tf_r2r/
transforms.rs

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pub use nalgebra;
use nalgebra::geometry::{Isometry3, Translation3, UnitQuaternion};
use r2r::{
    geometry_msgs::msg::{Pose, Quaternion, Transform, TransformStamped, Vector3},
    std_msgs::msg::Header,
};

pub fn isometry_from_pose(pose: &Pose) -> Isometry3<f64> {
    let trans = Translation3::new(pose.position.x, pose.position.y, pose.position.z);
    let rot = UnitQuaternion::new_normalize(nalgebra::geometry::Quaternion::new(
        pose.orientation.w,
        pose.orientation.x,
        pose.orientation.y,
        pose.orientation.z,
    ));

    Isometry3::from_parts(trans, rot)
}

pub fn isometry_from_transform(tf: &Transform) -> Isometry3<f64> {
    let trans = Translation3::new(tf.translation.x, tf.translation.y, tf.translation.z);
    let rot = UnitQuaternion::new_normalize(nalgebra::geometry::Quaternion::new(
        tf.rotation.w,
        tf.rotation.x,
        tf.rotation.y,
        tf.rotation.z,
    ));

    Isometry3::from_parts(trans, rot)
}

pub fn isometry_to_transform(iso: Isometry3<f64>) -> Transform {
    Transform {
        translation: Vector3 {
            x: iso.translation.x,
            y: iso.translation.y,
            z: iso.translation.z,
        },
        rotation: Quaternion {
            x: iso.rotation.i,
            y: iso.rotation.j,
            z: iso.rotation.k,
            w: iso.rotation.w,
        },
    }
}

pub fn get_inverse(trans: &TransformStamped) -> TransformStamped {
    TransformStamped {
        header: Header {
            stamp: trans.header.stamp.clone(),
            frame_id: trans.child_frame_id.clone(),
        },
        child_frame_id: trans.header.frame_id.clone(),
        transform: isometry_to_transform(
            isometry_from_transform(&trans.transform).clone().inverse(),
        ),
    }
}

///Chain multiple transforms together. Takes in a vector of transforms. The vector should be in order of desired transformations
pub fn chain_transforms(transforms: &[Transform]) -> Transform {
    let mut final_transform = Isometry3::identity();
    for t in transforms {
        let tf = isometry_from_transform(t);
        final_transform *= tf;
    }
    isometry_to_transform(final_transform)
}

pub fn interpolate(t1: Transform, t2: Transform, weight: f64) -> Transform {
    let r1 = nalgebra::geometry::Quaternion::new(
        t1.rotation.w,
        t1.rotation.x,
        t1.rotation.y,
        t1.rotation.z,
    );
    let r2 = nalgebra::geometry::Quaternion::new(
        t2.rotation.w,
        t2.rotation.x,
        t2.rotation.y,
        t2.rotation.z,
    );
    let r1 = UnitQuaternion::from_quaternion(r1);
    let r2 = UnitQuaternion::from_quaternion(r2);
    let res = r1.try_slerp(&r2, weight, 1e-9);
    match res {
        Some(qt) => Transform {
            translation: Vector3 {
                x: t1.translation.x * weight + t2.translation.x * (1.0 - weight),
                y: t1.translation.y * weight + t2.translation.y * (1.0 - weight),
                z: t1.translation.z * weight + t2.translation.z * (1.0 - weight),
            },
            rotation: Quaternion {
                x: qt.coords[0],
                y: qt.coords[1],
                z: qt.coords[2],
                w: qt.coords[3],
            },
        },
        None => {
            if weight > 0.5 {
                Transform {
                    translation: Vector3 {
                        x: t1.translation.x * weight + t2.translation.x * (1.0 - weight),
                        y: t1.translation.y * weight + t2.translation.y * (1.0 - weight),
                        z: t1.translation.z * weight + t2.translation.z * (1.0 - weight),
                    },
                    rotation: t1.rotation,
                }
            } else {
                Transform {
                    translation: Vector3 {
                        x: t1.translation.x * weight + t2.translation.x * (1.0 - weight),
                        y: t1.translation.y * weight + t2.translation.y * (1.0 - weight),
                        z: t1.translation.z * weight + t2.translation.z * (1.0 - weight),
                    },
                    rotation: t2.rotation,
                }
            }
        }
    }
}

pub(crate) fn to_transform_stamped(
    tf: Transform,
    from: std::string::String,
    to: std::string::String,
    time: &r2r::builtin_interfaces::msg::Time,
) -> TransformStamped {
    TransformStamped {
        header: Header {
            frame_id: from,
            stamp: time.clone(),
        },
        child_frame_id: to,
        transform: tf,
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_basic_translation_chaining() {
        let tf1 = Transform {
            translation: Vector3 {
                x: 1f64,
                y: 1f64,
                z: 0f64,
            },
            rotation: Quaternion {
                x: 0f64,
                y: 0f64,
                z: 0f64,
                w: 1f64,
            },
        };
        let expected_tf = Transform {
            translation: Vector3 {
                x: 2f64,
                y: 2f64,
                z: 0f64,
            },
            rotation: Quaternion {
                x: 0f64,
                y: 0f64,
                z: 0f64,
                w: 1f64,
            },
        };
        let transform_chain = vec![tf1.clone(), tf1];
        let res = chain_transforms(&transform_chain);
        assert_eq!(res, expected_tf);
    }

    #[test]
    fn test_basic_interpolation() {
        let tf1 = Transform {
            translation: Vector3 {
                x: 1f64,
                y: 1f64,
                z: 0f64,
            },
            rotation: Quaternion {
                x: 0f64,
                y: 0f64,
                z: 0f64,
                w: 1f64,
            },
        };
        let tf2 = Transform {
            translation: Vector3 {
                x: 2f64,
                y: 2f64,
                z: 0f64,
            },
            rotation: Quaternion {
                x: 0f64,
                y: 0f64,
                z: 0f64,
                w: 1f64,
            },
        };
        let expected = Transform {
            translation: Vector3 {
                x: 1.5f64,
                y: 1.5f64,
                z: 0f64,
            },
            rotation: Quaternion {
                x: 0f64,
                y: 0f64,
                z: 0f64,
                w: 1f64,
            },
        };
        assert_eq!(interpolate(tf1, tf2, 0.5), expected);
    }
}