almost first rendering, fixing renderer issues

third_party/glm/gtx/fast_square_root.inl

@@ -0,0 +1,75 @@
+/// @ref gtx_fast_square_root
+
+namespace glm
+{
+	// fastSqrt
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType fastSqrt(genType x)
+	{
+		GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559, "'fastSqrt' only accept floating-point input");
+
+		return genType(1) / fastInverseSqrt(x);
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER vec<L, T, Q> fastSqrt(vec<L, T, Q> const& x)
+	{
+		return detail::functor1<vec, L, T, T, Q>::call(fastSqrt, x);
+	}
+
+	// fastInversesqrt
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType fastInverseSqrt(genType x)
+	{
+		return detail::compute_inversesqrt<1, genType, lowp, detail::is_aligned<lowp>::value>::call(vec<1, genType, lowp>(x)).x;
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER vec<L, T, Q> fastInverseSqrt(vec<L, T, Q> const& x)
+	{
+		return detail::compute_inversesqrt<L, T, Q, detail::is_aligned<Q>::value>::call(x);
+	}
+
+	// fastLength
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType fastLength(genType x)
+	{
+		GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559, "'fastLength' only accept floating-point inputs");
+
+		return abs(x);
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER T fastLength(vec<L, T, Q> const& x)
+	{
+		GLM_STATIC_ASSERT(std::numeric_limits<T>::is_iec559, "'fastLength' only accept floating-point inputs");
+
+		return fastSqrt(dot(x, x));
+	}
+
+	// fastDistance
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType fastDistance(genType x, genType y)
+	{
+		return fastLength(y - x);
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER T fastDistance(vec<L, T, Q> const& x, vec<L, T, Q> const& y)
+	{
+		return fastLength(y - x);
+	}
+
+	// fastNormalize
+	template<typename genType>
+	GLM_FUNC_QUALIFIER genType fastNormalize(genType x)
+	{
+		return x > genType(0) ? genType(1) : -genType(1);
+	}
+
+	template<length_t L, typename T, qualifier Q>
+	GLM_FUNC_QUALIFIER vec<L, T, Q> fastNormalize(vec<L, T, Q> const& x)
+	{
+		return x * fastInverseSqrt(dot(x, x));
+	}
+}//namespace glm