JailAudioSDL3/jail_audio.cpp

#include "jail_audio.h"
#include "stb_vorbis.c"
#include <SDL2/SDL.h>

#define JA_MAX_SIMULTANEOUS_CHANNELS 5

struct JA_Sound_t {
    Uint32  length {0};
    Uint8*  buffer {NULL};
};

enum JA_Channel_state { JA_CHANNEL_FREE, JA_CHANNEL_PLAYING, JA_CHANNEL_PAUSED };

struct JA_Channel_t {
    JA_Sound            sound;
    int                 pos {0};
    int                 times {0};
    JA_Channel_state    state { JA_CHANNEL_FREE };
};

enum JA_Music_state { JA_MUSIC_INVALID, JA_MUSIC_PLAYING, JA_MUSIC_PAUSED, JA_MUSIC_STOPPED };

struct JA_Music_t {
    int             samples {0};
    int             pos {0};
    int             times {0};
    short*          output {NULL};
    JA_Music_state  state {JA_MUSIC_INVALID};
};

JA_Music        current_music{NULL};
JA_Channel_t    channels[JA_MAX_SIMULTANEOUS_CHANNELS];

int             JA_freq {48000};
SDL_AudioFormat JA_format {AUDIO_S16};
Uint8           JA_channels {2};

void audioCallback(void * userdata, uint8_t * stream, int len) {
    SDL_memset(stream, 0, len);
    if (current_music != NULL && current_music->state == JA_MUSIC_PLAYING) {
        const int size = SDL_min(len, current_music->samples*2-current_music->pos);
        SDL_memcpy(stream, current_music->output+current_music->pos, size);
        current_music->pos += size/2;
        if (size < len) {
            if (current_music->times != 0) {
                SDL_memcpy(stream+size, current_music->output, len-size);
                current_music->pos = (len-size)/2;
                if (current_music->times > 0) current_music->times--;
            } else {
                current_music->pos = 0;
                current_music->state = JA_MUSIC_STOPPED;
            }
        }
    }
    // Mixar els channels mi amol
    for (int i = 0; i < JA_MAX_SIMULTANEOUS_CHANNELS; i++) {
        if (channels[i].state == JA_CHANNEL_PLAYING) {
            const int size = SDL_min(len, channels[i].sound->length - channels[i].pos);
            SDL_MixAudioFormat(stream, channels[i].sound->buffer + channels[i].pos, AUDIO_S16, size, 64);
            channels[i].pos += size;
            if (size < len) {
                if (channels[i].times != 0) {
                    SDL_MixAudioFormat(stream + size, channels[i].sound->buffer, AUDIO_S16, len-size, 64);
                    channels[i].pos = len-size;
                    if (channels[i].times > 0) channels[i].times--;
                } else {
                    JA_StopChannel(i);
                }
            }
        }
    }
}

void JA_Init(const int freq, const SDL_AudioFormat format, const int channels) {
    JA_freq = freq;
    JA_format = format;
    JA_channels = channels;
    SDL_AudioSpec audioSpec{JA_freq, JA_format, JA_channels, 0, 1024, 0, 0, audioCallback, NULL};
    SDL_AudioDeviceID sdlAudioDevice = SDL_OpenAudioDevice(NULL, 0, &audioSpec, NULL, 0);
    SDL_PauseAudioDevice(sdlAudioDevice, 0);
}

JA_Music JA_LoadMusic(const char* filename) {
    int chan, samplerate;
    JA_Music music = (JA_Music)SDL_malloc(sizeof(JA_Music_t));
    music->samples = stb_vorbis_decode_filename(filename, &chan, &samplerate, &music->output);

    SDL_AudioCVT cvt;
    SDL_BuildAudioCVT(&cvt, AUDIO_S16, chan, samplerate, JA_format, JA_channels, JA_freq);
    cvt.len = music->samples * chan * 2;
    cvt.buf = (Uint8 *) SDL_malloc(cvt.len * cvt.len_mult);
    SDL_memcpy(cvt.buf, music->output, cvt.len);
    SDL_ConvertAudio(&cvt);
    free(music->output);
    music->output = (short*)cvt.buf;

    music->pos = 0;
    music->state = JA_MUSIC_STOPPED;

    return music;
}

void JA_PlayMusic(JA_Music music, const int loop) {
    if (current_music != NULL) {
        current_music->pos = 0;
        current_music->state = JA_MUSIC_STOPPED;
    }
    current_music = music;
    current_music->pos = 0;
    current_music->state = JA_MUSIC_PLAYING;
    current_music->times = loop;
}

void JA_PauseMusic() {
    if (current_music == NULL || current_music->state == JA_MUSIC_INVALID) return;
    current_music->state = JA_MUSIC_PAUSED;
}

void JA_ResumeMusic() {
    if (current_music == NULL || current_music->state == JA_MUSIC_INVALID) return;
    current_music->state = JA_MUSIC_PLAYING;
}

void JA_StopMusic() {
    if (current_music == NULL || current_music->state == JA_MUSIC_INVALID) return;
    current_music->pos = 0;
    current_music->state = JA_MUSIC_STOPPED;
}

bool JA_IsMusicPlaying() {
    return current_music != NULL && current_music->state == JA_MUSIC_PLAYING;
}

void JA_DeleteMusic(JA_Music music) {
    if (current_music == music) current_music = NULL;
    free(music->output);
    free(music);
}

JA_Sound JA_LoadSound(const char* filename) {
    JA_Sound sound = new JA_Sound_t();
    SDL_AudioSpec wavSpec;
    SDL_LoadWAV(filename, &wavSpec, &sound->buffer, &sound->length);

    SDL_AudioCVT cvt;
    SDL_BuildAudioCVT(&cvt, wavSpec.format, wavSpec.channels, wavSpec.freq, JA_format, JA_channels, JA_freq);
    cvt.len = sound->length;
    cvt.buf = (Uint8 *) SDL_malloc(cvt.len * cvt.len_mult);
    SDL_memcpy(cvt.buf, sound->buffer, sound->length);
    SDL_ConvertAudio(&cvt);
    free(sound->buffer);
    sound->buffer = cvt.buf;
    sound->length = cvt.len_cvt;

    return sound;
}

int JA_PlaySound(JA_Sound sound, const int loop) {
    int channel = 0;
    while (channel < JA_MAX_SIMULTANEOUS_CHANNELS && channels[channel].state != JA_CHANNEL_FREE) { channel++; }
    if (channel == JA_MAX_SIMULTANEOUS_CHANNELS) channel = 0;

    channels[channel].sound = sound;
    channels[channel].times = loop;
    channels[channel].pos = 0;
    channels[channel].state = JA_CHANNEL_PLAYING;
    return channel;
}

void JA_DeleteSound(JA_Sound sound) {
    for (int i = 0; i < JA_MAX_SIMULTANEOUS_CHANNELS; i++) {
        if (channels[i].sound == sound) JA_StopChannel(i);
    }
    SDL_FreeWAV(sound->buffer);
    delete sound;
}

void JA_PauseChannel(const int channel) {
    if (channel == -1) {
        for (int i = 0; i < JA_MAX_SIMULTANEOUS_CHANNELS; i++) {
            if (channels[i].state == JA_CHANNEL_PLAYING) channels[i].state = JA_CHANNEL_PAUSED;
        }
    } else if (channel >= 0 && channel < JA_MAX_SIMULTANEOUS_CHANNELS) {
        if (channels[channel].state == JA_CHANNEL_PLAYING) channels[channel].state = JA_CHANNEL_PAUSED;
    }
}

void JA_ResumeChannel(const int channel) {
    if (channel == -1) {
        for (int i = 0; i < JA_MAX_SIMULTANEOUS_CHANNELS; i++) {
            if (channels[i].state == JA_CHANNEL_PAUSED) channels[i].state = JA_CHANNEL_PLAYING;
        }
    } else if (channel >= 0 && channel < JA_MAX_SIMULTANEOUS_CHANNELS) {
        if (channels[channel].state == JA_CHANNEL_PAUSED) channels[channel].state = JA_CHANNEL_PLAYING;
    }
}

void JA_StopChannel(const int channel) {
    if (channel == -1) {
        for (int i = 0; i < JA_MAX_SIMULTANEOUS_CHANNELS; i++) {
            channels[i].state = JA_CHANNEL_FREE;
            channels[i].pos = 0;
            channels[i].sound = NULL;
        }
    } else if (channel >= 0 && channel < JA_MAX_SIMULTANEOUS_CHANNELS) {
        channels[channel].state = JA_CHANNEL_FREE;
        channels[channel].pos = 0;
        channels[channel].sound = NULL;
    }
}

bool JA_IsChannelPlaying(const int channel) {
    if (channel < 0 || channel >= JA_MAX_SIMULTANEOUS_CHANNELS) return false;
    return channels[channel].state == JA_CHANNEL_PLAYING;
}