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#ifndef CORE_MIXER_H
#define CORE_MIXER_H
#include <array>
#include <cmath>
#include <stddef.h>
#include <type_traits>
#include "alspan.h"
#include "ambidefs.h"
#include "bufferline.h"
#include "devformat.h"
struct MixParams;
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;
/**
* 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,MaxAmbiChannels> 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,MaxAmbiChannels> CalcDirectionCoeffs(const float (&dir)[3],
const float spread)
{
/* Convert from OpenAL coords to Ambisonics. */
return CalcAmbiCoeffs(-dir[0], dir[1], -dir[2], spread);
}
/**
* CalcDirectionCoeffs
*
* Calculates ambisonic coefficients based on an OpenAL direction vector. The
* vector must be normalized (unit length).
*/
constexpr std::array<float,MaxAmbiChannels> CalcDirectionCoeffs(const float (&dir)[3])
{
/* Convert from OpenAL coords to Ambisonics. */
return CalcAmbiCoeffs(-dir[0], dir[1], -dir[2]);
}
/**
* 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,MaxAmbiChannels> 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,MaxAmbiChannels> 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,MaxAmbiChannels> 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);
}
}
#endif /* CORE_MIXER_H */
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