95 lines
2.2 KiB
C
95 lines
2.2 KiB
C
#include "./delay.h"
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#include <assert.h>
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#include <stddef.h>
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#include <stdint.h>
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#include "util/math/algorithm.h"
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#include "util/math/rational.h"
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#include "util/memory/memory.h"
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#include "./effect.h"
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#include "./format.h"
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struct jukebox_delay_t {
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jukebox_effect_t super;
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jukebox_format_t format;
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float source;
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float feedback;
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size_t length;
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size_t offset;
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size_t cursor;
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float buffer[1];
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};
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static void jukebox_delay_affect_(
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jukebox_effect_t* effect, const jukebox_effect_pcm_t* pcm) {
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assert(effect != NULL);
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assert(pcm != NULL);
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jukebox_delay_t* d = (typeof(d)) effect;
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const int32_t ch = d->format.channels;
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const size_t pcmlen = pcm->frames*ch;
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for (size_t i = 0; i < pcmlen; ++i) {
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float* bufoff = &d->buffer[d->offset];
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float* bufcur = &d->buffer[d->cursor];
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float* pcmptr = &pcm->ptr[i];
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*bufoff *= d->feedback;
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*bufoff += *pcmptr * d->source;
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*pcmptr += *bufcur;
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if (MATH_ABS(*pcmptr) >= 1.0f) {
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*pcmptr = MATH_SIGN(*pcmptr) * 0.99f;
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}
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if (++d->offset >= d->length) d->offset = 0;
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if (++d->cursor >= d->length) d->cursor = 0;
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}
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}
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jukebox_delay_t* jukebox_delay_new(
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const jukebox_format_t* format,
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const rational_t* duration,
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float source_attenuation,
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float feedback_attenuation) {
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assert(jukebox_format_valid(format));
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assert(rational_valid(duration));
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assert(MATH_FLOAT_VALID(source_attenuation));
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assert(MATH_FLOAT_VALID(feedback_attenuation));
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rational_t dur_r = rational(format->channels*duration->num, duration->den);
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rational_normalize(&dur_r, format->sample_rate);
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const size_t length = dur_r.num;
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jukebox_delay_t* d =
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memory_new(sizeof(*d) + (length-1)*sizeof(d->buffer[0]));
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*d = (typeof(*d)) {
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.super = {
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.vtable = {
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.affect = jukebox_delay_affect_,
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},
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},
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.format = *format,
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.source = source_attenuation,
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.feedback = feedback_attenuation,
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.length = length,
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.offset = dur_r.num,
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.cursor = 0,
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};
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for (size_t i = 0; i < d->length; ++i) d->buffer[i] = 0;
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return d;
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}
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void jukebox_delay_delete(jukebox_delay_t* delay) {
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if (delay == NULL) return;
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memory_delete(delay);
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}
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