Add #6173: New SDL 2 based video and sound drivers (#7086)

src/sound/sdl2_s.cpp

@@ -0,0 +1,70 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD 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, version 2.
+ * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file sdl2_s.cpp Playing sound via SDL2. */
+
+#ifdef WITH_SDL2
+
+#include "../stdafx.h"
+
+#include "../mixer.h"
+#include "sdl_s.h"
+#include <SDL.h>
+
+#include "../safeguards.h"
+
+/** Factory for the SDL sound driver. */
+static FSoundDriver_SDL iFSoundDriver_SDL;
+
+/**
+ * Callback that fills the sound buffer.
+ * @param userdata Ignored.
+ * @param stream   The stream to put data into.
+ * @param len      The length of the stream in bytes.
+ */
+static void CDECL fill_sound_buffer(void *userdata, Uint8 *stream, int len)
+{
+	MxMixSamples(stream, len / 4);
+}
+
+const char *SoundDriver_SDL::Start(const char * const *parm)
+{
+	SDL_AudioSpec spec;
+	SDL_AudioSpec spec_actual;
+
+	/* Only initialise SDL if the video driver hasn't done it already */
+	int ret_code = 0;
+	if (SDL_WasInit(SDL_INIT_EVERYTHING) == 0) {
+		ret_code = SDL_Init(SDL_INIT_AUDIO);
+	} else if (SDL_WasInit(SDL_INIT_AUDIO) == 0) {
+		ret_code = SDL_InitSubSystem(SDL_INIT_AUDIO);
+	}
+	if (ret_code == -1) return SDL_GetError();
+
+	spec.freq = GetDriverParamInt(parm, "hz", 44100);
+	spec.format = AUDIO_S16SYS;
+	spec.channels = 2;
+	spec.samples = GetDriverParamInt(parm, "samples", 1024);
+	spec.callback = fill_sound_buffer;
+	SDL_AudioDeviceID dev = SDL_OpenAudioDevice(nullptr, 0, &spec, &spec_actual, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE);
+	MxInitialize(spec_actual.freq);
+	SDL_PauseAudioDevice(dev, 0);
+	return nullptr;
+}
+
+void SoundDriver_SDL::Stop()
+{
+	SDL_CloseAudio();
+	SDL_QuitSubSystem(SDL_INIT_AUDIO);
+	if (SDL_WasInit(SDL_INIT_EVERYTHING) == 0) {
+		SDL_Quit(); // If there's nothing left, quit SDL
+	}
+}
+
+#endif /* WITH_SDL2 */