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synthio: Add default triangle waveform to LFO, improve docs

This commit is contained in:
Jeff Epler 2023-05-22 10:53:29 -05:00
parent 1059c99f6e
commit 8626130af7
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GPG Key ID: D5BF15AB975AB4DE
1 changed files with 13 additions and 6 deletions
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19
shared-bindings/synthio/LFO.c
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@ -33,13 +33,17 @@
#include "shared-bindings/synthio/LFO.h"
#include "shared-module/synthio/LFO.h"
STATIC const uint16_t triangle[] = {0, 32767, 0, -32767};
//| class LFO:
//| """A low-frequency oscillator block
//|
//| Every `rate` seconds, the output of the LFO cycles through its `waveform`.
//| The output at any particular moment is ``waveform[idx] * scale + offset``.
//|
//| `rate`, `offset`, `scale`, and `once` can be changed at run-time. `waveform` may be mutated.
//| If `waveform` is None, a triangle waveform is used.
//|
//| `rate`, `phase_offset`, `offset`, `scale`, and `once` can be changed at run-time. `waveform` may be mutated.
//|
//| `waveform` must be a ``ReadableBuffer`` with elements of type ``'h'``
//| (16-bit signed integer). Internally, the elements of `waveform` are scaled
@ -58,18 +62,18 @@
//|
//| def __init__(
//| self,
//| waveform: ReadableBuffer,
//| waveform: ReadableBuffer = None,
//| *,
//| rate: BlockInput = 1.0,
//| scale: BlockInput = 1.0,
//| offset: BlockInput = 0,
//| phase_offset: BlockInput = 0,
//| offset: BlockInput = 0.0,
//| phase_offset: BlockInput = 0.0,
//| once=False,
//| interpolate=True
//| ):
//| pass
static const mp_arg_t lfo_properties[] = {
{ MP_QSTR_waveform, MP_ARG_OBJ | MP_ARG_REQUIRED, {.u_obj = NULL } },
{ MP_QSTR_waveform, MP_ARG_OBJ, {.u_obj = MP_ROM_NONE } },
{ MP_QSTR_rate, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = MP_ROM_INT(1) } },
{ MP_QSTR_scale, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = MP_ROM_INT(1) } },
{ MP_QSTR_offset, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = MP_ROM_INT(0) } },
@ -87,7 +91,10 @@ STATIC mp_obj_t synthio_lfo_make_new(const mp_obj_type_t *type_in, size_t n_args
synthio_lfo_obj_t *self = m_new_obj(synthio_lfo_obj_t);
self->base.base.type = &synthio_lfo_type;
synthio_synth_parse_waveform(&self->waveform_bufinfo, args[ARG_waveform].u_obj);
self->waveform_bufinfo = ((mp_buffer_info_t) {.buf = triangle, .len = MP_ARRAY_SIZE(triangle)});
if (args[ARG_waveform].u_obj != mp_const_none) {
synthio_synth_parse_waveform(&self->waveform_bufinfo, args[ARG_waveform].u_obj);
}
self->waveform_obj = args[ARG_waveform].u_obj;
self->base.last_tick = synthio_global_tick;