Back color configurable, added fps counter checkbox

Runtime/PSXSceneExporter.cs

@@ -30,11 +30,11 @@ namespace SplashEdit.RuntimeCode
         public float GTEScaling = 100.0f;
         public LuaFile SceneLuaFile;
         
-        [Header("Fog Configuration")]
-        [Tooltip("Enable distance fog. Fog color is also used as the GPU clear color.")]
-        public bool FogEnabled = false;
-        [Tooltip("Fog color (RGB). Also used as the sky/clear color.")]
+        [Header("Fog & Background")]
+        [Tooltip("Background clear color. Also used as the fog blend target when fog is enabled.")]
         public Color FogColor = new Color(0.5f, 0.5f, 0.6f);
+        [Tooltip("Enable distance fog that blends geometry toward the background color.")]
+        public bool FogEnabled = false;
         [Tooltip("Fog density (1 = light haze, 10 = pea soup).")]
         [Range(1, 10)]
         public int FogDensity = 5;
@@ -82,8 +82,7 @@ namespace SplashEdit.RuntimeCode
             }
         }
         
-        // Phase 3+4: World collision and nav regions
-        private PSXCollisionExporter _collisionExporter;
+        // Phase 4: Nav regions
         private PSXNavRegionBuilder _navRegionBuilder;
         
         // Phase 5: Room/portal system (interior scenes)
@@ -186,12 +185,6 @@ namespace SplashEdit.RuntimeCode
             _bvh = new BVH(_exporters.ToList());
             _bvh.Build();
 
-            // Phase 3: Build world collision soup
-            _collisionExporter = new PSXCollisionExporter();
-            _collisionExporter.Build(_exporters, GTEScaling);
-            if (_collisionExporter.MeshCount == 0)
-                Debug.LogWarning("No collision meshes! Set CollisionType=Static on your floor/wall objects.");
-
             // Phase 4+5: Room volumes are needed by BOTH the nav region builder
             // (for spatial room assignment) and the room builder (for triangle assignment).
             // Collect them early so both systems use the same room indices.