Changeset 2427:fd28722d924e in roaraudio

Timestamp:

08/19/09 05:17:41 (15 years ago)

Author:

phi

Branch:

default

Phase:

public

Message:

very simple mono synth

File:

• libroardsp/synth.c (modified) (4 diffs)

libroardsp/synth.c

@@ -26 +26 @@
 
 #define _CHECK_BASIC() if ( state == NULL ) return -1
+#define _CHECK_PCMOUT() _CHECK_BASIC(); if ( frames == 0 ) return 0; if ( out == NULL ) return -1
 
 int roar_synth_init(struct roar_synth_state * state, struct roar_note_octave * note, int rate) {
@@ -54 +55 @@
  _CHECK_BASIC();
 
+ if ( func == NULL )
+  return -1;
+
  state->func = func;
 
@@ -60 +64 @@
 
 int roar_synth_pcmout_i16n(struct roar_synth_state * state, int16_t * out, size_t frames, int channels) {
- _CHECK_BASIC();
-
- if ( out == NULL )
-  return -1;
-
- if ( frames == 0 )
-  return 0;
+ _CHECK_PCMOUT();
 
  switch (channels) {
@@ -78 +76 @@
 
 int roar_synth_pcmout_i161(struct roar_synth_state * state, int16_t * out, size_t frames) {
- _CHECK_BASIC();
+ float t_step;
+ float t_cur;
+ int i;
+
+ _CHECK_PCMOUT();
+
+ t_step = 1.0/state->rate;
+
+ t_cur  = t_step * state->pcmoffset;
+
+ for (i = 0; i < frames; i++, t_cur += t_step) {
+  out[i] = 32767.0*state->func(t_cur, state);
+ }
+
+ state->pcmoffset += frames;
 
  return -1;