251 lines
9.4 KiB
C++
251 lines
9.4 KiB
C++
#ifndef CORE_AMBIDEFS_H
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#define CORE_AMBIDEFS_H
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#include <array>
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#include <stddef.h>
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#include <stdint.h>
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#include "alnumbers.h"
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using uint = unsigned int;
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/* The maximum number of Ambisonics channels. For a given order (o), the size
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* needed will be (o+1)**2, thus zero-order has 1, first-order has 4, second-
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* order has 9, third-order has 16, and fourth-order has 25.
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*/
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constexpr uint8_t MaxAmbiOrder{3};
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constexpr inline size_t AmbiChannelsFromOrder(size_t order) noexcept
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{ return (order+1) * (order+1); }
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constexpr size_t MaxAmbiChannels{AmbiChannelsFromOrder(MaxAmbiOrder)};
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/* A bitmask of ambisonic channels for 0 to 4th order. This only specifies up
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* to 4th order, which is the highest order a 32-bit mask value can specify (a
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* 64-bit mask could handle up to 7th order).
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*/
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constexpr uint Ambi0OrderMask{0x00000001};
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constexpr uint Ambi1OrderMask{0x0000000f};
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constexpr uint Ambi2OrderMask{0x000001ff};
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constexpr uint Ambi3OrderMask{0x0000ffff};
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constexpr uint Ambi4OrderMask{0x01ffffff};
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/* A bitmask of ambisonic channels with height information. If none of these
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* channels are used/needed, there's no height (e.g. with most surround sound
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* speaker setups). This is ACN ordering, with bit 0 being ACN 0, etc.
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*/
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constexpr uint AmbiPeriphonicMask{0xfe7ce4};
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/* The maximum number of ambisonic channels for 2D (non-periphonic)
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* representation. This is 2 per each order above zero-order, plus 1 for zero-
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* order. Or simply, o*2 + 1.
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*/
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constexpr inline size_t Ambi2DChannelsFromOrder(size_t order) noexcept
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{ return order*2 + 1; }
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constexpr size_t MaxAmbi2DChannels{Ambi2DChannelsFromOrder(MaxAmbiOrder)};
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/* NOTE: These are scale factors as applied to Ambisonics content. Decoder
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* coefficients should be divided by these values to get proper scalings.
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*/
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struct AmbiScale {
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static auto& FromN3D() noexcept
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{
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static constexpr const std::array<float,MaxAmbiChannels> ret{{
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1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
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1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f
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}};
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return ret;
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}
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static auto& FromSN3D() noexcept
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{
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static constexpr const std::array<float,MaxAmbiChannels> ret{{
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1.000000000f, /* ACN 0, sqrt(1) */
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1.732050808f, /* ACN 1, sqrt(3) */
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1.732050808f, /* ACN 2, sqrt(3) */
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1.732050808f, /* ACN 3, sqrt(3) */
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2.236067978f, /* ACN 4, sqrt(5) */
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2.236067978f, /* ACN 5, sqrt(5) */
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2.236067978f, /* ACN 6, sqrt(5) */
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2.236067978f, /* ACN 7, sqrt(5) */
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2.236067978f, /* ACN 8, sqrt(5) */
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2.645751311f, /* ACN 9, sqrt(7) */
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2.645751311f, /* ACN 10, sqrt(7) */
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2.645751311f, /* ACN 11, sqrt(7) */
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2.645751311f, /* ACN 12, sqrt(7) */
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2.645751311f, /* ACN 13, sqrt(7) */
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2.645751311f, /* ACN 14, sqrt(7) */
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2.645751311f, /* ACN 15, sqrt(7) */
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}};
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return ret;
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}
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static auto& FromFuMa() noexcept
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{
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static constexpr const std::array<float,MaxAmbiChannels> ret{{
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1.414213562f, /* ACN 0 (W), sqrt(2) */
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1.732050808f, /* ACN 1 (Y), sqrt(3) */
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1.732050808f, /* ACN 2 (Z), sqrt(3) */
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1.732050808f, /* ACN 3 (X), sqrt(3) */
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1.936491673f, /* ACN 4 (V), sqrt(15)/2 */
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1.936491673f, /* ACN 5 (T), sqrt(15)/2 */
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2.236067978f, /* ACN 6 (R), sqrt(5) */
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1.936491673f, /* ACN 7 (S), sqrt(15)/2 */
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1.936491673f, /* ACN 8 (U), sqrt(15)/2 */
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2.091650066f, /* ACN 9 (Q), sqrt(35/8) */
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1.972026594f, /* ACN 10 (O), sqrt(35)/3 */
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2.231093404f, /* ACN 11 (M), sqrt(224/45) */
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2.645751311f, /* ACN 12 (K), sqrt(7) */
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2.231093404f, /* ACN 13 (L), sqrt(224/45) */
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1.972026594f, /* ACN 14 (N), sqrt(35)/3 */
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2.091650066f, /* ACN 15 (P), sqrt(35/8) */
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}};
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return ret;
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}
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static auto& FromUHJ() noexcept
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{
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static constexpr const std::array<float,MaxAmbiChannels> ret{{
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1.000000000f, /* ACN 0 (W), sqrt(1) */
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1.224744871f, /* ACN 1 (Y), sqrt(3/2) */
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1.224744871f, /* ACN 2 (Z), sqrt(3/2) */
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1.224744871f, /* ACN 3 (X), sqrt(3/2) */
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/* Higher orders not relevant for UHJ. */
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1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
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}};
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return ret;
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}
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/* Retrieves per-order HF scaling factors for "upsampling" ambisonic data. */
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static std::array<float,MaxAmbiOrder+1> GetHFOrderScales(const uint src_order,
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const uint dev_order) noexcept;
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static const std::array<std::array<float,MaxAmbiChannels>,4> FirstOrderUp;
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static const std::array<std::array<float,MaxAmbiChannels>,4> FirstOrder2DUp;
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static const std::array<std::array<float,MaxAmbiChannels>,9> SecondOrderUp;
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static const std::array<std::array<float,MaxAmbiChannels>,9> SecondOrder2DUp;
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static const std::array<std::array<float,MaxAmbiChannels>,16> ThirdOrderUp;
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static const std::array<std::array<float,MaxAmbiChannels>,16> ThirdOrder2DUp;
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static const std::array<std::array<float,MaxAmbiChannels>,25> FourthOrder2DUp;
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};
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struct AmbiIndex {
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static auto& FromFuMa() noexcept
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{
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static constexpr const std::array<uint8_t,MaxAmbiChannels> ret{{
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0, /* W */
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3, /* X */
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1, /* Y */
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2, /* Z */
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6, /* R */
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7, /* S */
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5, /* T */
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8, /* U */
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4, /* V */
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12, /* K */
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13, /* L */
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11, /* M */
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14, /* N */
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10, /* O */
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15, /* P */
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9, /* Q */
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}};
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return ret;
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}
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static auto& FromFuMa2D() noexcept
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{
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static constexpr const std::array<uint8_t,MaxAmbi2DChannels> ret{{
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0, /* W */
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3, /* X */
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1, /* Y */
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8, /* U */
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4, /* V */
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15, /* P */
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9, /* Q */
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}};
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return ret;
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}
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static auto& FromACN() noexcept
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{
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static constexpr const std::array<uint8_t,MaxAmbiChannels> ret{{
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0, 1, 2, 3, 4, 5, 6, 7,
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8, 9, 10, 11, 12, 13, 14, 15
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}};
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return ret;
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}
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static auto& FromACN2D() noexcept
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{
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static constexpr const std::array<uint8_t,MaxAmbi2DChannels> ret{{
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0, 1,3, 4,8, 9,15
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}};
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return ret;
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}
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static auto& OrderFromChannel() noexcept
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{
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static constexpr const std::array<uint8_t,MaxAmbiChannels> ret{{
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0, 1,1,1, 2,2,2,2,2, 3,3,3,3,3,3,3,
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}};
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return ret;
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}
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static auto& OrderFrom2DChannel() noexcept
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{
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static constexpr const std::array<uint8_t,MaxAmbi2DChannels> ret{{
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0, 1,1, 2,2, 3,3,
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}};
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return ret;
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}
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};
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/**
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* Calculates ambisonic encoder coefficients using the X, Y, and Z direction
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* components, which must represent a normalized (unit length) vector.
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*
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* NOTE: The components use ambisonic coordinates. As a result:
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*
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* Ambisonic Y = OpenAL -X
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* Ambisonic Z = OpenAL Y
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* Ambisonic X = OpenAL -Z
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*
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* The components are ordered such that OpenAL's X, Y, and Z are the first,
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* second, and third parameters respectively -- simply negate X and Z.
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*/
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constexpr auto CalcAmbiCoeffs(const float y, const float z, const float x)
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{
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const float xx{x*x}, yy{y*y}, zz{z*z}, xy{x*y}, yz{y*z}, xz{x*z};
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return std::array<float,MaxAmbiChannels>{{
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/* Zeroth-order */
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1.0f, /* ACN 0 = 1 */
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/* First-order */
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al::numbers::sqrt3_v<float> * y, /* ACN 1 = sqrt(3) * Y */
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al::numbers::sqrt3_v<float> * z, /* ACN 2 = sqrt(3) * Z */
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al::numbers::sqrt3_v<float> * x, /* ACN 3 = sqrt(3) * X */
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/* Second-order */
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3.872983346e+00f * xy, /* ACN 4 = sqrt(15) * X * Y */
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3.872983346e+00f * yz, /* ACN 5 = sqrt(15) * Y * Z */
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1.118033989e+00f * (3.0f*zz - 1.0f), /* ACN 6 = sqrt(5)/2 * (3*Z*Z - 1) */
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3.872983346e+00f * xz, /* ACN 7 = sqrt(15) * X * Z */
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1.936491673e+00f * (xx - yy), /* ACN 8 = sqrt(15)/2 * (X*X - Y*Y) */
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/* Third-order */
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2.091650066e+00f * (y*(3.0f*xx - yy)), /* ACN 9 = sqrt(35/8) * Y * (3*X*X - Y*Y) */
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1.024695076e+01f * (z*xy), /* ACN 10 = sqrt(105) * Z * X * Y */
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1.620185175e+00f * (y*(5.0f*zz - 1.0f)), /* ACN 11 = sqrt(21/8) * Y * (5*Z*Z - 1) */
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1.322875656e+00f * (z*(5.0f*zz - 3.0f)), /* ACN 12 = sqrt(7)/2 * Z * (5*Z*Z - 3) */
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1.620185175e+00f * (x*(5.0f*zz - 1.0f)), /* ACN 13 = sqrt(21/8) * X * (5*Z*Z - 1) */
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5.123475383e+00f * (z*(xx - yy)), /* ACN 14 = sqrt(105)/2 * Z * (X*X - Y*Y) */
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2.091650066e+00f * (x*(xx - 3.0f*yy)), /* ACN 15 = sqrt(35/8) * X * (X*X - 3*Y*Y) */
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/* Fourth-order */
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/* ACN 16 = sqrt(35)*3/2 * X * Y * (X*X - Y*Y) */
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/* ACN 17 = sqrt(35/2)*3/2 * (3*X*X - Y*Y) * Y * Z */
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/* ACN 18 = sqrt(5)*3/2 * X * Y * (7*Z*Z - 1) */
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/* ACN 19 = sqrt(5/2)*3/2 * Y * Z * (7*Z*Z - 3) */
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/* ACN 20 = 3/8 * (35*Z*Z*Z*Z - 30*Z*Z + 3) */
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/* ACN 21 = sqrt(5/2)*3/2 * X * Z * (7*Z*Z - 3) */
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/* ACN 22 = sqrt(5)*3/4 * (X*X - Y*Y) * (7*Z*Z - 1) */
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/* ACN 23 = sqrt(35/2)*3/2 * (X*X - 3*Y*Y) * X * Z */
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/* ACN 24 = sqrt(35)*3/8 * (X*X*X*X - 6*X*X*Y*Y + Y*Y*Y*Y) */
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}};
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}
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#endif /* CORE_AMBIDEFS_H */
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