tidy of audio api

examples/audio/audio.cpp

@@ -103,7 +103,7 @@ void update(uint32_t tick) {
   // if the current sound has finished playing, or we changed a dial value
   // then restart the sound
   uint32_t full_duration = get_dial_value("duration") + get_dial_value("release") + get_dial_value("reverb");
-  if(change || audio_position() > full_duration) {
+  if(change || position() > full_duration) {
     set_voice();
   }
 }
@@ -188,6 +188,6 @@ void draw(uint32_t tick) {
 
   // draw current playback marker
   pen(0, 15, 15);
-  uint32_t pos = (audio_position() * 230) / full_duration;
+  uint32_t pos = (position() * 230) / full_duration;
   frect(pos + 5, 5, 2, 50);
 }

libraries/audio.cpp

@@ -19,13 +19,8 @@ namespace picosystem {
     _ms = 0;
   }
 
-  uint32_t audio_position() {
-    return _ms;
-  }
-
-  // Convenience function to tell if the note is still playing
-  bool audio_playing() {
-    return !(_ms > _duration + _voice.release + _voice.reverb);
+  int32_t position() {
+    return (_ms > _duration + _voice.release + _voice.reverb) ? -1 : _ms;
   }
 
   uint8_t audio_sample(uint32_t ms) {

libraries/picosystem.hpp

@@ -174,8 +174,8 @@ namespace picosystem {
                 voice_t voice, uint32_t frequency,
                 uint32_t duration = 500, uint32_t volume = 100);
   uint8_t     audio_sample(uint32_t ms);
-  uint32_t    audio_position();
-  bool        audio_playing();
+  int32_t     position();
+  bool        playing();
 
   // utility
   std::string str(float v, uint8_t precision = 2);