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#ifndef ALU_H
#define ALU_H
#include <array>
#include <cmath>
#include <cstddef>
#include <type_traits>
#include "AL/al.h"
#include "alcmain.h"
#include "alspan.h"
struct ALCcontext;
struct ALeffectslot;
#define MAX_PITCH 10
#define MAX_SENDS 6
using MixerFunc = void(*)(const al::span<const float> InSamples,
const al::span<FloatBufferLine> OutBuffer, float *CurrentGains, const float *TargetGains,
const size_t Counter, const size_t OutPos);
extern MixerFunc MixSamples;
constexpr float GainMixMax{1000.0f}; /* +60dB */
constexpr float GainSilenceThreshold{0.00001f}; /* -100dB */
constexpr float SpeedOfSoundMetersPerSec{343.3f};
constexpr float AirAbsorbGainHF{0.99426f}; /* -0.05dB */
/** Target gain for the reverb decay feedback reaching the decay time. */
constexpr float ReverbDecayGain{0.001f}; /* -60 dB */
constexpr int MixerFracBits{12};
constexpr int MixerFracOne{1 << MixerFracBits};
constexpr int MixerFracMask{MixerFracOne - 1};
inline float lerp(float val1, float val2, float mu) noexcept
{ return val1 + (val2-val1)*mu; }
inline float cubic(float val1, float val2, float val3, float val4, float mu) noexcept
{
const float mu2{mu*mu}, mu3{mu2*mu};
const float a0{-0.5f*mu3 + mu2 + -0.5f*mu};
const float a1{ 1.5f*mu3 + -2.5f*mu2 + 1.0f};
const float a2{-1.5f*mu3 + 2.0f*mu2 + 0.5f*mu};
const float a3{ 0.5f*mu3 + -0.5f*mu2};
return val1*a0 + val2*a1 + val3*a2 + val4*a3;
}
enum HrtfRequestMode {
Hrtf_Default = 0,
Hrtf_Enable = 1,
Hrtf_Disable = 2,
};
void aluInit(void);
void aluInitMixer(void);
/* aluInitRenderer
*
* Set up the appropriate panning method and mixing method given the device
* properties.
*/
void aluInitRenderer(ALCdevice *device, int hrtf_id, HrtfRequestMode hrtf_appreq,
HrtfRequestMode hrtf_userreq);
void aluInitEffectPanning(ALeffectslot *slot, ALCcontext *context);
/**
* Calculates ambisonic encoder coefficients using the X, Y, and Z direction
* components, which must represent a normalized (unit length) vector, and the
* spread is the angular width of the sound (0...tau).
*
* NOTE: The components use ambisonic coordinates. As a result:
*
* Ambisonic Y = OpenAL -X
* Ambisonic Z = OpenAL Y
* Ambisonic X = OpenAL -Z
*
* The components are ordered such that OpenAL's X, Y, and Z are the first,
* second, and third parameters respectively -- simply negate X and Z.
*/
std::array<float,MAX_AMBI_CHANNELS> CalcAmbiCoeffs(const float y, const float z, const float x,
const float spread);
/**
* CalcDirectionCoeffs
*
* Calculates ambisonic coefficients based on an OpenAL direction vector. The
* vector must be normalized (unit length), and the spread is the angular width
* of the sound (0...tau).
*/
inline std::array<float,MAX_AMBI_CHANNELS> CalcDirectionCoeffs(const float (&dir)[3],
const float spread)
{
/* Convert from OpenAL coords to Ambisonics. */
return CalcAmbiCoeffs(-dir[0], dir[1], -dir[2], spread);
}
/**
* CalcAngleCoeffs
*
* Calculates ambisonic coefficients based on azimuth and elevation. The
* azimuth and elevation parameters are in radians, going right and up
* respectively.
*/
inline std::array<float,MAX_AMBI_CHANNELS> CalcAngleCoeffs(const float azimuth,
const float elevation, const float spread)
{
const float x{-std::sin(azimuth) * std::cos(elevation)};
const float y{ std::sin(elevation)};
const float z{ std::cos(azimuth) * std::cos(elevation)};
return CalcAmbiCoeffs(x, y, z, spread);
}
/**
* ComputePanGains
*
* Computes panning gains using the given channel decoder coefficients and the
* pre-calculated direction or angle coefficients. For B-Format sources, the
* coeffs are a 'slice' of a transform matrix for the input channel, used to
* scale and orient the sound samples.
*/
void ComputePanGains(const MixParams *mix, const float*RESTRICT coeffs, const float ingain,
const al::span<float,MAX_OUTPUT_CHANNELS> gains);
/** Helper to set an identity/pass-through panning for ambisonic mixing (3D input). */
template<typename T, typename I, typename F>
auto SetAmbiPanIdentity(T iter, I count, F func) -> std::enable_if_t<std::is_integral<I>::value>
{
if(count < 1) return;
std::array<float,MAX_AMBI_CHANNELS> coeffs{{1.0f}};
func(*iter, coeffs);
++iter;
for(I i{1};i < count;++i,++iter)
{
coeffs[i-1] = 0.0f;
coeffs[i ] = 1.0f;
func(*iter, coeffs);
}
}
extern const float ConeScale;
extern const float ZScale;
#endif
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