#ifndef CORE_AMBIDEFS_H #define CORE_AMBIDEFS_H #include #include #include #include "alnumbers.h" using uint = unsigned int; /* The maximum number of Ambisonics channels. For a given order (o), the size * needed will be (o+1)**2, thus zero-order has 1, first-order has 4, second- * order has 9, third-order has 16, and fourth-order has 25. */ constexpr uint8_t MaxAmbiOrder{3}; constexpr inline size_t AmbiChannelsFromOrder(size_t order) noexcept { return (order+1) * (order+1); } constexpr size_t MaxAmbiChannels{AmbiChannelsFromOrder(MaxAmbiOrder)}; /* A bitmask of ambisonic channels for 0 to 4th order. This only specifies up * to 4th order, which is the highest order a 32-bit mask value can specify (a * 64-bit mask could handle up to 7th order). */ constexpr uint Ambi0OrderMask{0x00000001}; constexpr uint Ambi1OrderMask{0x0000000f}; constexpr uint Ambi2OrderMask{0x000001ff}; constexpr uint Ambi3OrderMask{0x0000ffff}; constexpr uint Ambi4OrderMask{0x01ffffff}; /* A bitmask of ambisonic channels with height information. If none of these * channels are used/needed, there's no height (e.g. with most surround sound * speaker setups). This is ACN ordering, with bit 0 being ACN 0, etc. */ constexpr uint AmbiPeriphonicMask{0xfe7ce4}; /* The maximum number of ambisonic channels for 2D (non-periphonic) * representation. This is 2 per each order above zero-order, plus 1 for zero- * order. Or simply, o*2 + 1. */ constexpr inline size_t Ambi2DChannelsFromOrder(size_t order) noexcept { return order*2 + 1; } constexpr size_t MaxAmbi2DChannels{Ambi2DChannelsFromOrder(MaxAmbiOrder)}; /* NOTE: These are scale factors as applied to Ambisonics content. Decoder * coefficients should be divided by these values to get proper scalings. */ struct AmbiScale { static auto& FromN3D() noexcept { static constexpr const std::array ret{{ 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f }}; return ret; } static auto& FromSN3D() noexcept { static constexpr const std::array ret{{ 1.000000000f, /* ACN 0, sqrt(1) */ 1.732050808f, /* ACN 1, sqrt(3) */ 1.732050808f, /* ACN 2, sqrt(3) */ 1.732050808f, /* ACN 3, sqrt(3) */ 2.236067978f, /* ACN 4, sqrt(5) */ 2.236067978f, /* ACN 5, sqrt(5) */ 2.236067978f, /* ACN 6, sqrt(5) */ 2.236067978f, /* ACN 7, sqrt(5) */ 2.236067978f, /* ACN 8, sqrt(5) */ 2.645751311f, /* ACN 9, sqrt(7) */ 2.645751311f, /* ACN 10, sqrt(7) */ 2.645751311f, /* ACN 11, sqrt(7) */ 2.645751311f, /* ACN 12, sqrt(7) */ 2.645751311f, /* ACN 13, sqrt(7) */ 2.645751311f, /* ACN 14, sqrt(7) */ 2.645751311f, /* ACN 15, sqrt(7) */ }}; return ret; } static auto& FromFuMa() noexcept { static constexpr const std::array ret{{ 1.414213562f, /* ACN 0 (W), sqrt(2) */ 1.732050808f, /* ACN 1 (Y), sqrt(3) */ 1.732050808f, /* ACN 2 (Z), sqrt(3) */ 1.732050808f, /* ACN 3 (X), sqrt(3) */ 1.936491673f, /* ACN 4 (V), sqrt(15)/2 */ 1.936491673f, /* ACN 5 (T), sqrt(15)/2 */ 2.236067978f, /* ACN 6 (R), sqrt(5) */ 1.936491673f, /* ACN 7 (S), sqrt(15)/2 */ 1.936491673f, /* ACN 8 (U), sqrt(15)/2 */ 2.091650066f, /* ACN 9 (Q), sqrt(35/8) */ 1.972026594f, /* ACN 10 (O), sqrt(35)/3 */ 2.231093404f, /* ACN 11 (M), sqrt(224/45) */ 2.645751311f, /* ACN 12 (K), sqrt(7) */ 2.231093404f, /* ACN 13 (L), sqrt(224/45) */ 1.972026594f, /* ACN 14 (N), sqrt(35)/3 */ 2.091650066f, /* ACN 15 (P), sqrt(35/8) */ }}; return ret; } static auto& FromUHJ() noexcept { static constexpr const std::array ret{{ 1.000000000f, /* ACN 0 (W), sqrt(1) */ 1.224744871f, /* ACN 1 (Y), sqrt(3/2) */ 1.224744871f, /* ACN 2 (Z), sqrt(3/2) */ 1.224744871f, /* ACN 3 (X), sqrt(3/2) */ /* Higher orders not relevant for UHJ. */ 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, }}; return ret; } /* Retrieves per-order HF scaling factors for "upsampling" ambisonic data. */ static std::array GetHFOrderScales(const uint order) noexcept { if(order >= 3) return DecoderHFScale3O; if(order == 2) return DecoderHFScale2O; return DecoderHFScale10; } static const std::array DecoderHFScale10; static const std::array DecoderHFScale2O; static const std::array DecoderHFScale3O; static const std::array,4> FirstOrderUp; static const std::array,9> SecondOrderUp; static const std::array,16> ThirdOrderUp; }; struct AmbiIndex { static auto& FromFuMa() noexcept { static constexpr const std::array ret{{ 0, /* W */ 3, /* X */ 1, /* Y */ 2, /* Z */ 6, /* R */ 7, /* S */ 5, /* T */ 8, /* U */ 4, /* V */ 12, /* K */ 13, /* L */ 11, /* M */ 14, /* N */ 10, /* O */ 15, /* P */ 9, /* Q */ }}; return ret; } static auto& FromFuMa2D() noexcept { static constexpr const std::array ret{{ 0, /* W */ 3, /* X */ 1, /* Y */ 8, /* U */ 4, /* V */ 15, /* P */ 9, /* Q */ }}; return ret; } static auto& FromACN() noexcept { static constexpr const std::array ret{{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }}; return ret; } static auto& FromACN2D() noexcept { static constexpr const std::array ret{{ 0, 1,3, 4,8, 9,15 }}; return ret; } static auto& OrderFromChannel() noexcept { static constexpr const std::array ret{{ 0, 1,1,1, 2,2,2,2,2, 3,3,3,3,3,3,3, }}; return ret; } static auto& OrderFrom2DChannel() noexcept { static constexpr const std::array ret{{ 0, 1,1, 2,2, 3,3, }}; return ret; } }; /** * Calculates ambisonic encoder coefficients using the X, Y, and Z direction * components, which must represent a normalized (unit length) vector. * * 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. */ constexpr auto CalcAmbiCoeffs(const float y, const float z, const float x) { const float xx{x*x}, yy{y*y}, zz{z*z}, xy{x*y}, yz{y*z}, xz{x*z}; return std::array{{ /* Zeroth-order */ 1.0f, /* ACN 0 = 1 */ /* First-order */ al::numbers::sqrt3_v * y, /* ACN 1 = sqrt(3) * Y */ al::numbers::sqrt3_v * z, /* ACN 2 = sqrt(3) * Z */ al::numbers::sqrt3_v * x, /* ACN 3 = sqrt(3) * X */ /* Second-order */ 3.872983346e+00f * xy, /* ACN 4 = sqrt(15) * X * Y */ 3.872983346e+00f * yz, /* ACN 5 = sqrt(15) * Y * Z */ 1.118033989e+00f * (3.0f*zz - 1.0f), /* ACN 6 = sqrt(5)/2 * (3*Z*Z - 1) */ 3.872983346e+00f * xz, /* ACN 7 = sqrt(15) * X * Z */ 1.936491673e+00f * (xx - yy), /* ACN 8 = sqrt(15)/2 * (X*X - Y*Y) */ /* Third-order */ 2.091650066e+00f * (y*(3.0f*xx - yy)), /* ACN 9 = sqrt(35/8) * Y * (3*X*X - Y*Y) */ 1.024695076e+01f * (z*xy), /* ACN 10 = sqrt(105) * Z * X * Y */ 1.620185175e+00f * (y*(5.0f*zz - 1.0f)), /* ACN 11 = sqrt(21/8) * Y * (5*Z*Z - 1) */ 1.322875656e+00f * (z*(5.0f*zz - 3.0f)), /* ACN 12 = sqrt(7)/2 * Z * (5*Z*Z - 3) */ 1.620185175e+00f * (x*(5.0f*zz - 1.0f)), /* ACN 13 = sqrt(21/8) * X * (5*Z*Z - 1) */ 5.123475383e+00f * (z*(xx - yy)), /* ACN 14 = sqrt(105)/2 * Z * (X*X - Y*Y) */ 2.091650066e+00f * (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) */ }}; } #endif /* CORE_AMBIDEFS_H */