1 files changed, 99 insertions, 0 deletions
diff --git a/Src/external_dependencies/openmpt-trunk/soundlib/WindowedFIR.cpp b/Src/external_dependencies/openmpt-trunk/soundlib/WindowedFIR.cpp
new file mode 100644
index 00000000..256889ba
--- /dev/null
+++ b/Src/external_dependencies/openmpt-trunk/soundlib/WindowedFIR.cpp
@@ -0,0 +1,99 @@
+/*
+ * WindowedFIR.cpp
+ * ---------------
+ * Purpose: FIR resampling code
+ * Notes  : Original code from modplug-xmms
+ * Authors: OpenMPT Devs
+ *          ModPlug-XMMS Devs
+ * The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
+ */
+
+
+#include "stdafx.h"
+#include "WindowedFIR.h"
+#include "mpt/base/numbers.hpp"
+#include <cmath>
+
+OPENMPT_NAMESPACE_BEGIN
+
+double CWindowedFIR::coef( int _PCnr, double _POfs, double _PCut, int _PWidth, int _PType ) //float _PPos, float _PFc, int _PLen )
+{
+	const double epsilon = 1e-8;
+	const double _LWidthM1 = _PWidth - 1;
+	const double _LWidthM1Half = 0.5 * _LWidthM1;
+	const double _LPosU = (_PCnr - _POfs);
+	const double _LPIdl = (2.0 * mpt::numbers::pi) / _LWidthM1;
+	double _LPos = _LPosU - _LWidthM1Half;
+	double _LWc, _LSi;
+	if(std::abs(_LPos) < epsilon)
+	{
+		_LWc = 1.0;
+		_LSi = _PCut;
+	} else
+	{
+		switch(_PType)
+		{
+		case WFIR_HANN:
+			_LWc = 0.50 - 0.50 * std::cos(_LPIdl * _LPosU);
+			break;
+		case WFIR_HAMMING:
+			_LWc = 0.54 - 0.46 * std::cos(_LPIdl * _LPosU);
+			break;
+		case WFIR_BLACKMANEXACT:
+			_LWc = 0.42 - 0.50 * std::cos(_LPIdl * _LPosU) + 0.08 * std::cos(2.0 * _LPIdl * _LPosU);
+			break;
+		case WFIR_BLACKMAN3T61:
+			_LWc = 0.44959 - 0.49364 * std::cos(_LPIdl * _LPosU) + 0.05677 * std::cos(2.0 * _LPIdl * _LPosU);
+			break;
+		case WFIR_BLACKMAN3T67:
+			_LWc = 0.42323 - 0.49755 * std::cos(_LPIdl * _LPosU) + 0.07922 * std::cos(2.0 * _LPIdl * _LPosU);
+			break;
+		case WFIR_BLACKMAN4T92: // blackman harris
+			_LWc = 0.35875 - 0.48829 * std::cos(_LPIdl * _LPosU) + 0.14128 * std::cos(2.0 * _LPIdl * _LPosU) - 0.01168 * std::cos(3.0 * _LPIdl * _LPosU);
+			break;
+		case WFIR_BLACKMAN4T74:
+			_LWc = 0.40217 - 0.49703 * std::cos(_LPIdl * _LPosU) + 0.09392 * std::cos(2.0 * _LPIdl * _LPosU) - 0.00183 * std::cos(3.0 * _LPIdl * _LPosU);
+			break;
+		case WFIR_KAISER4T: // kaiser-bessel, alpha~7.5
+			_LWc = 0.40243 - 0.49804 * std::cos(_LPIdl * _LPosU) + 0.09831 * std::cos(2.0 * _LPIdl * _LPosU) - 0.00122 * std::cos(3.0 * _LPIdl * _LPosU);
+			break;
+		default:
+			_LWc = 1.0;
+			break;
+		}
+		_LPos *= mpt::numbers::pi;
+		_LSi = std::sin(_PCut * _LPos) / _LPos;
+	}
+	return (_LWc * _LSi);
+}
+
+void CWindowedFIR::InitTable(double WFIRCutoff, uint8 WFIRType)
+{
+	const double _LPcllen = (double)(1 << WFIR_FRACBITS);  // number of precalculated lines for 0..1 (-1..0)
+	const double _LNorm = 1.0 / (2.0 * _LPcllen);
+	const double _LCut = WFIRCutoff;
+	for(int _LPcl = 0; _LPcl < WFIR_LUTLEN; _LPcl++)
+	{
+		double _LGain = 0.0, _LCoefs[WFIR_WIDTH];
+		const double _LOfs = (_LPcl - _LPcllen) * _LNorm;
+		const int _LIdx = _LPcl << WFIR_LOG2WIDTH;
+		for(int _LCc = 0; _LCc < WFIR_WIDTH; _LCc++)
+		{
+			_LGain += (_LCoefs[_LCc] = coef(_LCc, _LOfs, _LCut, WFIR_WIDTH, WFIRType));
+		}
+		_LGain = 1.0 / _LGain;
+		for(int _LCc = 0; _LCc < WFIR_WIDTH; _LCc++)
+		{
+#ifdef MPT_INTMIXER
+			double _LCoef = std::floor(0.5 + WFIR_QUANTSCALE * _LCoefs[_LCc] * _LGain);
+			lut[_LIdx + _LCc] = (signed short)((_LCoef < -WFIR_QUANTSCALE) ? -WFIR_QUANTSCALE : ((_LCoef > WFIR_QUANTSCALE) ? WFIR_QUANTSCALE : _LCoef));
+#else
+			double _LCoef = _LCoefs[_LCc] * _LGain;
+			lut[_LIdx + _LCc] = (float)_LCoef;
+#endif // MPT_INTMIXER
+		}
+	}
+}
+
+
+OPENMPT_NAMESPACE_END