Add Quaternion.getEulerAnglesZYX()

and simplify Quaternion.getEulerAnglesXYZ()
JOML-CI · Dec 4, 2021 · 6fe925b · 6fe925b
1 parent 1587fbc
commit 6fe925b
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Showing 4 changed files with 52 additions and 6 deletions.
diff --git a/src/org/joml/Quaterniond.java b/src/org/joml/Quaterniond.java
@@ -2762,9 +2762,16 @@ public Quaterniond rotateYXZ(double angleY, double angleX, double angleZ, Quater
     }
 
     public Vector3d getEulerAnglesXYZ(Vector3d eulerAngles) {
-        eulerAngles.x = Math.atan2(2.0 * (x*w - y*z), 1.0 - 2.0 * (x*x + y*y));
-        eulerAngles.y = Math.safeAsin(2.0 * (x*z + y*w));
-        eulerAngles.z = Math.atan2(2.0 * (z*w - x*y), 1.0 - 2.0 * (y*y + z*z));
+        eulerAngles.x = Math.atan2(x * w - y * z, 0.5 - x * x - y * y);
+        eulerAngles.y = Math.safeAsin(2.0 * (x * z + y * w));
+        eulerAngles.z = Math.atan2(z * w - x * y, 0.5 - y * y - z * z);
+        return eulerAngles;
+    }
+
+    public Vector3d getEulerAnglesZYX(Vector3d eulerAngles) {
+        eulerAngles.x = Math.atan2(y * z + w * x, 0.5 - x * x + y * y);
+        eulerAngles.y = Math.safeAsin(-2.0 * (x * z - w * y));
+        eulerAngles.z = Math.atan2(x * y + w * z, 0.5 - y * y - z * z);
         return eulerAngles;
     }
 

diff --git a/src/org/joml/Quaterniondc.java b/src/org/joml/Quaterniondc.java
@@ -1751,13 +1751,29 @@ public interface Quaterniondc {
     /**
      * Get the euler angles in radians in rotation sequence <code>XYZ</code> of this quaternion and store them in the 
      * provided parameter <code>eulerAngles</code>.
+     * <p>
+     * The Euler angles are always returned as the angle around X in the {@link Vector3d#x} field, the angle around Y in the {@link Vector3d#y}
+     * field and the angle around Z in the {@link Vector3d#z} field of the supplied {@link Vector3d} instance.
      * 
      * @param eulerAngles
      *          will hold the euler angles in radians
      * @return the passed in vector
      */
     Vector3d getEulerAnglesXYZ(Vector3d eulerAngles);
 
+    /**
+     * Get the euler angles in radians in rotation sequence <code>ZYX</code> of this quaternion and store them in the 
+     * provided parameter <code>eulerAngles</code>.
+     * <p>
+     * The Euler angles are always returned as the angle around X in the {@link Vector3d#x} field, the angle around Y in the {@link Vector3d#y}
+     * field and the angle around Z in the {@link Vector3d#z} field of the supplied {@link Vector3d} instance.
+     * 
+     * @param eulerAngles
+     *          will hold the euler angles in radians
+     * @return the passed in vector
+     */
+    Vector3d getEulerAnglesZYX(Vector3d eulerAngles);
+
     /**
      * Apply a rotation to <code>this</code> quaternion rotating the given radians about the specified axis
      * and store the result in <code>dest</code>.

diff --git a/src/org/joml/Quaternionf.java b/src/org/joml/Quaternionf.java
@@ -1853,9 +1853,16 @@ public Quaternionf rotateYXZ(float angleY, float angleX, float angleZ, Quaternio
     }
 
     public Vector3f getEulerAnglesXYZ(Vector3f eulerAngles) {
-        eulerAngles.x = Math.atan2(2.0f * (x*w - y*z), 1.0f - 2.0f * (x*x + y*y));
-        eulerAngles.y = Math.safeAsin(2.0f * (x*z + y*w));
-        eulerAngles.z = Math.atan2(2.0f * (z*w - x*y), 1.0f - 2.0f * (y*y + z*z));
+        eulerAngles.x = Math.atan2(x * w - y * z, 0.5f - x * x - y * y);
+        eulerAngles.y = Math.safeAsin(2.0f * (x * z + y * w));
+        eulerAngles.z = Math.atan2(z * w - x * y, 0.5f - y * y - z * z);
+        return eulerAngles;
+    }
+
+    public Vector3f getEulerAnglesZYX(Vector3f eulerAngles) {
+        eulerAngles.x = Math.atan2(y * z + w * x, 0.5f - x * x + y * y);
+        eulerAngles.y = Math.safeAsin(-2.0f * (x * z - w * y));
+        eulerAngles.z = Math.atan2(x * y + w * z, 0.5f - y * y - z * z);
         return eulerAngles;
     }
 

diff --git a/src/org/joml/Quaternionfc.java b/src/org/joml/Quaternionfc.java
@@ -1557,13 +1557,29 @@ public interface Quaternionfc {
     /**
      * Get the euler angles in radians in rotation sequence <code>XYZ</code> of this quaternion and store them in the 
      * provided parameter <code>eulerAngles</code>.
+     * <p>
+     * The Euler angles are always returned as the angle around X in the {@link Vector3f#x} field, the angle around Y in the {@link Vector3f#y}
+     * field and the angle around Z in the {@link Vector3f#z} field of the supplied {@link Vector3f} instance.
      * 
      * @param eulerAngles
      *          will hold the euler angles in radians
      * @return the passed in vector
      */
     Vector3f getEulerAnglesXYZ(Vector3f eulerAngles);
 
+    /**
+     * Get the euler angles in radians in rotation sequence <code>ZYX</code> of this quaternion and store them in the 
+     * provided parameter <code>eulerAngles</code>.
+     * <p>
+     * The Euler angles are always returned as the angle around X in the {@link Vector3f#x} field, the angle around Y in the {@link Vector3f#y}
+     * field and the angle around Z in the {@link Vector3f#z} field of the supplied {@link Vector3f} instance.
+     * 
+     * @param eulerAngles
+     *          will hold the euler angles in radians
+     * @return the passed in vector
+     */
+    Vector3f getEulerAnglesZYX(Vector3f eulerAngles);
+
     /**
      * Return the square of the length of this quaternion.
      *