pose2d.hpp¶
Pose2d — a rigid-body pose on SE(2): position (x, y) + heading.
This header declares 1 type (6 members).
Extracted from include/shulib/math/pose2d.hpp — this page is that header's documentation, reformatted, so it cannot disagree with the code. Prose about how to think about the API lives in the user guide; worked recipes live in the cookbook; this page is the complete, mechanical list of what exists.
Contents¶
class Pose2d¶
A rigid-body pose on SE(2): position plus heading. The type carries NO frame tag — nearly every Pose2d in shulib is a FIELD pose (F1: +X right, +Y away from the red driver station, heading 0 along +X, CCW-positive), but a body-frame pose uses this same type (an AprilTag's pose relative to the robot is one), so which frame a given Pose2d is in is a fact about the variable, not about the type. Position is a type-safe Length in canonical inches and heading is the WRAPPING Angle, so comparing two poses is correct across the ±180° seam rather than reporting 358° of error.
class, declared at include/shulib/math/pose2d.hpp:23.
Pose2d::Pose2d¶
The origin at heading 0. NOT a "no pose" sentinel — it is indistinguishable from a robot genuinely sitting at the origin, which is why the Localizer publishes a separate Quality (Uninitialized / DeadReckon / …) instead of overloading a default pose.
function, declared at include/shulib/math/pose2d.hpp:28.
Pose2d::Pose2d (overload 2)¶
The origin at heading 0. NOT a "no pose" sentinel — it is indistinguishable from a robot genuinely sitting at the origin, which is why the Localizer publishes a separate Quality (Uninitialized / DeadReckon / …) instead of overloading a default pose. Position in canonical inches; heading is already a wrapped Angle so nothing is normalized here. NO validation: a non-finite Length passes straight through (Angle's factories reject non-finite input, Length has no such guard), so callers that care screen it themselves — the Localizer runs std::isfinite over a corrector's proposed x/y before fusing it.
function, declared at include/shulib/math/pose2d.hpp:34.
Pose2d::x¶
The x coordinate, in canonical inches. In the field frame +X points right, and heading 0 points along it — so x is the "forward" axis for a robot at heading 0.
function, declared at include/shulib/math/pose2d.hpp:39.
Pose2d::y¶
The y coordinate, in canonical inches. In the field frame +Y points away from the red driver station; with CCW-positive heading that pins the whole sign convention.
function, declared at include/shulib/math/pose2d.hpp:42.
Pose2d::heading¶
The heading, as the WRAPPING Angle: already normalized to (-π, π], CCW-positive, 0 along +X. Compare it with Angle::errorTo / approxEqual — differencing radians() as raw doubles reintroduces exactly the ±180° seam bug this type exists to make impossible.
function, declared at include/shulib/math/pose2d.hpp:46.
Pose2d::approxEqual¶
[[nodiscard]] bool approxEqual(const Pose2d& o, units::Length posTol = units::Length{1e-6}, double headTolRad = 1e-9) const noexcept
Component-wise closeness. Heading uses the SHORTEST angular error, so 179° vs -179° are 2° apart (not 358°) — comparison respects the wrap.
function, declared at include/shulib/math/pose2d.hpp:50.
Design commentary, from the header¶
The header opens with the reasoning behind these shapes. It is reproduced here in full because a reference that only lists signatures teaches nobody why.
The header’s own reasoning — 6 lines
Last updated 2026-08-15 — published from the main release branch, commit fa545ff. This site tracks releases, so between them it can lag the repository — that lag is deliberate, and it is what keeps the development log off the public site. For the current state of the code, see the repository.