1 files changed, 136 insertions, 0 deletions
diff --git a/include/gal/opengl/glm/gtx/fast_square_root.inl b/include/gal/opengl/glm/gtx/fast_square_root.inl
new file mode 100644
index 0000000..0f51fbb
--- /dev/null
+++ b/include/gal/opengl/glm/gtx/fast_square_root.inl
@@ -0,0 +1,136 @@
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// OpenGL Mathematics Copyright (c) 2005 - 2013 G-Truc Creation (www.g-truc.net)
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// Created : 2006-01-04
+// Updated : 2011-10-14
+// Licence : This source is under MIT License
+// File    : glm/gtx/fast_square_root.inl
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+namespace glm
+{
+	// fastSqrt
+	template <typename genType>
+	GLM_FUNC_QUALIFIER genType fastSqrt
+	(
+		genType const & x
+	)
+	{
+		GLM_STATIC_ASSERT(detail::type<genType>::is_float, "'fastSqrt' only accept floating-point input");
+
+		return genType(1) / fastInverseSqrt(x);
+	}
+
+	VECTORIZE_VEC(fastSqrt)
+
+	// fastInversesqrt
+	template <typename genType>
+	GLM_FUNC_QUALIFIER genType fastInverseSqrt
+	(
+		genType const & x
+	)
+	{
+		genType tmp = x;
+		float xhalf = 0.5f * float(tmp);
+		uint i = *(uint*)&x;
+		i = 0x5f375a86 - (i >> 1);
+		//x = *(float*)&i;
+		//x = *((float*)(char*)&i);
+		tmp = detail::uif(i).f;
+		tmp = tmp * (1.5f - xhalf * tmp * tmp);
+		return genType(tmp);
+	}
+
+	VECTORIZE_VEC(fastInverseSqrt)
+
+	// fastLength
+	template <typename genType>
+	GLM_FUNC_QUALIFIER genType fastLength
+	(
+		genType const & x
+	)
+	{
+		return abs(x);
+	}
+
+	template <typename valType>
+	GLM_FUNC_QUALIFIER valType fastLength
+	(
+		detail::tvec2<valType> const & x
+	)
+	{
+		valType sqr = x.x * x.x + x.y * x.y;
+		return fastSqrt(sqr);
+	}
+
+	template <typename valType>
+	GLM_FUNC_QUALIFIER valType fastLength
+	(
+		detail::tvec3<valType> const & x
+	)
+	{
+		valType sqr = x.x * x.x + x.y * x.y + x.z * x.z;
+		return fastSqrt(sqr);
+	}
+
+	template <typename valType>
+	GLM_FUNC_QUALIFIER valType fastLength
+	(
+		detail::tvec4<valType> const & x
+	)
+	{
+		valType sqr = x.x * x.x + x.y * x.y + x.z * x.z + x.w * x.w;
+		return fastSqrt(sqr);
+	}
+
+	// fastDistance
+	template <typename genType>
+	GLM_FUNC_QUALIFIER genType fastDistance
+	(
+		genType const & x, 
+		genType const & y
+	)
+	{
+		return fastLength(y - x);
+	}
+
+	// fastNormalize
+	template <typename genType>
+	GLM_FUNC_QUALIFIER genType fastNormalize
+	(
+		genType const & x
+	)
+	{
+		return x > genType(0) ? genType(1) : -genType(1);
+	}
+
+	template <typename valType>
+	GLM_FUNC_QUALIFIER detail::tvec2<valType> fastNormalize
+	(
+		detail::tvec2<valType> const & x
+	)
+	{
+		valType sqr = x.x * x.x + x.y * x.y;
+		return x * fastInverseSqrt(sqr);
+	}
+
+	template <typename valType>
+	GLM_FUNC_QUALIFIER detail::tvec3<valType> fastNormalize
+	(
+		detail::tvec3<valType> const & x
+	)
+	{
+		valType sqr = x.x * x.x + x.y * x.y + x.z * x.z;
+		return x * fastInverseSqrt(sqr);
+	}
+
+	template <typename valType>
+	GLM_FUNC_QUALIFIER detail::tvec4<valType> fastNormalize
+	(
+		detail::tvec4<valType> const & x
+	)
+	{
+		valType sqr = x.x * x.x + x.y * x.y + x.z * x.z + x.w * x.w;
+		return x * fastInverseSqrt(sqr);
+	}
+}//namespace glm