1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
|
"""
Using the conditional function
**07-condition.py**
The `if` function let the user set different processing branches
according to the result of a condition. The syntax is:
.. code-block:: scheme
(if (condition) (then) (else))
The example below uses two conditional statements. The first one
adjusts the duty cycle of a pulse-width-modulation waveform and
the second one split the positive and negative parts of the wave.
A slider, controlling a user variable, sets the gain of the
negative part.
"""
from pyo import *
s = Server().boot()
expression = """
// Width of the duty cycle.
(var #thresh 0.5)
// Gain of the negative part of the waveform.
(var #gain 1)
// Running phase.
(let #sig (~ 172))
// If running phase is below threshold,
// then 1.0, else -1.0
(let #rect (
if (<= #sig #thresh) (1.0) (-1.0)
)
)
// If positive, pass through, else,
// modulated by #gain variable.
(if (>= #rect 0)
(#rect)
(* #gain #rect)
)
"""
expr = Expr(Sig(0), expression, mul=0.5)
expr.editor()
threshold = Sig(0.5)
threshold.ctrl([SLMap(0.01, 0.5, "lin", "value", 0.5)], title="Duty Cycle")
rectifier = Sig(1.0)
rectifier.ctrl([SLMap(0.0, 1.0, "lin", "value", 1.0)], title="Rectifier")
def change():
"Sends new values to user variables in the expression."
expr.setVar(["#thresh", "#gain"], [threshold.get(), rectifier.get()])
# Calls the change() function every 20 ms to update the user variables.
pat = Pattern(change, 0.025).play()
sc = Scope(expr)
pan = Pan(expr).out()
s.gui(locals())
|
