Synthesis/Oscillator.cpp at master · arnolduis/Synthesis · GitHub

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#include "Oscillator.h"

void Oscillator::setMode(OscillatorMode mode) {
    mOscillatorMode = mode;
}

void Oscillator::setFrequency(double frequency) {
    mFrequency = frequency;
    updateIncrement();
}

void Oscillator::setSampleRate(double sampleRate) {
    mSampleRate = sampleRate;
    updateIncrement();
}

void Oscillator::updateIncrement() {
    mPhaseIncrement = mFrequency * 2 * mPI / mSampleRate;
}

void Oscillator::generate(double* buffer, int nFrames) {
    const double twoPI = 2 * mPI;
    switch (mOscillatorMode) {
        case OSCILLATOR_MODE_SINE:
            for (int i = 0; i < nFrames; i++) {
				buffer[i] = sin(mPhase);
				mPhase += mPhaseIncrement;
				while (mPhase >= twoPI) {
					mPhase -= twoPI;
				}
			}
            break;
        case OSCILLATOR_MODE_SAW:
            for (int i = 0; i < nFrames; i++) {
				buffer[i] = 1.0 - (2.0 * mPhase / twoPI);
				mPhase += mPhaseIncrement;
				while (mPhase >= twoPI) {
					mPhase -= twoPI;
				}
			}
            break;
        case OSCILLATOR_MODE_SQUARE:
            for (int i = 0; i < nFrames; i++) {
				if (mPhase <= mPI) {
					buffer[i] = 1.0;
				} else {
					buffer[i] = -1.0;
				}
				mPhase += mPhaseIncrement;
				while (mPhase >= twoPI) {
					mPhase -= twoPI;
				}
			}
            break;
        case OSCILLATOR_MODE_TRIANGLE:
            for (int i = 0; i < nFrames; i++) {
				double value = -1.0 + (2.0 * mPhase / twoPI);
				buffer[i] = 2.0 * (fabs(value) - 0.5);
				mPhase += mPhaseIncrement;
				while (mPhase >= twoPI) {
					mPhase -= twoPI;
				}
			}
            break;
    }
}

double Oscillator::nextSample() {
    double value = 0.0;
    if(isMuted) return value;

    switch (mOscillatorMode) {
        case OSCILLATOR_MODE_SINE:
            value = cos(mPhase);
            break;
        case OSCILLATOR_MODE_SAW:
            value = 1.0 - (2.0 * mPhase / twoPI);
            break;
        case OSCILLATOR_MODE_SQUARE:
            if (mPhase <= mPI) {
                value = 1.0;
            } else {
                value = -1.0;
            }
            break;
        case OSCILLATOR_MODE_TRIANGLE:
            value = -1.0 + (2.0 * mPhase / twoPI);
            value = 2.0 * (fabs(value) - 0.5);
            break;
    }
    mPhase += mPhaseIncrement;
    while (mPhase >= twoPI) {
        mPhase -= twoPI;
    }
    return value;
}