Files
forge-steel/src/tempo.c
T

128 lines
2.6 KiB
C

#include <math.h>
#include <string.h>
#include <sys/time.h>
#include "types.h"
#include "config.h"
#include "tempo.h"
static long now() {
struct timeval now;
gettimeofday(&now, NULL);
return now.tv_sec * 1000 + now.tv_usec / 1000;
}
static void reset_tap_chain(Tempo *tempo, long t) {
tempo->last_reset = t;
tempo->last_tap = 0;
tempo->taps_in_chain = 0;
tempo->tap_duration_index = 0;
tempo->last_tap_skipped = false;
memset(tempo->tap_durations, 0, sizeof(tempo->tap_durations));
}
void tempo_init(Tempo *tempo) {
long t;
t = now();
reset_tap_chain(tempo, t);
}
static bool is_chain_active(const Tempo tempo, long t) {
return (tempo.last_tap + MAX_BEAT_LENGTH) > t &&
(tempo.last_tap + (tempo.beat_length * BEATS_UNTIL_CHAIN_RESET)) > t;
}
static long get_average_tap_duration(const Tempo tempo) {
unsigned int amount;
long running_total;
long average_tap_duration;
amount = tempo.taps_in_chain - 1;
if (amount > TOTAL_TAP_VALUES) {
amount = TOTAL_TAP_VALUES;
}
running_total = 0;
for (unsigned int i = 0; i < amount; i++) {
running_total += tempo.tap_durations[i];
}
if (amount == 0) {
amount = 1; // should never happen
}
average_tap_duration = running_total / amount;
if (average_tap_duration < MIN_BEAT_LENGTH) {
return MIN_BEAT_LENGTH;
}
return average_tap_duration;
}
static void add_tap_to_chain(Tempo *tempo, long t) {
long duration;
duration = t - tempo->last_tap;
tempo->last_tap = t;
tempo->taps_in_chain++;
if (tempo->taps_in_chain == 1) {
return;
}
if (tempo->taps_in_chain > 2 && !tempo->last_tap_skipped &&
duration > tempo->beat_length * SKIPPED_TAP_THRESHOLD_LOW &&
duration < tempo->beat_length * SKIPPED_TAP_THRESHOLD_HIGH) {
duration = duration >> 1;
tempo->last_tap_skipped = true;
} else {
tempo->last_tap_skipped = false;
}
tempo->tap_durations[tempo->tap_duration_index++] = duration;
if (tempo->tap_duration_index == TOTAL_TAP_VALUES) {
tempo->tap_duration_index = 0;
}
tempo->beat_length = get_average_tap_duration(*tempo);
tempo->tempo = 60000.0 / tempo->beat_length;
}
void tempo_set(Tempo *tempo, float value) {
tempo->tempo = value;
tempo->beat_length = 60000.0 / value;
}
void tempo_tap(Tempo *tempo) {
long t;
t = now();
if (!is_chain_active(*tempo, t)) {
reset_tap_chain(tempo, t);
}
add_tap_to_chain(tempo, t);
}
double tempo_total(const Tempo *tempo) {
long t;
t = now();
return (double)(t - tempo->last_reset) / (double)tempo->beat_length;
}
double tempo_progress(const Tempo *tempo, double modulo) {
return fmod(tempo_total(tempo), modulo);
}