Source code of Windows XP (NT5)
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318 lines
7.4 KiB

// Mixf.cpp
// Copyright (c) Microsoft Corporation 1996-1999
// Filtered Mix Engine
#include "simple.h"
#include <mmsystem.h>
#include "synth.h"
//>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
#pragma message ("Programer note: property hack")
//#define DEBUG_DUMP_FILE
#pragma warning(disable : 4101 4102 4146)
//>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
#ifdef DEBUG_DUMP_FILE
DWORD dmp_bufsize = 4000000;
DWORD dmp_samplesrecorded;
DWORD dmp_buffercount;
short dmp_soundbuffer[4000000];
#endif
//>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
DWORD CDigitalAudio::Mix16Filtered(
short **ppBuffers,
DWORD *pdwChannels,
DWORD dwBufferCount,
DWORD dwLength,
DWORD dwDeltaPeriod,
VFRACT vfDeltaLVolume,
VFRACT vfDeltaRVolume,
PFRACT pfDeltaPitch,
PFRACT pfSampleLength,
PFRACT pfLoopLength,
COEFFDELTA cfdK,
COEFFDELTA cfdB1,
COEFFDELTA cfdB2)
{
DWORD dwI;
DWORD dwIndex;
DWORD dwPosition;
long lA;
long lM;
DWORD dwIncDelta = dwDeltaPeriod;
VFRACT dwFract;
short * pcWave = m_pnWave;
PFRACT pfSamplePos = m_pfLastSample;
VFRACT vfLVolume = m_vfLastLVolume;
VFRACT vfRVolume = m_vfLastRVolume;
PFRACT pfPitch = m_pfLastPitch;
PFRACT pfPFract = pfPitch << 8;
VFRACT vfLVFract = vfLVolume << 8;
VFRACT vfRVFract = vfRVolume << 8;
COEFF cfK = m_cfLastK;
COEFF cfB1 = m_cfLastB1;
COEFF cfB2 = m_cfLastB2;
for (dwI = 0; dwI < dwLength;)
{
if (pfSamplePos >= pfSampleLength)
{
if (pfLoopLength)
{
pfSamplePos -= pfLoopLength;
}
else
break;
}
dwIncDelta--;
if (!dwIncDelta)
{
dwIncDelta = dwDeltaPeriod;
pfPFract += pfDeltaPitch;
pfPitch = pfPFract >> 8;
vfLVFract += vfDeltaLVolume;
vfLVolume = vfLVFract >> 8;
vfRVFract += vfDeltaRVolume;
vfRVolume = vfRVFract >> 8;
cfK += cfdK;
cfB1 += cfdB1;
cfB2 += cfdB2;
}
dwPosition = pfSamplePos >> 12;
dwFract = pfSamplePos & 0xFFF;
pfSamplePos += pfPitch;
// Interpolate
lA = (long)pcWave[dwPosition];
lM = (((pcWave[dwPosition+1] - lA) * dwFract) >> 12) + lA;
//
// Filter
//
// z = k*s - b1*z1 - b2*b2
// >>>> We store the negative of b1 in the table, so we flip the sign again by
// >>>> adding here
// >>>> Lookinto simply using a float here, it may just be faster, save a div
//
lM = MulDiv(lM, cfK, (1 << 30))
+ MulDiv(m_lPrevSample, cfB1, (1 << 30))
- MulDiv(m_lPrevPrevSample, cfB2, (1 << 30));
//
//
//
m_lPrevPrevSample = m_lPrevSample;
m_lPrevSample = lM;
//
//
//
lA = lM;
lA *= vfLVolume;
lA >>= 13; // Signal bumps up to 15 bits.
lM *= vfRVolume;
lM >>= 13;
dwIndex = 0;
while ( dwIndex < dwBufferCount )
{
short *pBuffer = &ppBuffers[dwIndex][dwI];
if ( pdwChannels[dwIndex] & WAVELINK_CHANNEL_LEFT )
{
// Keep this around so we can use it to generate new assembly code (see below...)
*pBuffer += (short) lA;
_asm{jno no_oflowl}
*pBuffer = 0x7fff;
_asm{js no_oflowl}
*pBuffer = (short) 0x8000;
}
no_oflowl:
if ( pdwChannels[dwIndex] & WAVELINK_CHANNEL_RIGHT )
{
// Keep this around so we can use it to generate new assembly code (see below...)
*pBuffer += (short) lM;
_asm{jno no_oflowr}
*pBuffer = 0x7fff;
_asm{js no_oflowr}
*pBuffer = (short) 0x8000;
}
no_oflowr:
dwIndex++;
}
#ifdef DEBUG_DUMP_FILE
dmp_soundbuffer[dmp_samplesrecorded] = pBuffer[dwI];
if (dmp_samplesrecorded < dmp_bufsize)
dmp_samplesrecorded++ ;
#endif
dwI++;
}
m_vfLastLVolume = vfLVolume;
m_vfLastRVolume = vfRVolume;
m_pfLastPitch = pfPitch;
m_pfLastSample = pfSamplePos;
m_cfLastK = cfK;
m_cfLastB1 = cfB1;
m_cfLastB2 = cfB2;
return (dwI);
}
DWORD CDigitalAudio::Mix16FilteredInterleaved(
short **ppBuffers,
DWORD *pdwChannels,
DWORD dwBufferCount,
DWORD dwLength,
DWORD dwDeltaPeriod,
VFRACT vfDeltaLVolume,
VFRACT vfDeltaRVolume,
PFRACT pfDeltaPitch,
PFRACT pfSampleLength,
PFRACT pfLoopLength,
COEFFDELTA cfdK,
COEFFDELTA cfdB1,
COEFFDELTA cfdB2)
{
DWORD dwI;
DWORD dwIndex;
DWORD dwPosition;
long lA;
long lM;
DWORD dwIncDelta = dwDeltaPeriod;
VFRACT dwFract;
short * pcWave = m_pnWave;
PFRACT pfSamplePos = m_pfLastSample;
VFRACT vfLVolume = m_vfLastLVolume;
VFRACT vfRVolume = m_vfLastRVolume;
PFRACT pfPitch = m_pfLastPitch;
PFRACT pfPFract = pfPitch << 8;
VFRACT vfLVFract = vfLVolume << 8;
VFRACT vfRVFract = vfRVolume << 8;
COEFF cfK = m_cfLastK;
COEFF cfB1 = m_cfLastB1;
COEFF cfB2 = m_cfLastB2;
dwLength <<= 1;
for (dwI = 0; dwI < dwLength;)
{
if (pfSamplePos >= pfSampleLength)
{
if (pfLoopLength)
{
pfSamplePos -= pfLoopLength;
}
else
break;
}
dwIncDelta--;
if (!dwIncDelta)
{
dwIncDelta = dwDeltaPeriod;
pfPFract += pfDeltaPitch;
pfPitch = pfPFract >> 8;
vfLVFract += vfDeltaLVolume;
vfLVolume = vfLVFract >> 8;
vfRVFract += vfDeltaRVolume;
vfRVolume = vfRVFract >> 8;
cfK += cfdK;
cfB1 += cfdB1;
cfB2 += cfdB2;
}
dwPosition = pfSamplePos >> 12;
dwFract = pfSamplePos & 0xFFF;
pfSamplePos += pfPitch;
// Interpolate
lA = (long)pcWave[dwPosition];
lM = (((pcWave[dwPosition+1] - lA) * dwFract) >> 12) + lA;
//
// Filter
//
// z = k*s - b1*z1 - b2*b2
// >>>> We store the negative of b1 in the table, so we flip the sign again by
// >>>> adding here
// >>>> Lookinto simply using a float here, it may just be faster, save a div
//
lM = MulDiv(lM, cfK, (1 << 30))
+ MulDiv(m_lPrevSample, cfB1, (1 << 30))
- MulDiv(m_lPrevPrevSample, cfB2, (1 << 30));
//
//
//
m_lPrevPrevSample = m_lPrevSample;
m_lPrevSample = lM;
//
//
//
lA = lM;
lA *= vfLVolume;
lA >>= 13; // Signal bumps up to 15 bits.
lM *= vfRVolume;
lM >>= 13;
dwIndex = 0;
while ( dwIndex < dwBufferCount )
{
short *pBuffer = &ppBuffers[dwIndex][dwI];
if ( pdwChannels[dwIndex] & WAVELINK_CHANNEL_LEFT )
{
// Keep this around so we can use it to generate new assembly code (see below...)
*pBuffer += (short) lA;
_asm{jno no_oflowl}
*pBuffer = 0x7fff;
_asm{js no_oflowl}
*pBuffer = (short) 0x8000;
}
no_oflowl:
if ( pdwChannels[dwIndex] & WAVELINK_CHANNEL_RIGHT )
{
// Keep this around so we can use it to generate new assembly code (see below...)
pBuffer++;
*pBuffer += (short) lM;
_asm{jno no_oflowr}
*pBuffer = 0x7fff;
_asm{js no_oflowr}
*pBuffer = (short) 0x8000;
}
no_oflowr:
dwIndex++;
}
#ifdef DEBUG_DUMP_FILE
dmp_soundbuffer[dmp_samplesrecorded] = pBuffer[dwI];
if (dmp_samplesrecorded < dmp_bufsize)
dmp_samplesrecorded++ ;
#endif
dwI += 2;
}
m_vfLastLVolume = vfLVolume;
m_vfLastRVolume = vfRVolume;
m_pfLastPitch = pfPitch;
m_pfLastSample = pfSamplePos;
m_cfLastK = cfK;
m_cfLastB1 = cfB1;
m_cfLastB2 = cfB2;
return (dwI >> 1);
}