3 files changed, 10 insertions, 3 deletions
diff --git a/core/math/quaternion.cpp b/core/math/quaternion.cpp
index 7037db7112..3f1d2c58e5 100644
--- a/core/math/quaternion.cpp
+++ b/core/math/quaternion.cpp
@@ -33,6 +33,11 @@
 #include "core/math/basis.h"
 #include "core/string/print_string.h"
 
+real_t Quaternion::angle_to(const Quaternion &p_to) const {
+	real_t d = dot(p_to);
+	return Math::acos(CLAMP(d * d * 2 - 1, -1, 1));
+}
+
 // get_euler_xyz returns a vector containing the Euler angles in the format
 // (ax,ay,az), where ax is the angle of rotation around x axis,
 // and similar for other axes.
diff --git a/core/math/quaternion.h b/core/math/quaternion.h
index 796214b79e..35324323b3 100644
--- a/core/math/quaternion.h
+++ b/core/math/quaternion.h
@@ -28,8 +28,8 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-#ifndef QUAT_H
-#define QUAT_H
+#ifndef QUATERNION_H
+#define QUATERNION_H
 
 #include "core/math/math_defs.h"
 #include "core/math/math_funcs.h"
@@ -62,6 +62,7 @@ public:
 	bool is_normalized() const;
 	Quaternion inverse() const;
 	_FORCE_INLINE_ real_t dot(const Quaternion &p_q) const;
+	real_t angle_to(const Quaternion &p_to) const;
 
 	Vector3 get_euler_xyz() const;
 	Vector3 get_euler_yxz() const;
@@ -235,4 +236,4 @@ _FORCE_INLINE_ Quaternion operator*(const real_t &p_real, const Quaternion &p_qu
 	return p_quaternion * p_real;
 }
 
-#endif // QUAT_H
+#endif // QUATERNION_H
diff --git a/core/variant/variant_call.cpp b/core/variant/variant_call.cpp
index 05ed35c760..4064eba7fb 100644
--- a/core/variant/variant_call.cpp
+++ b/core/variant/variant_call.cpp
@@ -1552,6 +1552,7 @@ static void _register_variant_builtin_methods() {
 	bind_method(Quaternion, is_normalized, sarray(), varray());
 	bind_method(Quaternion, is_equal_approx, sarray("to"), varray());
 	bind_method(Quaternion, inverse, sarray(), varray());
+	bind_method(Quaternion, angle_to, sarray("to"), varray());
 	bind_method(Quaternion, dot, sarray("with"), varray());
 	bind_method(Quaternion, slerp, sarray("to", "weight"), varray());
 	bind_method(Quaternion, slerpni, sarray("to", "weight"), varray());