Initial community commit

Src/external_dependencies/openmpt-trunk/soundlib/MixerLoops.cpp

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