Merge pull request #11151 from jordan-woyak/quat-fix

Fix some bad quaternion math.

2 files changed, 4 insertions, 2 deletions

diff --git a/Source/Core/Common/Matrix.cpp b/Source/Core/Common/Matrix.cpp
index 724d28f17f..57be1a3cc4 100644
--- a/Source/Core/Common/Matrix.cpp
+++ b/Source/Core/Common/Matrix.cpp
@@ -78,7 +78,7 @@ Quaternion::Quaternion(float w, float x, float y, float z) : data(x, y, z, w)
 
 float Quaternion::Norm() const
 {
-  return data.Dot(data);
+  return std::sqrt(data.Dot(data));
 }
 
 Quaternion Quaternion::Normalized() const
diff --git a/Source/Core/Core/HW/WiimoteEmu/Dynamics.cpp b/Source/Core/Core/HW/WiimoteEmu/Dynamics.cpp
index dd21cd721a..b3864e3c8b 100644
--- a/Source/Core/Core/HW/WiimoteEmu/Dynamics.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/Dynamics.cpp
@@ -398,7 +398,9 @@ Common::Quaternion GetRotationFromAcceleration(const Common::Vec3& accel)
 
 Common::Quaternion GetRotationFromGyroscope(const Common::Vec3& gyro)
 {
-  return Common::Quaternion{1, gyro.x / 2, gyro.y / 2, gyro.z / 2};
+  const auto length = gyro.Length();
+  return (length != 0) ? Common::Quaternion::Rotate(length, gyro / length) :
+                         Common::Quaternion::Identity();
 }
 
 Common::Matrix33 GetRotationalMatrix(const Common::Vec3& angle)