2 files changed, 248 insertions, 0 deletions
diff --git a/backends/mixer/sdl/sdl-mixer.cpp b/backends/mixer/sdl/sdl-mixer.cpp
new file mode 100644
index 0000000000..3c826bfed8
--- /dev/null
+++ b/backends/mixer/sdl/sdl-mixer.cpp
@@ -0,0 +1,143 @@
+/* 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.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#if defined(SDL_BACKEND)
+
+#include "backends/mixer/sdl/sdl-mixer.h"
+#include "common/system.h"
+#include "common/config-manager.h"
+
+#ifdef GP2X
+#define SAMPLES_PER_SEC 11025
+#else
+#define SAMPLES_PER_SEC 22050
+#endif
+//#define SAMPLES_PER_SEC 44100
+
+SdlMixerManager::SdlMixerManager()
+	:
+	_mixer(0),
+	_audioSuspended(false) {
+
+}
+
+SdlMixerManager::~SdlMixerManager() {
+	_mixer->setReady(false);
+
+	SDL_CloseAudio();
+
+	delete _mixer;
+}
+
+void SdlMixerManager::init() {
+	// Start SDL Audio subsystem
+	if (SDL_InitSubSystem(SDL_INIT_AUDIO) == -1) {
+		error("Could not initialize SDL: %s", SDL_GetError());
+	}
+
+	// Get the desired audio specs
+	SDL_AudioSpec desired = getAudioSpec();
+
+	// Start SDL audio with the desired specs
+	if (SDL_OpenAudio(&desired, &_obtainedRate) != 0) {
+		warning("Could not open audio device: %s", SDL_GetError());
+
+		_mixer = new Audio::MixerImpl(g_system, desired.freq);
+		assert(_mixer); 
+		_mixer->setReady(false);
+	} else {
+		debug(1, "Output sample rate: %d Hz", _obtainedRate.freq);
+
+		_mixer = new Audio::MixerImpl(g_system, _obtainedRate.freq);
+		assert(_mixer); 
+		_mixer->setReady(true);
+
+		startAudio();
+	}
+}
+
+SDL_AudioSpec SdlMixerManager::getAudioSpec() {
+	SDL_AudioSpec desired;
+
+	// Determine the desired output sampling frequency.
+	uint32 samplesPerSec = 0;
+	if (ConfMan.hasKey("output_rate"))
+		samplesPerSec = ConfMan.getInt("output_rate");
+	if (samplesPerSec <= 0)
+		samplesPerSec = SAMPLES_PER_SEC;
+
+	// Determine the sample buffer size. We want it to store enough data for
+	// at least 1/16th of a second (though at most 8192 samples). Note
+	// that it must be a power of two. So e.g. at 22050 Hz, we request a
+	// sample buffer size of 2048.
+	uint32 samples = 8192;
+	while (samples * 16 > samplesPerSec * 2)
+		samples >>= 1;
+
+	memset(&desired, 0, sizeof(desired));
+	desired.freq = samplesPerSec;
+	desired.format = AUDIO_S16SYS;
+	desired.channels = 2;
+	desired.samples = (uint16)samples;
+	desired.callback = sdlCallback;
+	desired.userdata = this;
+
+	return desired;
+}
+
+void SdlMixerManager::startAudio() {
+	// Start the sound system
+	SDL_PauseAudio(0);
+}
+
+void SdlMixerManager::callbackHandler(byte *samples, int len) {
+	assert(_mixer);
+	_mixer->mixCallback(samples, len);
+}
+
+void SdlMixerManager::sdlCallback(void *this_, byte *samples, int len) {
+	SdlMixerManager *manager = (SdlMixerManager *)this_;
+	assert(manager);
+
+	manager->callbackHandler(samples, len);
+}
+
+void SdlMixerManager::suspendAudio() {
+	SDL_CloseAudio();
+	_audioSuspended = true;
+}
+
+int SdlMixerManager::resumeAudio() {
+	if (!_audioSuspended)
+		return -2;
+	if (SDL_OpenAudio(&_obtainedRate, NULL) < 0){
+		return -1;
+	}
+	SDL_PauseAudio(0);
+	_audioSuspended = false;
+	return 0;
+}
+
+#endif
diff --git a/backends/mixer/sdl/sdl-mixer.h b/backends/mixer/sdl/sdl-mixer.h
new file mode 100644
index 0000000000..1b3a3543dc
--- /dev/null
+++ b/backends/mixer/sdl/sdl-mixer.h
@@ -0,0 +1,105 @@
+/* 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.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#ifndef BACKENDS_MIXER_SDL_H
+#define BACKENDS_MIXER_SDL_H
+
+#if defined(__SYMBIAN32__)
+#include <esdl\SDL.h>
+#else
+#include <SDL.h>
+#endif
+
+#include "sound/mixer_intern.h"
+
+/**
+ * SDL mixer manager. It wraps the actual implementation
+ * of the Audio:Mixer used by the engine, and setups
+ * the SDL audio subsystem and the callback for the
+ * audio mixer implementation.
+ */
+class SdlMixerManager {
+public:
+	SdlMixerManager();
+	virtual ~SdlMixerManager();
+
+	/**
+	 * Initialize and setups the mixer
+	 */
+	virtual void init();
+
+	/**
+	 * Get the audio mixer implementation
+	 */
+	Audio::Mixer *getMixer() { return (Audio::Mixer *)_mixer; }
+
+	// Used by LinuxMoto Port
+
+	/**
+	 * Pauses the audio system
+	 */
+	virtual void suspendAudio();
+
+	/**
+	 * Resumes the audio system
+	 */
+	virtual int resumeAudio();
+
+protected:
+	/** The mixer implementation */
+	Audio::MixerImpl *_mixer;
+
+	/**
+	 * The obtained audio specification after opening the
+	 * audio system.
+	 */
+	SDL_AudioSpec _obtainedRate;
+
+	/** State of the audio system */
+	bool _audioSuspended;
+
+	/**
+	 * Returns the desired audio specification 
+	 */
+	virtual SDL_AudioSpec getAudioSpec();
+
+	/**
+	 * Starts SDL audio
+	 */
+	virtual void startAudio();
+
+	/**
+	 * Handles the audio callback
+	 */
+	virtual void callbackHandler(byte *samples, int len);
+
+	/**
+	 * The mixer callback entry point. Static functions can't be overrided
+	 * by subclasses, so it invokes the non-static function callbackHandler()
+	 */
+	static void sdlCallback(void *this_, byte *samples, int len);
+};
+
+#endif