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use crate::CartesianTreeError;
use crate::frame::{Frame, FrameKind, SharedTree, read_tree};
use crate::lazy_access::{LazyRotation, LazyTranslation};
use crate::rotation::Rotation;
use nalgebra::{Isometry3, Translation3, Vector3};
use std::ops::{Add, Mul, Sub};
use std::sync::Arc;
/// Use [`Frame::add_pose`] to create a new pose.
///
/// A pose shares ownership of the tree of the frame it lives in, so holding a pose
/// keeps the tree alive. `Pose` is `Send + Sync`.
#[derive(Clone)]
pub struct Pose {
/// The tree of the frame this pose lives in.
pub(crate) tree: SharedTree,
/// The frame this pose lives in.
pub(crate) anchor: FrameKind,
/// Transformation from this pose to its parent frame.
transform_to_parent: Isometry3<f64>,
}
impl std::fmt::Debug for Pose {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
// Deliberately does not lock the tree, so Debug is safe in any context.
f.debug_struct("Pose")
.field("anchor", &self.anchor)
.field("transform_to_parent", &self.transform_to_parent)
.finish_non_exhaustive()
}
}
impl Pose {
/// Creates a new pose relative to a frame.
///
/// This function is intended for internal use. To create a pose associated with a frame,
/// use [`Frame::add_pose`], which handles the association safely.
pub(crate) fn new(
tree: SharedTree,
anchor: FrameKind,
position: Vector3<f64>,
orientation: impl Into<Rotation>,
) -> Self {
Self {
tree,
anchor,
transform_to_parent: Isometry3::from_parts(
Translation3::from(position),
orientation.into().as_quaternion(),
),
}
}
/// Returns the parent frame of this pose.
///
/// # Returns
/// `Some(Frame)` if the frame still exists in the tree, or `None` if it has been
/// removed.
///
/// # Example
/// ```
/// use cartesian_tree::Frame;
/// use nalgebra::{Vector3, UnitQuaternion};
///
/// let frame = Frame::new_origin("base");
/// let pose = frame.add_pose(Vector3::new(0.0, 0.0, 0.0), UnitQuaternion::identity());
/// assert_eq!(pose.frame().unwrap().name(), "base");
/// ```
#[must_use]
pub fn frame(&self) -> Option<Frame> {
let guard = read_tree(&self.tree);
guard.contains(self.anchor.anchor()).then(|| Frame {
tree: Arc::clone(&self.tree),
kind: self.anchor.clone(),
})
}
/// Returns the transformation from this pose to its parent frame.
///
/// # Returns
/// The transformation of the pose in its parent frame.
#[must_use]
pub const fn transformation(&self) -> Isometry3<f64> {
self.transform_to_parent
}
/// Returns the position of this pose relative to its parent frame.
/// # Returns
/// The position of the pose in its parent frame.
#[must_use]
pub const fn position(&self) -> Vector3<f64> {
self.transform_to_parent.translation.vector
}
/// Returns the orientation of this pose relative to its parent frame.
/// # Returns
/// The orientation of the pose in its parent frame.
#[must_use]
pub fn orientation(&self) -> Rotation {
self.transform_to_parent.rotation.into()
}
/// Sets the pose's transformation relative to its parent.
///
/// # Arguments
/// - `position`: A 3D vector representing the new translational offset from the parent.
/// - `orientation`: An orientation convertible into a unit quaternion for new orientational offset from the parent.
///
/// # Example
/// ```
/// use cartesian_tree::Frame;
/// use nalgebra::{Vector3, UnitQuaternion};
///
/// let root = Frame::new_origin("root");
/// let mut pose = root.add_pose(Vector3::new(0.0, 0.0, 1.0), UnitQuaternion::identity());
/// pose.set(Vector3::new(1.0, 0.0, 0.0), UnitQuaternion::identity());
/// ```
pub fn set(&mut self, position: Vector3<f64>, orientation: impl Into<Rotation>) {
self.transform_to_parent = Isometry3::from_parts(
Translation3::from(position),
orientation.into().as_quaternion(),
);
}
/// Applies the provided isometry interpreted in the parent frame to the pose.
///
/// # Arguments
/// - `isometry`: The isometry (describing a motion in the parent frame coordinates) to apply to the current transformation.
///
/// # Example
/// ```
/// use cartesian_tree::Frame;
/// use nalgebra::{Isometry3, Translation3, Vector3, UnitQuaternion};
///
/// let root = Frame::new_origin("root");
/// let mut pose = root.add_pose(Vector3::new(0.0, 0.0, 1.0), UnitQuaternion::identity());
/// pose.apply_in_parent_frame(&Isometry3::from_parts(Translation3::new(1.0, 0.0, 0.0), UnitQuaternion::identity()));
/// ```
pub fn apply_in_parent_frame(&mut self, isometry: &Isometry3<f64>) {
self.transform_to_parent = isometry * self.transform_to_parent;
}
/// Applies the provided isometry interpreted in the body frame to this pose.
///
/// # Arguments
/// - `isometry`: The isometry (describing a motion in the body frame coordinates) to apply to the current transformation.
///
/// # Example
/// ```
/// use cartesian_tree::Frame;
/// use nalgebra::{Isometry3, Translation3, Vector3, UnitQuaternion};
///
/// let root = Frame::new_origin("root");
/// let mut pose = root.add_pose(Vector3::new(0.0, 0.0, 1.0), UnitQuaternion::identity());
/// pose.apply_in_local_frame(&Isometry3::from_parts(Translation3::new(1.0, 0.0, 0.0), UnitQuaternion::identity()));
/// ```
pub fn apply_in_local_frame(&mut self, isometry: &Isometry3<f64>) {
self.transform_to_parent *= isometry;
}
/// Transforms this pose into the coordinate system of the given target frame.
///
/// The computation runs under a single read lock, so it sees a consistent snapshot
/// of the tree even while other threads are updating transforms.
///
/// # Arguments
/// * `target` - The frame to express this pose in.
///
/// # Returns
/// A new `Pose`, expressed in the `target` frame.
///
/// # Errors
/// Returns a [`CartesianTreeError`] if:
/// - The pose's frame or the target frame has been removed from the tree.
/// - The frames belong to different trees.
/// - There is no common ancestor between `self` and `target`.
///
/// # Example
/// ```
/// use cartesian_tree::Frame;
/// use nalgebra::{Vector3, UnitQuaternion};
///
/// let root = Frame::new_origin("root");
/// let pose = root.add_pose(Vector3::new(0.0, 0.0, 1.0), UnitQuaternion::identity());
/// let new_frame = root.add_child("child", Vector3::new(1.0, 0.0, 0.0), UnitQuaternion::identity()).unwrap();
/// let pose_in_new_frame = pose.in_frame(&new_frame);
/// ```
pub fn in_frame(&self, target: &Frame) -> Result<Self, CartesianTreeError> {
if !Arc::ptr_eq(&self.tree, &target.tree) {
let own_name = self
.frame()
.map_or_else(|| "<removed>".to_owned(), |frame| frame.name());
return Err(CartesianTreeError::DifferentTrees(own_name, target.name()));
}
let guard = read_tree(&self.tree);
let source_anchor = self.anchor.anchor();
let target_anchor = target.kind.anchor();
let ancestor = guard.lca(source_anchor, target_anchor)?.ok_or_else(|| {
CartesianTreeError::NoCommonAncestor(
guard.name_of(source_anchor),
guard.name_of(target_anchor),
)
})?;
// Transformation from the pose up to the ancestor.
let tf_up = guard.transform_up(
source_anchor,
self.anchor.offset() * self.transform_to_parent,
ancestor,
)?;
// Transformation from the target's anchor up to the ancestor (to be inverted).
let tf_down = guard.transform_up(target_anchor, Isometry3::identity(), ancestor)?;
Ok(Self {
tree: Arc::clone(&self.tree),
anchor: target.kind.clone(),
transform_to_parent: target.kind.offset().inverse() * (tf_down.inverse() * tf_up),
})
}
}
impl Add<LazyTranslation> for &Pose {
type Output = Pose;
fn add(self, rhs: LazyTranslation) -> Self::Output {
let mut new_pose = self.clone();
new_pose.apply_in_parent_frame(&rhs.inner);
new_pose
}
}
impl Sub<LazyTranslation> for &Pose {
type Output = Pose;
fn sub(self, rhs: LazyTranslation) -> Self::Output {
let mut new_pose = self.clone();
new_pose.apply_in_parent_frame(&rhs.inner.inverse());
new_pose
}
}
impl Mul<LazyRotation> for &Pose {
type Output = Pose;
fn mul(self, rhs: LazyRotation) -> Self::Output {
let mut new_pose = self.clone();
new_pose.apply_in_local_frame(&rhs.inner);
new_pose
}
}