refactor: state into namespace

src/state.h

@@ -6,12 +6,13 @@
 
 class Shader;
 
-class State {
-public:
-	static std::shared_ptr<Shader> default_shader_;
-	static glm::mat4	       projection_matrix_;
-	static glm::mat4	       view_matrix_;
-	static glm::mat4	       model_matrix_;
-};
+namespace state {
+
+inline std::shared_ptr<Shader> default_shader	 = nullptr;
+inline glm::mat4	       projection_matrix = glm::mat4(1.0f);
+inline glm::mat4	       view_matrix	 = glm::mat4(1.0f);
+inline glm::mat4	       model_matrix	 = glm::mat4(1.0f);
+
+} // namespace state
 
 #endif // STATE_H_