104 lines
2.8 KiB
C
104 lines
2.8 KiB
C
#include <string.h>
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#include <math.h>
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typedef struct plugin {
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float sample_rate;
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size_t delay_line_length;
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float gain;
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float delay;
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float cutoff;
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char bypass;
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float * delay_line;
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size_t delay_line_cur;
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float z1;
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float cutoff_k;
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} plugin;
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static void plugin_init(plugin *instance) {
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}
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static void plugin_fini(plugin *instance) {
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}
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static void plugin_set_sample_rate(plugin *instance, float sample_rate) {
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instance->sample_rate = sample_rate;
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instance->delay_line_length = ceilf(sample_rate) + 1;
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}
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static size_t plugin_mem_req(plugin *instance) {
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return instance->delay_line_length * sizeof(float);
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}
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static void plugin_mem_set(plugin *instance, void *mem) {
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instance->delay_line = mem;
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}
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static void plugin_reset(plugin *instance) {
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memset(instance->delay_line, 0, instance->delay_line_length * sizeof(float));
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instance->delay_line_cur = 0;
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instance->z1 = 0.f;
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instance->cutoff_k = 1.f;
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}
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static void plugin_set_parameter(plugin *instance, size_t index, float value) {
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switch (index) {
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case 0:
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instance->gain = powf(10.f, 0.05f * value);
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break;
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case 1:
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instance->delay = 0.001f * value;
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break;
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case 2:
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instance->cutoff = value;
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break;
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case 3:
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instance->bypass = value >= 0.5f;
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break;
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}
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}
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static float plugin_get_parameter(plugin *instance, size_t index) {
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// no output parameters
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return 0.f;
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}
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static size_t calc_index(size_t cur, size_t delay, size_t len) {
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return (cur < delay ? cur + len : cur) - delay;
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}
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static void plugin_process(plugin *instance, const float **inputs, float **outputs, size_t n_samples) {
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size_t delay = roundf(instance->sample_rate * instance->delay);
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const float mA1 = instance->sample_rate / (instance->sample_rate + 6.283185307179586f * instance->cutoff * instance->cutoff_k);
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for (size_t i = 0; i < n_samples; i++) {
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instance->delay_line[instance->delay_line_cur] = inputs[0][i];
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const float x = instance->delay_line[calc_index(instance->delay_line_cur, delay, instance->delay_line_length)];
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instance->delay_line_cur++;
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if (instance->delay_line_cur == instance->delay_line_length)
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instance->delay_line_cur = 0;
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const float y = x + mA1 * (instance->z1 - x);
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instance->z1 = y;
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outputs[0][i] = instance->bypass ? inputs[0][i] : instance->gain * y;
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}
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}
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static void plugin_note_on(plugin *instance, size_t index, uint8_t note, float velocity) {
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instance->cutoff_k = powf(2.f, (1.f / 12.f) * (note - 60));
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}
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static void plugin_note_off(plugin *instance, size_t index, uint8_t note, float velocity) {
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}
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static void plugin_all_sounds_off(plugin *instance, size_t index) {
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}
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static void plugin_all_notes_off(plugin *instance, size_t index) {
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}
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static void plugin_channel_pressure(plugin *instance, size_t index, float value) {
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}
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static void plugin_pitch_bend_change(plugin *instance, size_t index, float value) {
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}
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