chore(build): use SDL3

vendor/sdl-3.2.10/examples/audio/04-multiple-streams/README.txt

@@ -0,0 +1,5 @@
+If you're running this in a web browser, you need to click the window before you'll hear anything!
+
+This example code loads two .wav files, puts them an audio streams and binds
+them for playback, repeating both sounds on loop. This shows several streams
+mixing into a single playback device.

vendor/sdl-3.2.10/examples/audio/04-multiple-streams/multiple-streams.c

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+/*
+ * This example code loads two .wav files, puts them an audio streams and
+ * binds them for playback, repeating both sounds on loop. This shows several
+ * streams mixing into a single playback device.
+ *
+ * This code is public domain. Feel free to use it for any purpose!
+ */
+
+#define SDL_MAIN_USE_CALLBACKS 1  /* use the callbacks instead of main() */
+#include <SDL3/SDL.h>
+#include <SDL3/SDL_main.h>
+
+/* We will use this renderer to draw into this window every frame. */
+static SDL_Window *window = NULL;
+static SDL_Renderer *renderer = NULL;
+static SDL_AudioDeviceID audio_device = 0;
+
+/* things that are playing sound (the audiostream itself, plus the original data, so we can refill to loop. */
+typedef struct Sound {
+    Uint8 *wav_data;
+    Uint32 wav_data_len;
+    SDL_AudioStream *stream;
+} Sound;
+
+static Sound sounds[2];
+
+static bool init_sound(const char *fname, Sound *sound)
+{
+    bool retval = false;
+    SDL_AudioSpec spec;
+    char *wav_path = NULL;
+
+    /* Load the .wav files from wherever the app is being run from. */
+    SDL_asprintf(&wav_path, "%s%s", SDL_GetBasePath(), fname);  /* allocate a string of the full file path */
+    if (!SDL_LoadWAV(wav_path, &spec, &sound->wav_data, &sound->wav_data_len)) {
+        SDL_Log("Couldn't load .wav file: %s", SDL_GetError());
+        return false;
+    }
+
+    /* Create an audio stream. Set the source format to the wav's format (what
+       we'll input), leave the dest format NULL here (it'll change to what the
+       device wants once we bind it). */
+    sound->stream = SDL_CreateAudioStream(&spec, NULL);
+    if (!sound->stream) {
+        SDL_Log("Couldn't create audio stream: %s", SDL_GetError());
+    } else if (!SDL_BindAudioStream(audio_device, sound->stream)) {  /* once bound, it'll start playing when there is data available! */
+        SDL_Log("Failed to bind '%s' stream to device: %s", fname, SDL_GetError());
+    } else {
+        retval = true;  /* success! */
+    }
+
+    SDL_free(wav_path);  /* done with this string. */
+    return retval;
+}
+
+
+/* This function runs once at startup. */
+SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
+{
+
+    SDL_SetAppMetadata("Example Audio Multiple Streams", "1.0", "com.example.audio-multiple-streams");
+
+    if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO)) {
+        SDL_Log("Couldn't initialize SDL: %s", SDL_GetError());
+        return SDL_APP_FAILURE;
+    }
+
+    if (!SDL_CreateWindowAndRenderer("examples/audio/multiple-streams", 640, 480, 0, &window, &renderer)) {
+        SDL_Log("Couldn't create window/renderer: %s", SDL_GetError());
+        return SDL_APP_FAILURE;
+    }
+
+    /* open the default audio device in whatever format it prefers; our audio streams will adjust to it. */
+    audio_device = SDL_OpenAudioDevice(SDL_AUDIO_DEVICE_DEFAULT_PLAYBACK, NULL);
+    if (audio_device == 0) {
+        SDL_Log("Couldn't open audio device: %s", SDL_GetError());
+        return SDL_APP_FAILURE;
+    }
+
+    if (!init_sound("sample.wav", &sounds[0])) {
+        return SDL_APP_FAILURE;
+    } else if (!init_sound("sword.wav", &sounds[1])) {
+        return SDL_APP_FAILURE;
+    }
+
+    return SDL_APP_CONTINUE;  /* carry on with the program! */
+}
+
+/* This function runs when a new event (mouse input, keypresses, etc) occurs. */
+SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
+{
+    if (event->type == SDL_EVENT_QUIT) {
+        return SDL_APP_SUCCESS;  /* end the program, reporting success to the OS. */
+    }
+    return SDL_APP_CONTINUE;  /* carry on with the program! */
+}
+
+/* This function runs once per frame, and is the heart of the program. */
+SDL_AppResult SDL_AppIterate(void *appstate)
+{
+    int i;
+
+    for (i = 0; i < SDL_arraysize(sounds); i++) {
+        /* If less than a full copy of the audio is queued for playback, put another copy in there.
+           This is overkill, but easy when lots of RAM is cheap. One could be more careful and
+           queue less at a time, as long as the stream doesn't run dry.  */
+        if (SDL_GetAudioStreamQueued(sounds[i].stream) < ((int) sounds[i].wav_data_len)) {
+            SDL_PutAudioStreamData(sounds[i].stream, sounds[i].wav_data, (int) sounds[i].wav_data_len);
+        }
+    }
+
+    /* just blank the screen. */
+    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
+    SDL_RenderClear(renderer);
+    SDL_RenderPresent(renderer);
+
+    return SDL_APP_CONTINUE;  /* carry on with the program! */
+}
+
+/* This function runs once at shutdown. */
+void SDL_AppQuit(void *appstate, SDL_AppResult result)
+{
+    int i;
+
+    SDL_CloseAudioDevice(audio_device);
+
+    for (i = 0; i < SDL_arraysize(sounds); i++) {
+        if (sounds[i].stream) {
+            SDL_DestroyAudioStream(sounds[i].stream);
+        }
+        SDL_free(sounds[i].wav_data);
+    }
+
+    /* SDL will clean up the window/renderer for us. */
+}