GLK: FROTZ: Implement os_beep method

I instantiate a PCSpeaker instance in the main engine just for beeps,
because I don't know any simpler way. But hey, it works.

engines/glk/frotz/glk_interface.cpp

@@ -322,6 +322,7 @@ void GlkInterface::os_stop_sample(int a) {
 }
 
 void GlkInterface::os_beep(int volume) {
+	beep();
 }
 
 bool GlkInterface::os_picture_data(int picture, uint *height, uint *width) {

engines/glk/glk.cpp

@@ -48,7 +48,7 @@ GlkEngine::GlkEngine(OSystem *syst, const GlkGameDescription &gameDesc) :
 		_clipboard(nullptr), _conf(nullptr), _events(nullptr), _pictures(nullptr),
 		_screen(nullptr), _selection(nullptr), _sounds(nullptr), _windows(nullptr),
 		_copySelect(false), _terminated(false), gli_unregister_obj(nullptr),
-		gli_register_arr(nullptr), gli_unregister_arr(nullptr) {
+		_pcSpeaker(nullptr), gli_register_arr(nullptr), gli_unregister_arr(nullptr) {
 	g_vm = this;
 }
 
@@ -57,6 +57,7 @@ GlkEngine::~GlkEngine() {
 	delete _clipboard;
 	delete _conf;
 	delete _events;
+	delete _pcSpeaker;
 	delete _pictures;
 	delete _screen;
 	delete _selection;
@@ -79,6 +80,7 @@ void GlkEngine::initialize() {
 	_screen->initialize();
 	_clipboard = new Clipboard();
 	_events = new Events();
+	_pcSpeaker = new PCSpeaker(_mixer);
 	_pictures = new Pictures();
 	_selection = new Selection();
 	_sounds = new Sounds();
@@ -199,4 +201,8 @@ Common::Error GlkEngine::saveGameState(int slot, const Common::String &desc) {
 	return result;
 }
 
+void GlkEngine::beep() {
+	_pcSpeaker->speakerOn(50, 50);
+}
+
 } // End of namespace Glk

engines/glk/glk.h

@@ -30,6 +30,7 @@
 #include "engines/engine.h"
 #include "glk/glk_types.h"
 #include "glk/streams.h"
+#include "glk/pc_speaker.h"
 
 namespace Glk {
 
@@ -77,6 +78,7 @@ protected:
 	Common::RandomSource _random;
 	int _loadSaveSlot;
 	Common::File _gameFile;
+	PCSpeaker *_pcSpeaker;
 
 	// Engine APIs
 	virtual Common::Error run();
@@ -213,6 +215,11 @@ public:
 	 * Save the game to the passed file
 	 */
 	virtual Common::Error saveGameData(strid_t file, const Common::String &desc) = 0;
+
+	/**
+	 * Generate a beep
+	 */
+	void beep();
 };
 
 extern GlkEngine *g_vm;

engines/glk/module.mk

@@ -8,6 +8,7 @@ MODULE_OBJS := \
 	fonts.o \
 	glk.o \
 	glk_api.o \
+	pc_speaker.o \
 	picture.o \
 	raw_decoder.o \
 	screen.o \

engines/glk/pc_speaker.cpp

@@ -0,0 +1,52 @@
+/* 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 "audio/softsynth/pcspk.h"
+#include "glk/pc_speaker.h"
+
+namespace Glk {
+
+PCSpeaker::PCSpeaker(Audio::Mixer *mixer) : _mixer(mixer) {
+	_stream = new Audio::PCSpeaker(_mixer->getOutputRate());
+	_mixer->playStream(Audio::Mixer::kSFXSoundType,
+			&_handle, _stream, -1, 50, 0, DisposeAfterUse::NO, true);
+}
+
+PCSpeaker::~PCSpeaker() {
+	_mixer->stopHandle(_handle);
+	delete _stream;
+}
+
+void PCSpeaker::speakerOn(int16 frequency, int32 length) {
+	_stream->play(Audio::PCSpeaker::kWaveFormSquare, frequency, length);
+}
+
+void PCSpeaker::speakerOff() {
+	_stream->stop();
+}
+
+void PCSpeaker::onUpdate(uint32 millis) {
+	if (_stream->isPlaying())
+		_stream->stop(millis);
+}
+
+} // End of namespace Glk

engines/glk/pc_speaker.h

@@ -0,0 +1,50 @@
+/* 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.
+ *
+ */
+
+#ifndef GLK_PC_SPEAKER_H
+#define GLK_PC_SPEAKER_H
+
+#include "audio/mixer.h"
+
+namespace Audio {
+class PCSpeaker;
+}
+
+namespace Glk {
+
+class PCSpeaker {
+private:
+	Audio::Mixer *_mixer;
+	Audio::PCSpeaker *_stream;
+	Audio::SoundHandle _handle;
+public:
+	PCSpeaker(Audio::Mixer *mixer);
+	~PCSpeaker();
+
+	void speakerOn(int16 frequency, int32 length = -1);
+	void speakerOff();
+	void onUpdate(uint32 millis);
+};
+
+} // End of namespace Glk
+
+#endif