tone-generator/tone.hpp

#pragma once

#include <inttypes.h>
#include <avr/pgmspace.h>

struct Tone {
	uint32_t phase;
	uint16_t frequency;
	uint8_t amplitude;

	inline static int8_t sin_lookup[256];

	static void init();

	inline bool active() const {
		return amplitude > 0;
	}

	inline void update(uint32_t t) {
		phase += t * frequency;
	}

	inline int get() const {
		uint8_t id = phase >> 12;
		return (int)sin_lookup[id] * amplitude;
	}
};