181 lines
3.4 KiB
C
181 lines
3.4 KiB
C
#include <inttypes.h>
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#ifndef PROGMEM
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#define PROGMEM /* nix */
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#endif
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#define arpeggio_DELAY 128
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#define BIT(x,n) (((x)&(1<<(n)))>>(n))
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#define SO(x) (sizeof((x))/sizeof(*(x)))
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#define A1 0
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#define As1 1
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#define B1 2
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#define C1 3
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#define Cs1 4
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#define D1 5
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#define Ds1 6
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#define E1 7
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#define F1 8
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#define Fs1 9
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#define G1 10
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#define Gs1 11
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#define A2 12
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#define Aa2 13
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#define B2 14
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#define C2 15
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#define Cs2 16
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#define D2 17
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#define Ds2 18
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#define E2 19
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#define F2 20
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#define Fs2 21
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#define G2 22
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#define Gs2 23
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#define HOLD 24
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static const PROGMEM uint8_t sin[] = {0, 49, 97, 141, 180, 212, 235, 250, 254, 250, 235, 212, 180, 141, 97, 49 };
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static const PROGMEM uint8_t octave_delay[] = { 36, 34, 32, 31, 29, 27, 26, 24, 23, 22, 20, 19, 18, 17, 16, 15, 14, 14, 13, 12, 11, 11, 10, 10 };
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static const PROGMEM struct { uint8_t a; uint8_t b; } synth[] = { { 7, 6}, {7, 5}, {7,5}, {6,5} };
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static const PROGMEM uint8_t arpeggiobase[] = { 3, 4, 4, 5 };
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static const PROGMEM uint8_t bassdrum[] = { 1, 1, 1, 1 };
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static const PROGMEM uint8_t snare[] = { 1, 1, 1, 1 };
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static const PROGMEM uint8_t melody[] =
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{
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D2, 0, D2, 0, 0, 0, 0, 0, D2, 0,
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A1, 0, B1, 0, D2, 0, D2, 0, D2, 0
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};
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static inline uint8_t next_note()
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{
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static uint8_t idx=0;
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const uint8_t v = melody[idx++];
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if(idx == SO(melody))
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idx = 0;
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return v;
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}
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static inline uint8_t next_rnd()
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{
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static unsigned short rnd = 13373;
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const uint8_t f1 = (rnd&(3<<13))>>13;
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const uint8_t f2 = (rnd&(3<<10))>>10;
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rnd <<=1;
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rnd |= f1^f2;
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return sin[((uint8_t)rnd)%SO(sin)];
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}
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static inline uint8_t next_sin(const uint8_t step)
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{
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static uint8_t sinoff=SO(sin)-1;
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sinoff += step;
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sinoff &= SO(sin) - 1;
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return sin[sinoff];
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}
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static inline uint8_t next_sample()
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{
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static uint16_t t=0;
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static uint8_t t8=0;
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static uint8_t barevent=0;
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static uint8_t bars=0;
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static uint8_t pc = 0;
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static uint8_t arpeggiocnt = 1;
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static uint8_t next_sin_time = 0;
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static uint8_t current_tone = 0;
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static uint8_t current_tone_base = 12;
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static unsigned short snaredelay;
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static unsigned short bassdelay;
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static uint8_t synth1;
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static uint8_t synth2;
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if(t%1024 == 0)
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{
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// implicit rollover of t roughly every 2 seconds
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if(t==0) t8 = 0;
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else ++t8;
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// determine which note we're playing
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barevent |= 8;
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if(t8%2 == 0) barevent |= 4;
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if(t8%4 == 0) barevent |= 2;
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if(t8%8 == 0) barevent |= 1;
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}
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else barevent = 0;
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if(barevent & 8)
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{
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current_tone = current_tone_base = next_note();
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}
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// increment bar counter
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if(barevent & 1) ++bars;
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// increment pattern counter
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if(bars % 8 == 0)
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{
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++pc;
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pc %= SO(arpeggiobase);
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}
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// increment arpeggio
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if(t % arpeggio_DELAY == 0)
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{
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// arpeggio
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++arpeggiocnt;
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arpeggiocnt &= 3;
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current_tone = current_tone_base + 4 * arpeggiocnt;
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}
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// render synth
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synth1 = ((t&(t>>(synth[pc].a))) | (t&(t>>(synth[pc].b))) << 1);
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if(t == next_sin_time)
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{
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next_sin_time += octave_delay[current_tone];
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synth2 = next_sin(5);
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}
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// mix two synth lines
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unsigned int mix = (synth1>>1) | (synth2>>1);
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// load or decrement snare delay
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if(barevent & 8 && snare[pc]) snaredelay = 800;
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else if(snaredelay > 0) --snaredelay;
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// add snare drum
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if(snaredelay>0) mix = (next_rnd() & 7) << 3;
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// load or decrement bass delay
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if(barevent & 4 && bassdrum[pc]) bassdelay = 800;
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else if(bassdelay > 0) --bassdelay;
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// add bass drum
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if(bassdelay>0) mix = next_sin(1);
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++t;
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// here comes the noize!
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return mix;
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}
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#ifndef NOISEPLUG_BIATCH
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int main()
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{
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while(1) putchar(next_sample());
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}
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#endif
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