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Midiplay plugin ehancements

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- Improved robustness
 - Improved sound quality
 - Use mixer and DSP

Patch by Igor Poretsky

Change-Id: I6fa617158cbaa53ae842295cdbdbe3a478e49ded
This commit is contained in:
Solomon Peachy 2019-08-04 16:58:20 -04:00
parent eea5bfc9ae
commit ed724fecb1
7 changed files with 232 additions and 115 deletions
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43
apps/plugins/midi/synth.c
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@ -300,7 +300,8 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
s1 = so->decay;
s2 = s1 * pan;
s1 = (s1 << 7) -s2;
*(out++) += ((s1 << 9) & 0xFFFF0000) | ((s2 >> 7) &0xFFFF);
*(out++) += s1;
*(out++) += s2;
continue;
}
} else /* OK to advance voice */
@ -431,7 +432,8 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
s2 = s1 * pan;
s1 = (s1 << 7) - s2;
*(out++) += ((s1 << 9) & 0xFFFF0000) | ((s2 >> 7) &0xFFFF);
*(out++) += s1;
*(out++) += s2;
}
/* store these again */
@ -441,40 +443,29 @@ static inline void synthVoice(struct SynthObject * so, int32_t * out, unsigned i
return;
}
/* buffer to hold all the samples for the current tick, this is a hack
neccesary for coldfire targets as pcm_play_data uses the dma which cannot
access iram */
int32_t samp_buf[512] IBSS_ATTR;
/* synth num_samples samples and write them to the */
/* buffer pointed to by buf_ptr */
void synthSamples(int32_t *buf_ptr, unsigned int num_samples) ICODE_ATTR;
void synthSamples(int32_t *buf_ptr, unsigned int num_samples)
size_t synthSamples(int32_t *buf_ptr, size_t num_samples) ICODE_ATTR;
size_t synthSamples(int32_t *buf_ptr, size_t num_samples)
{
if (UNLIKELY(num_samples > 512))
DEBUGF("num_samples is too big!\n");
else
unsigned int i;
struct SynthObject *voicept;
size_t nsamples = MIN(num_samples, MAX_SAMPLES);
rb->memset(buf_ptr, 0, nsamples * 2 * sizeof(int32_t));
for(i=0; i < MAX_VOICES; i++)
{
int i;
struct SynthObject *voicept;
rb->memset(samp_buf, 0, num_samples*4);
for(i=0; i < MAX_VOICES; i++)
voicept=&voices[i];
if(voicept->isUsed)
{
voicept=&voices[i];
if(voicept->isUsed)
{
synthVoice(voicept, samp_buf, num_samples);
}
synthVoice(voicept, buf_ptr, nsamples);
}
rb->memcpy(buf_ptr, samp_buf, num_samples*4);
}
/* TODO: Automatic Gain Control, anyone? */
/* Or, should this be implemented on the DSP's output volume instead? */
return; /* No more ghetto lowpass filter. Linear interpolation works well. */
return nsamples; /* No more ghetto lowpass filter. Linear interpolation works well. */
}