60 lines
1.1 KiB
C
60 lines
1.1 KiB
C
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#define LOOKUP_SAMPLES 3600
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extern double _lookup_table[6][LOOKUP_SAMPLES + 1];
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enum {
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OSC_SINE,
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OSC_SAW,
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OSC_TRIANGLE,
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OSC_SQUARE,
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OSC_MOOGSAW,
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OSC_EXP,
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};
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struct osc_t
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{
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double freq;
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double step;
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double ramp;
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double level;
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uint8_t shape;
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};
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void osc_init();
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void osc_setfreq(struct osc_t *osc, double freq);
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static inline void osc_setphase(struct osc_t *osc, double phase)
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{
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osc->ramp = LOOKUP_SAMPLES * phase;
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}
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static inline void osc_tick(struct osc_t *osc)
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{
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osc->ramp += osc->step;
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if (osc->ramp > LOOKUP_SAMPLES) osc->ramp -= LOOKUP_SAMPLES;
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//uint32_t pos = floor(osc->ramp);
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//osc->sin = _sin_table[pos];
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//osc->saw = _saw_table[pos];
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//osc->tri = _tri_table[pos];
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}
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static inline double osc_getsample(const struct osc_t *osc)
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{
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uint32_t pos = osc->ramp;
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return _lookup_table[osc->shape][pos] * osc->level;
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}
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static inline double osc_getsamplewithphase(const struct osc_t *osc, float phase)
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{
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double sample = osc->ramp + phase * LOOKUP_SAMPLES;
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if (sample < 0.0) sample += LOOKUP_SAMPLES;
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else if (sample > LOOKUP_SAMPLES) sample -= LOOKUP_SAMPLES;
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uint32_t pos = sample;
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return _lookup_table[osc->shape][pos] * osc->level;
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}
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