diff options
Diffstat (limited to 'core')
| -rw-r--r-- | core/mixer.cpp | 126 | ||||
| -rw-r--r-- | core/mixer.h | 101 |
2 files changed, 227 insertions, 0 deletions
diff --git a/core/mixer.cpp b/core/mixer.cpp new file mode 100644 index 00000000..71e48fe3 --- /dev/null +++ b/core/mixer.cpp @@ -0,0 +1,126 @@ + +#include "config.h" + +#include "mixer.h" + +#include <cmath> + +#include "devformat.h" +#include "device.h" +#include "math_defs.h" +#include "mixer/defs.h" + +struct CTag; + + +MixerFunc MixSamples{Mix_<CTag>}; + + +std::array<float,MaxAmbiChannels> CalcAmbiCoeffs(const float y, const float z, const float x, + const float spread) +{ + std::array<float,MaxAmbiChannels> coeffs; + + /* Zeroth-order */ + coeffs[0] = 1.0f; /* ACN 0 = 1 */ + /* First-order */ + coeffs[1] = 1.732050808f * y; /* ACN 1 = sqrt(3) * Y */ + coeffs[2] = 1.732050808f * z; /* ACN 2 = sqrt(3) * Z */ + coeffs[3] = 1.732050808f * x; /* ACN 3 = sqrt(3) * X */ + /* Second-order */ + const float xx{x*x}, yy{y*y}, zz{z*z}, xy{x*y}, yz{y*z}, xz{x*z}; + coeffs[4] = 3.872983346f * xy; /* ACN 4 = sqrt(15) * X * Y */ + coeffs[5] = 3.872983346f * yz; /* ACN 5 = sqrt(15) * Y * Z */ + coeffs[6] = 1.118033989f * (3.0f*zz - 1.0f); /* ACN 6 = sqrt(5)/2 * (3*Z*Z - 1) */ + coeffs[7] = 3.872983346f * xz; /* ACN 7 = sqrt(15) * X * Z */ + coeffs[8] = 1.936491673f * (xx - yy); /* ACN 8 = sqrt(15)/2 * (X*X - Y*Y) */ + /* Third-order */ + coeffs[9] = 2.091650066f * (y*(3.0f*xx - yy)); /* ACN 9 = sqrt(35/8) * Y * (3*X*X - Y*Y) */ + coeffs[10] = 10.246950766f * (z*xy); /* ACN 10 = sqrt(105) * Z * X * Y */ + coeffs[11] = 1.620185175f * (y*(5.0f*zz - 1.0f)); /* ACN 11 = sqrt(21/8) * Y * (5*Z*Z - 1) */ + coeffs[12] = 1.322875656f * (z*(5.0f*zz - 3.0f)); /* ACN 12 = sqrt(7)/2 * Z * (5*Z*Z - 3) */ + coeffs[13] = 1.620185175f * (x*(5.0f*zz - 1.0f)); /* ACN 13 = sqrt(21/8) * X * (5*Z*Z - 1) */ + coeffs[14] = 5.123475383f * (z*(xx - yy)); /* ACN 14 = sqrt(105)/2 * Z * (X*X - Y*Y) */ + coeffs[15] = 2.091650066f * (x*(xx - 3.0f*yy)); /* ACN 15 = sqrt(35/8) * X * (X*X - 3*Y*Y) */ + /* Fourth-order */ + /* ACN 16 = sqrt(35)*3/2 * X * Y * (X*X - Y*Y) */ + /* ACN 17 = sqrt(35/2)*3/2 * (3*X*X - Y*Y) * Y * Z */ + /* ACN 18 = sqrt(5)*3/2 * X * Y * (7*Z*Z - 1) */ + /* ACN 19 = sqrt(5/2)*3/2 * Y * Z * (7*Z*Z - 3) */ + /* ACN 20 = 3/8 * (35*Z*Z*Z*Z - 30*Z*Z + 3) */ + /* ACN 21 = sqrt(5/2)*3/2 * X * Z * (7*Z*Z - 3) */ + /* ACN 22 = sqrt(5)*3/4 * (X*X - Y*Y) * (7*Z*Z - 1) */ + /* ACN 23 = sqrt(35/2)*3/2 * (X*X - 3*Y*Y) * X * Z */ + /* ACN 24 = sqrt(35)*3/8 * (X*X*X*X - 6*X*X*Y*Y + Y*Y*Y*Y) */ + + if(spread > 0.0f) + { + /* Implement the spread by using a spherical source that subtends the + * angle spread. See: + * http://www.ppsloan.org/publications/StupidSH36.pdf - Appendix A3 + * + * When adjusted for N3D normalization instead of SN3D, these + * calculations are: + * + * ZH0 = -sqrt(pi) * (-1+ca); + * ZH1 = 0.5*sqrt(pi) * sa*sa; + * ZH2 = -0.5*sqrt(pi) * ca*(-1+ca)*(ca+1); + * ZH3 = -0.125*sqrt(pi) * (-1+ca)*(ca+1)*(5*ca*ca - 1); + * ZH4 = -0.125*sqrt(pi) * ca*(-1+ca)*(ca+1)*(7*ca*ca - 3); + * ZH5 = -0.0625*sqrt(pi) * (-1+ca)*(ca+1)*(21*ca*ca*ca*ca - 14*ca*ca + 1); + * + * The gain of the source is compensated for size, so that the + * loudness doesn't depend on the spread. Thus: + * + * ZH0 = 1.0f; + * ZH1 = 0.5f * (ca+1.0f); + * ZH2 = 0.5f * (ca+1.0f)*ca; + * ZH3 = 0.125f * (ca+1.0f)*(5.0f*ca*ca - 1.0f); + * ZH4 = 0.125f * (ca+1.0f)*(7.0f*ca*ca - 3.0f)*ca; + * ZH5 = 0.0625f * (ca+1.0f)*(21.0f*ca*ca*ca*ca - 14.0f*ca*ca + 1.0f); + */ + const float ca{std::cos(spread * 0.5f)}; + /* Increase the source volume by up to +3dB for a full spread. */ + const float scale{std::sqrt(1.0f + spread/al::MathDefs<float>::Tau())}; + + const float ZH0_norm{scale}; + const float ZH1_norm{scale * 0.5f * (ca+1.f)}; + const float ZH2_norm{scale * 0.5f * (ca+1.f)*ca}; + const float ZH3_norm{scale * 0.125f * (ca+1.f)*(5.f*ca*ca-1.f)}; + + /* Zeroth-order */ + coeffs[0] *= ZH0_norm; + /* First-order */ + coeffs[1] *= ZH1_norm; + coeffs[2] *= ZH1_norm; + coeffs[3] *= ZH1_norm; + /* Second-order */ + coeffs[4] *= ZH2_norm; + coeffs[5] *= ZH2_norm; + coeffs[6] *= ZH2_norm; + coeffs[7] *= ZH2_norm; + coeffs[8] *= ZH2_norm; + /* Third-order */ + coeffs[9] *= ZH3_norm; + coeffs[10] *= ZH3_norm; + coeffs[11] *= ZH3_norm; + coeffs[12] *= ZH3_norm; + coeffs[13] *= ZH3_norm; + coeffs[14] *= ZH3_norm; + coeffs[15] *= ZH3_norm; + } + + return coeffs; +} + +void ComputePanGains(const MixParams *mix, const float*RESTRICT coeffs, const float ingain, + const al::span<float,MAX_OUTPUT_CHANNELS> gains) +{ + auto ambimap = mix->AmbiMap.cbegin(); + + auto iter = std::transform(ambimap, ambimap+mix->Buffer.size(), gains.begin(), + [coeffs,ingain](const BFChannelConfig &chanmap) noexcept -> float + { return chanmap.Scale * coeffs[chanmap.Index] * ingain; } + ); + std::fill(iter, gains.end(), 0.0f); +} diff --git a/core/mixer.h b/core/mixer.h new file mode 100644 index 00000000..309f4224 --- /dev/null +++ b/core/mixer.h @@ -0,0 +1,101 @@ +#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); +} + +/** + * 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,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,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 */ |