blob: 89f947e029911eb1cea400ed0d0b09d048a5051c (
plain)
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
71
72
73
74
75
76
77
78
79
80
81
|
import Const, Op from require 'core'
class lfo extends Op
@doc: "(lfo freq [wave]) - low-frequency oscillator
oscillates between 0 and 1 at the frequency freq.
wave selects the wave shape from the following (default sin):
- sin
- saw
- tri"
tau = math.pi * 2
new: (...) =>
super ...
@phase = 0
default_wave = Const 'str', 'sin'
setup: (@freq, @wave=default_wave) =>
assert @freq, "lfo requires a frequency value"
L\trace "setup #{@}, freq=#{@freq}, wave=#{@wave}"
update: (dt) =>
@freq\update dt
@wave\update dt
@phase += dt * @freq\get!
@value = switch @wave\get!
when 'sin' then .5 + .5 * math.cos @phase * tau
when 'saw' then @phase % 1
when 'tri' then math.abs (2*@phase % 2) - 1
else error "unknown wave type"
class ramp extends Op
@doc: "(ramp period [max]) - sawtooth lfo
ramps from 0 to max (default same as ramp) once every period seconds"
new: (...) =>
super ...
@phase = 0
setup: (@period, @max) =>
assert @period, "tick requires a period value"
update: (dt) =>
@period\update dt
max = if @max
@max\update dt
@max\get!
else
@period\get!
@phase += dt / @period\get!
if @phase >= 1
@phase -= 1
@value = @phase * max
class tick extends Op
@doc: "(tick period) - count ticks
counts upwards every period seconds and returns the number of completed ticks."
new: (...) =>
super ...
@phase = 0
setup: (@period) =>
assert @period, "tick requires a period value"
update: (dt) =>
@period\update dt
@phase += dt / @period\get!
@value = math.floor @phase
{
:lfo
:ramp
:tick
}
|
