smack-a-brother/src/audio.cpp

#include "audio.h"
#include "renderer.h"
#include <SDL3/SDL.h>

#include <stb_vorbis.c>

constexpr float PITCH_VARIANCE = 0.06f;
constexpr Uint64 SOUND_GAP = 40 * SDL_NS_PER_MS;
constexpr const char* SOUND_NAMES[SOUND_COUNT] = {
    "beam",
    "blast",
    "boomerang",
    "boomerang_heavy",
    "bounce",
    "bow",
    "bow_heavy",
    "break",
    "cast",
    "charge",
    "chat",
    "crawl",
    "dash",
    "death",
    "detonate",
    "detonate_empty",
    "duck",
    "echo",
    "equip",
    "explosion",
    "fall",
    "finish",
    "fireball",
    "flail",
    "flail_heavy",
    "flail_land",
    "flame",
    "grapple",
    "grapple_heavy",
    "hit_blunt",
    "hit_blunt_heavy",
    "hit_bullet",
    "hit_bullet_heavy",
    "hit_energy",
    "hit_energy_heavy",
    "hit_explosive",
    "hit_explosive_heavy",
    "hit_fire",
    "hit_fire_heavy",
    "hit_lash",
    "hit_lash_heavy",
    "hit_magic",
    "hit_magic_heavy",
    "hit_pierce",
    "hit_pierce_heavy",
    "hit_slash",
    "hit_slash_heavy",
    "impact_arrow",
    "impact_blaster",
    "impact_boomerang",
    "impact_bullet",
    "impact_mine",
    "jump",
    "land",
    "latch",
    "level_down",
    "level_up",
    "mine",
    "poke",
    "poke_heavy",
    "pound",
    "punch",
    "ready",
    "ricochet",
    "rocket",
    "rocket_heavy",
    "roll",
    "select",
    "shotgun",
    "shotgun_heavy",
    "slam",
    "slash",
    "slash_heavy",
    "step",
    "swap",
    "swing",
    "swing_heavy",
    "teleport",
    "teleport_warp",
    "unduck",
    "unequip",
    "uppercut",
    "uzi",
    "uzi_heavy",
    "whip",
    "whip_heavy",
    "wisp",
    "zap",
};

void Audio::init()
{
    if (SDL_InitSubSystem(SDL_INIT_AUDIO))
        device = SDL_OpenAudioDevice(SDL_AUDIO_DEVICE_DEFAULT_PLAYBACK, nullptr);
    if (!device)
    {
        SDL_Log("Failed to open audio: %s", SDL_GetError());
        return;
    }

    for (int i = 0; i < SOUND_COUNT; i++)
    {
        std::string path = path_get("sfx/") + SOUND_NAMES[i] + ".ogg";
        Sound& sound = sounds[i];
        sound.frames = stb_vorbis_decode_filename(path.c_str(), &sound.channels, &sound.rate, &sound.samples);
        if (sound.frames <= 0)
            SDL_Log("Failed to load %s", path.c_str());
    }

    SDL_AudioSpec deviceSpec = {};
    SDL_GetAudioDeviceFormat(device, &deviceSpec, nullptr);
    for (SDL_AudioStream*& voice : voices)
    {
        voice = SDL_CreateAudioStream(&deviceSpec, &deviceSpec);
        SDL_BindAudioStream(device, voice);
    }
}

// Plays a sound with a slight random pitch and returns the voice used, or -1 if it was skipped.
int Audio::play(SoundId id)
{
    if (id == SOUND_NONE)
        return -1;
    Sound& sound = sounds[id];
    Uint64 now = SDL_GetTicksNS();
    if (!device || sound.frames <= 0 || now - sound.played < SOUND_GAP)
        return -1;
    sound.played = now;

    int voice = voiceNext;
    for (int i = 0; i < VOICE_COUNT; i++)
    {
        if (SDL_GetAudioStreamQueued(voices[i]) == 0)
        {
            voice = i;
            break;
        }
    }
    voiceNext = (voice + 1) % VOICE_COUNT;

    SDL_AudioStream* stream = voices[voice];
    SDL_AudioSpec spec = {SDL_AUDIO_S16, sound.channels, sound.rate};
    SDL_ClearAudioStream(stream);
    SDL_SetAudioStreamFormat(stream, &spec, nullptr);
    SDL_SetAudioStreamFrequencyRatio(stream, random_get(1 - PITCH_VARIANCE, 1 + PITCH_VARIANCE));
    SDL_PutAudioStreamData(stream, sound.samples, sound.frames * sound.channels * sizeof(short));
    return voice;
}

// Sets the volume of everything played, from silent at 0 to full at 1.
void Audio::gain_set(float gain)
{
    if (device)
        SDL_SetAudioDeviceGain(device, gain);
}

void Audio::stop(int voice)
{
    if (voice >= 0)
        SDL_ClearAudioStream(voices[voice]);
}