desc: trigger - Sends a short trigger pulse when the gate opens

slider1:0<0,22000,10>HPF (Hz)
slider2:22000<10,22000,10>LPF (Hz)
slider3:0<0,1,1{-12,-24}>Slope (dB/oct)
slider4:-20<-120,6,1>Threshold (dB)
//slider5:1000<30,5000,1>pulse frequency (Hz)
slider6:-3<-120,6,1>Dry (dB)
slider7:-3<-120,6,1>Filtered (dB)
slider8:-3<-120,6,1>Pulse (dB)
slider9:200<0,1000,0.1>Hold (ms)

@init

    // pdc
    pdc_delay = 64;
    pdc_bot_ch = 0;
    pdc_top_ch = 2;

    in_buffer = 0;                                                  // starting position of the input buffer
    eq_buffer = 2 * pdc_delay;                                      // starting position of the eq:ed buffer
    pulse_buffer = 4 * pdc_delay;                                   // starting position of the pulse buffer

    buf_pos = 0;
    last_pulse_pos = 0;

    // precalculate sinus pulse
    pulse = 6 * pdc_delay;                                          // starting position of the pulse waveform
    frequency = 1000;                                               // in Hz
    fadeout_time = 20;                                              // in ms
    fadeout_length = fadeout_time * srate / 1000;                   // in samples
    fadeout_length |= 0;                                            // convert to integer
    i = 0;
    while (
        pulse[i] = sin(i * 2 * $pi * frequency / srate) * (fadeout_length - i) / fadeout_length;
        i += 1;
        i < fadeout_length;
    );

@slider

    hpf_f0 = slider1;
    lpf_f0 = slider2;
    slider1 == 0 ? hpf_on = 0 : hpf_on = 1;
    slider2 == 22000 ? lpf_on = 0 : lpf_on = 1;
    db24_on = slider3;

    threshold = 2 ^ (slider4 / 6);

    slider6 == -120 ? dry_gain = 0 : dry_gain = 2 ^ (slider6 / 6);
    slider7 == -120 ? eq_gain = 0 : eq_gain = 2 ^ (slider7 / 6);
    slider8 == -120 ? pulse_gain = 0 : pulse_gain = 2 ^ (slider8 / 6);
    hold = slider9 * srate / 1000;


@sample

    in_buffer[buf_pos] = spl0;                                      // save original samples for later
    in_buffer[buf_pos+1] = spl1;

    // filter section
    eq_buffer[buf_pos] = spl0;
    eq_buffer[buf_pos + 1] = spl1;

    spl0 = in_buffer[buf_pos] * dry_gain + eq_buffer[buf_pos] * eq_gain + pulse_buffer[buf_pos] * pulse_gain;
    spl1 = in_buffer[buf_pos + 1] * dry_gain + eq_buffer[buf_pos + 1] * eq_gain + pulse_buffer[buf_pos + 1] * pulse_gain;
    buf_pos < pdc_delay * 2 ? buf_pos += 2 : buf_pos = 0;