Cheaptune/Mixer.cpp at master · skywodd/Cheaptune · GitHub

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/* Dependencies */
#include <stdint.h>
#include "Mixer.h"
#include "AmplitudeModulator.h"

namespace CheapTune {

Mixer::Mixer(Amplitude_t globalAmplitude) :
		_channels(), /*_filter(),*/ _globalAmplitude(globalAmplitude) {
}

void Mixer::setGlobalAmplitude(Amplitude_t globalAmplitude) {
	_globalAmplitude = globalAmplitude;
}

Sample_t Mixer::mixTwoSamples(Sample_t _A, Sample_t _B) {
	int32_t Z, A = _A, B = _B;
	if (A < 0 && B < 0)
		Z = (A + B) - ((A * B) / SAMPLE_VMIN);
	else if ((A > 0) & (B > 0))
		Z = (A + B) - ((A * B) / SAMPLE_VMAX);
	else
		Z = A + B;
	return Z;
}

Sample_t Mixer::getSample() {

	/* Get the first channel sample */
	Sample_t sample = _channels[0].getSample();

	/* Get all other channels samples */
	for (unsigned char i = 1; i < CHANNELS_COUNT; ++i) {

		/* Get channel sample and mix them with the previous sample */
		sample = mixTwoSamples(sample, _channels[i].getSample());
	}

	/* Pass the resulting sample into the filter */
	//sample = _filter.computeSample(sample);

	/* Amplitude modulate the sample */
	sample = AmplitudeModulator::compute(sample, _globalAmplitude);

	/* Return the final sample value */
	return sample;
}

void Mixer::reset() {
	for (unsigned char i = 0; i < CHANNELS_COUNT; ++i)
		_channels[i].reset();
	//_filter.reset();
	_globalAmplitude = 255;
}

Channel& Mixer::channel(unsigned char index) {
	return _channels[index];
}

/*Filter& Mixer::filter() {
	return _filter;
}*/

}