usynth

commit cee75e2bb82c9a8f9430164a7d5efe92ee581133
parent 49130e2ffe3fcf7bc3f2047fc38f613670fbbb71
Author: zavok <an2qzavok@gmail.com>
Date:   Mon,  4 Nov 2019 17:01:59 +0300

moved synth code to separate file.

Diffstat:
M
fm.c
 | 
51
+++++++++++++++++++++++++++++++++++++++++++++++++++
M
fm.h
 | 
4
++++
M
usynth.c
 | 
44
+++-----------------------------------------

3 files changed, 58 insertions(+), 41 deletions(-)
diff --git a/fm.c b/fm.c
@@ -1,2 +1,53 @@
 #include <stdio.h>
 #include "fm.h"
+
+double tune[]={
+16.35, //C  36 
+17.32, //C# 37
+18.35, //D  38
+19.45, //D# 39
+20.60, //E  40
+21.83, //F  41
+23.12, //F# 42
+24.50, //G  43
+25.96, //G# 44
+27.50, //A  45 - 440 - 100
+29.14, //A# 46
+30.87, //B  47
+};
+
+size_t c, dt;
+int16_t vol;
+
+int16_t fmsynth(void);
+
+int16_t
+fm_synth(void)
+{
+	c++;
+	if (dt == 0) return 0;
+	if (c%dt > dt / 2) return vol;
+	return -vol;
+}
+
+void
+fm_fillbuf(int16_t *buf, size_t nsamples)
+{
+	size_t i;
+	for (i=0; i < nsamples; i+=2){
+		buf[i] = buf[i+1] = fm_synth();
+	}
+}
+
+void
+fm_note_on(uint8_t *mm)
+{
+	dt = 44100.0 / (tune[mm[2]%12] * (1 << mm[2]/12)); 
+	vol = 0x7fff * mm[3] / 0xff;
+}
+
+void
+fm_note_off(uint8_t *mm)
+{
+	vol = 0;
+}
diff --git a/fm.h b/fm.h
@@ -0,0 +1,4 @@
+void fm_fillbuf(int16_t*, size_t);
+void fm_note_on(uint8_t*);
+void fm_note_off(uint8_t*);
+
diff --git a/usynth.c b/usynth.c
@@ -9,22 +9,6 @@
 
 struct sio_hdl *sh;
 size_t bs;
-int16_t vol, dt;
-
-double tune[]={
-16.35, //C  36 
-17.32, //C# 37
-18.35, //D  38
-19.45, //D# 39
-20.60, //E  40
-21.83, //F  41
-23.12, //F# 42
-24.50, //G  43
-25.96, //G# 44
-27.50, //A  45 - 440 - 100
-29.14, //A# 46
-30.87, //B  47
-};
 
 size_t rt, wt;
 
@@ -59,45 +43,23 @@ sinit(void)
 	sio_start(sh);
 }
 
-void
-note_on(uint8_t *mm)
-{
-	dt = 44100 / (tune[mm[2]%12] * (1 << (mm[2]/12)));
-	vol = mm[3]*100;
-}
-
-void
-note_off(uint8_t *mm)
-{
-	vol = 0;
-}
-
 int
 main(int argc, char **argv)
 {
-	int64_t c;
 	int16_t *sbuf;
-	vol = 0;
 	wt = 0;
 	rt = 0;
 	sinit();
 	m_init("rmidi/0");
-	m_vector.note_on = note_on;
-	m_vector.note_off = note_off;
+	m_vector.note_on = fm_note_on;
+	m_vector.note_off = fm_note_off;
 	sbuf = malloc(bs * 2 * sizeof(int16_t));
-	c = 0;
-	dt = 100;
 	printf("entering main loop\n");
 	while (1){
 		size_t n;
 		int i;
 		m_read();
-		for (i=0; i<bs * 2; i+=2){
-			c++;
-			sbuf[i] = (c%dt > (dt/2))? vol : -vol;
-			sbuf[i+1] = sbuf[i];
-		}
-		n = 0;
+		fm_fillbuf(sbuf, bs * 2);
 		n = sio_write(sh, sbuf, bs * 2 * sizeof(int16_t)); 
 		wt += n;
 	}