64 lines
2.3 KiB
C
64 lines
2.3 KiB
C
/*
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* Mixer.h
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* -------
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* Purpose: Basic mixer constants
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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 "openmpt/soundbase/MixSample.hpp"
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OPENMPT_NAMESPACE_BEGIN
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#define MPT_INTMIXER
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#ifdef MPT_INTMIXER
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using mixsample_t = MixSampleIntTraits::sample_type;
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enum { MIXING_FILTER_PRECISION = MixSampleIntTraits::filter_precision_bits }; // Fixed point resonant filter bits
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#else
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using mixsample_t = MixSampleFloat;
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#endif
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enum { MIXING_ATTENUATION = MixSampleIntTraits::mix_headroom_bits };
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enum { MIXING_FRACTIONAL_BITS = MixSampleIntTraits::mix_fractional_bits };
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inline constexpr float MIXING_SCALEF = MixSampleIntTraits::mix_scale<float>;
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#ifdef MPT_INTMIXER
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static_assert(sizeof(mixsample_t) == 4);
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static_assert(MIXING_FILTER_PRECISION == 24);
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static_assert(MIXING_ATTENUATION == 4);
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static_assert(MIXING_FRACTIONAL_BITS == 27);
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static_assert(MixSampleIntTraits::mix_clip_max == int32(0x7FFFFFF));
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static_assert(MixSampleIntTraits::mix_clip_min == (0 - int32(0x7FFFFFF)));
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static_assert(MIXING_SCALEF == 134217728.0f);
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#else
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static_assert(sizeof(mixsample_t) == 4);
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#endif
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#define MIXBUFFERSIZE 512
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#define NUMMIXINPUTBUFFERS 4
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#define VOLUMERAMPPRECISION 12 // Fractional bits in volume ramp variables
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// The absolute maximum number of sampling points any interpolation algorithm is going to look at in any direction from the current sampling point
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// Currently, the maximum is 4 sampling points forwards and 3 sampling points backwards (Polyphase / FIR algorithms).
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// Hence, this value must be at least 4.
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inline constexpr uint8 InterpolationMaxLookahead = 4;
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// While we could directly use the previous value in various places such as the interpolation wrap-around handling at loop points,
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// choosing a higher value (e.g. 16) will reduce CPU usage when using many extremely short (length < 16) samples.
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inline constexpr uint8 InterpolationLookaheadBufferSize = 16;
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static_assert(InterpolationLookaheadBufferSize >= InterpolationMaxLookahead);
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// Maximum size of a sampling point of a sample, in bytes.
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// The biggest sampling point size is currently 16-bit stereo = 2 * 2 bytes.
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inline constexpr uint8 MaxSamplingPointSize = 4;
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OPENMPT_NAMESPACE_END
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