mss_track.c

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#include "mss_private.h"
 
#include <SDL3/SDL.h>
 
#define STEREO_BYTE_MAX 128.0f
#define MIN_FREQUENCY_RATIO 0.01f
#define MAX_FREQUENCY_RATIO 100.0f
 
float dttr_mss_track_gain(int volume, float master_gain, float headroom) {
    if (volume <= 0) {
        return 0.0f;
    }
 
    const float gain = master_gain * headroom;
    if (volume >= DTTR_MSS_DEFAULT_VOLUME) {
        return gain;
    }
 
    return gain * ((float)volume / DTTR_MSS_MAX_VOLUME);
}
 
void dttr_mss_track_apply_pan(MIX_Track *track, int pan) {
    if (!track) {
        return;
    }
 
    int left = 128;
    int right = 128;
    dttr_mss_pan_to_stereo_bytes(pan, &left, &right);
    MIX_StereoGains gains = {
        (float)left / STEREO_BYTE_MAX,
        (float)right / STEREO_BYTE_MAX,
    };
 
    MIX_SetTrackStereo(track, &gains);
}
 
void dttr_mss_track_play(MIX_Track *track, int sdl_loops) {
    if (!track) {
        return;
    }
 
    SDL_PropertiesID props = SDL_CreateProperties();
    if (!props) {
        MIX_PlayTrack(track, 0);
        return;
    }
 
    SDL_SetNumberProperty(props, MIX_PROP_PLAY_LOOPS_NUMBER, sdl_loops);
    MIX_PlayTrack(track, props);
    SDL_DestroyProperties(props);
}
 
float dttr_mss_track_frequency_ratio(int rate, int reference_rate) {
    if (rate <= 0 || reference_rate <= 0) {
        return 0.0f;
    }
 
    float ratio = (float)rate / (float)reference_rate;
    if (ratio < MIN_FREQUENCY_RATIO) {
        return MIN_FREQUENCY_RATIO;
    }
 
    if (ratio > MAX_FREQUENCY_RATIO) {
        return MAX_FREQUENCY_RATIO;
    }
 
    return ratio;
}
 
int dttr_mss_track_status(MIX_Track *track, int previous_status) {
    const int stopped_status = previous_status == DTTR_MSS_STATUS_STOPPED
                                   ? DTTR_MSS_STATUS_STOPPED
                                   : DTTR_MSS_STATUS_DONE;
    if (!track) {
        return stopped_status;
    }
 
    if (MIX_TrackPlaying(track) || MIX_TrackPaused(track)) {
        return DTTR_MSS_STATUS_PLAYING;
    }
 
    return stopped_status;
}