184 lines
4.2 KiB
C++
184 lines
4.2 KiB
C++
/*
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* MixerLoops.cpp
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* --------------
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* Purpose: Utility inner loops for mixer-related functionality.
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* Notes : This file contains performance-critical loops.
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* Authors: Olivier Lapicque
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* OpenMPT Devs
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* The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
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*/
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#include "stdafx.h"
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#include "MixerLoops.h"
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#include "Snd_defs.h"
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#include "ModChannel.h"
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OPENMPT_NAMESPACE_BEGIN
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void FloatToStereoMix(const float *pIn1, const float *pIn2, int32 *pOut, uint32 nCount, const float _f2ic)
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{
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for(uint32 i=0; i<nCount; ++i)
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{
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*pOut++ = (int)(*pIn1++ * _f2ic);
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*pOut++ = (int)(*pIn2++ * _f2ic);
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}
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}
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void StereoMixToFloat(const int32 *pSrc, float *pOut1, float *pOut2, uint32 nCount, const float _i2fc)
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{
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for(uint32 i=0; i<nCount; ++i)
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{
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*pOut1++ = *pSrc++ * _i2fc;
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*pOut2++ = *pSrc++ * _i2fc;
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}
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}
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void FloatToMonoMix(const float *pIn, int32 *pOut, uint32 nCount, const float _f2ic)
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{
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for(uint32 i=0; i<nCount; ++i)
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{
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*pOut++ = (int)(*pIn++ * _f2ic);
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}
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}
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void MonoMixToFloat(const int32 *pSrc, float *pOut, uint32 nCount, const float _i2fc)
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{
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for(uint32 i=0; i<nCount; ++i)
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{
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*pOut++ = *pSrc++ * _i2fc;
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}
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}
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void InitMixBuffer(mixsample_t *pBuffer, uint32 nSamples)
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{
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std::memset(pBuffer, 0, nSamples * sizeof(mixsample_t));
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}
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void InterleaveFrontRear(mixsample_t *pFrontBuf, mixsample_t *pRearBuf, uint32 nFrames)
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{
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// copy backwards as we are writing back into FrontBuf
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for(int i=nFrames-1; i>=0; i--)
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{
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pFrontBuf[i*4+3] = pRearBuf[i*2+1];
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pFrontBuf[i*4+2] = pRearBuf[i*2+0];
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pFrontBuf[i*4+1] = pFrontBuf[i*2+1];
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pFrontBuf[i*4+0] = pFrontBuf[i*2+0];
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}
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}
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void MonoFromStereo(mixsample_t *pMixBuf, uint32 nSamples)
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{
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for(uint32 i=0; i<nSamples; ++i)
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{
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pMixBuf[i] = (pMixBuf[i*2] + pMixBuf[i*2+1]) / 2;
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}
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}
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#define OFSDECAYSHIFT 8
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#define OFSDECAYMASK 0xFF
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#define OFSTHRESHOLD static_cast<mixsample_t>(1.0 / (1 << 20)) // Decay threshold for floating point mixer
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void StereoFill(mixsample_t *pBuffer, uint32 nSamples, mixsample_t &rofs, mixsample_t &lofs)
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{
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if((!rofs) && (!lofs))
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{
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InitMixBuffer(pBuffer, nSamples*2);
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return;
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}
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for(uint32 i=0; i<nSamples; i++)
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{
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#ifdef MPT_INTMIXER
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// Equivalent to int x_r = (rofs + (rofs > 0 ? 255 : -255)) / 256;
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const mixsample_t x_r = mpt::rshift_signed(rofs + (mpt::rshift_signed(-rofs, sizeof(mixsample_t) * 8 - 1) & OFSDECAYMASK), OFSDECAYSHIFT);
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const mixsample_t x_l = mpt::rshift_signed(lofs + (mpt::rshift_signed(-lofs, sizeof(mixsample_t) * 8 - 1) & OFSDECAYMASK), OFSDECAYSHIFT);
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#else
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const mixsample_t x_r = rofs * (1.0f / (1 << OFSDECAYSHIFT));
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const mixsample_t x_l = lofs * (1.0f / (1 << OFSDECAYSHIFT));
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#endif
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rofs -= x_r;
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lofs -= x_l;
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pBuffer[i*2] = rofs;
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pBuffer[i*2+1] = lofs;
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}
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#ifndef MPT_INTMIXER
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if(fabs(rofs) < OFSTHRESHOLD) rofs = 0;
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if(fabs(lofs) < OFSTHRESHOLD) lofs = 0;
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#endif
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}
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void EndChannelOfs(ModChannel &chn, mixsample_t *pBuffer, uint32 nSamples)
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{
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mixsample_t rofs = chn.nROfs;
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mixsample_t lofs = chn.nLOfs;
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if((!rofs) && (!lofs))
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{
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return;
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}
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for(uint32 i=0; i<nSamples; i++)
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{
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#ifdef MPT_INTMIXER
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const mixsample_t x_r = mpt::rshift_signed(rofs + (mpt::rshift_signed(-rofs, sizeof(mixsample_t) * 8 - 1) & OFSDECAYMASK), OFSDECAYSHIFT);
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const mixsample_t x_l = mpt::rshift_signed(lofs + (mpt::rshift_signed(-lofs, sizeof(mixsample_t) * 8 - 1) & OFSDECAYMASK), OFSDECAYSHIFT);
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#else
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const mixsample_t x_r = rofs * (1.0f / (1 << OFSDECAYSHIFT));
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const mixsample_t x_l = lofs * (1.0f / (1 << OFSDECAYSHIFT));
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#endif
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rofs -= x_r;
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lofs -= x_l;
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pBuffer[i*2] += rofs;
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pBuffer[i*2+1] += lofs;
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}
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#ifndef MPT_INTMIXER
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if(std::abs(rofs) < OFSTHRESHOLD) rofs = 0;
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if(std::abs(lofs) < OFSTHRESHOLD) lofs = 0;
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#endif
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chn.nROfs = rofs;
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chn.nLOfs = lofs;
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}
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void InterleaveStereo(const mixsample_t * MPT_RESTRICT inputL, const mixsample_t * MPT_RESTRICT inputR, mixsample_t * MPT_RESTRICT output, size_t numSamples)
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{
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while(numSamples--)
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{
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*(output++) = *(inputL++);
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*(output++) = *(inputR++);
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}
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}
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void DeinterleaveStereo(const mixsample_t * MPT_RESTRICT input, mixsample_t * MPT_RESTRICT outputL, mixsample_t * MPT_RESTRICT outputR, size_t numSamples)
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{
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while(numSamples--)
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{
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*(outputL++) = *(input++);
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*(outputR++) = *(input++);
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}
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}
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OPENMPT_NAMESPACE_END
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