65 lines
1.8 KiB
C++
65 lines
1.8 KiB
C++
#ifndef SYNTH_ENGINE_H
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#define SYNTH_ENGINE_H
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#include <stdint.h>
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/**
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* @class SynthEngine
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* @brief A portable, platform-agnostic synthesizer engine.
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*
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* This class contains the core digital signal processing (DSP) logic.
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* It has no dependencies on any specific hardware, OS, or audio API.
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* It works by filling a provided buffer with 16-bit signed audio samples.
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*
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* The oscillator uses a 32-bit unsigned integer as a phase accumulator,
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* which is highly efficient and avoids floating-point math in the audio loop,
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* making it ideal for the RP2040.
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*/
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class SynthEngine {
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public:
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enum Waveform {
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SAWTOOTH,
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SQUARE,
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SINE
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};
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/**
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* @brief Constructs the synthesizer engine.
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* @param sampleRate The audio sample rate in Hz (e.g., 44100).
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*/
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SynthEngine(uint32_t sampleRate);
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/**
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* @brief Fills a buffer with audio samples. This is the main audio callback.
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* @param buffer Pointer to the output buffer to be filled.
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* @param numFrames The number of audio frames (samples) to generate.
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*/
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void process(int16_t* buffer, uint32_t numFrames);
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/**
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* @brief Sets the frequency of the oscillator.
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* @param freq The frequency in Hz.
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*/
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void setFrequency(float freq);
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/**
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* @brief Sets the output volume.
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* @param vol Volume from 0.0 (silent) to 1.0 (full).
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*/
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void setVolume(float vol);
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/**
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* @brief Sets the oscillator's waveform.
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* @param form The waveform to use.
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*/
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void setWaveform(Waveform form);
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private:
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uint32_t _sampleRate;
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uint32_t _phase; // Phase accumulator for the oscillator.
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uint32_t _increment; // Phase increment per sample, determines frequency.
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float _volume;
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Waveform _waveform;
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};
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#endif // SYNTH_ENGINE_H
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