[wpilib] Document zero angle in SingleJointedArmSim (NFC) (#7756)

Fixes #7752

---------

Co-authored-by: sciencewhiz <sciencewhiz@users.noreply.github.com>
Co-authored-by: Tyler Veness <calcmogul@gmail.com>

Author: 3 people

wpilibc/src/main/native/include/frc/simulation/SingleJointedArmSim.h

@@ -30,10 +30,13 @@ class SingleJointedArmSim : public LinearSystemSim<2, 1, 2> {
    * @param gearing            The gear ratio of the arm (numbers greater than 1
    *                           represent reductions).
    * @param armLength          The length of the arm.
-   * @param minAngle           The minimum angle that the arm is capable of.
-   * @param maxAngle           The maximum angle that the arm is capable of.
+   * @param minAngle           The minimum angle that the arm is capable of,
+   *                           with 0 being horizontal.
+   * @param maxAngle           The maximum angle that the arm is capable of,
+   *                           with 0 being horizontal.
    * @param simulateGravity    Whether gravity should be simulated or not.
-   * @param startingAngle      The initial position of the arm.
+   * @param startingAngle      The initial position of the arm, with 0 being
+   *                           horizontal.
    * @param measurementStdDevs The standard deviations of the measurements.
    */
   SingleJointedArmSim(const LinearSystem<2, 1, 2>& system,
@@ -52,10 +55,13 @@ class SingleJointedArmSim : public LinearSystemSim<2, 1, 2> {
    * @param moi                The moment of inertia of the arm. This can be
    *                           calculated from CAD software.
    * @param armLength          The length of the arm.
-   * @param minAngle           The minimum angle that the arm is capable of.
-   * @param maxAngle           The maximum angle that the arm is capable of.
+   * @param minAngle           The minimum angle that the arm is capable of,
+   *                           with 0 being horizontal.
+   * @param maxAngle           The maximum angle that the arm is capable of,
+   *                           with 0 being horizontal.
    * @param simulateGravity    Whether gravity should be simulated or not.
-   * @param startingAngle      The initial position of the arm.
+   * @param startingAngle      The initial position of the arm, with 0 being
+   *                           horizontal.
    * @param measurementStdDevs The standard deviation of the measurement noise.
    */
   SingleJointedArmSim(const DCMotor& gearbox, double gearing,

wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/SingleJointedArmSim.java

@@ -44,10 +44,13 @@ public class SingleJointedArmSim extends LinearSystemSim<N2, N1, N2> {
    * @param gearbox The type of and number of motors in the arm gearbox.
    * @param gearing The gearing of the arm (numbers greater than 1 represent reductions).
    * @param armLengthMeters The length of the arm.
-   * @param minAngleRads The minimum angle that the arm is capable of.
-   * @param maxAngleRads The maximum angle that the arm is capable of.
+   * @param minAngleRads The minimum angle that the arm is capable of, with 0 radians being
+   *     horizontal.
+   * @param maxAngleRads The maximum angle that the arm is capable of, with 0 radians being
+   *     horizontal.
    * @param simulateGravity Whether gravity should be simulated or not.
-   * @param startingAngleRads The initial position of the Arm simulation in radians.
+   * @param startingAngleRads The initial position of the Arm simulation in radians, with 0 radians
+   *     being horizontal.
    * @param measurementStdDevs The standard deviations of the measurements. Can be omitted if no
    *     noise is desired. If present must have 1 element for position.
    */
@@ -80,10 +83,13 @@ public SingleJointedArmSim(
    * @param gearing The gearing of the arm (numbers greater than 1 represent reductions).
    * @param jKgMetersSquared The moment of inertia of the arm; can be calculated from CAD software.
    * @param armLengthMeters The length of the arm.
-   * @param minAngleRads The minimum angle that the arm is capable of.
-   * @param maxAngleRads The maximum angle that the arm is capable of.
+   * @param minAngleRads The minimum angle that the arm is capable of, with 0 radians being
+   *     horizontal.
+   * @param maxAngleRads The maximum angle that the arm is capable of, with 0 radians being
+   *     horizontal.
    * @param simulateGravity Whether gravity should be simulated or not.
-   * @param startingAngleRads The initial position of the Arm simulation in radians.
+   * @param startingAngleRads The initial position of the Arm simulation in radians, with 0 radians
+   *     being horizontal.
    * @param measurementStdDevs The standard deviations of the measurements. Can be omitted if no
    *     noise is desired. If present must have 1 element for position.
    */