.go -var=stbvorbis_js
+//go:generate file2byteslice -package=stb -input=wasm.js -output=wasmjs_file_js.go -var=wasm_js

audio/vorbis/internal/stb/genwasmjs.go

@@ -0,0 +1,43 @@
+// Copyright 2018 The Ebiten Authors
+//
+// 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.
+
+// +build ignore
+
+package main
+
+import (
+	"encoding/base64"
+	"fmt"
+	"io/ioutil"
+	"os"
+)
+
+func run() error {
+	bin, err := ioutil.ReadAll(os.Stdin)
+	if err != nil {
+		return err
+	}
+
+	fmt.Println("// Code generated by genwasmjs.go. DO NOT EDIT.")
+	fmt.Println("")
+	fmt.Println("var Module = typeof Module !== 'undefined' ? Module : {};")
+	fmt.Printf("Module['wasmBinary'] = Uint8Array.from(atob(%q), c => c.charCodeAt(0));\n", base64.StdEncoding.EncodeToString(bin))
+	return nil
+}
+
+func main() {
+	if err := run(); err != nil {
+		panic(err)
+	}
+}

audio/vorbis/vorbis.go

@@ -20,8 +20,6 @@ import (
 	"io"
 	"runtime"
 
-	"github.com/jfreymuth/oggvorbis"
-
 	"github.com/hajimehoshi/ebiten/audio"
 	"github.com/hajimehoshi/ebiten/audio/internal/convert"
 )
@@ -63,13 +61,20 @@ func (s *Stream) Size() int64 {
 	return s.Length()
 }
 
+type decoder interface {
+	Read([]float32) (int, error)
+	Length() int64
+	Channels() int
+	SampleRate() int
+}
+
 type decoded struct {
 	data       []float32
 	totalBytes int
 	readBytes  int
 	posInBytes int
 	source     io.Closer
-	decoder    *oggvorbis.Reader
+	decoder    decoder
 }
 
 func (d *decoded) readUntil(posInBytes int) error {
@@ -93,7 +98,6 @@ func (d *decoded) readUntil(posInBytes int) error {
 		if err != nil {
 			return err
 		}
-		runtime.Gosched()
 	}
 	return nil
 }
@@ -157,7 +161,7 @@ func (d *decoded) Length() int64 {
 
 // decode accepts an ogg stream and returns a decorded stream.
 func decode(in audio.ReadSeekCloser) (*decoded, int, int, error) {
-	r, err := oggvorbis.NewReader(in)
+	r, err := newDecoder(in)
 	if err != nil {
 		return nil, 0, 0, err
 	}

audio/vorbis/vorbis_js.go

@@ -0,0 +1,72 @@
+// Copyright 2018 The Ebiten Authors
+//
+// 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.
+
+// +build js
+
+package vorbis
+
+import (
+	"io"
+	"io/ioutil"
+
+	"github.com/hajimehoshi/ebiten/audio"
+	"github.com/hajimehoshi/ebiten/audio/vorbis/internal/stb"
+)
+
+type decoderImpl struct {
+	data       []int16
+	channels   int
+	sampleRate int
+}
+
+func (d *decoderImpl) Read(buf []float32) (int, error) {
+	if len(d.data) == 0 {
+		return 0, io.EOF
+	}
+
+	n := len(buf)
+	if n > len(d.data) {
+		n = len(d.data)
+	}
+	for i := 0; i < n; i++ {
+		buf[i] = float32(d.data[i]) / 32768
+	}
+	d.data = d.data[n:]
+	return n, nil
+}
+
+func (d *decoderImpl) Length() int64 {
+	return int64(len(d.data) / d.channels)
+}
+
+func (d *decoderImpl) Channels() int {
+	return d.channels
+}
+
+func (d *decoderImpl) SampleRate() int {
+	return d.sampleRate
+}
+
+func newDecoder(in audio.ReadSeekCloser) (decoder, error) {
+	buf, err := ioutil.ReadAll(in)
+	if err != nil {
+		return nil, err
+	}
+
+	data, channels, sampleRate, err := stb.DecodeVorbis(buf)
+	if err != nil {
+		return nil, err
+	}
+	return &decoderImpl{data, channels, sampleRate}, nil
+}

audio/vorbis/vorbis_notjs.go

@@ -0,0 +1,27 @@
+// Copyright 2018 The Ebiten Authors
+//
+// 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.
+
+// +build !js
+
+package vorbis
+
+import (
+	"github.com/jfreymuth/oggvorbis"
+
+	"github.com/hajimehoshi/ebiten/audio"
+)
+
+func newDecoder(in audio.ReadSeekCloser) (decoder, error) {
+	return oggvorbis.NewReader(in)
+}