Unify pitch bending calcs for all FM usages

rhargreaves · Jun 27, 2024 · 9cfee02 · 9cfee02
1 parent 36a067c
commit 9cfee02
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Showing 3 changed files with 11 additions and 19 deletions.
diff --git a/src/midi_fm.c b/src/midi_fm.c
@@ -27,7 +27,6 @@ static u8 pitchIsOutOfRange(u8 pitch);
 static u8 effectiveVolume(MidiFmChannel* channelState);
 static void updatePan(u8 chan);
 void midi_fm_reset(void);
-static u16 effectiveFreq(MidiFmChannel* fmChan);
 
 static const FmChannel** presets;
 static const PercussionPreset** percussionPresets;
@@ -67,9 +66,8 @@ void midi_fm_note_on(u8 chan, u8 pitch, u8 velocity)
     fmChan->velocity = velocity;
     synth_volume(chan, effectiveVolume(fmChan));
     fmChan->pitch = pitch;
-
-    u16 freq = effectiveFreq(fmChan);
-    synth_pitch(chan, midi_fm_pitchToOctave(fmChan->pitch), freq);
+    synth_pitch(chan, midi_fm_pitchToOctave(fmChan->pitch),
+        midi_fm_pitchAndPitchBendToFreqNum(fmChan->pitch, fmChan->pitchBend));
     synth_noteOn(chan);
 }
 
@@ -86,19 +84,19 @@ void midi_fm_channel_volume(u8 chan, u8 volume)
     synth_volume(chan, effectiveVolume(fmChan));
 }
 
-static u16 effectiveFreq(MidiFmChannel* fmChan)
+u16 midi_fm_pitchAndPitchBendToFreqNum(u8 pitch, u16 pitchBend)
 {
-    u16 freq = midi_fm_pitchToFreqNumber(fmChan->pitch);
-    s16 bendRelative = fmChan->pitchBend - MIDI_PITCH_BEND_CENTRE;
+    u16 freq = midi_fm_pitchToFreqNumber(pitch);
+    s16 bendRelative = pitchBend - MIDI_PITCH_BEND_CENTRE;
     return freq + (bendRelative / 75);
 }
 
 void midi_fm_pitch_bend(u8 chan, u16 bend)
 {
     MidiFmChannel* fmChan = &fmChannels[chan];
     fmChan->pitchBend = bend;
-    u16 freq = effectiveFreq(fmChan);
-    synth_pitch(chan, midi_fm_pitchToOctave(fmChan->pitch), freq);
+    synth_pitch(chan, midi_fm_pitchToOctave(fmChan->pitch),
+        midi_fm_pitchAndPitchBendToFreqNum(fmChan->pitch, fmChan->pitchBend));
 }
 
 void midi_fm_program(u8 chan, u8 program)

diff --git a/src/midi_fm.h b/src/midi_fm.h
@@ -26,4 +26,5 @@ void midi_fm_program(u8 chan, u8 program);
 void midi_fm_all_notes_off(u8 chan);
 void midi_fm_percussive(u8 chan, bool enabled);
 u8 midi_fm_pitchToOctave(u8 pitch);
-u16 midi_fm_pitchToFreqNumber(u8 pitch);
+u16 midi_fm_pitchToFreqNumber(u8 pitch);
+u16 midi_fm_pitchAndPitchBendToFreqNum(u8 pitch, u16 pitchBend);
diff --git a/src/midi_fm_sm.c b/src/midi_fm_sm.c
@@ -13,19 +13,12 @@ struct SpecialModeOperator {
 
 static SpecialModeOperator smOperators[SM_OP_LEN];
 
-static u16 effectiveFreq(u8 pitch, u16 pitchBend)
-{
-    u16 freq = midi_fm_pitchToFreqNumber(pitch);
-    s16 bendRelative = pitchBend - MIDI_PITCH_BEND_CENTRE;
-    return freq + (bendRelative / 75);
-}
-
 void midi_fm_sm_note_on(u8 op, u8 pitch, u8 velocity)
 {
     SpecialModeOperator* smOp = &smOperators[op];
     smOp->pitch = pitch;
     synth_specialModePitch(op, midi_fm_pitchToOctave(smOp->pitch),
-        effectiveFreq(smOp->pitch, smOp->pitchBend));
+        midi_fm_pitchAndPitchBendToFreqNum(smOp->pitch, smOp->pitchBend));
     synth_specialModeVolume(op, velocity);
 }
 
@@ -34,7 +27,7 @@ void midi_fm_sm_pitch_bend(u8 op, u16 bend)
     SpecialModeOperator* smOp = &smOperators[op];
     smOp->pitchBend = bend;
     synth_specialModePitch(op, midi_fm_pitchToOctave(smOp->pitch),
-        effectiveFreq(smOp->pitch, smOp->pitchBend));
+        midi_fm_pitchAndPitchBendToFreqNum(smOp->pitch, smOp->pitchBend));
 }
 
 void midi_fm_sm_reset(void)