Package edu.wpi.first.math.geometry

Class Rotation2d

java.lang.Object
edu.wpi.first.math.geometry.Rotation2d
All Implemented Interfaces:
Interpolatable<Rotation2d>, ProtobufSerializable, StructSerializable, WPISerializable
public class Rotation2d extends Object implements Interpolatable<Rotation2d>, ProtobufSerializable, StructSerializable
A rotation in a 2D coordinate frame represented by a point on the unit circle (cosine and sine).

The angle is continuous, that is if a Rotation2d is constructed with 361 degrees, it will return 361 degrees. This allows algorithms that wouldn't want to see a discontinuity in the rotations as it sweeps past from 360 to 0 on the second time around.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final Rotation2d
    k180deg
    A preallocated Rotation2d representing a counterclockwise rotation by 180° (π rad).
    static final Rotation2d
    kCCW_90deg
    A preallocated Rotation2d representing a counterclockwise rotation by 90° (π/2 rad).
    static final Rotation2d
    kCCW_Pi_2
    A preallocated Rotation2d representing a counterclockwise rotation by π/2 rad (90°).
    static final Rotation2d
    kCW_90deg
    A preallocated Rotation2d representing a clockwise rotation by 90° (π/2 rad).
    static final Rotation2d
    kCW_Pi_2
    A preallocated Rotation2d representing a clockwise rotation by π/2 rad (90°).
    static final Rotation2d
    kPi
    A preallocated Rotation2d representing a counterclockwise rotation by π rad (180°).
    static final Rotation2d
    kZero
    A preallocated Rotation2d representing no rotation.
    static final Rotation2dProto
    proto
    Rotation2d protobuf for serialization.
    static final Rotation2dStruct
    struct
    Rotation2d struct for serialization.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Rotation2d()
    Constructs a Rotation2d with a default angle of 0 degrees.
    Rotation2d(double value)
    Constructs a Rotation2d with the given radian value.
    Rotation2d(double x, double y)
    Constructs a Rotation2d with the given x and y (cosine and sine) components.
    Rotation2d(Matrix<N2,N2> rotationMatrix)
    Constructs a Rotation2d from a rotation matrix.
    Rotation2d(Angle angle)
    Constructs a Rotation2d with the given angle.

  • Method Summary

    Modifier and Type
    Method
    Description
    Rotation2d
    div(double scalar)
    Divides the current rotation by a scalar.
    boolean
    equals(Object obj)
    Checks equality between this Rotation2d and another object.
    static Rotation2d
    fromDegrees(double degrees)
    Constructs and returns a Rotation2d with the given degree value.
    static Rotation2d
    fromRadians(double radians)
    Constructs and returns a Rotation2d with the given radian value.
    static Rotation2d
    fromRotations(double rotations)
    Constructs and returns a Rotation2d with the given number of rotations.
    double
    getCos()
    Returns the cosine of the Rotation2d.
    double
    getDegrees()
    Returns the degree value of the Rotation2d.
    Angle
    getMeasure()
    Returns the measure of the Rotation2d.
    double
    getRadians()
    Returns the radian value of the Rotation2d.
    double
    getRotations()
    Returns the number of rotations of the Rotation2d.
    double
    getSin()
    Returns the sine of the Rotation2d.
    double
    getTan()
    Returns the tangent of the Rotation2d.
    int
    hashCode()
     
    Rotation2d
    interpolate(Rotation2d endValue, double t)
    Return the interpolated value.
    Rotation2d
    minus(Rotation2d other)
    Subtracts the new rotation from the current rotation and returns the new rotation.
    Rotation2d
    plus(Rotation2d other)
    Adds two rotations together, with the result being bounded between -π and π.
    Rotation2d
    rotateBy(Rotation2d other)
    Adds the new rotation to the current rotation using a rotation matrix.
    Rotation2d
    times(double scalar)
    Multiplies the current rotation by a scalar.
    Matrix<N2,N2>
    toMatrix()
    Returns matrix representation of this rotation.
    String
    toString()
     
    Rotation2d
    unaryMinus()
    Takes the inverse of the current rotation.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • kZero

      public static final Rotation2d kZero
      A preallocated Rotation2d representing no rotation.

      This exists to avoid allocations for common rotations.

    • kCW_Pi_2

      public static final Rotation2d kCW_Pi_2
      A preallocated Rotation2d representing a clockwise rotation by π/2 rad (90°).

      This exists to avoid allocations for common rotations.

    • kCW_90deg

      public static final Rotation2d kCW_90deg
      A preallocated Rotation2d representing a clockwise rotation by 90° (π/2 rad).

      This exists to avoid allocations for common rotations.

    • kCCW_Pi_2

      public static final Rotation2d kCCW_Pi_2
      A preallocated Rotation2d representing a counterclockwise rotation by π/2 rad (90°).

      This exists to avoid allocations for common rotations.

    • kCCW_90deg

      public static final Rotation2d kCCW_90deg
      A preallocated Rotation2d representing a counterclockwise rotation by 90° (π/2 rad).

      This exists to avoid allocations for common rotations.

    • kPi

      public static final Rotation2d kPi
      A preallocated Rotation2d representing a counterclockwise rotation by π rad (180°).

      This exists to avoid allocations for common rotations.

    • k180deg

      public static final Rotation2d k180deg
      A preallocated Rotation2d representing a counterclockwise rotation by 180° (π rad).

      This exists to avoid allocations for common rotations.

    • proto

      public static final Rotation2dProto proto
      Rotation2d protobuf for serialization.

    • struct

      public static final Rotation2dStruct struct
      Rotation2d struct for serialization.

  • Constructor Details

    • Rotation2d

      public Rotation2d()
      Constructs a Rotation2d with a default angle of 0 degrees.

    • Rotation2d

      public Rotation2d(double value)
      Constructs a Rotation2d with the given radian value.
      Parameters:
      value - The value of the angle in radians.

    • Rotation2d

      public Rotation2d(double x, double y)
      Constructs a Rotation2d with the given x and y (cosine and sine) components.
      Parameters:
      x - The x component or cosine of the rotation.
      y - The y component or sine of the rotation.

    • Rotation2d

      public Rotation2d(Angle angle)
      Constructs a Rotation2d with the given angle.
      Parameters:
      angle - The angle of the rotation.

    • Rotation2d

      public Rotation2d(Matrix<N2,N2> rotationMatrix)
      Constructs a Rotation2d from a rotation matrix.
      Parameters:
      rotationMatrix - The rotation matrix.
      Throws:
      IllegalArgumentException - if the rotation matrix isn't special orthogonal.

  • Method Details

    • fromRadians

      public static Rotation2d fromRadians(double radians)
      Constructs and returns a Rotation2d with the given radian value.
      Parameters:
      radians - The value of the angle in radians.
      Returns:
      The rotation object with the desired angle value.

    • fromDegrees

      public static Rotation2d fromDegrees(double degrees)
      Constructs and returns a Rotation2d with the given degree value.
      Parameters:
      degrees - The value of the angle in degrees.
      Returns:
      The rotation object with the desired angle value.

    • fromRotations

      public static Rotation2d fromRotations(double rotations)
      Constructs and returns a Rotation2d with the given number of rotations.
      Parameters:
      rotations - The value of the angle in rotations.
      Returns:
      The rotation object with the desired angle value.

    • plus

      public Rotation2d plus(Rotation2d other)
      Adds two rotations together, with the result being bounded between -π and π.

      For example, Rotation2d.fromDegrees(30).plus(Rotation2d.fromDegrees(60)) equals Rotation2d(Math.PI/2.0)

      Parameters:
      other - The rotation to add.
      Returns:
      The sum of the two rotations.

    • minus

      public Rotation2d minus(Rotation2d other)
      Subtracts the new rotation from the current rotation and returns the new rotation.

      For example, Rotation2d.fromDegrees(10).minus(Rotation2d.fromDegrees(100)) equals Rotation2d(-Math.PI/2.0)

      Parameters:
      other - The rotation to subtract.
      Returns:
      The difference between the two rotations.

    • unaryMinus

      public Rotation2d unaryMinus()
      Takes the inverse of the current rotation. This is simply the negative of the current angular value.
      Returns:
      The inverse of the current rotation.

    • times

      public Rotation2d times(double scalar)
      Multiplies the current rotation by a scalar.
      Parameters:
      scalar - The scalar.
      Returns:
      The new scaled Rotation2d.

    • div

      public Rotation2d div(double scalar)
      Divides the current rotation by a scalar.
      Parameters:
      scalar - The scalar.
      Returns:
      The new scaled Rotation2d.

    • rotateBy

      public Rotation2d rotateBy(Rotation2d other)
      Adds the new rotation to the current rotation using a rotation matrix.

      The matrix multiplication is as follows: 

       [cos_new]   [other.cos, -other.sin][cos]
 [sin_new] = [other.sin,  other.cos][sin]
 value_new = atan2(sin_new, cos_new)
      Parameters:
      other - The rotation to rotate by.
      Returns:
      The new rotated Rotation2d.

    • toMatrix

      public Matrix<N2,N2> toMatrix()
      Returns matrix representation of this rotation.
      Returns:
      Matrix representation of this rotation.

    • getMeasure

      public Angle getMeasure()
      Returns the measure of the Rotation2d.
      Returns:
      The measure of the Rotation2d.

    • getRadians

      public double getRadians()
      Returns the radian value of the Rotation2d.
      Returns:
      The radian value of the Rotation2d.
      See Also:

    • getDegrees

      public double getDegrees()
      Returns the degree value of the Rotation2d.
      Returns:
      The degree value of the Rotation2d.
      See Also:

    • getRotations

      public double getRotations()
      Returns the number of rotations of the Rotation2d.
      Returns:
      The number of rotations of the Rotation2d.

    • getCos

      public double getCos()
      Returns the cosine of the Rotation2d.
      Returns:
      The cosine of the Rotation2d.

    • getSin

      public double getSin()
      Returns the sine of the Rotation2d.
      Returns:
      The sine of the Rotation2d.

    • getTan

      public double getTan()
      Returns the tangent of the Rotation2d.
      Returns:
      The tangent of the Rotation2d.

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • equals

      public boolean equals(Object obj)
      Checks equality between this Rotation2d and another object.
      Overrides:
      equals in class Object
      Parameters:
      obj - The other object.
      Returns:
      Whether the two objects are equal or not.

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • interpolate

      public Rotation2d interpolate(Rotation2d endValue, double t)
      Description copied from interface: Interpolatable
      Return the interpolated value. This object is assumed to be the starting position, or lower bound.
      Specified by:
      interpolate in interface Interpolatable<Rotation2d>
      Parameters:
      endValue - The upper bound, or end.
      t - How far between the lower and upper bound we are. This should be bounded in [0, 1].
      Returns:
      The interpolated value.