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dexed/lv2-examples/beep2.lv2tools/beep.cpp

95 lines
2.3 KiB

// from: http://ll-plugins.nongnu.org/lv2pftci/#A_synth
#include <lv2synth.hpp>
#include "beep.peg"
#include <cstdlib>
class BeepVoice : public LV2::Voice {
public:
BeepVoice(double rate)
: m_key(LV2::INVALID_KEY), m_rate(rate), m_period(10), m_counter(0) {
}
void on(unsigned char key, unsigned char velocity) {
m_key = key;
m_period = m_rate * 4.0 / LV2::key2hz(m_key);
m_pos = std::rand() / float(RAND_MAX);
m_envelope = velocity / 128.0;
}
void off(unsigned char velocity) {
m_key = LV2::INVALID_KEY;
}
unsigned char get_key() const {
return m_key;
}
void render(uint32_t from, uint32_t to) {
if (m_key == LV2::INVALID_KEY)
return;
for (uint32_t i = from; i < to; ++i) {
float pwm = *p(p_pwm) + (1 - *p(p_pwm)) * m_envelope;
float s = -0.25 + 0.5 * (m_counter > m_period * (1 + pwm) / 2);
m_counter = (m_counter + 1) % m_period;
p(p_left)[i] += (1 - m_pos) * s;
p(p_right)[i] += m_pos * s;
if (m_envelope > 0)
m_envelope -= 0.5 / m_rate;
}
}
protected:
unsigned char m_key;
double m_rate;
uint32_t m_period;
uint32_t m_counter;
float m_pos;
float m_envelope;
};
class Beep : public LV2::Synth<BeepVoice, Beep> {
public:
Beep(double rate)
: LV2::Synth<BeepVoice, Beep>(p_n_ports, p_midi),
m_buf_pos(0), m_delay(rate / 3),
m_l_buffer(new float[m_delay]), m_r_buffer(new float[m_delay]) {
add_voices(new BeepVoice(rate), new BeepVoice(rate), new BeepVoice(rate));
add_audio_outputs(p_left, p_right);
for (unsigned i = 0; i < m_delay; ++i) {
m_l_buffer[i] = 0;
m_r_buffer[i] = 0;
}
}
void post_process(uint32_t from, uint32_t to) {
for (uint32_t i = from; i < to; ++i) {
float mono = (p(p_left)[i] + p(p_right)[i]) / 2;
p(p_left)[i] += m_l_buffer[m_buf_pos];
p(p_right)[i] += m_r_buffer[m_buf_pos];
float tmp = m_l_buffer[m_buf_pos];
m_l_buffer[m_buf_pos] = 0.6 * (mono + m_r_buffer[m_buf_pos]);
m_r_buffer[m_buf_pos] = 0.6 * tmp;
m_buf_pos = (m_buf_pos + 1) % m_delay;
p(p_left)[i] *= *p(p_gain);
p(p_right)[i] *= *p(p_gain);
}
}
protected:
unsigned m_buf_pos;
unsigned m_delay;
float* m_l_buffer;
float* m_r_buffer;
};
static int _ = Beep::register_class(p_uri);