From 5af85dd1bb27d72eaf78b6d0a17e9b8175413919 Mon Sep 17 00:00:00 2001
From: Thad House <ThadHouse@users.noreply.github.com>
Date: Sun, 10 Jun 2018 20:13:36 -0700
Subject: [PATCH] Explicitly states the gyro direction contract for the Gyro
 interface (#1151)

---
 wpilibc/src/main/native/include/interfaces/Gyro.h         | 8 ++++++++
 .../main/java/edu/wpi/first/wpilibj/interfaces/Gyro.java  | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/wpilibc/src/main/native/include/interfaces/Gyro.h b/wpilibc/src/main/native/include/interfaces/Gyro.h
index 11ba3f6aee..507b61d0de 100644
--- a/wpilibc/src/main/native/include/interfaces/Gyro.h
+++ b/wpilibc/src/main/native/include/interfaces/Gyro.h
@@ -42,6 +42,10 @@ class Gyro {
    * allows algorithms that wouldn't want to see a discontinuity in the gyro
    * output as it sweeps past from 360 to 0 on the second time around.
    *
+   * The angle is expected to increase as the gyro turns clockwise when looked
+   * at from the top. It needs to follow NED axis conventions in order to work
+   * properly with dependent control loops.
+   *
    * @return the current heading of the robot in degrees. This heading is based
    *         on integration of the returned rate from the gyro.
    */
@@ -52,6 +56,10 @@ class Gyro {
    *
    * The rate is based on the most recent reading of the gyro analog value.
    *
+   * The rate is expected to be positive as the gyro turns clockwise when looked
+   * at from the top. It needs to follow NED axis conventions in order to work
+   * properly with dependent control loops.
+   *
    * @return the current rate in degrees per second
    */
   virtual double GetRate() const = 0;
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/interfaces/Gyro.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/interfaces/Gyro.java
index a752d6ed72..a8b2ab63d8 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/interfaces/Gyro.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/interfaces/Gyro.java
@@ -34,6 +34,10 @@ public interface Gyro extends AutoCloseable {
    * from 360 to 361 degrees. This allows algorithms that wouldn't want to see a discontinuity in
    * the gyro output as it sweeps past from 360 to 0 on the second time around.
    *
+   * <p>The angle is expected to increase as the gyro turns clockwise when looked
+   * at from the top. It needs to follow NED axis conventions in order to work
+   * properly with dependent control loops.
+   *
    * <p>This heading is based on integration of the returned rate from the gyro.
    *
    * @return the current heading of the robot in degrees.
@@ -45,6 +49,10 @@ public interface Gyro extends AutoCloseable {
    *
    * <p>The rate is based on the most recent reading of the gyro analog value
    *
+   * <p>The rate is expected to be positive as the gyro turns clockwise when looked
+   * at from the top. It needs to follow NED axis conventions in order to work
+   * properly with dependent control loops.
+   *
    * @return the current rate in degrees per second
    */
   double getRate();