02-score-calls.py - Sequencing the function calls. — Pyo 1.0.4 documentation

Pyo 1.0.4 documentation

# 02-score-calls.py - Sequencing the function calls.

The Score object takes in input an audio stream containing integers and any time the integer changes, it calls a function with a generic name to which the integer is added. This allows the user to build a sequence of functions and to control how and when each one is called.

This example uses a metronome and a counter to generate a stream of integers at a specific rate. The called functions change the oscillator frequencies to produce a chords sequence.

    from pyo import *

    s = Server().boot()

    # A four-streams oscillator to produce a chord.
    osc = SineLoop(freq=[0, 0, 0, 0], feedback=0.05, mul=0.2)
    rev = WGVerb(osc.mix(2), feedback=0.8, cutoff=4000, bal=0.2).out()

    def set_osc_freqs(notes):
        # PyoObject.set() method allow to change the value of an attribute
        # with an audio ramp to smooth out the change.
        osc.set(attr="freq", value=midiToHz(notes), port=0.005)

    # The sequence of functions (some call set_osc_freqs to change the notes).
    def event_0():
        set_osc_freqs([60, 64, 67, 72])

    def event_1():
        pass

    def event_2():
        set_osc_freqs([60, 64, 67, 69])

    def event_3():
        pass

    def event_4():
        set_osc_freqs([60, 65, 69, 76])

    def event_5():
        pass

    def event_6():
        set_osc_freqs([62, 65, 69, 74])

    def event_7():
        set_osc_freqs([59, 65, 67, 74])

    # Integer generator (more about triggers in section 12-triggers)
    metro = Metro(time=0.5).play()
    count = Counter(metro, min=0, max=8)

    # Score calls the function named "event_" + count. (if count is 3,
    # function named "event_3" is called without argument.
    score = Score(count, fname="event_")

    s.gui(locals())