94 lines
2.7 KiB
C++
94 lines
2.7 KiB
C++
/*
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Peacock-8 VA polysynth
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Copyright 2025 Gordon JC Pearce <gordonjcp@gjcp.net>
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <math.h>
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#include "module.hpp"
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// antialiasing using polybleps, as described in KVRAudio forum by Mystran
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static inline float poly3blep0(float t) {
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float t2 = t * t;
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return t * t2 - 0.5f * t2 * t2;
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}
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static inline float poly3blep1(float t) {
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return -poly3blep0(1 - t);
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}
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Voice::Voice() {
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omega = 0.0;
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theta = 0.0;
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amp = 0;
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}
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void Voice::on(uint8_t note) {
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omega = 261.63 * powf(2, (note - 60) / 12.0f) / 48000.0f;
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amp = 1;
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}
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void Voice::off() {
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amp = 0;
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}
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void Voice::run(Module *m, float* buffer, uint32_t samples) {
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// carry out per-voice calculations for each block of samples
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float out, t;
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for (uint32_t i = 0; i < samples; i++) {
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out = delay;
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delay = 0;
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theta += omega;
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while (true) {
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if (pulseStage == 0) {
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if (theta < m->pw) break;
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t = (theta - m->pw) / (lastpw - m->pw + omega);
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out -= poly3blep0(t) * m->square;
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delay -= poly3blep1(t) * m->square;
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pulseStage = 1;
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}
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if (pulseStage == 1) {
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if (theta < 1) break; // no need to blep yet
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t = (theta - 1) / omega; // scaled remainder of phase
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out += poly3blep0(t) * (m->saw + m->square);
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delay += poly3blep1(t) * (m->saw + m->square);
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out -= poly3blep0(t) * (m->sub * subosc);
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delay -= poly3blep1(t) * (m->sub * subosc);
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pulseStage = 0;
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subosc = -subosc;
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theta -= 1;
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}
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}
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delay += m->saw * (1 - (2 * theta));
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delay += m->square * (pulseStage ? -1.f : 1.f);
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delay += m->sub * subosc;
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// delay += (1-(m->noisegen/(float)(1<<30))) * m->noise; FIXME figure out what to do about noise
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buffer[i] = 0.125 * amp * out;
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lastpw = m->pw;
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}
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}
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