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/detail/compute_common.hpp

@@ -0,0 +1,50 @@
+#pragma once
+
+#include "setup.hpp"
+#include <limits>
+
+namespace glm{
+namespace detail
+{
+	template<typename genFIType, bool /*signed*/>
+	struct compute_abs
+	{};
+
+	template<typename genFIType>
+	struct compute_abs<genFIType, true>
+	{
+		GLM_FUNC_QUALIFIER GLM_CONSTEXPR static genFIType call(genFIType x)
+		{
+			GLM_STATIC_ASSERT(
+				std::numeric_limits<genFIType>::is_iec559 || std::numeric_limits<genFIType>::is_signed,
+				"'abs' only accept floating-point and integer scalar or vector inputs");
+
+			return x >= genFIType(0) ? x : -x;
+			// TODO, perf comp with: *(((int *) &x) + 1) &= 0x7fffffff;
+		}
+	};
+
+#if GLM_COMPILER & GLM_COMPILER_CUDA
+	template<>
+	struct compute_abs<float, true>
+	{
+		GLM_FUNC_QUALIFIER GLM_CONSTEXPR static float call(float x)
+		{
+			return fabsf(x);
+		}
+	};
+#endif
+
+	template<typename genFIType>
+	struct compute_abs<genFIType, false>
+	{
+		GLM_FUNC_QUALIFIER GLM_CONSTEXPR static genFIType call(genFIType x)
+		{
+			GLM_STATIC_ASSERT(
+				(!std::numeric_limits<genFIType>::is_signed && std::numeric_limits<genFIType>::is_integer),
+				"'abs' only accept floating-point and integer scalar or vector inputs");
+			return x;
+		}
+	};
+}//namespace detail
+}//namespace glm