|  | // Ceres Solver - A fast non-linear least squares minimizer | 
|  | // Copyright 2023 Google Inc. All rights reserved. | 
|  | // http://ceres-solver.org/ | 
|  | // | 
|  | // Redistribution and use in source and binary forms, with or without | 
|  | // modification, are permitted provided that the following conditions are met: | 
|  | // | 
|  | // * Redistributions of source code must retain the above copyright notice, | 
|  | //   this list of conditions and the following disclaimer. | 
|  | // * Redistributions in binary form must reproduce the above copyright notice, | 
|  | //   this list of conditions and the following disclaimer in the documentation | 
|  | //   and/or other materials provided with the distribution. | 
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|  | //   used to endorse or promote products derived from this software without | 
|  | //   specific prior written permission. | 
|  | // | 
|  | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | 
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|  | // POSSIBILITY OF SUCH DAMAGE. | 
|  |  | 
|  | #ifndef CERES_PUBLIC_INTERNAL_EULER_ANGLES_H_ | 
|  | #define CERES_PUBLIC_INTERNAL_EULER_ANGLES_H_ | 
|  |  | 
|  | #include <type_traits> | 
|  |  | 
|  | namespace ceres { | 
|  | namespace internal { | 
|  |  | 
|  | // The EulerSystem struct represents an Euler Angle Convention in compile time. | 
|  | // It acts like a trait structure and is also used as a tag for dispatching | 
|  | // Euler angle conversion function templates | 
|  | // | 
|  | // Internally, it implements the convention laid out in "Euler angle | 
|  | // conversion", Ken Shoemake, Graphics Gems IV, where a choice of axis for the | 
|  | // first rotation (out of 3) and 3 binary choices compactly specify all 24 | 
|  | // rotation conventions | 
|  | // | 
|  | //  - InnerAxis: Axis for the first rotation. This is specified by struct tags | 
|  | //  axis::X, axis::Y, and axis::Z | 
|  | // | 
|  | //  - Parity: Defines the parity of the axis permutation. The axis sequence has | 
|  | //  Even parity if the second axis of rotation is 'greater-than' the first axis | 
|  | //  of rotation according to the order X<Y<Z<X, otherwise it has Odd parity. | 
|  | //  This is specified by struct tags Even and Odd | 
|  | // | 
|  | //  - AngleConvention: Defines whether Proper Euler Angles (originally defined | 
|  | //  by Euler, which has the last axis repeated, i.e. ZYZ, ZXZ, etc), or | 
|  | //  Tait-Bryan Angles (introduced by the nautical and aerospace fields, i.e. | 
|  | //  using ZYX for roll-pitch-yaw) are used. This is specified by struct Tags | 
|  | //  ProperEuler and TaitBryan. | 
|  | // | 
|  | //  - FrameConvention: Defines whether the three rotations are be in a global | 
|  | //  frame of reference (extrinsic) or in a body centred frame of reference | 
|  | //  (intrinsic). This is specified by struct tags Extrinsic and Intrinsic | 
|  |  | 
|  | namespace axis { | 
|  | struct X : std::integral_constant<int, 0> {}; | 
|  | struct Y : std::integral_constant<int, 1> {}; | 
|  | struct Z : std::integral_constant<int, 2> {}; | 
|  | }  // namespace axis | 
|  |  | 
|  | struct Even; | 
|  | struct Odd; | 
|  |  | 
|  | struct ProperEuler; | 
|  | struct TaitBryan; | 
|  |  | 
|  | struct Extrinsic; | 
|  | struct Intrinsic; | 
|  |  | 
|  | template <typename InnerAxisType, | 
|  | typename ParityType, | 
|  | typename AngleConventionType, | 
|  | typename FrameConventionType> | 
|  | struct EulerSystem { | 
|  | static constexpr bool kIsParityOdd = std::is_same_v<ParityType, Odd>; | 
|  | static constexpr bool kIsProperEuler = | 
|  | std::is_same_v<AngleConventionType, ProperEuler>; | 
|  | static constexpr bool kIsIntrinsic = | 
|  | std::is_same_v<FrameConventionType, Intrinsic>; | 
|  |  | 
|  | static constexpr int kAxes[3] = { | 
|  | InnerAxisType::value, | 
|  | (InnerAxisType::value + 1 + static_cast<int>(kIsParityOdd)) % 3, | 
|  | (InnerAxisType::value + 2 - static_cast<int>(kIsParityOdd)) % 3}; | 
|  | }; | 
|  |  | 
|  | }  // namespace internal | 
|  |  | 
|  | // Define human readable aliases to the type of the tags | 
|  | using ExtrinsicXYZ = internal::EulerSystem<internal::axis::X, | 
|  | internal::Even, | 
|  | internal::TaitBryan, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicXYX = internal::EulerSystem<internal::axis::X, | 
|  | internal::Even, | 
|  | internal::ProperEuler, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicXZY = internal::EulerSystem<internal::axis::X, | 
|  | internal::Odd, | 
|  | internal::TaitBryan, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicXZX = internal::EulerSystem<internal::axis::X, | 
|  | internal::Odd, | 
|  | internal::ProperEuler, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicYZX = internal::EulerSystem<internal::axis::Y, | 
|  | internal::Even, | 
|  | internal::TaitBryan, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicYZY = internal::EulerSystem<internal::axis::Y, | 
|  | internal::Even, | 
|  | internal::ProperEuler, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicYXZ = internal::EulerSystem<internal::axis::Y, | 
|  | internal::Odd, | 
|  | internal::TaitBryan, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicYXY = internal::EulerSystem<internal::axis::Y, | 
|  | internal::Odd, | 
|  | internal::ProperEuler, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicZXY = internal::EulerSystem<internal::axis::Z, | 
|  | internal::Even, | 
|  | internal::TaitBryan, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicZXZ = internal::EulerSystem<internal::axis::Z, | 
|  | internal::Even, | 
|  | internal::ProperEuler, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicZYX = internal::EulerSystem<internal::axis::Z, | 
|  | internal::Odd, | 
|  | internal::TaitBryan, | 
|  | internal::Extrinsic>; | 
|  | using ExtrinsicZYZ = internal::EulerSystem<internal::axis::Z, | 
|  | internal::Odd, | 
|  | internal::ProperEuler, | 
|  | internal::Extrinsic>; | 
|  | /* Rotating axes */ | 
|  | using IntrinsicZYX = internal::EulerSystem<internal::axis::X, | 
|  | internal::Even, | 
|  | internal::TaitBryan, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicXYX = internal::EulerSystem<internal::axis::X, | 
|  | internal::Even, | 
|  | internal::ProperEuler, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicYZX = internal::EulerSystem<internal::axis::X, | 
|  | internal::Odd, | 
|  | internal::TaitBryan, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicXZX = internal::EulerSystem<internal::axis::X, | 
|  | internal::Odd, | 
|  | internal::ProperEuler, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicXZY = internal::EulerSystem<internal::axis::Y, | 
|  | internal::Even, | 
|  | internal::TaitBryan, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicYZY = internal::EulerSystem<internal::axis::Y, | 
|  | internal::Even, | 
|  | internal::ProperEuler, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicZXY = internal::EulerSystem<internal::axis::Y, | 
|  | internal::Odd, | 
|  | internal::TaitBryan, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicYXY = internal::EulerSystem<internal::axis::Y, | 
|  | internal::Odd, | 
|  | internal::ProperEuler, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicYXZ = internal::EulerSystem<internal::axis::Z, | 
|  | internal::Even, | 
|  | internal::TaitBryan, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicZXZ = internal::EulerSystem<internal::axis::Z, | 
|  | internal::Even, | 
|  | internal::ProperEuler, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicXYZ = internal::EulerSystem<internal::axis::Z, | 
|  | internal::Odd, | 
|  | internal::TaitBryan, | 
|  | internal::Intrinsic>; | 
|  | using IntrinsicZYZ = internal::EulerSystem<internal::axis::Z, | 
|  | internal::Odd, | 
|  | internal::ProperEuler, | 
|  | internal::Intrinsic>; | 
|  |  | 
|  | }  // namespace ceres | 
|  |  | 
|  | #endif  // CERES_PUBLIC_INTERNAL_EULER_ANGLES_H_ |