- Added identity functions #765

glm/detail/qualifier.hpp

@@ -152,5 +152,45 @@ namespace detail
 		typedef glm_u64vec4 type;
 	};
 #	endif
+
+	enum genTypeEnum
+	{
+		GENTYPE_VEC,
+		GENTYPE_MAT,
+		GENTYPE_QUAT
+	};
+
+	template <typename genType>
+	struct genTypeTrait
+	{};
+
+	template <length_t C, length_t R, typename T>
+	struct genTypeTrait<mat<C, R, T> >
+	{
+		static const genTypeEnum GENTYPE = GENTYPE_MAT;
+	};
+
+	template<typename genType, genTypeEnum type>
+	struct init_gentype
+	{
+	};
+
+	template<typename genType>
+	struct init_gentype<genType, GENTYPE_QUAT>
+	{
+		GLM_FUNC_QUALIFIER static genType identity()
+		{
+			return genType(1, 0, 0, 0);
+		}
+	};
+
+	template<typename genType>
+	struct init_gentype<genType, GENTYPE_MAT>
+	{
+		GLM_FUNC_QUALIFIER static genType identity()
+		{
+			return genType(1);
+		}
+	};
 }//namespace detail
 }//namespace glm

glm/gtc/matrix_transform.hpp

@@ -36,6 +36,10 @@ namespace glm
 	/// @addtogroup gtc_matrix_transform
 	/// @{
 
+	/// Builds an identity matrix.
+	template<typename genType>
+	GLM_FUNC_DECL genType identity();
+
 	/// Builds a translation 4 * 4 matrix created from a vector of 3 components.
 	///
 	/// @param m Input matrix multiplied by this translation matrix.

glm/gtc/matrix_transform.inl

@@ -7,6 +7,12 @@
 
 namespace glm
 {
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType identity()
+	{
+		return detail::init_gentype<genType, detail::genTypeTrait<genType>::GENTYPE>::identity();
+	}
+
 	template<typename T, qualifier Q>
 	GLM_FUNC_QUALIFIER mat<4, 4, T, Q> translate(mat<4, 4, T, Q> const& m, vec<3, T, Q> const& v)
 	{

glm/gtc/quaternion.hpp

@@ -19,6 +19,7 @@
 #include "../vec3.hpp"
 #include "../vec4.hpp"
 #include "../gtc/constants.hpp"
+#include "../gtc/matrix_transform.hpp"
 
 #if GLM_MESSAGES == GLM_ENABLE && !defined(GLM_EXT_INCLUDED)
 #	pragma message("GLM: GLM_GTC_quaternion extension included")
@@ -159,6 +160,10 @@ namespace glm
 	template<typename T, qualifier Q>
 	GLM_FUNC_DECL bool operator!=(tquat<T, Q> const& q1, tquat<T, Q> const& q2);
 
+	/// Builds an identity quaternion.
+	template<typename genType>
+	GLM_FUNC_DECL genType identity();
+
 	/// Returns the length of the quaternion.
 	///
 	/// @tparam T Floating-point scalar types.

glm/gtc/quaternion.inl

@@ -10,6 +10,12 @@
 namespace glm{
 namespace detail
 {
+	template <typename T>
+	struct genTypeTrait<tquat<T> >
+	{
+		static const genTypeEnum GENTYPE = GENTYPE_QUAT;
+	};
+
 	template<typename T, qualifier Q, bool Aligned>
 	struct compute_dot<tquat<T, Q>, T, Aligned>
 	{