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Fix Dungeons of Daggorath's heartbeat sound #334

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Merged
merged 1 commit into from
Jun 3, 2025
Merged

Fix Dungeons of Daggorath's heartbeat sound #334

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43 changes: 10 additions & 33 deletions mc6821.c
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Original file line number Diff line number Diff line change
Expand Up @@ -421,39 +421,16 @@ void SetCart(unsigned char cart)

unsigned int GetDACSample(void)
{
static unsigned int RetVal=0;
static unsigned short SampleLeft=0,SampleRight=0,PakSample=0;
static unsigned short OutLeft=0,OutRight=0;
static unsigned short LastLeft=0,LastRight=0;
PakSample=PackAudioSample();
SampleLeft=(PakSample>>8)+Asample+Ssample;
SampleRight=(PakSample & 0xFF)+Asample+Ssample; //9 Bits each
SampleLeft=SampleLeft<<6; //Conver to 16 bit values
SampleRight=SampleRight<<6; //For Max volume
if (SampleLeft==LastLeft) //Simulate a slow high pass filter
{
if (OutLeft)
OutLeft--;
}
else
{
OutLeft=SampleLeft;
LastLeft=SampleLeft;
}

if (SampleRight==LastRight)
{
if (OutRight)
OutRight--;
}
else
{
OutRight=SampleRight;
LastRight=SampleRight;
}

RetVal=(OutLeft<<16)+(OutRight);
return(RetVal);
auto pakSample = PackAudioSample();
auto pakLeft = pakSample >> 8;
auto pakRight = pakSample & 0xFF;
auto dacSample = Asample;
auto bitSample = Ssample;
auto left = (pakLeft + dacSample + bitSample) << 7;
auto right = (pakRight + dacSample + bitSample) << 7;
// removed previous "slow high pass filter" that
// destroys daggorath's proper heartbeat sound -ca 2025-06-02
return (left << 16) | (right & 0xFFFF);
}

unsigned char SetCartAutoStart(unsigned char Tmp)
Expand Down