sdlout: Add support for SDL3 and require SDL2

See also: https://wiki.libsdl.org/SDL3/README/migration

Author: radioactiveman

.github/actions/install-dependencies/install-dependencies.sh

@@ -2,7 +2,6 @@
 
 # --- Dependency configuration ---
 #
-# ubuntu-20.04:      Qt 5 + GTK 2
 # ubuntu-22.04:      Qt 5 + GTK 3
 # ubuntu-24.04:      Qt 6 + GTK 3
 # Windows:           Qt 6 + GTK 2
@@ -32,7 +31,7 @@ ubuntu_qt5_packages='libqt5opengl5-dev libqt5svg5-dev libqt5x11extras5-dev
 ubuntu_qt6_packages='qt6-base-dev qt6-multimedia-dev qt6-svg-dev'
 
 macos_packages='adplug faad2 ffmpeg libbs2b libcue libmms libmodplug libnotify
-                libopenmpt libsamplerate libsoxr neon opusfile sdl2 wavpack'
+                libopenmpt libsamplerate libsoxr neon opusfile sdl3 wavpack'
 
 case "$os" in
   ubuntu-22.04)

configure.ac

@@ -622,17 +622,23 @@ dnl SDL Output
 dnl ==========
 
 AC_ARG_WITH(libsdl,
- AS_HELP_STRING([--with-libsdl=1,2], [select which SDL version to use (default=auto)]),
+ AS_HELP_STRING([--with-libsdl=2,3], [select which SDL version to use (default=auto)]),
  [with_libsdl=$withval], [with_libsdl=auto])
 
 test_sdlout () {
-    if test "x$with_libsdl" = "x1"; then
-        PKG_CHECK_MODULES(SDL, sdl >= 1.2.11, have_sdlout=yes, have_sdlout=no)
-    elif test "x$with_libsdl" = "x2"; then
+    if test "x$with_libsdl" = "x2"; then
         PKG_CHECK_MODULES(SDL, sdl2 >= 2.0, have_sdlout=yes, have_sdlout=no)
+    elif test "x$with_libsdl" = "x3"; then
+        PKG_CHECK_MODULES(SDL, sdl3 >= 3.2.0, [
+            AC_DEFINE(HAVE_LIBSDL3, 1, [Define if libsdl version is >= 3.2.0])
+            have_sdlout=yes
+        ], [have_sdlout=no])
     else
-        PKG_CHECK_MODULES(SDL, sdl2 >= 2.0, have_sdlout=yes, [
-            PKG_CHECK_MODULES(SDL, sdl >= 1.2.11, have_sdlout=yes, have_sdlout=no)
+        PKG_CHECK_MODULES(SDL, sdl3 >= 3.2.0, [
+            AC_DEFINE(HAVE_LIBSDL3, 1, [Define if libsdl version is >= 3.2.0])
+            have_sdlout=yes
+        ], [
+            PKG_CHECK_MODULES(SDL, sdl2 >= 2.0, have_sdlout=yes, have_sdlout=no)
         ])
     fi
 }

src/config.h.meson

@@ -30,6 +30,7 @@
 
 #mesondefine HAVE_LIBCDDB
 #mesondefine HAVE_LIBCUE2
+#mesondefine HAVE_LIBSDL3
 #mesondefine HAVE_SNDIO_1_9
 
 #mesondefine HAVE_ADPLUG_NEMUOPL_H

src/sdlout/meson.build

@@ -1,11 +1,14 @@
-sdl_dep = dependency('sdl2', version: '>= 2.0', required: false)
+sdl_dep = dependency('sdl3', version: '>= 3.2.0', required: false)
 
 if not sdl_dep.found()
-  sdl_dep = dependency('sdl', version: '>= 1.2.11', required: false)
+  sdl_dep = dependency('sdl2', version: '>= 2.0', required: false)
 endif
 
-have_sdlout = sdl_dep.found()
+if sdl_dep.version().version_compare('>= 3.2.0')
+  conf.set10('HAVE_LIBSDL3', true)
+endif
 
+have_sdlout = sdl_dep.found()
 
 if have_sdlout
   shared_module('sdlout',

src/sdlout/sdlout.cc

@@ -22,8 +22,11 @@
 #include <string.h>
 #include <sys/time.h>
 
+#if HAVE_LIBSDL3
+#include <SDL3/SDL.h>
+#else
 #include <SDL.h>
-#include <SDL_audio.h>
+#endif
 
 #include <libaudcore/audstrings.h>
 #include <libaudcore/i18n.h>
@@ -73,9 +76,10 @@ const char SDLOutput::about[] =
     "Copyright 2010 John Lindgren");
 
 const char * const SDLOutput::defaults[] = {
- "vol_left", "100",
- "vol_right", "100",
- nullptr};
+    "vol_left", "100",
+    "vol_right", "100",
+    nullptr
+};
 
 static pthread_mutex_t sdlout_mutex = PTHREAD_MUTEX_INITIALIZER;
 static pthread_cond_t sdlout_cond = PTHREAD_COND_INITIALIZER;
@@ -84,6 +88,10 @@ static volatile int vol_left, vol_right;
 
 static int sdlout_chan, sdlout_rate;
 
+#if HAVE_LIBSDL3
+static SDL_AudioStream * sdlout_stream;
+#endif
+
 static RingBuf<unsigned char> buffer;
 
 static bool prebuffer_flag, paused_flag;
@@ -98,7 +106,11 @@ bool SDLOutput::init ()
     vol_left = aud_get_int ("sdlout", "vol_left");
     vol_right = aud_get_int ("sdlout", "vol_right");
 
+#if HAVE_LIBSDL3
+    if (! SDL_Init (SDL_INIT_AUDIO))
+#else
     if (SDL_Init (SDL_INIT_AUDIO) < 0)
+#endif
     {
         AUDERR ("Failed to init SDL: %s.\n", SDL_GetError ());
         return false;
@@ -186,6 +198,23 @@ static void callback (void * user, unsigned char * buf, int len)
     pthread_mutex_unlock (& sdlout_mutex);
 }
 
+#if HAVE_LIBSDL3
+static void SDLCALL sdl3_callback (void * user, SDL_AudioStream * stream,
+                                   int additional_amount, int total_amount)
+{
+    if (additional_amount <= 0)
+        return;
+
+    Uint8 * data = SDL_stack_alloc (Uint8, additional_amount);
+    if (! data)
+        return;
+
+    callback (user, data, additional_amount);
+    SDL_PutAudioStreamData (stream, data, additional_amount);
+    SDL_stack_free (data);
+}
+#endif
+
 bool SDLOutput::open_audio (int format, int rate, int chan, String & error)
 {
     if (format != FMT_S16_NE)
@@ -205,15 +234,22 @@ bool SDLOutput::open_audio (int format, int rate, int chan, String & error)
     prebuffer_flag = true;
     paused_flag = false;
 
-    SDL_AudioSpec spec = {0};
+#if HAVE_LIBSDL3
+    const SDL_AudioSpec spec = { SDL_AUDIO_S16, chan, rate };
+    sdlout_stream = SDL_OpenAudioDeviceStream (
+     SDL_AUDIO_DEVICE_DEFAULT_PLAYBACK, & spec, sdl3_callback, nullptr);
 
+    if (! sdlout_stream)
+#else
+    SDL_AudioSpec spec = {0};
     spec.freq = rate;
     spec.format = AUDIO_S16;
     spec.channels = chan;
     spec.samples = 4096;
     spec.callback = callback;
 
     if (SDL_OpenAudio (& spec, nullptr) < 0)
+#endif
     {
         error = String (str_printf
          ("SDL error: Failed to open audio stream: %s.", SDL_GetError ()));
@@ -227,7 +263,14 @@ bool SDLOutput::open_audio (int format, int rate, int chan, String & error)
 void SDLOutput::close_audio ()
 {
     AUDDBG ("Closing audio.\n");
+
+#if HAVE_LIBSDL3
+    SDL_DestroyAudioStream (sdlout_stream);
+    sdlout_stream = nullptr;
+#else
     SDL_CloseAudio ();
+#endif
+
     buffer.destroy ();
 }
 
@@ -239,7 +282,12 @@ static void check_started ()
     AUDDBG ("Starting playback.\n");
     prebuffer_flag = false;
     block_delay = 0;
+
+#if HAVE_LIBSDL3
+    SDL_ResumeAudioStreamDevice (sdlout_stream);
+#else
     SDL_PauseAudio (0);
+#endif
 }
 
 void SDLOutput::period_wait ()
@@ -311,7 +359,16 @@ void SDLOutput::pause (bool pause)
     paused_flag = pause;
 
     if (! prebuffer_flag)
+    {
+#if HAVE_LIBSDL3
+        if (pause)
+            SDL_PauseAudioStreamDevice (sdlout_stream);
+        else
+            SDL_ResumeAudioStreamDevice (sdlout_stream);
+#else
         SDL_PauseAudio (pause);
+#endif
+    }
 
     pthread_cond_broadcast (& sdlout_cond); /* wake up period wait */
     pthread_mutex_unlock (& sdlout_mutex);