Update GLM to latest version (0.9.9.3). This includes GLM's change of matrices no longer default initializing to the identity matrix. This commit thus also includes the update of all of LearnOpenGL's code to reflect this: all matrices are now constructor-initialized to the identity matrix where relevant.

includes/glm/ext/quaternion_transform.hpp

@@ -0,0 +1,47 @@
+/// @ref ext_quaternion_transform
+/// @file glm/ext/quaternion_transform.hpp
+///
+/// @defgroup ext_quaternion_transform GLM_EXT_quaternion_transform
+/// @ingroup ext
+///
+/// Provides transformation functions for quaternion types
+///
+/// Include <glm/ext/quaternion_transform.hpp> to use the features of this extension.
+///
+/// @see ext_quaternion_float
+/// @see ext_quaternion_double
+/// @see ext_quaternion_exponential
+/// @see ext_quaternion_geometric
+/// @see ext_quaternion_relational
+/// @see ext_quaternion_trigonometric
+
+#pragma once
+
+// Dependency:
+#include "../common.hpp"
+#include "../trigonometric.hpp"
+#include "../geometric.hpp"
+
+#if GLM_MESSAGES == GLM_ENABLE && !defined(GLM_EXT_INCLUDED)
+#	pragma message("GLM: GLM_EXT_quaternion_transform extension included")
+#endif
+
+namespace glm
+{
+	/// @addtogroup ext_quaternion_transform
+	/// @{
+
+	/// Rotates a quaternion from a vector of 3 components axis and an angle.
+	///
+	/// @param q Source orientation
+	/// @param angle Angle expressed in radians.
+	/// @param axis Axis of the rotation
+	///
+	/// @tparam T Floating-point scalar types
+	/// @tparam Q Value from qualifier enum
+	template<typename T, qualifier Q>
+	GLM_FUNC_DECL qua<T, Q> rotate(qua<T, Q> const& q, T const& angle, vec<3, T, Q> const& axis);
+	/// @}
+} //namespace glm
+
+#include "quaternion_transform.inl"