From cf6bf16d6220edc123b71e76af7444c57198de12 Mon Sep 17 00:00:00 2001
From: Christophe Riccio <christophe.riccio@unity3d.com>
Date: Tue, 7 Aug 2018 01:22:19 +0200
Subject: [PATCH] Make matrix relational constexpr

---
 glm/ext/matrix_relational.hpp | 12 +++---
 glm/ext/matrix_relational.inl | 74 +++++++++++++++++++++++++++++------
 2 files changed, 69 insertions(+), 17 deletions(-)

diff --git a/glm/ext/matrix_relational.hpp b/glm/ext/matrix_relational.hpp
index c9976f71..426422f3 100644
--- a/glm/ext/matrix_relational.hpp
+++ b/glm/ext/matrix_relational.hpp
@@ -35,7 +35,7 @@ namespace glm
 	///
 	/// @see ext_matrix_relational
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_DECL vec<C, bool, Q> equal(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y);
+	GLM_FUNC_DECL GLM_CONSTEXPR vec<C, bool, Q> equal(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y);
 
 	/// Returns the component-wise comparison of |x - y| < epsilon.
 	/// True if this expression is satisfied.
@@ -47,7 +47,7 @@ namespace glm
 	///
 	/// @see ext_matrix_relational
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_DECL vec<C, bool, Q> equal(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y, T epsilon);
+	GLM_FUNC_DECL GLM_CONSTEXPR vec<C, bool, Q> equal(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y, T epsilon);
 
 	/// Returns the component-wise comparison of |x - y| < epsilon.
 	/// True if this expression is satisfied.
@@ -59,7 +59,7 @@ namespace glm
 	///
 	/// @see ext_matrix_relational
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_DECL vec<C, bool, Q> equal(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y, vec<C, T, Q> const& epsilon);
+	GLM_FUNC_DECL GLM_CONSTEXPR vec<C, bool, Q> equal(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y, vec<C, T, Q> const& epsilon);
 
 	/// Perform a component-wise not-equal-to comparison of two matrices.
 	/// Return a boolean vector which components value is True if this expression is satisfied per column of the matrices.
@@ -71,7 +71,7 @@ namespace glm
 	///
 	/// @see ext_matrix_relational
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_DECL vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y);
+	GLM_FUNC_DECL GLM_CONSTEXPR vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y);
 
 	/// Returns the component-wise comparison of |x - y| < epsilon.
 	/// True if this expression is not satisfied.
@@ -83,7 +83,7 @@ namespace glm
 	///
 	/// @see ext_matrix_relational
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_DECL vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y, T epsilon);
+	GLM_FUNC_DECL GLM_CONSTEXPR vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y, T epsilon);
 
 	/// Returns the component-wise comparison of |x - y| >= epsilon.
 	/// True if this expression is not satisfied.
@@ -95,7 +95,7 @@ namespace glm
 	///
 	/// @see ext_vector_relational
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_DECL vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y, vec<C, T, Q> const& epsilon);
+	GLM_FUNC_DECL GLM_CONSTEXPR vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y, vec<C, T, Q> const& epsilon);
 
 	/// @}
 }//namespace glm
diff --git a/glm/ext/matrix_relational.inl b/glm/ext/matrix_relational.inl
index efc2d6c5..ca3383e2 100644
--- a/glm/ext/matrix_relational.inl
+++ b/glm/ext/matrix_relational.inl
@@ -5,47 +5,99 @@
 #include "../ext/vector_relational.hpp"
 #include "../common.hpp"
 
-namespace glm
+namespace glm{
+namespace detail
 {
+	enum matrix_relational_type
+	{
+		MAT_EQUAL,
+		MAT_NOT_EQUAL
+	};
+
+	template <relational_type R>
+	struct matrix_relational
+	{
+		template<typename vecType, typename T>
+		GLM_FUNC_QUALIFIER GLM_CONSTEXPR static bool call(vecType const& Src0, vecType const& Src1, T Epsilon);
+	};
+
+	template <>
+	struct matrix_relational<EQUAL>
+	{
+		template<typename vecType, typename T>
+		GLM_FUNC_QUALIFIER GLM_CONSTEXPR static bool call(vecType const& Src0, vecType const& Src1, T Epsilon)
+		{
+			return all(equal(Src0, Src1, Epsilon));
+		}
+	};
+
+	template <>
+	struct matrix_relational<NOT_EQUAL>
+	{
+		template<typename vecType, typename T>
+		GLM_FUNC_QUALIFIER GLM_CONSTEXPR static bool call(vecType const& Src0, vecType const& Src1, T Epsilon)
+		{
+			return any(notEqual(Src0, Src1, Epsilon));
+		}
+	};
+
+	template<length_t I, length_t N, relational_type R>
+	struct loop_matrix_relational
+	{
+		template<typename vecBType, typename matType, typename vecType>
+		GLM_FUNC_QUALIFIER GLM_CONSTEXPR static void call(vecBType& Dst, matType const& Src0, matType const& Src1, vecType const& Epsilon)
+		{
+			Dst[I] = matrix_relational<R>::call(Src0[I], Src1[I], Epsilon[I]);
+			loop_matrix_relational<I + 1, N, R>::call(Dst, Src0, Src1, Epsilon);
+		}
+	};
+
+	template <length_t N, relational_type R>
+	struct loop_matrix_relational<N, N, R>
+	{
+		template<typename vecBType, typename matType, typename vecType>
+		GLM_FUNC_QUALIFIER GLM_CONSTEXPR static void call(vecBType&, matType const&, matType const&, vecType const&)
+		{}
+	};
+}//namespace detail
+
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_QUALIFIER vec<C, bool, Q> equal(mat<C, R, T, Q> const& a, mat<C, R, T, Q> const& b)
+	GLM_FUNC_QUALIFIER GLM_CONSTEXPR vec<C, bool, Q> equal(mat<C, R, T, Q> const& a, mat<C, R, T, Q> const& b)
 	{
 		return equal(a, b, static_cast<T>(0));
 	}
 
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_QUALIFIER vec<C, bool, Q> equal(mat<C, R, T, Q> const& a, mat<C, R, T, Q> const& b, T epsilon)
+	GLM_FUNC_QUALIFIER GLM_CONSTEXPR vec<C, bool, Q> equal(mat<C, R, T, Q> const& a, mat<C, R, T, Q> const& b, T epsilon)
 	{
 		return equal(a, b, vec<C, T, Q>(epsilon));
 	}
 
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_QUALIFIER vec<C, bool, Q> equal(mat<C, R, T, Q> const& a, mat<C, R, T, Q> const& b, vec<C, T, Q> const& epsilon)
+	GLM_FUNC_QUALIFIER GLM_CONSTEXPR vec<C, bool, Q> equal(mat<C, R, T, Q> const& a, mat<C, R, T, Q> const& b, vec<C, T, Q> const& epsilon)
 	{
 		vec<C, bool, Q> Result;
-		for(length_t i = 0, n = C; i < n; ++i)
-			Result[i] = all(equal(a[i], b[i], epsilon[i]));
+		detail::loop_matrix_relational<0, C, detail::EQUAL>::call(Result, a, b, epsilon);
 		return Result;
 	}
 
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_QUALIFIER vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y)
+	GLM_FUNC_QUALIFIER GLM_CONSTEXPR vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y)
 	{
 		return notEqual(x, y, static_cast<T>(0));
 	}
 
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_QUALIFIER vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y, T epsilon)
+	GLM_FUNC_QUALIFIER GLM_CONSTEXPR vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& x, mat<C, R, T, Q> const& y, T epsilon)
 	{
 		return notEqual(x, y, vec<C, T, Q>(epsilon));
 	}
 
 	template<length_t C, length_t R, typename T, qualifier Q>
-	GLM_FUNC_QUALIFIER vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& a, mat<C, R, T, Q> const& b, vec<C, T, Q> const& epsilon)
+	GLM_FUNC_QUALIFIER GLM_CONSTEXPR vec<C, bool, Q> notEqual(mat<C, R, T, Q> const& a, mat<C, R, T, Q> const& b, vec<C, T, Q> const& epsilon)
 	{
 		vec<C, bool, Q> Result;
-		for(length_t i = 0, n = C; i < n; ++i)
-			Result[i] = any(notEqual(a[i], b[i], epsilon[i]));
+		detail::loop_matrix_relational<0, C, detail::NOT_EQUAL>::call(Result, a, b, epsilon);
 		return Result;
 	}
 }//namespace glm