audio: Add a mock implementation for MonoGame

Updates #1078

audio/context.go

@@ -18,8 +18,6 @@ import (
 	"io"
 	"sync"
 
-	"github.com/hajimehoshi/oto"
-
 	"github.com/hajimehoshi/ebiten/internal/hooks"
 )
 
@@ -30,69 +28,6 @@ type context interface {
 
 var contextForTesting context
 
-type otoContext struct {
-	sampleRate int
-	initCh     <-chan struct{}
-
-	c    *oto.Context
-	once sync.Once
-}
-
-func (c *otoContext) NewPlayer() io.WriteCloser {
-	return &otoPlayer{c: c}
-}
-
-func (c *otoContext) Close() error {
-	if c.c == nil {
-		return nil
-	}
-	return c.c.Close()
-}
-
-func (c *otoContext) ensureContext() error {
-	var err error
-	c.once.Do(func() {
-		<-c.initCh
-		c.c, err = oto.NewContext(c.sampleRate, channelNum, bytesPerSample/channelNum, bufferSize())
-	})
-	return err
-}
-
-type otoPlayer struct {
-	c    *otoContext
-	p    *oto.Player
-	once sync.Once
-}
-
-func (p *otoPlayer) Write(buf []byte) (int, error) {
-	// Initialize oto.Player lazily to enable calling NewContext in an 'init' function.
-	// Accessing oto.Player functions requires the environment to be already initialized,
-	// but if Ebiten is used for a shared library, the timing when init functions are called
-	// is unexpectable.
-	// e.g. a variable for JVM on Android might not be set.
-	if err := p.ensurePlayer(); err != nil {
-		return 0, err
-	}
-	return p.p.Write(buf)
-}
-
-func (p *otoPlayer) Close() error {
-	if p.p == nil {
-		return nil
-	}
-	return p.p.Close()
-}
-
-func (p *otoPlayer) ensurePlayer() error {
-	if err := p.c.ensureContext(); err != nil {
-		return err
-	}
-	p.once.Do(func() {
-		p.p = p.c.c.NewPlayer()
-	})
-	return nil
-}
-
 func newContext(sampleRate int) context {
 	if contextForTesting != nil {
 		return contextForTesting
@@ -106,10 +41,7 @@ func newContext(sampleRate int) context {
 		})
 		return nil
 	})
-	return &otoContext{
-		sampleRate: sampleRate,
-		initCh:     ch,
-	}
+	return newContextImpl(sampleRate, ch)
 }
 
 type hook interface {

audio/contextimpl_monogame.go

@@ -0,0 +1,58 @@
+// Copyright 2020 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 monogame
+
+package audio
+
+import (
+	"io"
+	"time"
+)
+
+func newContextImpl(sampleRate int, initCh chan struct{}) context {
+	return &mockContext{
+		sampleRate: sampleRate,
+	}
+}
+
+type mockContext struct {
+	sampleRate int
+}
+
+func (*mockContext) Close() error {
+	return nil
+}
+
+func (m *mockContext) NewPlayer() io.WriteCloser {
+	return &mockPlayer{
+		sampleRate: m.sampleRate,
+	}
+}
+
+type mockPlayer struct {
+	sampleRate int
+}
+
+func (m *mockPlayer) Write(bs []byte) (int, error) {
+	bytesPerSec := 4 * m.sampleRate
+
+	n := len(bs)
+	time.Sleep(time.Duration(n) * time.Second / time.Duration(bytesPerSec))
+	return n, nil
+}
+
+func (*mockPlayer) Close() error {
+	return nil
+}

audio/contextimpl_oto.go

@@ -0,0 +1,94 @@
+// Copyright 2020 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 !monogame
+
+package audio
+
+import (
+	"io"
+	"sync"
+
+	"github.com/hajimehoshi/oto"
+)
+
+func newContextImpl(sampleRate int, initCh chan struct{}) context {
+	return &otoContext{
+		sampleRate: sampleRate,
+		initCh:     initCh,
+	}
+}
+
+type otoContext struct {
+	sampleRate int
+	initCh     <-chan struct{}
+
+	c    *oto.Context
+	once sync.Once
+}
+
+func (c *otoContext) NewPlayer() io.WriteCloser {
+	return &otoPlayer{c: c}
+}
+
+func (c *otoContext) Close() error {
+	if c.c == nil {
+		return nil
+	}
+	return c.c.Close()
+}
+
+func (c *otoContext) ensureContext() error {
+	var err error
+	c.once.Do(func() {
+		<-c.initCh
+		c.c, err = oto.NewContext(c.sampleRate, channelNum, bytesPerSample/channelNum, bufferSize())
+	})
+	return err
+}
+
+type otoPlayer struct {
+	c    *otoContext
+	p    *oto.Player
+	once sync.Once
+}
+
+func (p *otoPlayer) Write(buf []byte) (int, error) {
+	// Initialize oto.Player lazily to enable calling NewContext in an 'init' function.
+	// Accessing oto.Player functions requires the environment to be already initialized,
+	// but if Ebiten is used for a shared library, the timing when init functions are called
+	// is unexpectable.
+	// e.g. a variable for JVM on Android might not be set.
+	if err := p.ensurePlayer(); err != nil {
+		return 0, err
+	}
+	return p.p.Write(buf)
+}
+
+func (p *otoPlayer) Close() error {
+	if p.p == nil {
+		return nil
+	}
+	return p.p.Close()
+}
+
+func (p *otoPlayer) ensurePlayer() error {
+	if err := p.c.ensureContext(); err != nil {
+		return err
+	}
+	p.once.Do(func() {
+		p.p = p.c.c.NewPlayer()
+	})
+	return nil
+}