jsutil: Refactoring: SliceToTypedArray -> CopySliceToJS

This unifieslocations of the temporary buffer.

audio/mp3/decode_gopherjs.go

@@ -27,7 +27,6 @@ import (
 	"time"
 
 	"github.com/hajimehoshi/ebiten/audio"
-	"github.com/hajimehoshi/ebiten/internal/jsutil"
 )
 
 // TODO: This just uses decodeAudioData, that can treat audio files other than MP3.
@@ -176,9 +175,9 @@ func init() {
 
 func float32ArrayToSlice(arr js.Value) []float32 {
 	f := make([]float32, arr.Length())
-	a, free := jsutil.SliceToTypedArray(f)
+	a := js.TypedArrayOf(f)
 	a.Call("set", arr)
-	free()
+	a.Release()
 	return f
 }
 
@@ -197,7 +196,8 @@ func decode(context *audio.Context, buf []byte, try int) (*Stream, error) {
 	// TODO: 1 is a correct second argument?
 	oc := offlineAudioContextClass.New(2, 1, context.SampleRate())
 
-	u8, free := jsutil.SliceToTypedArray(buf)
+	u8 := js.TypedArrayOf(buf)
+	defer u8.Release()
 	a := u8.Get("buffer").Call("slice", u8.Get("byteOffset"), u8.Get("byteOffset").Int()+u8.Get("byteLength").Int())
 
 	succeeded := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
@@ -231,7 +231,6 @@ func decode(context *audio.Context, buf []byte, try int) (*Stream, error) {
 	defer failed.Release()
 
 	oc.Call("decodeAudioData", a, succeeded, failed)
-	free()
 
 	timeout := time.Duration(math.Pow(2, float64(try))) * time.Second
 	t := time.NewTimer(timeout)

audio/vorbis/internal/stb/decode.go

@@ -20,8 +20,6 @@ import (
 	"fmt"
 	"io"
 	"syscall/js"
-
-	"github.com/hajimehoshi/ebiten/internal/jsutil"
 )
 
 var flatten = js.Global().Get("window").Call("eval", `(function(arr) {
@@ -121,9 +119,9 @@ func DecodeVorbis(buf []byte) (*Samples, int, int, error) {
 		}
 
 		s := make([]float32, flattened.Length())
-		arr, free := jsutil.SliceToTypedArray(s)
+		arr := js.TypedArrayOf(s)
 		arr.Call("set", flattened)
-		free()
+		arr.Release()
 
 		samples.samples = append(samples.samples, s)
 		samples.lengthInSamples += int64(len(s)) / int64(samples.channels)
@@ -131,9 +129,9 @@ func DecodeVorbis(buf []byte) (*Samples, int, int, error) {
 	})
 	defer f.Release()
 
-	arr, free := jsutil.SliceToTypedArray(buf)
+	arr := js.TypedArrayOf(buf)
 	js.Global().Get("stbvorbis").Call("decode", arr, f)
-	free()
+	arr.Release()
 
 	if err := <-ch; err != nil {
 		return nil, 0, 0, err

internal/graphicsdriver/opengl/context_js.go

@@ -90,11 +90,6 @@ var (
 	unsignedShort       = contextPrototype.Get("UNSIGNED_SHORT")
 )
 
-// temporaryBuffer is a temporary buffer used at gl.readPixels.
-// The read data is converted to Go's byte slice as soon as possible.
-// To avoid often allocating ArrayBuffer, reuse the buffer whenever possible.
-var temporaryBuffer = js.Global().Get("ArrayBuffer").New(16)
-
 type contextImpl struct {
 	gl            js.Value
 	lastProgramID programID
@@ -196,14 +191,7 @@ func (c *context) framebufferPixels(f *framebuffer, width, height int) ([]byte,
 
 	c.bindFramebuffer(f.native)
 
-	l := 4 * width * height
+	p := jsutil.TemporaryUint8Array(4 * width * height)
-	if bufl := temporaryBuffer.Get("byteLength").Int(); bufl < l {
-		for bufl < l {
-			bufl *= 2
-		}
-		temporaryBuffer = js.Global().Get("ArrayBuffer").New(bufl)
-	}
-	p := js.Global().Get("Uint8Array").New(temporaryBuffer, 0, l)
 	gl.Call("readPixels", 0, 0, width, height, rgba, unsignedByte, p)
 
 	return jsutil.Uint8ArrayToSlice(p), nil
@@ -240,9 +228,9 @@ func (c *context) texSubImage2D(t textureNative, pixels []byte, x, y, width, hei
 	// void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
 	//                    GLsizei width, GLsizei height,
 	//                    GLenum format, GLenum type, ArrayBufferView? pixels);
-	p, free := jsutil.SliceToTypedArray(pixels)
+	arr := jsutil.TemporaryUint8Array(len(pixels))
-	gl.Call("texSubImage2D", texture2d, 0, x, y, width, height, rgba, unsignedByte, p)
+	jsutil.CopySliceToJS(arr, pixels)
-	free()
+	gl.Call("texSubImage2D", texture2d, 0, x, y, width, height, rgba, unsignedByte, arr)
 }
 
 func (c *context) newFramebuffer(t textureNative) (framebufferNative, error) {
@@ -380,9 +368,10 @@ func (c *context) uniformFloats(p program, location string, v []float32) {
 	case 4:
 		gl.Call("uniform4f", js.Value(l), v[0], v[1], v[2], v[3])
 	case 16:
-		arr, free := jsutil.SliceToTypedArray(v)
+		arr8 := jsutil.TemporaryUint8Array(len(v) * 4)
+		arr := js.Global().Get("Float32Array").New(arr8.Get("buffer"), arr8.Get("byteOffset"), len(v))
+		jsutil.CopySliceToJS(arr, v)
 		gl.Call("uniformMatrix4fv", js.Value(l), false, arr)
-		free()
 	default:
 		panic(fmt.Sprintf("opengl: invalid uniform floats num: %d", len(v)))
 	}
@@ -433,17 +422,19 @@ func (c *context) bindBuffer(bufferType bufferType, b buffer) {
 func (c *context) arrayBufferSubData(data []float32) {
 	c.ensureGL()
 	gl := c.gl
-	arr, free := jsutil.SliceToTypedArray(data)
+	arr8 := jsutil.TemporaryUint8Array(len(data) * 4)
+	arr := js.Global().Get("Float32Array").New(arr8.Get("buffer"), arr8.Get("byteOffset"), len(data))
+	jsutil.CopySliceToJS(arr, data)
 	gl.Call("bufferSubData", int(arrayBuffer), 0, arr)
-	free()
 }
 
 func (c *context) elementArrayBufferSubData(data []uint16) {
 	c.ensureGL()
 	gl := c.gl
-	arr, free := jsutil.SliceToTypedArray(data)
+	arr8 := jsutil.TemporaryUint8Array(len(data) * 2)
+	arr := js.Global().Get("Uint16Array").New(arr8.Get("buffer"), arr8.Get("byteOffset"), len(data))
+	jsutil.CopySliceToJS(arr, data)
 	gl.Call("bufferSubData", int(elementArrayBuffer), 0, arr)
-	free()
 }
 
 func (c *context) deleteBuffer(b buffer) {

internal/jsutil/buf_js.go

@@ -0,0 +1,34 @@
+// Copyright 2019 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 jsutil
+
+import (
+	"syscall/js"
+)
+
+// temporaryBuffer is a temporary buffer used at gl.readPixels.
+// The read data is converted to Go's byte slice as soon as possible.
+// To avoid often allocating ArrayBuffer, reuse the buffer whenever possible.
+var temporaryBuffer = js.Global().Get("ArrayBuffer").New(16)
+
+func TemporaryUint8Array(byteLength int) js.Value {
+	if bufl := temporaryBuffer.Get("byteLength").Int(); bufl < byteLength {
+		for bufl < byteLength {
+			bufl *= 2
+		}
+		temporaryBuffer = js.Global().Get("ArrayBuffer").New(bufl)
+	}
+	return js.Global().Get("Uint8Array").New(temporaryBuffer, 0, byteLength)
+}

internal/jsutil/go112_js.go

@@ -35,10 +35,11 @@ func ArrayBufferToSlice(value js.Value) []byte {
 	return Uint8ArrayToSlice(js.Global().Get("Uint8Array").New(value))
 }
 
-func SliceToTypedArray(s interface{}) (js.Value, func()) {
+func CopySliceToJS(dst js.Value, src interface{}) {
 	// Note that TypedArrayOf cannot work correcly on Wasm.
 	// See https://github.com/golang/go/issues/31980
 
-	a := js.TypedArrayOf(s)
+	a := js.TypedArrayOf(src)
-	return a.Value, func() { a.Release() }
+	dst.Call("set", a)
+	a.Release()
 }

internal/jsutil/go113_js.go

@@ -96,60 +96,14 @@ func sliceToByteSlice(s interface{}) (bs []byte) {
 	return
 }
 
-var temporaryBuffer = js.Global().Get("ArrayBuffer").New(16)
+func CopySliceToJS(dst js.Value, src interface{}) {
-
+	switch s := src.(type) {
-func getTemporaryUint8Array(size int) js.Value {
-	if l := temporaryBuffer.Get("byteLength").Int(); l < size {
-		for l < size {
-			l *= 2
-		}
-		temporaryBuffer = js.Global().Get("ArrayBuffer").New(l)
-	}
-	return js.Global().Get("Uint8Array").New(temporaryBuffer, 0, size)
-}
-
-func SliceToTypedArray(s interface{}) (js.Value, func()) {
-	switch s := s.(type) {
-	case []int8:
-		a := getTemporaryUint8Array(len(s))
-		js.CopyBytesToJS(a, sliceToByteSlice(s))
-		buf := a.Get("buffer")
-		return js.Global().Get("Int8Array").New(buf, a.Get("byteOffset"), a.Get("byteLength")), func() {}
-	case []int16:
-		a := getTemporaryUint8Array(len(s) * 2)
-		js.CopyBytesToJS(a, sliceToByteSlice(s))
-		buf := a.Get("buffer")
-		return js.Global().Get("Int16Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/2), func() {}
-	case []int32:
-		a := getTemporaryUint8Array(len(s) * 4)
-		js.CopyBytesToJS(a, sliceToByteSlice(s))
-		buf := a.Get("buffer")
-		return js.Global().Get("Int32Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/4), func() {}
 	case []uint8:
-		a := getTemporaryUint8Array(len(s))
+		js.CopyBytesToJS(dst, s)
-		js.CopyBytesToJS(a, s)
+	case []int8, []int16, []int32, []uint16, []uint32, []float32, []float64:
-		return a, func() {}
+		a := js.Global().Get("Uint8Array").New(dst.Get("buffer"), dst.Get("byteOffset"), dst.Get("byteLength"))
-	case []uint16:
-		a := getTemporaryUint8Array(len(s) * 2)
 		js.CopyBytesToJS(a, sliceToByteSlice(s))
-		buf := a.Get("buffer")
-		return js.Global().Get("Uint16Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/2), func() {}
-	case []uint32:
-		a := getTemporaryUint8Array(len(s) * 4)
-		js.CopyBytesToJS(a, sliceToByteSlice(s))
-		buf := a.Get("buffer")
-		return js.Global().Get("Uint32Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/4), func() {}
-	case []float32:
-		a := getTemporaryUint8Array(len(s) * 4)
-		js.CopyBytesToJS(a, sliceToByteSlice(s))
-		buf := a.Get("buffer")
-		return js.Global().Get("Float32Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/4), func() {}
-	case []float64:
-		a := getTemporaryUint8Array(len(s) * 8)
-		js.CopyBytesToJS(a, sliceToByteSlice(s))
-		buf := a.Get("buffer")
-		return js.Global().Get("Float64Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/8), func() {}
 	default:
-		panic(fmt.Sprintf("jsutil: unexpected value at SliceToTypedArray: %T", s))
+		panic(fmt.Sprintf("jsutil: unexpected value at CopySliceToJS: %T", s))
 	}
 }

internal/jsutil/jsutil_test.go

@@ -27,7 +27,7 @@ func TestArrayBufferToSlice(t *testing.T) {
 	// TODO
 }
 
-func TestSliceToTypedArray(t *testing.T) {
+func TestCopySliceToJS(t *testing.T) {
 	tests := []struct {
 		in  interface{}
 		out js.Value
@@ -66,12 +66,9 @@ func TestSliceToTypedArray(t *testing.T) {
 		},
 	}
 	for _, test := range tests {
-		got, free := SliceToTypedArray(test.in)
+		got := test.out.Get("constructor").New(test.out.Get("length"))
-		defer free()
+		CopySliceToJS(got, test.in)
 		want := test.out
-		if got.Get("constructor") != want.Get("constructor") {
-			t.Errorf("class: got: %s, want: %s", got.Get("constructor").Get("name"), want.Get("constructor").Get("name"))
-		}
 		if got.Length() != want.Length() {
 			t.Errorf("length: got: %d, want: %d", got.Length(), want.Length())
 		}