winamp/Src/external_dependencies/openmpt-trunk/soundlib/Mixer.h
2024-09-24 14:54:57 +02:00

64 lines
2.3 KiB
C

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