feat: replace triangle test by cube

inc/core/camera.hpp

@@ -5,6 +5,8 @@
 #include "glm/ext/matrix_float4x4.hpp"
 #include "glm/ext/vector_float3.hpp"
 
+namespace core
+{
 class Camera
 {
  private:
@@ -63,5 +65,5 @@ class Camera
   void setFov(float newFov);
   void setPosition(const glm::vec3& newPosition);
 };
-
+}  // namespace core
 #endif