Package edu.wpi.first.math.geometry

Class Rotation2d

java.lang.Object
edu.wpi.first.math.geometry.Rotation2d
All Implemented Interfaces:
Interpolatable<Rotation2d>
public class Rotation2d
extends Object
implements Interpolatable<Rotation2d>
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 Details

  • 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​(Measure<Angle> angle)
      Constructs a Rotation2d with the given angle.
      Parameters:
      angle - The angle of the rotation.

  • 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 -pi and pi.

      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.

    • getRadians

      public double getRadians()
      Returns the radian value of the Rotation2d.
      Returns:
      The radian value of the Rotation2d.
      See Also:
      to constrain the angle within (-pi, pi]

    • getDegrees

      public double getDegrees()
      Returns the degree value of the Rotation2d.
      Returns:
      The degree value of the Rotation2d.
      See Also:
      to constrain the angle within (-180, 180]

    • 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.