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allwpilib/wpimath/src/main/native/include/wpi/math/geometry/Pose2d.hpp
2026-04-08 08:28:28 -07:00

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// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
#pragma once
#include <algorithm>
#include <initializer_list>
#include <span>
#include <utility>
#include <gcem.hpp>
#include "wpi/math/geometry/Rotation2d.hpp"
#include "wpi/math/geometry/Translation2d.hpp"
#include "wpi/units/length.hpp"
#include "wpi/util/SymbolExports.hpp"
namespace wpi::util {
class json;
} // namespace wpi::util
namespace wpi::math {
class Transform2d;
/**
* Represents a 2D pose containing translational and rotational elements.
*/
class WPILIB_DLLEXPORT Pose2d {
public:
/**
* Constructs a pose at the origin facing toward the positive X axis.
*/
constexpr Pose2d() = default;
/**
* Constructs a pose with the specified translation and rotation.
*
* @param translation The translational component of the pose.
* @param rotation The rotational component of the pose.
*/
constexpr Pose2d(Translation2d translation, Rotation2d rotation)
: m_translation{std::move(translation)},
m_rotation{std::move(rotation)} {}
/**
* Constructs a pose with x and y translations instead of a separate
* Translation2d.
*
* @param x The x component of the translational component of the pose.
* @param y The y component of the translational component of the pose.
* @param rotation The rotational component of the pose.
*/
constexpr Pose2d(wpi::units::meter_t x, wpi::units::meter_t y,
Rotation2d rotation)
: m_translation{x, y}, m_rotation{std::move(rotation)} {}
/**
* Constructs a pose with the specified affine transformation matrix.
*
* @param matrix The affine transformation matrix.
* @throws std::domain_error if the affine transformation matrix is invalid.
*/
constexpr explicit Pose2d(const Eigen::Matrix3d& matrix)
: m_translation{Eigen::Vector2d{{matrix(0, 2)}, {matrix(1, 2)}}},
m_rotation{Eigen::Matrix2d{{matrix(0, 0), matrix(0, 1)},
{matrix(1, 0), matrix(1, 1)}}} {
if (matrix(2, 0) != 0.0 || matrix(2, 1) != 0.0 || matrix(2, 2) != 1.0) {
throw std::domain_error("Affine transformation matrix is invalid");
}
}
/**
* Transforms the pose by the given transformation and returns the new
* transformed pose.
*
* <pre>
* [x_new] [cos, -sin, 0][transform.x]
* [y_new] += [sin, cos, 0][transform.y]
* [t_new] [ 0, 0, 1][transform.t]
* </pre>
*
* @param other The transform to transform the pose by.
*
* @return The transformed pose.
*/
constexpr Pose2d operator+(const Transform2d& other) const {
return TransformBy(other);
}
/**
* Returns the Transform2d that maps the one pose to another.
*
* @param other The initial pose of the transformation.
* @return The transform that maps the other pose to the current pose.
*/
constexpr Transform2d operator-(const Pose2d& other) const;
/**
* Checks equality between this Pose2d and another object.
*/
constexpr bool operator==(const Pose2d&) const = default;
/**
* Returns the underlying translation.
*
* @return Reference to the translational component of the pose.
*/
constexpr const Translation2d& Translation() const { return m_translation; }
/**
* Returns the X component of the pose's translation.
*
* @return The x component of the pose's translation.
*/
constexpr wpi::units::meter_t X() const { return m_translation.X(); }
/**
* Returns the Y component of the pose's translation.
*
* @return The y component of the pose's translation.
*/
constexpr wpi::units::meter_t Y() const { return m_translation.Y(); }
/**
* Returns the underlying rotation.
*
* @return Reference to the rotational component of the pose.
*/
constexpr const Rotation2d& Rotation() const { return m_rotation; }
/**
* Multiplies the current pose by a scalar.
*
* @param scalar The scalar.
*
* @return The new scaled Pose2d.
*/
constexpr Pose2d operator*(double scalar) const {
return Pose2d{m_translation * scalar, m_rotation * scalar};
}
/**
* Divides the current pose by a scalar.
*
* @param scalar The scalar.
*
* @return The new scaled Pose2d.
*/
constexpr Pose2d operator/(double scalar) const {
return *this * (1.0 / scalar);
}
/**
* Rotates the pose around the origin and returns the new pose.
*
* @param other The rotation to transform the pose by.
*
* @return The rotated pose.
*/
constexpr Pose2d RotateBy(const Rotation2d& other) const {
return {m_translation.RotateBy(other), m_rotation.RotateBy(other)};
}
/**
* Transforms the pose by the given transformation and returns the new pose.
* See + operator for the matrix multiplication performed.
*
* @param other The transform to transform the pose by.
*
* @return The transformed pose.
*/
constexpr Pose2d TransformBy(const Transform2d& other) const;
/**
* Returns the current pose relative to the given pose.
*
* This function can often be used for trajectory tracking or pose
* stabilization algorithms to get the error between the reference and the
* current pose.
*
* @param other The pose that is the origin of the new coordinate frame that
* the current pose will be converted into.
*
* @return The current pose relative to the new origin pose.
*/
constexpr Pose2d RelativeTo(const Pose2d& other) const;
/**
* Rotates the current pose around a point in 2D space.
*
* @param point The point in 2D space to rotate around.
* @param rot The rotation to rotate the pose by.
*
* @return The new rotated pose.
*/
constexpr Pose2d RotateAround(const Translation2d& point,
const Rotation2d& rot) const {
return {m_translation.RotateAround(point, rot), m_rotation.RotateBy(rot)};
}
/**
* Returns an affine transformation matrix representation of this pose.
*/
constexpr Eigen::Matrix3d ToMatrix() const {
auto vec = m_translation.ToVector();
auto mat = m_rotation.ToMatrix();
return Eigen::Matrix3d{{mat(0, 0), mat(0, 1), vec(0)},
{mat(1, 0), mat(1, 1), vec(1)},
{0.0, 0.0, 1.0}};
}
/**
* Returns the nearest Pose2d from a collection of poses.
*
* If two or more poses in the collection have the same distance from this
* pose, return the one with the closest rotation component.
*
* @param poses The collection of poses.
* @return The nearest Pose2d from the collection.
*/
constexpr Pose2d Nearest(std::span<const Pose2d> poses) const {
return *std::min_element(
poses.begin(), poses.end(), [this](const Pose2d& a, const Pose2d& b) {
auto aDistance = this->Translation().Distance(a.Translation());
auto bDistance = this->Translation().Distance(b.Translation());
// If the distances are equal sort by difference in rotation
if (aDistance == bDistance) {
return gcem::abs(
(this->Rotation() - a.Rotation()).Radians().value()) <
gcem::abs(
(this->Rotation() - b.Rotation()).Radians().value());
}
return aDistance < bDistance;
});
}
/**
* Returns the nearest Pose2d from a collection of poses.
*
* If two or more poses in the collection have the same distance from this
* pose, return the one with the closest rotation component.
*
* @param poses The collection of poses.
* @return The nearest Pose2d from the collection.
*/
constexpr Pose2d Nearest(std::initializer_list<Pose2d> poses) const {
return *std::min_element(
poses.begin(), poses.end(), [this](const Pose2d& a, const Pose2d& b) {
auto aDistance = this->Translation().Distance(a.Translation());
auto bDistance = this->Translation().Distance(b.Translation());
// If the distances are equal sort by difference in rotation
if (aDistance == bDistance) {
return gcem::abs(
(this->Rotation() - a.Rotation()).Radians().value()) <
gcem::abs(
(this->Rotation() - b.Rotation()).Radians().value());
}
return aDistance < bDistance;
});
}
private:
Translation2d m_translation;
Rotation2d m_rotation;
};
WPILIB_DLLEXPORT
void to_json(wpi::util::json& json, const Pose2d& pose);
WPILIB_DLLEXPORT
void from_json(const wpi::util::json& json, Pose2d& pose);
} // namespace wpi::math
#include "wpi/math/geometry/Transform2d.hpp"
#include "wpi/math/geometry/proto/Pose2dProto.hpp"
#include "wpi/math/geometry/struct/Pose2dStruct.hpp"
namespace wpi::math {
constexpr Transform2d Pose2d::operator-(const Pose2d& other) const {
const auto pose = this->RelativeTo(other);
return Transform2d{pose.Translation(), pose.Rotation()};
}
constexpr Pose2d Pose2d::TransformBy(
const wpi::math::Transform2d& other) const {
return {m_translation + (other.Translation().RotateBy(m_rotation)),
other.Rotation().RotateBy(m_rotation)};
}
constexpr Pose2d Pose2d::RelativeTo(const Pose2d& other) const {
const Transform2d transform{other, *this};
return {transform.Translation(), transform.Rotation()};
}
} // namespace wpi::math