| // Ceres Solver - A fast non-linear least squares minimizer | 
 | // Copyright 2022 Google Inc. All rights reserved. | 
 | // http://ceres-solver.org/ | 
 | // | 
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 | // modification, are permitted provided that the following conditions are met: | 
 | // | 
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 | //   this list of conditions and the following disclaimer. | 
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 | //   used to endorse or promote products derived from this software without | 
 | //   specific prior written permission. | 
 | // | 
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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_ |