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sound, fix minor clipping in psg audio

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This commit is contained in:
kub 2021-09-28 21:10:02 +02:00
parent fa0c5b4539
commit 6985cdd8a9
1 changed files with 4 additions and 2 deletions
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6
pico/sound/sn76496.c
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@ -90,6 +90,7 @@ void SN76496Write(int data)
case 4: /* tone 2 : frequency */ case 4: /* tone 2 : frequency */
R->Period[c] = R->UpdateStep * data; R->Period[c] = R->UpdateStep * data;
if (R->Period[c] == 0) R->Period[c] = R->UpdateStep; if (R->Period[c] == 0) R->Period[c] = R->UpdateStep;
if (R->Count[c] > R->Period[c]) R->Count[c] = R->Period[c];
if (r == 4) if (r == 4)
{ {
/* update noise shift frequency */ /* update noise shift frequency */
@ -155,8 +156,9 @@ void SN76496Update(short *buffer, int length, int stereo)
/* and vol[i] incremented only if the exit status of the square */ /* and vol[i] incremented only if the exit status of the square */
/* wave is 1. */ /* wave is 1. */
if (R->Count[i] < -2*R->Period[i] || R->Volume[i] == 0) { if (R->Count[i] < -2*R->Period[i] || R->Volume[i] == 0) {
/* Cut of anything above the Nyquist freqency */ /* Cut off anything above the Nyquist frequency. */
/* It will only create aliasing anyway */ /* It will only create aliasing anyway. This is actually an */
/* ideal lowpass filter with Nyquist corner frequency. */
vol[i] += STEP/2; // mean value vol[i] += STEP/2; // mean value
R->Count[i] = R->Output[i] = 0; R->Count[i] = R->Output[i] = 0;
} }