streaming de audio

2026-04-13 20:12:04 +02:00
parent 1451327fcc
commit ccdf9732d1
1 changed files with 114 additions and 32 deletions
--- a/source/jail_audio.hpp
+++ b/source/jail_audio.hpp
@@ -43,18 +43,22 @@ struct JA_Channel_t {

 struct JA_Music_t {
    SDL_AudioSpec spec{SDL_AUDIO_S16, 2, 48000};
-    Uint32 length{0};
-    Uint8* buffer{nullptr};
+
+    // OGG comprimit en memòria. Propietat nostra; es copia des del fitxer una
+    // sola vegada en JA_LoadMusic i es descomprimix en chunks per streaming.
+    Uint8* ogg_data{nullptr};
+    Uint32 ogg_length{0};
+    stb_vorbis* vorbis{nullptr};  // Handle del decoder, viu tot el cicle del JA_Music_t
+
    char* filename{nullptr};

-    int pos{0};
-    int times{0};
+    int times{0};  // Loops restants (-1 = infinit, 0 = un sol play)
    SDL_AudioStream* stream{nullptr};
    JA_Music_state state{JA_MUSIC_INVALID};
 };

 // --- Internal Global State ---
-// Marcado 'inline' (C++17) para asegurar una unica instancia.
+// Marcado 'inline' (C++17) para asegurar una única instancia.

 inline JA_Music_t* current_music{nullptr};
 inline JA_Channel_t channels[JA_MAX_SIMULTANEOUS_CHANNELS];
@@ -76,6 +80,57 @@ inline void JA_StopMusic();
 inline void JA_StopChannel(const int channel);
 inline int JA_PlaySoundOnChannel(JA_Sound_t* sound, const int channel, const int loop = 0, const int group = 0);

+// --- Music streaming internals ---
+// Bytes-per-sample per canal (sempre s16)
+static constexpr int JA_MUSIC_BYTES_PER_SAMPLE = 2;
+// Quants shorts decodifiquem per crida a get_samples_short_interleaved.
+// 8192 shorts = 4096 samples/channel en estèreo ≈ 85ms de so a 48kHz.
+static constexpr int JA_MUSIC_CHUNK_SHORTS = 8192;
+// Umbral d'audio per davant del cursor de reproducció. Mantenim ≥ 0.5 s a
+// l'SDL_AudioStream per absorbir jitter de frame i evitar underruns.
+static constexpr float JA_MUSIC_LOW_WATER_SECONDS = 0.5f;
+
+// Decodifica un chunk del vorbis i el volca a l'stream. Retorna samples
+// decodificats per canal (0 = EOF de l'stream vorbis).
+inline int JA_FeedMusicChunk(JA_Music_t* music) {
+    if (!music || !music->vorbis || !music->stream) return 0;
+
+    short chunk[JA_MUSIC_CHUNK_SHORTS];
+    const int channels = music->spec.channels;
+    const int samples_per_channel = stb_vorbis_get_samples_short_interleaved(
+        music->vorbis,
+        channels,
+        chunk,
+        JA_MUSIC_CHUNK_SHORTS);
+    if (samples_per_channel <= 0) return 0;
+
+    const int bytes = samples_per_channel * channels * JA_MUSIC_BYTES_PER_SAMPLE;
+    SDL_PutAudioStreamData(music->stream, chunk, bytes);
+    return samples_per_channel;
+}
+
+// Reompli l'stream fins que tinga ≥ JA_MUSIC_LOW_WATER_SECONDS bufferats.
+// En arribar a EOF del vorbis, aplica el loop (times) o deixa drenar.
+inline void JA_PumpMusic(JA_Music_t* music) {
+    if (!music || !music->vorbis || !music->stream) return;
+
+    const int bytes_per_second = music->spec.freq * music->spec.channels * JA_MUSIC_BYTES_PER_SAMPLE;
+    const int low_water_bytes = static_cast<int>(JA_MUSIC_LOW_WATER_SECONDS * static_cast<float>(bytes_per_second));
+
+    while (SDL_GetAudioStreamAvailable(music->stream) < low_water_bytes) {
+        const int decoded = JA_FeedMusicChunk(music);
+        if (decoded > 0) continue;
+
+        // EOF: si queden loops, rebobinar; si no, tallar i deixar drenar.
+        if (music->times != 0) {
+            stb_vorbis_seek_start(music->vorbis);
+            if (music->times > 0) music->times--;
+        } else {
+            break;
+        }
+    }
+}
+
 // --- Core Functions ---

 inline void JA_Update() {
@@ -93,13 +148,11 @@ inline void JA_Update() {
            }
        }

-        if (current_music->times != 0) {
-            if ((Uint32)SDL_GetAudioStreamAvailable(current_music->stream) < (current_music->length / 2)) {
-                SDL_PutAudioStreamData(current_music->stream, current_music->buffer, current_music->length);
-            }
-            if (current_music->times > 0) current_music->times--;
-        } else {
-            if (SDL_GetAudioStreamAvailable(current_music->stream) == 0) JA_StopMusic();
+        // Streaming: rellenem l'stream fins al low-water-mark i parem si el
+        // vorbis s'ha esgotat i no queden loops.
+        JA_PumpMusic(current_music);
+        if (current_music->times == 0 && SDL_GetAudioStreamAvailable(current_music->stream) == 0) {
+            JA_StopMusic();
        }
    }

@@ -139,19 +192,31 @@ inline void JA_Quit() {
 // --- Music Functions ---

 inline JA_Music_t* JA_LoadMusic(const Uint8* buffer, Uint32 length) {
-    JA_Music_t* music = new JA_Music_t();
+    if (!buffer || length == 0) return nullptr;

-    int chan, samplerate;
-    short* output;
-    music->length = stb_vorbis_decode_memory(buffer, length, &chan, &samplerate, &output) * chan * 2;
+    // Còpia del OGG comprimit: stb_vorbis llig de forma persistent aquesta
+    // memòria mentre el handle estiga viu, així que hem de posseir-la nosaltres.
+    Uint8* ogg_copy = static_cast<Uint8*>(SDL_malloc(length));
+    if (!ogg_copy) return nullptr;
+    SDL_memcpy(ogg_copy, buffer, length);

-    music->spec.channels = chan;
-    music->spec.freq = samplerate;
+    int error = 0;
+    stb_vorbis* vorbis = stb_vorbis_open_memory(ogg_copy, static_cast<int>(length), &error, nullptr);
+    if (!vorbis) {
+        SDL_free(ogg_copy);
+        SDL_Log("JA_LoadMusic: stb_vorbis_open_memory failed (error %d)", error);
+        return nullptr;
+    }
+
+    auto* music = new JA_Music_t();
+    music->ogg_data = ogg_copy;
+    music->ogg_length = length;
+    music->vorbis = vorbis;
+
+    const stb_vorbis_info info = stb_vorbis_get_info(vorbis);
+    music->spec.channels = info.channels;
+    music->spec.freq = static_cast<int>(info.sample_rate);
    music->spec.format = SDL_AUDIO_S16;
-    music->buffer = static_cast<Uint8*>(SDL_malloc(music->length));
-    SDL_memcpy(music->buffer, output, music->length);
-    free(output);
-    music->pos = 0;
    music->state = JA_MUSIC_STOPPED;

    return music;
@@ -189,26 +254,38 @@ inline JA_Music_t* JA_LoadMusic(const char* filename) {
 }

 inline void JA_PlayMusic(JA_Music_t* music, const int loop = -1) {
-    if (!JA_musicEnabled || !music) return;
+    if (!JA_musicEnabled || !music || !music->vorbis) return;

    JA_StopMusic();

    current_music = music;
-    current_music->pos = 0;
    current_music->state = JA_MUSIC_PLAYING;
    current_music->times = loop;

+    // Rebobinem l'stream de vorbis al principi. Cobreix tant play-per-primera-
+    // vegada com replays/canvis de track que tornen a la mateixa pista.
+    stb_vorbis_seek_start(current_music->vorbis);
+
    current_music->stream = SDL_CreateAudioStream(&current_music->spec, &JA_audioSpec);
    if (!current_music->stream) {
        SDL_Log("Failed to create audio stream!");
        current_music->state = JA_MUSIC_STOPPED;
        return;
    }
-    if (!SDL_PutAudioStreamData(current_music->stream, current_music->buffer, current_music->length)) printf("[ERROR] SDL_PutAudioStreamData failed!\n");
    SDL_SetAudioStreamGain(current_music->stream, JA_musicVolume);
+
+    // Pre-cargem el buffer abans de bindejar per evitar un underrun inicial.
+    JA_PumpMusic(current_music);
+
    if (!SDL_BindAudioStream(sdlAudioDevice, current_music->stream)) printf("[ERROR] SDL_BindAudioStream failed!\n");
 }

+inline char* JA_GetMusicFilename(const JA_Music_t* music = nullptr) {
+    if (!music) music = current_music;
+    if (!music) return nullptr;
+    return music->filename;
+}
+
 inline void JA_PauseMusic() {
    if (!JA_musicEnabled) return;
    if (!current_music || current_music->state != JA_MUSIC_PLAYING) return;
@@ -228,12 +305,16 @@ inline void JA_ResumeMusic() {
 inline void JA_StopMusic() {
    if (!current_music || current_music->state == JA_MUSIC_INVALID || current_music->state == JA_MUSIC_STOPPED) return;

-    current_music->pos = 0;
    current_music->state = JA_MUSIC_STOPPED;
    if (current_music->stream) {
        SDL_DestroyAudioStream(current_music->stream);
        current_music->stream = nullptr;
    }
+    // Deixem el handle de vorbis viu — es tanca en JA_DeleteMusic.
+    // Rebobinem perquè un futur JA_PlayMusic comence des del principi.
+    if (current_music->vorbis) {
+        stb_vorbis_seek_start(current_music->vorbis);
+    }
 }

 inline void JA_FadeOutMusic(const int milliseconds) {
@@ -259,8 +340,9 @@ inline void JA_DeleteMusic(JA_Music_t* music) {
        JA_StopMusic();
        current_music = nullptr;
    }
-    SDL_free(music->buffer);
    if (music->stream) SDL_DestroyAudioStream(music->stream);
+    if (music->vorbis) stb_vorbis_close(music->vorbis);
+    SDL_free(music->ogg_data);
    free(music->filename);
    delete music;
 }
@@ -273,14 +355,14 @@ inline float JA_SetMusicVolume(float volume) {
    return JA_musicVolume;
 }

-inline void JA_SetMusicPosition(float value) {
-    if (!current_music) return;
-    current_music->pos = value * current_music->spec.freq;
+inline void JA_SetMusicPosition(float /*value*/) {
+    // No implementat amb el backend de streaming. Mai va arribar a usar-se
+    // en el codi existent, així que es manté com a stub.
 }

 inline float JA_GetMusicPosition() {
-    if (!current_music) return 0;
-    return float(current_music->pos) / float(current_music->spec.freq);
+    // Veure nota a JA_SetMusicPosition.
+    return 0.0f;
 }

 inline void JA_EnableMusic(const bool value) {