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94 lines
2.3 KiB
94 lines
2.3 KiB
// from: http://ll-plugins.nongnu.org/lv2pftci/#A_synth
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#include <lvtk/synth.hpp>
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#include "beep.peg"
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class BeepVoice : public lvtk::Voice {
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public:
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BeepVoice(double rate)
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: m_key(lvtk::INVALID_KEY), m_rate(rate), m_period(10), m_counter(0) {
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}
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void on(unsigned char key, unsigned char velocity) {
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m_key = key;
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m_period = m_rate * 4.0 / lvtk::key2hz(m_key);
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m_pos = std::rand() / float(RAND_MAX);
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m_envelope = velocity / 128.0;
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}
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void off(unsigned char velocity) {
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m_key = lvtk::INVALID_KEY;
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}
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unsigned char get_key() const {
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return m_key;
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}
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void render(uint32_t from, uint32_t to) {
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if (m_key == lvtk::INVALID_KEY)
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return;
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for (uint32_t i = from; i < to; ++i) {
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float pwm = *p(p_pwm) + (1 - *p(p_pwm)) * m_envelope;
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float s = -0.25 + 0.5 * (m_counter > m_period * (1 + pwm) / 2);
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m_counter = (m_counter + 1) % m_period;
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p(p_left)[i] += (1 - m_pos) * s;
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p(p_right)[i] += m_pos * s;
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if (m_envelope > 0)
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m_envelope -= 0.5 / m_rate;
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}
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}
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protected:
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unsigned char m_key;
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double m_rate;
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uint32_t m_period;
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uint32_t m_counter;
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float m_pos;
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float m_envelope;
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};
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class Beep : public lvtk::Synth<BeepVoice, Beep> {
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public:
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Beep(double rate)
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: lvtk::Synth<BeepVoice, Beep>(p_n_ports, p_midi),
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m_buf_pos(0), m_delay(rate / 3),
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m_l_buffer(new float[m_delay]), m_r_buffer(new float[m_delay]) {
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add_voices(new BeepVoice(rate), new BeepVoice(rate), new BeepVoice(rate));
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add_audio_outputs(p_left, p_right);
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for (unsigned i = 0; i < m_delay; ++i) {
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m_l_buffer[i] = 0;
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m_r_buffer[i] = 0;
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}
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}
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void post_process(uint32_t from, uint32_t to) {
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for (uint32_t i = from; i < to; ++i) {
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float mono = (p(p_left)[i] + p(p_right)[i]) / 2;
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p(p_left)[i] += m_l_buffer[m_buf_pos];
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p(p_right)[i] += m_r_buffer[m_buf_pos];
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float tmp = m_l_buffer[m_buf_pos];
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m_l_buffer[m_buf_pos] = 0.6 * (mono + m_r_buffer[m_buf_pos]);
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m_r_buffer[m_buf_pos] = 0.6 * tmp;
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m_buf_pos = (m_buf_pos + 1) % m_delay;
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p(p_left)[i] *= *p(p_gain);
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p(p_right)[i] *= *p(p_gain);
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}
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}
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protected:
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unsigned m_buf_pos;
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unsigned m_delay;
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float* m_l_buffer;
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float* m_r_buffer;
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};
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static int _ = Beep::register_class(p_uri);
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