1 files changed, 85 insertions, 0 deletions
diff --git a/src/include/glm/ext/quaternion_exponential.inl b/src/include/glm/ext/quaternion_exponential.inl
new file mode 100644
index 0000000..7f063e0
--- /dev/null
+++ b/src/include/glm/ext/quaternion_exponential.inl
@@ -0,0 +1,85 @@
+#include "scalar_constants.hpp"
+
+namespace glm
+{
+	template<typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER qua<T, Q> exp(qua<T, Q> const& q)
+	{
+		vec<3, T, Q> u(q.x, q.y, q.z);
+		T const Angle = glm::length(u);
+		if (Angle < epsilon<T>())
+			return qua<T, Q>();
+
+		vec<3, T, Q> const v(u / Angle);
+		return qua<T, Q>(cos(Angle), sin(Angle) * v);
+	}
+
+	template<typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER qua<T, Q> log(qua<T, Q> const& q)
+	{
+		vec<3, T, Q> u(q.x, q.y, q.z);
+		T Vec3Len = length(u);
+
+		if (Vec3Len < epsilon<T>())
+		{
+			if(q.w > static_cast<T>(0))
+				return qua<T, Q>(log(q.w), static_cast<T>(0), static_cast<T>(0), static_cast<T>(0));
+			else if(q.w < static_cast<T>(0))
+				return qua<T, Q>(log(-q.w), pi<T>(), static_cast<T>(0), static_cast<T>(0));
+			else
+				return qua<T, Q>(std::numeric_limits<T>::infinity(), std::numeric_limits<T>::infinity(), std::numeric_limits<T>::infinity(), std::numeric_limits<T>::infinity());
+		}
+		else
+		{
+			T t = atan(Vec3Len, T(q.w)) / Vec3Len;
+			T QuatLen2 = Vec3Len * Vec3Len + q.w * q.w;
+			return qua<T, Q>(static_cast<T>(0.5) * log(QuatLen2), t * q.x, t * q.y, t * q.z);
+		}
+	}
+
+	template<typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER qua<T, Q> pow(qua<T, Q> const& x, T y)
+	{
+		//Raising to the power of 0 should yield 1
+		//Needed to prevent a division by 0 error later on
+		if(y > -epsilon<T>() && y < epsilon<T>())
+			return qua<T, Q>(1,0,0,0);
+
+		//To deal with non-unit quaternions
+		T magnitude = sqrt(x.x * x.x + x.y * x.y + x.z * x.z + x.w *x.w);
+
+		T Angle;
+		if(abs(x.w / magnitude) > cos_one_over_two<T>())
+		{
+			//Scalar component is close to 1; using it to recover angle would lose precision
+			//Instead, we use the non-scalar components since sin() is accurate around 0
+
+			//Prevent a division by 0 error later on
+			T VectorMagnitude = x.x * x.x + x.y * x.y + x.z * x.z;
+			if (glm::abs(VectorMagnitude - static_cast<T>(0)) < glm::epsilon<T>()) {
+				//Equivalent to raising a real number to a power
+				return qua<T, Q>(pow(x.w, y), 0, 0, 0);
+			}
+
+			Angle = asin(sqrt(VectorMagnitude) / magnitude);
+		}
+		else
+		{
+			//Scalar component is small, shouldn't cause loss of precision
+			Angle = acos(x.w / magnitude);
+		}
+
+		T NewAngle = Angle * y;
+		T Div = sin(NewAngle) / sin(Angle);
+		T Mag = pow(magnitude, y - static_cast<T>(1));
+		return qua<T, Q>(cos(NewAngle) * magnitude * Mag, x.x * Div * Mag, x.y * Div * Mag, x.z * Div * Mag);
+	}
+
+	template<typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER qua<T, Q> sqrt(qua<T, Q> const& x)
+	{
+		return pow(x, static_cast<T>(0.5));
+	}
+}//namespace glm
+
+