Initial community commit

Src/external_dependencies/openmpt-trunk/soundlib/MixerInterface.h

@@ -0,0 +1,99 @@
+/*
+ * MixerInterface.h
+ * ----------------
+ * Purpose: The basic mixer interface and main mixer loop, completely agnostic of the actual sample input / output formats.
+ * Notes  : (currently none)
+ * Authors: OpenMPT Devs
+ * The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
+ */
+
+
+#pragma once
+
+#include "openmpt/all/BuildSettings.hpp"
+
+#include "Snd_defs.h"
+#include "ModChannel.h"
+
+OPENMPT_NAMESPACE_BEGIN
+
+class CResampler;
+
+//////////////////////////////////////////////////////////////////////////
+// Sample conversion traits
+
+template<int channelsOut, int channelsIn, typename out, typename in>
+struct MixerTraits
+{
+	enum : int { numChannelsIn = channelsIn };	// Number of channels in sample
+	enum : int { numChannelsOut = channelsOut };	// Number of mixer output channels
+	typedef out output_t;							// Output buffer sample type
+	typedef in input_t;								// Input buffer sample type
+	typedef out outbuf_t[channelsOut];				// Output buffer sampling point type
+	// To perform sample conversion, add a function with the following signature to your derived classes:
+	// static MPT_CONSTEXPRINLINE output_t Convert(const input_t x)
+};
+
+
+//////////////////////////////////////////////////////////////////////////
+// Interpolation templates
+
+template<class Traits>
+struct NoInterpolation
+{
+	MPT_FORCEINLINE NoInterpolation(const ModChannel &, const CResampler &, unsigned int) { }
+
+	MPT_FORCEINLINE void operator() (typename Traits::outbuf_t &outSample, const typename Traits::input_t * const inBuffer, const int32)
+	{
+		static_assert(static_cast<int>(Traits::numChannelsIn) <= static_cast<int>(Traits::numChannelsOut), "Too many input channels");
+
+		for(int i = 0; i < Traits::numChannelsIn; i++)
+		{
+			outSample[i] = Traits::Convert(inBuffer[i]);
+		}
+	}
+};
+
+// Other interpolation algorithms depend on the input format type (integer / float) and can thus be found in FloatMixer.h and IntMixer.h
+
+
+//////////////////////////////////////////////////////////////////////////
+// Main sample render loop template
+
+// Template parameters:
+// Traits: A class derived from MixerTraits that defines the number of channels, sample buffer types, etc..
+// InterpolationFunc: Functor for reading the sample data and doing the SRC
+// FilterFunc: Functor for applying the resonant filter
+// MixFunc: Functor for mixing the computed sample data into the output buffer
+template<class Traits, class InterpolationFunc, class FilterFunc, class MixFunc>
+static void SampleLoop(ModChannel &chn, const CResampler &resampler, typename Traits::output_t * MPT_RESTRICT outBuffer, unsigned int numSamples)
+{
+	ModChannel &c = chn;
+	const typename Traits::input_t * MPT_RESTRICT inSample = static_cast<const typename Traits::input_t *>(c.pCurrentSample);
+
+	InterpolationFunc interpolate{c, resampler, numSamples};
+	FilterFunc filter{c};
+	MixFunc mix{c};
+
+	unsigned int samples = numSamples;
+	SamplePosition smpPos = c.position;	// Fixed-point sample position
+	const SamplePosition increment = c.increment;	// Fixed-point sample increment
+
+	while(samples--)
+	{
+		typename Traits::outbuf_t outSample;
+		interpolate(outSample, inSample + smpPos.GetInt() * Traits::numChannelsIn, smpPos.GetFract());
+		filter(outSample, c);
+		mix(outSample, c, outBuffer);
+		outBuffer += Traits::numChannelsOut;
+
+		smpPos += increment;
+	}
+
+	c.position = smpPos;
+}
+
+// Type of the SampleLoop function above
+typedef void (*MixFuncInterface)(ModChannel &, const CResampler &, mixsample_t *, unsigned int);
+
+OPENMPT_NAMESPACE_END