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