Split filter off to separate file

Put voice initialization in one place

CMakeLists.txt

@@ -23,6 +23,8 @@ SET(SOURCES
 	engine.h
 	env.c
 	env.h
+	filter.c
+	filter.h
 	osc.c
 	osc.h
 	psyn.c

engine.c

@@ -4,6 +4,7 @@
 #include <math.h>
 #include "env.h"
 #include "osc.h"
+#include "filter.h"
 #include "voice.h"
 #include "engine.h"
 #include "psyn.h"
@@ -54,15 +55,15 @@ void engine_startvoice(struct engine_t *engine, uint8_t note, uint8_t velocity)
 	for (i = 0; i < NUM_POLYPHONY; i++, v++) {
 		if (v->playing) continue;
 
+		/* Constant voice parameters */
 		v->playing  = true;
 		v->sample   = 0;
 		v->released = 0;
 		v->note     = note;
 		v->velocity = velocity / 127.0;
 
-		osc_setfreq(&v->osc[0], _freqs[note]);
-		osc_setfreq(&v->osc[1], _freqs[note] * 2);
-		osc_setfreq(&v->osc[2], _freqs[note] * 5);
+		/* Voice parameters which determine sound */
+		voice_init(v, _freqs[note]);
 
 		return;
 	}

filter.c

@@ -0,0 +1,33 @@
+#include <math.h>
+#include "filter.h"
+#include "psyn.h"
+
+void filter_init_rc(struct filter_t *filter, double R, double C)
+{
+	filter->k = 1.0 / (R * C) / _sample_rate;
+	filter->r = 1.0;
+}
+
+void filter_init_freq(struct filter_t *filter, double freq)
+{
+	filter->k = (2.0 * M_PI * freq) / _sample_rate;
+	filter->r = 1.0;
+}
+
+void filter_run_lp(struct filter_t *filter, double left, double right)
+{
+	filter->v_l += filter->k * (left - filter->last_out_l);
+	filter->v_r += filter->k * (right - filter->last_out_r);
+	filter->last_out_l = filter->v_l;
+	filter->last_out_r = filter->v_r;
+	filter->v_l *= filter->r;
+	filter->v_r *= filter->r;
+}
+
+void filter_run_hp(struct filter_t *filter, double left, double right)
+{
+	filter->last_out_l = filter->k * (filter->last_out_l + left - filter->last_in_l);
+	filter->last_out_r = filter->k * (filter->last_out_r + right - filter->last_in_r);
+	filter->last_in_l = left;
+	filter->last_in_r = right;
+}

filter.h

@@ -0,0 +1,16 @@
+
+struct filter_t {
+	double k;
+	double r;
+	double v_l;
+	double v_r;
+	double last_in_l;
+	double last_in_r;
+	double last_out_l;
+	double last_out_r;
+};
+
+void filter_init_rc(struct filter_t *filter, double R, double C);
+void filter_init_freq(struct filter_t *filter, double freq);
+void filter_run_lp(struct filter_t *filter, double left, double right);
+void filter_run_hp(struct filter_t *filter, double left, double right);

psyn.c

@@ -6,6 +6,7 @@
 #include "lv2_event_helpers.h"
 #include "lv2_uri_map.h"
 #include "osc.h"
+#include "filter.h"
 #include "voice.h"
 #include "engine.h"
 #include "psyn.h"

rng.h

@@ -0,0 +1,10 @@
+
+static inline double rng()
+{
+	static double b = 19.1919191919191919191919;
+
+	b += 19.0;
+	b *= b;
+	b -= (int)b;
+	return (b - 0.5) * 2.0;
+}

voice.c

@@ -4,8 +4,22 @@
 #include <math.h>
 #include "osc.h"
 #include "env.h"
+#include "filter.h"
 #include "voice.h"
 #include "psyn.h"
+#include "rng.h"
+
+void voice_init(struct voice_t *voice, double freq)
+{
+//	filter_init_rc(&voice->fil[0], 1000.0, 0.000000047);
+//	filter_init_rc(&voice->fil[1], 47000.0, 0.000000047);
+	filter_init_freq(&voice->fil[0], 2000.0);
+	filter_init_freq(&voice->fil[1], 150.0);
+
+	osc_setfreq(&voice->osc[0], freq);
+	osc_setfreq(&voice->osc[1], freq * 1.2);
+	osc_setfreq(&voice->osc[2], freq * 5);
+}
 
 static inline void voice_tick(struct voice_t *voice)
 {
@@ -17,17 +31,6 @@ static inline void voice_tick(struct voice_t *voice)
 	voice->sample++;
 }
 
-static double _R = 4700.0;
-static double _C = 0.000000047;
-
-static inline void voice_filter(struct voice_t *voice, float l, float r)
-{
-	double k = 1.0 / (_R * _C) / _sample_rate;
-
-	voice->last_l += k * (l - voice->last_l);
-	voice->last_r += k * (r - voice->last_r);
-}
-
 void voice_run(struct voice_t *voice, uint32_t samples, float *left, float *right)
 {
 //	uint32_t pos;
@@ -47,8 +50,8 @@ void voice_run(struct voice_t *voice, uint32_t samples, float *left, float *righ
 
 	amplitude *= voice->velocity;
 
-	l = amplitude * voice->osc[0].saw;
-	r = amplitude * voice->osc[0].saw;
+	l = amplitude * voice->osc[0].sin * (1.0 + rng() * 0.25);
+	r = amplitude * voice->osc[0].sin * (1.0 + rng() * 0.25);
 
 	amplitude = env_getamplitude(&_env2, voice->sample, voice->released) * voice->velocity * voice->velocity * 1.5;
 
@@ -57,9 +60,13 @@ void voice_run(struct voice_t *voice, uint32_t samples, float *left, float *righ
 		r += amplitude * voice->osc[1].tri * (1.0 + voice->osc[2].sin * 0.25);
 	}
 
-	voice_filter(voice, l, r);
+	*left += l;
+	*right += r;
+
+//	filter_run_lp(&voice->fil[0], l, r);
+//	filter_run_hp(&voice->fil[1], voice->fil[0].last_out_l, voice->fil[0].last_out_r);
 
-	*left += voice->last_l;
-	*right += voice->last_r;
+//	*left += voice->fil[0].last_out_l;
+//	*right += voice->fil[0].last_out_r;
 //	}
 }

voice.h

@@ -1,4 +1,5 @@
 #define VOICE_OSCILLATORS 4
+#define VOICE_FILTERS 2
 
 struct voice_t
 {
@@ -10,8 +11,8 @@ struct voice_t
 	double velocity;
 	struct osc_t osc[VOICE_OSCILLATORS];
 
-	double last_l;
-	double last_r;
+	struct filter_t fil[VOICE_FILTERS];
 };
 
+void voice_init(struct voice_t *voice, double freq);
 void voice_run(struct voice_t *voice, uint32_t samples, float *left, float *right);