add mp3 support

rts/Lua/LuaUnsyncedCtrl.cpp

@@ -774,7 +774,7 @@ int LuaUnsyncedCtrl::PlaySoundFile(lua_State* L)
 }
 
 
-/*** Allows to play an Ogg Vorbis (.OGG) compressed sound file.
+/*** Allows to play an Ogg Vorbis (.OGG) and mp3 compressed sound file.
  *
  * @function Spring.PlaySoundStream
  *

rts/System/Sound/CMakeLists.txt

@@ -33,7 +33,9 @@ if    (NOT NO_SOUND)
 			OpenAL/EFXfuncs.cpp
 			OpenAL/EFXPresets.cpp
 			OpenAL/AudioChannel.cpp
-			OpenAL/OggStream.cpp
+			OpenAL/OggDecoder.cpp
+			OpenAL/Mp3Decoder.cpp
+			OpenAL/MusicStream.cpp
 			OpenAL/Sound.cpp
 			OpenAL/SoundChannels.cpp
 			OpenAL/SoundBuffer.cpp

rts/System/Sound/OpenAL/Mp3Decoder.cpp

@@ -0,0 +1,41 @@
+/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */
+
+#define DR_MP3_IMPLEMENTATION
+#define DR_MP3_NO_STDIO
+#include "lib/dr_mp3/dr_mp3.h"
+
+#include "System/Sound/OpenAL/Mp3Decoder.h"
+#include "System/Sound/SoundLog.h"
+
+
+int Mp3Decoder::GetChannels() const
+{
+	return data.channels;
+}
+
+long Mp3Decoder::GetRate() const
+{
+	return data.sampleRate;
+}
+
+long Mp3Decoder::Read(uint8_t *buffer,int length, int bigendianp,int word,int sgned,int *bitstream)
+{
+	auto bytesToFrames = sizeof(drmp3_int16) / sizeof(*buffer);
+	return drmp3_read_pcm_frames_s16(&data, length / bytesToFrames / data.channels,
+			reinterpret_cast<drmp3_int16*>(buffer)) * bytesToFrames * data.channels;
+}
+
+float Mp3Decoder::GetTotalTime()
+{
+	return 1.0f * drmp3_get_pcm_frame_count(&data) / data.sampleRate; // linear complexity
+}
+
+bool Mp3Decoder::LoadData(const uint8_t* mem, size_t len)
+{
+	if (!drmp3_init_memory(&data, mem, len, NULL)) {
+		LOG_L(L_ERROR, "[Mp3Decoder::LoadFile] Failed to load");
+		return false;
+	}
+	return true;
+}
+

rts/System/Sound/OpenAL/Mp3Decoder.h

@@ -0,0 +1,22 @@
+/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */
+
+#ifndef MP3DECODER_H
+#define MP3DECODER_H
+
+#include "lib/dr_mp3/dr_mp3.h"
+#include <cstdint>
+
+class Mp3Decoder
+{
+public:
+	long Read(uint8_t *buffer, int length, int , int , int , int *);
+	bool LoadData(const uint8_t* mem, size_t len);
+	int GetChannels() const;
+	long GetRate() const;
+	float GetTotalTime();
+
+private:
+	drmp3 data;
+};
+
+#endif // MP3DECODER_H