psyn/osc.h

#define LOOKUP_SAMPLES 3600

extern double _lookup_table[6][LOOKUP_SAMPLES + 1];

enum {
	OSC_SINE,
	OSC_SAW,
	OSC_TRIANGLE,
	OSC_SQUARE,
	OSC_MOOGSAW,
	OSC_EXP,
};

struct osc_t
{
	double freq;
	double step;
	double ramp;
	double level;

	uint8_t shape;
};

void osc_init();
void osc_setfreq(struct osc_t *osc, double freq);

static inline void osc_setphase(struct osc_t *osc, double phase)
{
	osc->ramp = LOOKUP_SAMPLES * phase;
}

static inline void osc_tick(struct osc_t *osc)
{
	osc->ramp += osc->step;
	if (osc->ramp > LOOKUP_SAMPLES) osc->ramp -= LOOKUP_SAMPLES;

	//uint32_t pos = floor(osc->ramp);

	//osc->sin = _sin_table[pos];
	//osc->saw = _saw_table[pos];
	//osc->tri = _tri_table[pos];
}

static inline double osc_getsample(const struct osc_t *osc)
{
	uint32_t pos = osc->ramp;
	return _lookup_table[osc->shape][pos] * osc->level;
}

static inline double osc_getsamplewithphase(const struct osc_t *osc, float phase)
{
	double sample = osc->ramp + phase * LOOKUP_SAMPLES;
	if (sample < 0.0) sample += LOOKUP_SAMPLES;
	else if (sample > LOOKUP_SAMPLES) sample -= LOOKUP_SAMPLES;

	uint32_t pos = sample;
	return _lookup_table[osc->shape][pos] * osc->level;
}