usynth

commit 531c33391dbd8c2d619d09cf5e41c9e9dfa272ad
parent 5b59813e2bdd8eadf0a126b88620b466c3d70a09
Author: zavok <an2qzavok@gmail.com>
Date:   Wed,  6 Nov 2019 22:13:06 +0300

fixed phase modulation

Diffstat:
M
fm.c
 | 
10
+++++-----
M
operator.c
 | 
6
+++---
M
operator.h
 | 
2
+-

3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/fm.c b/fm.c
@@ -40,8 +40,8 @@ fm_synth(struct voice *v)
 	if (v->velocity == 0) return 0;
 	ch = &fm_channels[v->channel];
 	dt = (double)(0xff00)*(tune[v->note%12] * (1 << (v->note/12)))/44100.0;
-	out = op_fetch(&v->op[1], dt) * v->velocity / 0x7f;
-	out += op_fetch(&v->op[0], dt) * v->velocity / 0x7f;
+	out = op_fetch(&v->op[1], dt*2, 0);
+	out = op_fetch(&v->op[0], dt*3, out) * v->velocity / 0x7f;
 	return out;
 }
 
@@ -94,12 +94,12 @@ fm_note_on(uint8_t *mm)
 	v = &fm_voices[nmin];
 	v->op[0].p = 0;
 	v->op[0].conf.waveform = wavetable[1];
-	v->op[0].conf.gain = 0x40;
+	v->op[0].conf.gain = 0xff;
 	v->op[0].conf.freq_multiplier = 1;
 	v->op[1].p = 0;
 	v->op[1].conf.waveform = wavetable[1];
-	v->op[1].conf.gain = 0x40;
-	v->op[1].conf.freq_multiplier = 1.01;
+	v->op[1].conf.gain = 0xff;
+	v->op[1].conf.freq_multiplier = 1;
 	v->id = nmax+1;
 	v->channel = mm[1];
 	v->note = mm[2];
diff --git a/operator.c b/operator.c
@@ -3,11 +3,11 @@
 #include "operator.h"
 
 int64_t
-op_fetch(struct op_state *op, size_t dp)
+op_fetch(struct op_state *op, size_t dp, int16_t mod)
 {
 	uint8_t pos;
 	op->p += dp * op->conf.freq_multiplier;
-	pos = op->p >> 8;
-	return op->conf.waveform[pos] * op->conf.gain / 0x7f;
+	pos = (mod + op->p) >> 8;
+	return op->conf.waveform[pos] * op->conf.gain / 0xff;
 }
 
diff --git a/operator.h b/operator.h
@@ -9,5 +9,5 @@ struct op_state {
 	size_t p;
 };
 
-int64_t op_fetch(struct op_state*, size_t);
+int64_t op_fetch(struct op_state*, size_t, int16_t);