usynth

commit eadf2ce1fa6978a1d9e201d9b4235fa3f5bd33a3
parent 98274b9e971e78f0481ba0180f19aafd9ef21f04
Author: prenev <an2qzavok@gmail.com>
Date:   Sat, 10 Apr 2021 19:41:22 +0300

wavetable: enlarge, fix triangle

Diffstat:
M
machine.c
 | 
2
+-
M
wavetable.c
 | 
20
+++++++++++---------
M
wavetable.h
 | 
2
+-

3 files changed, 13 insertions(+), 11 deletions(-)
diff --git a/machine.c b/machine.c
@@ -142,7 +142,7 @@ void
 i_wave(int16_t *vm, uint8_t arg)
 {
 	uint16_t d;
-	d = ((uint16_t)TOS(vm)) / WT_LENGTH;
+	d = ((uint16_t)TOS(vm)) * WT_LENGTH / 0xffff;
 	d = d%WT_LENGTH;
 	TOS(vm) = wavetable[arg][d];
 }
diff --git a/wavetable.c b/wavetable.c
@@ -19,21 +19,23 @@ wt_init(void)
 	wavetable = malloc(sizeof(int16_t*) * WT_SIZE);
 	for (i=0;i<WT_SIZE;i++)
 		wavetable[i] = malloc(sizeof(int16_t) * WT_LENGTH);
-	wt_pulse(wavetable[0]);
-	wt_silence(wavetable[1]);
-	wt_silence(wavetable[2]);
+	wt_sin(wavetable[0]);
+	wt_triangle(wavetable[1]);
+	wt_pulse(wavetable[2]);
 	wt_silence(wavetable[3]);
 }
 
 void
 wt_triangle(int16_t *w)
 {
-	/* TODO: fix clipping */
 	size_t i, pos;
-	for (i = 0; i < WT_LENGTH; i++){
+	for (i = 0; i < WT_LENGTH/2; i++){
 		pos = (i-WT_LENGTH/4)%WT_LENGTH;
-		if (i < WT_LENGTH/2) w[pos] = 0x7fff + 0xffff*2*i/WT_LENGTH;
-		else w[pos] = 0x7fff - 0xffff*i*2/WT_LENGTH;
+		w[pos] = -0x7fff + i * 0xffff * 2 / WT_LENGTH;
+	}
+	for (i = 0;      i < WT_LENGTH/2;   i++){
+		pos = (i+WT_LENGTH/4)%WT_LENGTH;
+		w[pos] = 0x7fff - i * 0xffff * 2 / WT_LENGTH;
 	}
 }
 
@@ -41,8 +43,8 @@ void
 wt_pulse(int16_t *w)
 {
 	size_t i;
-	for (i=0; i<WT_LENGTH/2; i++) w[i] = -0x07ff;
-	for (;    i<WT_LENGTH;   i++) w[i] = 0x07ff;
+	for (i=0; i<WT_LENGTH/2; i++) w[i] = -0x7fff;
+	for (;    i<WT_LENGTH;   i++) w[i] =  0x7fff;
 }
 
 void
diff --git a/wavetable.h b/wavetable.h
@@ -1,4 +1,4 @@
-#define WT_LENGTH 256 
+#define WT_LENGTH 1024
 #define WT_SIZE   8
 extern int16_t **wavetable;