lfo, partial sub
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Gordon JC Pearce
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81904ead80
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a06266892e
@ -38,7 +38,6 @@ void AlphaOsc::initAudioPort(bool input, uint32_t index, AudioPort &port) {
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void AlphaOsc::activate() {
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// calculate filter coefficients and stuff
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printf("called activate()\n");
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omega = (1 << 31) / sampleRate * 130;
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lfoOmega = (1 << 31) / sampleRate * 3.51;
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omega = (130 / sampleRate) * (1 << 23);
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}
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@ -57,16 +56,23 @@ void AlphaOsc::run(const float **, float **outputs, uint32_t frames, const MidiE
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uint16_t i;
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uint32_t osc;
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uint8_t lfo;
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float saw, sqr, sub, wave;
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float saw, sqr, sub;
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float oct1, oct3, pwg;
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float sub1, sub2;
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float out, in;
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// steeply "logarithmic" curve similar to the Juno 106 LFO rate curve
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// goes from about 0.1Hz to about 60Hz because this "feels about right"
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// totally unscientific
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lfoOmega = (0.1 + (pwmrate / (1 + (1 - pwmrate) * 4.75)*60)) / sampleRate * (1<<23);
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omega = (130 / sampleRate) * (1 << 23);
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// calculate an entire block of samples
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for (i = 0; i < frames; i++) {
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// increment phase of saw counter
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// phase is a 32-bit counter because we're on a PC and we can afford to be profligate with silicon
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// phase is a 24-bit counter because we're on a PC and we can afford to be profligate with silicon
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// the actual Alpha Juno oscillators might well have been 8-bit for reasons loosely explained in the README
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phase += omega;
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@ -78,10 +84,10 @@ void AlphaOsc::run(const float **, float **outputs, uint32_t frames, const MidiE
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osc = phase >> 14;
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// LFO is 7-bit triangle
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lfo = (lfoPhase >> 24) & 0x7f;
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lfo = (lfoPhase & 0x80000000) ? lfo : 127 - lfo;
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lfo = (lfoPhase >> 16) & 0x7f;
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lfo = (lfoPhase & 0x00800000) ? lfo : 127 - lfo;
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pw = 0;
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pw = lfo * pwmdepth;
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// the oscillator outputs in the chip are probably digital signals
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// with the saw being the 8-bit outputs of the counter
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@ -95,13 +101,40 @@ void AlphaOsc::run(const float **, float **outputs, uint32_t frames, const MidiE
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sqr = (float)(osc & 0x80) != 0;
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oct1 = (float)(osc & 0x40) != 0;
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oct3 = (float)(osc & 0x10) != 0;
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sub1 = (float)(osc & 0x40) != 0;
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sub2 = (float)(osc & 0x10) != 0;
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// pulse width gate
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// lower seven bits of the saw osc, compared with PW setting
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pw = lfo*0.5;
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pwg = (float)((osc & 0x7f) >= pw) != 0;
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// calculate the oscillator output
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switch (submode) {
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case 0:
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sub = sub1;
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break; // one octave down
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case 1:
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sub = sub1 * sqr;
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break; // saw is fine, do nothing
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case 2:
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saw *= oct1; // pulsed
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break;
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case 3:
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saw *= pwg; // pwm
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break;
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case 4:
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saw *= oct3; // oct3 pulse
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break;
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case 5:
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saw *= oct1 * oct3; // both pulse
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break;
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}
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switch (sqrmode) {
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case 0:
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case 4:
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@ -137,6 +170,9 @@ void AlphaOsc::run(const float **, float **outputs, uint32_t frames, const MidiE
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break;
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}
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// mix the signals, probably done with some resistors in the chip
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in = (saw * 0.8) + (sqr * 0.63); // scaled similarly to Juno 106
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@ -27,10 +27,11 @@ class AlphaOsc : public Plugin {
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enum Parameters {
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pSqrMode,
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pSawMode,
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//pSubMode,
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pSubMode,
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pSubLevel,
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//pLFORate,
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//pLFODepth,
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pPWMRate,
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pPWMDepth,
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parameterCount
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};
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@ -59,7 +60,6 @@ class AlphaOsc : public Plugin {
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void deactivate() override;
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void run(const float **, float **outputs, uint32_t frames, const MidiEvent *midiEvents, uint32_t midiEventCount) override;
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private:
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double sampleRate;
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uint32_t omega, lfoOmega;
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@ -67,9 +67,10 @@ class AlphaOsc : public Plugin {
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uint8_t pw;
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float pwmrate, pwmdepth, sublevel;
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uint8_t sqrmode, sawmode, submode;
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float hpfx, hpfy;
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float hpfx = 0, hpfy = 0;
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DISTRHO_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(AlphaOsc);
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};
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@ -74,6 +74,61 @@ void AlphaOsc::initParameter(uint32_t index, Parameter& parameter) {
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parameter.enumValues.values = enumValues;
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}
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break;
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case pSubMode:
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// set up Sub slider
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parameter.hints = kParameterIsAutomatable | kParameterIsInteger;
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parameter.name = "Sub";
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parameter.symbol = "ao_sub";
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parameter.ranges.min = 0.0f;
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parameter.ranges.max = 5.0f;
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parameter.ranges.def = 1.0f;
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parameter.enumValues.count = 6;
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parameter.enumValues.restrictedMode = true;
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{
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ParameterEnumerationValue* const enumValues = new ParameterEnumerationValue[6];
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enumValues[0].value = 0;
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enumValues[0].label = "-1 oct";
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enumValues[1].value = 1;
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enumValues[1].label = "-1 oct 25%";
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enumValues[2].value = 2;
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enumValues[2].label = "-1 oct + 2 oct";
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enumValues[3].value = 3;
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enumValues[3].label = "-1 oct + 3 oct";
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enumValues[3].value = 4;
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enumValues[3].label = "-2 oct";
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enumValues[3].value = 5;
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enumValues[3].label = "-2 oct 25%";
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parameter.enumValues.values = enumValues;
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}
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break;
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case pSubLevel:
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// set up Sub slider
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parameter.hints = kParameterIsAutomatable;
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parameter.name = "Sub Level";
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parameter.symbol = "ao_sublev";
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parameter.ranges.min = 0.0f;
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parameter.ranges.max = 1.0f;
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parameter.ranges.def = 0.0f;
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break;
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case pPWMRate:
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// set up PWM Rate slider
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parameter.hints = kParameterIsAutomatable;
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parameter.name = "PWM Rate";
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parameter.symbol = "ao_pwmrate";
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parameter.ranges.min = 0.0f;
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parameter.ranges.max = 1.0f;
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parameter.ranges.def = 0.5f;
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break;
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case pPWMDepth:
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// set up PWM Depth slider
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parameter.hints = kParameterIsAutomatable;
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parameter.name = "PWM Depth";
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parameter.symbol = "ao_pwmdepth";
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parameter.ranges.min = 0.0f;
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parameter.ranges.max = 1.0f;
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parameter.ranges.def = 0.5f;
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break;
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}
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}
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@ -85,6 +140,18 @@ void AlphaOsc::setParameterValue(uint32_t index, float value) {
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case pSawMode:
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sawmode = value;
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break;
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case pSubMode:
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submode = value;
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break;
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case pSubLevel:
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sublevel = value;
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break;
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case pPWMDepth:
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pwmdepth = value;
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break;
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case pPWMRate:
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pwmrate = value;
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break;
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}
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// we don't need to handle a default condition
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// if there's a parameter left unhandled, it's probably
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