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Optimize synth code by pre-computing the volume scaling for each note.

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Scaling is now calculated once per MIDI event at the most, instead of
once per sample. Increase voice ramping speed, increase number of
active voices a little.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@9870 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Stepan Moskovchenko 2006-05-03 19:32:22 +00:00
parent 7f1d214801
commit 28b5afd05a
4 changed files with 35 additions and 27 deletions
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12
apps/plugins/midi/synth.c
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@ -255,7 +255,6 @@ inline void stopVoice(struct SynthObject * so)
}
signed short int synthVoice(struct SynthObject * so)
{
struct GWaveform * wf;
@ -362,16 +361,21 @@ signed short int synthVoice(struct SynthObject * so)
if(so->state == STATE_RAMPDOWN)
{
so->decay--;
if(so->decay == 0)
so->decay-=5;
if(so->decay < 5)
so->isUsed=0;
s = (s * so->decay) >> 8;
}
return s*((signed short int)so->vol*(signed short int)chVol[so->ch])>>14;
/* Scaling by channel volume and note volume is done in sequencer.c */
/* That saves us some multiplication and pointer operations */
return s*so->volscale>>14;
}
inline void synthSample(int * mixL, int * mixR)
{
register int dL=0;