Oto 1.0 driver for the Kinc library

driver_darwin.go

@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build !js
-// +build !js
+//go:build !js && !kinc
+// +build !js && !kinc
 
 package oto
 

driver_kinc.go

@@ -0,0 +1,119 @@
+// Copyright 2022 Sam Hocevar <[email protected]>
+//
+// 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.
+
+//go:build kinc
+// +build kinc
+
+package oto
+
+/*
+#include <kinc/audio2/audio.h>
+
+typedef void (*audio_callback_t)(kinc_a2_buffer_t *buffer, int samples);
+typedef void (*sample_rate_callback_t)(void);
+
+void audio_callback(kinc_a2_buffer_t *buffer, int samples);
+void sample_rate_callback(void);
+*/
+import "C"
+
+import (
+	"sync"
+	"unsafe"
+)
+
+const (
+	MaxBufferLength = 4096 // Max number of samples we want in the audio queue
+)
+
+type driver struct {
+	buf	[]int16
+	mutex	sync.Mutex
+}
+
+var gDriver *driver
+
+func (buffer *C.kinc_a2_buffer_t) SampleCount() int {
+	return int((buffer.write_location + buffer.data_size - buffer.read_location) % buffer.data_size) / 4
+}
+
+//export audio_callback
+func audio_callback(buffer *C.kinc_a2_buffer_t, samples int32) {
+	gDriver.mutex.Lock()
+	defer gDriver.mutex.Unlock()
+
+	// Protect against accessing gDriver.buf[0]
+	if len(gDriver.buf) == 0 {
+		return
+	}
+
+	// Bluntly drop data if our buffer is too full
+	if buffer.SampleCount() >= MaxBufferLength {
+		gDriver.buf = gDriver.buf[:]
+		return
+	}
+
+	dst := unsafe.Slice((*float32)(unsafe.Pointer(buffer.data)), int(buffer.data_size) / 4)
+	for i := 0; i < int(samples); i++ {
+		if i < len(gDriver.buf) {
+			dst[buffer.write_location / 4] = float32(gDriver.buf[i]) / 32768
+		} else {
+			dst[buffer.write_location / 4] = 0
+		}
+
+		buffer.write_location += 4
+		if buffer.write_location >= buffer.data_size {
+			buffer.write_location = 0
+		}
+	}
+	gDriver.buf = gDriver.buf[min(len(gDriver.buf), int(samples)):]
+}
+
+//export sample_rate_callback
+func sample_rate_callback() {
+	// TODO: handle rate changes?
+}
+
+func newDriver(sampleRate, numChans, bitDepthInBytes, bufferSizeInBytes int) (tryWriteCloser, error) {
+	p := &driver{
+		buf: []int16{},
+	}
+
+	C.kinc_a2_init()
+	C.kinc_a2_set_callback((C.audio_callback_t)(C.audio_callback))
+	gDriver = p
+
+	return p, nil
+}
+
+func (p *driver) TryWrite(data []byte) (n int, err error) {
+	p.mutex.Lock()
+	defer p.mutex.Unlock()
+
+	samples := unsafe.Slice((*int16)(unsafe.Pointer(&data[0])), len(data) / 2)
+	sampleCount := min(len(samples), max(0, MaxBufferLength - len(p.buf)))
+	p.buf = append(p.buf, samples[:sampleCount]...)
+	return sampleCount * 2, nil
+}
+
+func (p *driver) Close() error {
+	C.kinc_a2_shutdown()
+	gDriver = nil
+
+	return nil
+}
+
+func (d *driver) tryWriteCanReturnWithoutWaiting() bool {
+	return true
+}

driver_linux.go

@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build !js && !android && !ios
-// +build !js,!android,!ios
+//go:build !js && !android && !ios && !kinc
+// +build !js,!android,!ios,!kinc
 
 package oto
 

driver_macos.go

@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build darwin && !ios && !js
-// +build darwin,!ios,!js
+//go:build darwin && !ios && !js && !kinc
+// +build darwin,!ios,!js,!kinc
 
 package oto
 

driver_windows.go

@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build !js
-// +build !js
+//go:build !js && !kinc
+// +build !js,!kinc
 
 package oto
 

go.mod

@@ -1,6 +1,6 @@
 module github.com/hajimehoshi/oto
 
-go 1.13
+go 1.17
 
 require (
 	golang.org/x/mobile v0.0.0-20190415191353-3e0bab5405d6

winmm_windows.go

@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build !js
-// +build !js
+//go:build !js && !kinc
+// +build !js && !kinc
 
 package oto