AudioMixer/hid_mixer.c

#include "hid_mixer.h"

#include "tusb.h"

#include <string.h>

static mixer_state_t g_state;
static int16_t enc1_acc;
static int16_t enc2_acc;
static uint8_t flags_acc;
static uint8_t pot_val;
static bool pot_dirty;
static bool need_send;

void hid_mixer_init(void) {
    memset(&g_state, 0, sizeof(g_state));
    g_state.ui_dirty = true;
    enc1_acc = 0;
    enc2_acc = 0;
    flags_acc = 0;
    pot_val = 50;
    pot_dirty = true;
    need_send = true;
}

mixer_state_t *hid_mixer_state(void) {
    return &g_state;
}

bool hid_mixer_mounted(void) {
    return tud_mounted() && tud_hid_ready();
}

void hid_mixer_add_enc1(int8_t delta) {
    enc1_acc += delta;
    if (enc1_acc > 127) {
        enc1_acc = 127;
    }
    if (enc1_acc < -127) {
        enc1_acc = -127;
    }
    need_send = true;
}

void hid_mixer_add_enc2(int8_t delta) {
    enc2_acc += delta;
    if (enc2_acc > 127) {
        enc2_acc = 127;
    }
    if (enc2_acc < -127) {
        enc2_acc = -127;
    }
    need_send = true;
}

void hid_mixer_set_e1_sw(bool pressed) {
    if (pressed) {
        flags_acc |= AUSIO_FLAG_E1_SW;
        need_send = true;
    }
}

void hid_mixer_set_e2_sw(bool pressed) {
    if (pressed) {
        flags_acc |= AUSIO_FLAG_E2_SW;
        need_send = true;
    }
}

void hid_mixer_set_pot(uint8_t pot_0_100) {
    if (pot_0_100 > 100) {
        pot_0_100 = 100;
    }
    if (pot_val != pot_0_100) {
        pot_val = pot_0_100;
        pot_dirty = true;
        need_send = true;
    }
}

static void send_input_if_needed(void) {
    if (!need_send && !pot_dirty) {
        return;
    }
    if (!tud_hid_ready()) {
        return;
    }

    uint8_t report[AUSIO_INPUT_SIZE];
    memset(report, 0, sizeof(report));
    report[0] = AUSIO_REPORT_ID_INPUT;
    report[1] = (uint8_t)(int8_t)enc1_acc;
    report[2] = (uint8_t)(int8_t)enc2_acc;
    report[3] = flags_acc;
    report[4] = pot_val;

    if (tud_hid_report(AUSIO_REPORT_ID_INPUT, report + 1, AUSIO_INPUT_SIZE - 1)) {
        enc1_acc = 0;
        enc2_acc = 0;
        flags_acc = 0;
        pot_dirty = false;
        need_send = false;
    }
}

void hid_mixer_task(void) {
    tud_task();
    bool alive = tud_mounted();
    if (alive != g_state.host_alive) {
        g_state.host_alive = alive;
        g_state.ui_dirty = true;
    }
    send_input_if_needed();
}

/* TinyUSB callbacks */
void tud_hid_set_report_cb(uint8_t itf, uint8_t report_id, hid_report_type_t report_type,
                           uint8_t const *buffer, uint16_t bufsize) {
    (void)itf;
    (void)report_type;

    /* With report ID, TinyUSB may pass id separately and buffer without id,
       or include id in buffer depending on path. Handle both. */
    const uint8_t *p = buffer;
    uint16_t len = bufsize;

    if (report_id == 0 && len > 0) {
        report_id = p[0];
        p++;
        len--;
    }

    if (report_id != AUSIO_REPORT_ID_OUTPUT) {
        return;
    }
    if (len < (AUSIO_HDR_SIZE - 1)) {
        return;
    }

    /* p[0]=count, p[1]=selected, p[2]=master, p[3]=page, p[4]=n_vis (no report id) */
    mixer_state_t next = g_state;
    next.session_count = p[0];
    next.selected = p[1];
    next.master_vol = p[2];
    next.page_start = p[3];
    next.n_visible = p[4];
    if (next.n_visible > AUSIO_MAX_VISIBLE) {
        next.n_visible = AUSIO_MAX_VISIBLE;
    }
    uint16_t off = 5;
    for (uint8_t i = 0; i < next.n_visible; i++) {
        if (off + AUSIO_SLOT_SIZE > len) {
            next.n_visible = i;
            break;
        }
        next.visible[i].vol = p[off];
        memcpy(next.visible[i].name, &p[off + 1], AUSIO_NAME_CHARS);
        next.visible[i].name[AUSIO_NAME_CHARS] = '\0';
        off = (uint16_t)(off + AUSIO_SLOT_SIZE);
    }

    bool changed =
        next.session_count != g_state.session_count ||
        next.selected != g_state.selected ||
        next.master_vol != g_state.master_vol ||
        next.page_start != g_state.page_start ||
        next.n_visible != g_state.n_visible;
    if (!changed) {
        for (uint8_t i = 0; i < next.n_visible; i++) {
            if (next.visible[i].vol != g_state.visible[i].vol ||
                memcmp(next.visible[i].name, g_state.visible[i].name, AUSIO_NAME_CHARS) != 0) {
                changed = true;
                break;
            }
        }
    }

    if (changed) {
        next.ui_dirty = true;
        next.host_alive = g_state.host_alive;
        g_state = next;
    }
}

uint16_t tud_hid_get_report_cb(uint8_t itf, uint8_t report_id, hid_report_type_t report_type,
                               uint8_t *buffer, uint16_t reqlen) {
    (void)itf;
    (void)report_id;
    (void)report_type;
    (void)buffer;
    (void)reqlen;
    return 0;
}

void tud_hid_report_complete_cb(uint8_t itf, uint8_t const *report, uint16_t len) {
    (void)itf;
    (void)report;
    (void)len;
}