refactored MainWindow and Engine, changed project structure

src/resources/fonts.hpp

@@ -0,0 +1,12 @@
+#pragma once
+
+#include "imgui.h"
+#include "../common/std.hpp"
+
+namespace ougge::resources {
+
+ImFont* ImFont_LoadFromFile(const std::string& file_path, f32 font_size, f32 dpi);
+
+ImFont* ImFont_LoadFromResource(const std::string& font_name, f32 font_size, f32 dpi);
+
+}