Headless Mode fixes for the Backend (#65)

This PR brings some fixes that are needed for the backend to render
scenes.

studio/src/headless.rs

@@ -9,6 +9,7 @@ use wgpu::Extent3d;
 
 use crate::{
     bvh::{BvhAnimCompleteEvent, TestBvh},
+    scene::SceneState,
     screenshot::{ScreenCapture, ScreenShotPlugin},
     BvhPlugin, CommonPlugins, LoadLibraryObjectEvent, LoadSceneEvent, MainCamera,
     MixamoImportEvent, MixamoPlugin, SkyboxId, StudioMode, WorldGridPlugin,
@@ -64,7 +65,10 @@ pub fn start_headless(
                 },
             );
 
-            app.add_systems(PostUpdate, check_for_bvh_capture_complete);
+            app.add_systems(
+                PostUpdate,
+                check_for_bvh_capture_complete.run_if(in_state(SceneState::Active)),
+            );
         }
         HeadlessMode::Scene(scene, skybox) => {
             app.add_systems(
@@ -87,7 +91,10 @@ pub fn start_headless(
                     commands.insert_resource(SkyboxId(skybox.clone()));
                 },
             );
-            app.add_systems(PostUpdate, check_for_mixamo_capture_complete);
+            app.add_systems(
+                PostUpdate,
+                check_for_mixamo_capture_complete.run_if(in_state(SceneState::Active)),
+            );
 
             app.run();
         }
@@ -135,7 +142,6 @@ fn check_for_bvh_capture_complete(
         return;
     };
 
-    println!("Frames captured {}", screen_capture.frames_captured());
     if !screen_capture.should_capture() || !bvh_event_reader.is_empty() {
         screen_capture.stop_capturing();
         close_app.send(AppExit);