1 files changed, 110 insertions, 0 deletions
diff --git a/backends/platform/3ds/osystem-audio.cpp b/backends/platform/3ds/osystem-audio.cpp
new file mode 100644
index 0000000000..58262372cc
--- /dev/null
+++ b/backends/platform/3ds/osystem-audio.cpp
@@ -0,0 +1,110 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "osystem.h"
+#include "audio/mixer.h"
+
+namespace _3DS {
+
+static bool hasAudio = false;
+
+static void audioThreadFunc(void *arg) {
+	Audio::MixerImpl *mixer = (Audio::MixerImpl *)arg;
+	OSystem_3DS *osys = (OSystem_3DS *)g_system;
+
+	int i;
+	const int channel = 0;
+	int bufferIndex = 0;
+	const int bufferCount = 3;
+	const int bufferSize = 80000; // Can't be too small, based on delayMillis duration
+	const int sampleRate = mixer->getOutputRate();
+	int sampleLen = 0;
+	uint32 lastTime = osys->getMillis(true);
+	uint32 time = lastTime;
+	ndspWaveBuf buffers[bufferCount];
+
+	for (i = 0; i < bufferCount; ++i) {
+		memset(&buffers[i], 0, sizeof(ndspWaveBuf));
+		buffers[i].data_vaddr = linearAlloc(bufferSize);
+		buffers[i].looping = false;
+		buffers[i].status = NDSP_WBUF_FREE;
+	}
+
+	ndspChnReset(channel);
+	ndspChnSetInterp(channel, NDSP_INTERP_LINEAR);
+	ndspChnSetRate(channel, sampleRate);
+	ndspChnSetFormat(channel, NDSP_FORMAT_STEREO_PCM16);
+
+	while (!osys->exiting) {
+		osys->delayMillis(100); // Note: Increasing the delay requires a bigger buffer
+
+		time = osys->getMillis(true);
+		sampleLen = (time - lastTime) * 22 * 4; // sampleRate / 1000 * channelCount * sizeof(int16);
+		lastTime = time;
+
+		if (!osys->sleeping && sampleLen > 0) {
+			bufferIndex++;
+			bufferIndex %= bufferCount;
+			ndspWaveBuf *buf = &buffers[bufferIndex];
+
+			buf->nsamples = mixer->mixCallback(buf->data_adpcm, sampleLen);
+			if (buf->nsamples > 0) {
+				DSP_FlushDataCache(buf->data_vaddr, bufferSize);
+				ndspChnWaveBufAdd(channel, buf);
+			}
+		}
+	}
+
+	for (i = 0; i < bufferCount; ++i)
+		linearFree(buffers[i].data_pcm8);
+}
+
+void OSystem_3DS::initAudio() {
+	_mixer = new Audio::MixerImpl(this, 22050);
+
+	hasAudio = R_SUCCEEDED(ndspInit());
+	_mixer->setReady(false);
+
+	if (hasAudio) {
+		s32 prio = 0;
+		svcGetThreadPriority(&prio, CUR_THREAD_HANDLE);
+		audioThread = threadCreate(&audioThreadFunc, _mixer, 32 * 1048, prio - 1, -2, false);
+	}
+}
+
+void OSystem_3DS::destroyAudio() {
+	if (hasAudio) {
+		threadJoin(audioThread, U64_MAX);
+		threadFree(audioThread);
+		ndspExit();
+	}
+
+	delete _mixer;
+	_mixer = 0;
+}
+
+Audio::Mixer *OSystem_3DS::getMixer() {
+	assert(_mixer);
+	return _mixer;
+}
+
+} // namespace _3DS