diff --git a/Cargo.toml b/Cargo.toml
index 3fcf837..f3ac61b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,3 +8,4 @@ edition = "2021"
 [dependencies]
 bevy = "0.10.1"
 bevy_egui = "0.20.3"
+bevy-inspector-egui = "0.18.3"
diff --git a/src/global_state.rs b/src/global_state.rs
index 1e522e2..fcaad42 100644
--- a/src/global_state.rs
+++ b/src/global_state.rs
@@ -7,12 +7,23 @@ pub enum Camera {
 }
 
 impl Camera {
+    pub fn is_3d(&self) -> bool {
+        match self {
+            Camera::TwoD(_) => false,
+            Camera::ThreeD(_) => true,
+        }
+    }
+
+    pub fn is_2d(&self) -> bool {
+        !self.is_3d()
+    }
+
     fn create_2d(cmd: &mut Commands) -> Self {
         Self::TwoD(cmd.spawn(Camera2dBundle::default()).id())
     }
 
     fn create_3d(cmd: &mut Commands, window_extent: Vec2) -> Self {
-        Self::TwoD(
+        Self::ThreeD(
             cmd.spawn(Camera3dBundle {
                 transform: Transform::from_xyz(200.0, -600.0, 600.0)
                     .looking_at(window_extent.extend(0.0), Vec3::Z),
@@ -77,3 +88,39 @@ impl Default for GlobalState {
         }
     }
 }
+
+#[cfg(test)]
+mod test {
+    use bevy::{ecs::system::CommandQueue, prelude::*};
+
+    use super::GlobalState;
+
+    #[test]
+    fn camera_conversion() {
+        let world = World::new();
+        let mut command_queue = CommandQueue::default();
+
+        let mut cmd = Commands::new(&mut command_queue, &world);
+
+        // default global state
+        let mut global_state = GlobalState::default();
+
+        // create 2d cam
+        global_state.setup_2d_cam(&mut cmd);
+
+        assert!(global_state.camera.is_some());
+        assert!(global_state.camera.as_ref().unwrap().is_2d());
+
+        // switch to 3d cam
+        global_state.setup_3d_cam(&mut cmd);
+
+        assert!(global_state.camera.is_some());
+        assert!(global_state.camera.as_ref().unwrap().is_3d());
+
+        // switch to 2d cam
+        global_state.setup_2d_cam(&mut cmd);
+
+        assert!(global_state.camera.is_some());
+        assert!(global_state.camera.as_ref().unwrap().is_2d());
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index ce062c3..6acc4f5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -11,6 +11,7 @@ use bevy::{
 };
 
 use bevy_egui::{egui, EguiContexts, EguiPlugin};
+use bevy_inspector_egui::quick::WorldInspectorPlugin;
 use global_state::GlobalState;
 use polygon::ObjectInfos;
 
@@ -18,6 +19,7 @@ fn main() {
     App::new()
         .add_plugins(DefaultPlugins)
         .add_plugin(EguiPlugin)
+        .add_plugin(WorldInspectorPlugin::new())
         .insert_resource(GlobalState::default())
         .insert_resource(ObjectInfos::default())
         .add_startup_system(setup_camera)
@@ -57,6 +59,9 @@ fn update_ui_side_panel(
                     });
 
                     global_state.setup_3d_cam(&mut commands);
+
+                    debug_assert!(global_state.camera.is_some());
+                    debug_assert!(global_state.camera.as_ref().unwrap().is_3d());
                 }
             } else {
                 if ui.button("Change to 2D View").clicked() {
@@ -72,6 +77,9 @@ fn update_ui_side_panel(
                     });
 
                     global_state.setup_2d_cam(&mut commands);
+
+                    debug_assert!(global_state.camera.is_some());
+                    debug_assert!(global_state.camera.as_ref().unwrap().is_2d());
                 }
             }