SDL2: Use the newer sound API and make some requests to improve audio rendition

include/mixer.h

@@ -20,6 +20,16 @@
 #ifndef DOSBOX_MIXER_H
 #define DOSBOX_MIXER_H
 
+/*
+#ifdef C_SDL2
+#define SDL_LockAudio __DO_NOT_USE__1
+#define SDL_UnlockAudio __DO_NOT_USE__2
+#define SDL_PauseAudio __DO_NOT_USE__3
+#define SDL_CloseAudio __DO_NOT_USE__4
+#define SDL_OpenAudio __DO_NOT_USE__5
+#endif
+*/
+
 typedef void (*MIXER_MixHandler)(uint8_t * sampdate,uint32_t len);
 typedef void (*MIXER_Handler)(Bitu len);
 

src/hardware/mixer.cpp

@@ -64,6 +64,10 @@
 #define MIXER_SSIZE 4
 #define MIXER_VOLSHIFT 13
 
+#ifdef C_SDL2
+SDL_AudioDeviceID SDL2_AudioDevice = 0; /* valid IDs are 2 or higher, 1 for compat, 0 is never a valid ID */
+#endif
+
 static INLINE int16_t MIXER_CLIP(Bits SAMP) {
     if (SAMP < MAX_AUDIO) {
         if (SAMP > MIN_AUDIO)
@@ -837,11 +841,19 @@ static void MIXER_MixData(Bitu fracs/*render up to*/) {
 }
 
 static void MIXER_FillUp(void) {
+#ifdef C_SDL2
+    SDL_LockAudioDevice(SDL2_AudioDevice);
+#else
     SDL_LockAudio();
+#endif
     float index = PIC_TickIndex();
     if (index < 0) index = 0;
     MIXER_MixData((Bitu)((double)index * ((Bitu)mixer.samples_this_ms.w * mixer.samples_this_ms.fd)));
+#ifdef C_SDL2
+    SDL_UnlockAudioDevice(SDL2_AudioDevice);
+#else
     SDL_UnlockAudio();
+#endif
 }
 
 void MixerChannel::FillUp(void) {
@@ -856,7 +868,11 @@ void MIXER_MixSingle(Bitu /*val*/) {
 static void MIXER_Mix(void) {
     Bitu thr;
 
+#ifdef C_SDL2
+    SDL_LockAudioDevice(SDL2_AudioDevice);
+#else
     SDL_LockAudio();
+#endif
 
     /* render */
     assert((mixer.work_in+mixer.samples_per_ms.w) <= MIXER_BUFSIZE);
@@ -884,7 +900,11 @@ static void MIXER_Mix(void) {
     memset(&mixer.work[mixer.work_in][0],0,sizeof(int32_t)*2*mixer.samples_this_ms.w);
     mixer.samples_rendered_ms.fn = 0;
     mixer.samples_rendered_ms.w = 0;
+#ifdef C_SDL2
+    SDL_UnlockAudioDevice(SDL2_AudioDevice);
+#else
     SDL_UnlockAudio();
+#endif
     MIXER_FillUp();
 }
 
@@ -1208,10 +1228,21 @@ void MIXER_Init() {
     spec.userdata=NULL;
     spec.samples=(Uint16)mixer.blocksize;
 
+#ifdef C_SDL2
+    if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0) {
+        LOG(LOG_MISC,LOG_DEBUG)("MIXER:Can't initialize SDL audio: %s , running in nosound mode.",SDL_GetError());
+        mixer.nosound = true;
+    }
+#endif
+
     if (mixer.nosound) {
         LOG(LOG_MISC,LOG_DEBUG)("MIXER:No Sound Mode Selected.");
         TIMER_AddTickHandler(MIXER_Mix);
+#ifdef C_SDL2
+    } else if ((SDL2_AudioDevice=SDL_OpenAudioDevice(NULL, 0, &spec, &obtained, SDL_AUDIO_ALLOW_FREQUENCY_CHANGE | SDL_AUDIO_ALLOW_SAMPLES_CHANGE)) == 0) {
+#else
     } else if (SDL_OpenAudio(&spec, &obtained) <0 ) {
+#endif
         mixer.nosound = true;
         LOG(LOG_MISC,LOG_DEBUG)("MIXER:Can't open audio: %s , running in nosound mode.",SDL_GetError());
         TIMER_AddTickHandler(MIXER_Mix);
@@ -1219,7 +1250,12 @@ void MIXER_Init() {
         mixer.nosound = true;
         LOG(LOG_MISC,LOG_DEBUG)("MIXER:Failed to get the sample format I wanted.");
         TIMER_AddTickHandler(MIXER_Mix);
+#ifdef C_SDL2
+        SDL_CloseAudioDevice(SDL2_AudioDevice);
+        SDL2_AudioDevice = 0;
+#else
         SDL_CloseAudio();
+#endif
     } else {
         if(((Bitu)mixer.freq != (Bitu)obtained.freq) || ((Bitu)mixer.blocksize != (Bitu)obtained.samples))
             LOG(LOG_MISC,LOG_DEBUG)("MIXER:Got different values from SDL: freq %d, blocksize %d",(int)obtained.freq,(int)obtained.samples);
@@ -1228,7 +1264,11 @@ void MIXER_Init() {
         mixer.blocksize=obtained.samples;
         TIMER_AddTickHandler(MIXER_Mix);
         if (mixer.sampleaccurate) PIC_AddEvent(MIXER_MixSingle,1000.0 / mixer.freq);
+#ifdef C_SDL2
+        SDL_PauseAudioDevice(SDL2_AudioDevice, 0);
+#else
         SDL_PauseAudio(0);
+#endif
     }
     mixer_start_pic_time = PIC_FullIndex();
     mixer_sample_counter = 0;

src/misc/savestates.cpp

@@ -13,6 +13,7 @@
 #include "mapper.h"
 #include "control.h"
 #include "logging.h"
+#include "mixer.h"
 #include "build_timestamp.h"
 #ifdef WIN32
 #include "direct.h"
@@ -36,6 +37,10 @@
 #include "../libs/tinyfiledialogs/tinyfiledialogs.h"
 #endif
 
+#ifdef C_SDL2
+extern SDL_AudioDeviceID SDL2_AudioDevice; /* valid IDs are 2 or higher, 1 for compat, 0 is never a valid ID */
+#endif
+
 extern unsigned int page;
 extern int autosave_last[10], autosave_count;
 extern std::string autosave_name[10], savefilename;
@@ -1056,7 +1061,11 @@ int flagged_restore(char* zip);
 
 void SaveState::save(size_t slot) { //throw (Error)
 	if (slot >= SLOT_COUNT*MAX_PAGE)  return;
-	SDL_PauseAudio(0);
+#ifdef C_SDL2
+        SDL_PauseAudioDevice(SDL2_AudioDevice, 0);
+#else
+        SDL_PauseAudio(0);
+#endif
 	bool save_err=false;
 	if((MEM_TotalPages()*4096/1024/1024)>1024) {
 		LOG_MSG("Stopped. 1 GB is the maximum memory size for saving/loading states.");
@@ -1278,7 +1287,11 @@ void SaveState::load(size_t slot) const { //throw (Error)
 		notifyError("Unsupported memory size for loading states.", false);
 		return;
 	}
-	SDL_PauseAudio(0);
+#ifdef C_SDL2
+        SDL_PauseAudioDevice(SDL2_AudioDevice, 0);
+#else
+        SDL_PauseAudio(0);
+#endif
 	extern const char* RunningProgram;
 	bool read_version=false;
 	bool read_title=false;