Merge pull request #887 from timmmeh/master

'if constexpr' warning (c++17) #887

glm/detail/setup.hpp

@@ -293,6 +293,27 @@
 #	define GLM_CONSTEXPR
 #endif
 
+//
+#if GLM_HAS_CONSTEXPR
+# if (GLM_COMPILER & GLM_COMPILER_CLANG)
+#	define GLM_HAS_IF_CONSTEXPR __has_feature(cxx_if_constexpr)
+# elif (GLM_COMPILER & GLM_COMPILER_GCC) 
+#	define GLM_HAS_IF_CONSTEXPR GLM_COMPILER >= GLM_COMPILER_GCC7
+# elif (GLM_LANG & GLM_LANG_CXX17_FLAG)
+# 	define GLM_HAS_IF_CONSTEXPR 1
+# else
+# 	define GLM_HAS_IF_CONSTEXPR 0
+# endif
+#else
+#	define GLM_HAS_IF_CONSTEXPR 0
+#endif
+
+#if GLM_HAS_IF_CONSTEXPR
+# 	define GLM_IF_CONSTEXPR if constexpr
+#else
+#	define GLM_IF_CONSTEXPR if
+#endif
+
 //
 #if GLM_LANG & GLM_LANG_CXX11_FLAG
 #	define GLM_HAS_ASSIGNABLE 1

glm/ext/matrix_clip_space.inl

@@ -323,13 +323,13 @@ namespace glm
 	template<typename T>
 	GLM_FUNC_QUALIFIER mat<4, 4, T, defaultp> perspective(T fovy, T aspect, T zNear, T zFar)
 	{
-		if(GLM_CONFIG_CLIP_CONTROL == GLM_CLIP_CONTROL_LH_ZO)
+		GLM_IF_CONSTEXPR(GLM_CONFIG_CLIP_CONTROL == GLM_CLIP_CONTROL_LH_ZO)
 			return perspectiveLH_ZO(fovy, aspect, zNear, zFar);
-		else if(GLM_CONFIG_CLIP_CONTROL == GLM_CLIP_CONTROL_LH_NO)
+		else GLM_IF_CONSTEXPR(GLM_CONFIG_CLIP_CONTROL == GLM_CLIP_CONTROL_LH_NO)
 			return perspectiveLH_NO(fovy, aspect, zNear, zFar);
-		else if(GLM_CONFIG_CLIP_CONTROL == GLM_CLIP_CONTROL_RH_ZO)
+		else GLM_IF_CONSTEXPR(GLM_CONFIG_CLIP_CONTROL == GLM_CLIP_CONTROL_RH_ZO)
 			return perspectiveRH_ZO(fovy, aspect, zNear, zFar);
-		else if(GLM_CONFIG_CLIP_CONTROL == GLM_CLIP_CONTROL_RH_NO)
+		else GLM_IF_CONSTEXPR(GLM_CONFIG_CLIP_CONTROL == GLM_CLIP_CONTROL_RH_NO)
 			return perspectiveRH_NO(fovy, aspect, zNear, zFar);
 	}
 

glm/ext/matrix_transform.inl

@@ -144,7 +144,7 @@ namespace glm
 	template<typename T, qualifier Q>
 	GLM_FUNC_QUALIFIER mat<4, 4, T, Q> lookAt(vec<3, T, Q> const& eye, vec<3, T, Q> const& center, vec<3, T, Q> const& up)
 	{
-		if(GLM_CONFIG_CLIP_CONTROL & GLM_CLIP_CONTROL_LH_BIT)
+		GLM_IF_CONSTEXPR(GLM_CONFIG_CLIP_CONTROL & GLM_CLIP_CONTROL_LH_BIT)
 			return lookAtLH(eye, center, up);
 		else
 			return lookAtRH(eye, center, up);