Back color configurable, added fps counter checkbox

Editor/Core/SplashControlPanel.cs

@@ -594,6 +594,10 @@ namespace SplashEdit.EditorCode
                 new GUIContent("Memory Overlay", "Show heap/RAM usage bar at top-right during gameplay"),
                 SplashSettings.MemoryOverlay);
 
+            SplashSettings.FpsOverlay = EditorGUILayout.Toggle(
+                new GUIContent("FPS Overlay", "Show an FPS counter at top-left during gameplay"),
+                SplashSettings.FpsOverlay);
+
             // Serial port (only for Real Hardware)
             if (SplashSettings.Target == BuildTarget.RealHardware)
             {
@@ -1188,6 +1192,9 @@ namespace SplashEdit.EditorCode
             if (SplashSettings.MemoryOverlay)
                 buildArg += " MEMOVERLAY=1";
             
+            if (SplashSettings.FpsOverlay)
+                buildArg += " FPSOVERLAY=1";
+
             int jobCount = Math.Max(1, SystemInfo.processorCount - 1);
             string cleanPrefix = SplashSettings.CleanBuild ? "make clean && " : "";
             string makeCmd = $"{cleanPrefix}make all -j{jobCount} {buildArg}".Trim();

Editor/Core/SplashSettings.cs

@@ -136,6 +136,19 @@ namespace SplashEdit.EditorCode
             set => EditorPrefs.SetBool(Prefix + "MemoryOverlay", value);
         }
 
+
+        // --- FPS Overlay ---
+        /// <summary>
+        /// When enabled, compiles the runtime with an FPS counter
+        /// and text overlay at the top-left corner of the screen.
+        /// Passes FPSOVERLAY=1 to the native Makefile.
+        /// </summary>
+        public static bool FpsOverlay
+        {
+            get => EditorPrefs.GetBool(Prefix + "FpsOverlay", false);
+            set => EditorPrefs.SetBool(Prefix + "FpsOverlay", value);
+        }
+
         // --- Export settings ---
         public static float DefaultGTEScaling
         {

Editor/PSXSceneExporterEditor.cs

@@ -103,16 +103,19 @@ namespace SplashEdit.EditorCode
 
         private void DrawFogSection(PSXSceneExporter exporter)
         {
-            showFog = EditorGUILayout.Foldout(showFog, "Fog", true, PSXEditorStyles.FoldoutHeader);
+            showFog = EditorGUILayout.Foldout(showFog, "Fog & Background", true, PSXEditorStyles.FoldoutHeader);
             if (!showFog) return;
 
             EditorGUI.indentLevel++;
 
-            EditorGUILayout.PropertyField(fogEnabledProp, new GUIContent("Enabled"));
+            EditorGUILayout.PropertyField(fogColorProp, new GUIContent("Background Color",
+                "Background clear color. Also used as the fog blend target when fog is enabled."));
+
+            EditorGUILayout.PropertyField(fogEnabledProp, new GUIContent("Distance Fog"));
 
             if (fogEnabledProp.boolValue)
             {
-                EditorGUILayout.PropertyField(fogColorProp, new GUIContent("Color"));
+                EditorGUI.indentLevel++;
                 EditorGUILayout.PropertyField(fogDensityProp, new GUIContent("Density"));
 
                 float gteScale = exporter.GTEScaling;
@@ -125,6 +128,7 @@ namespace SplashEdit.EditorCode
                     $"<color=#aaaaaa>GTE range: {fogNearUnity:F1} - {fogFarUnity:F1} units  |  " +
                     $"{8000f / (density * 3f):F0} - {8000f / density:F0} SZ</color>",
                     PSXEditorStyles.RichLabel);
+                EditorGUI.indentLevel--;
             }
 
             EditorGUI.indentLevel--;

Runtime/PSXSceneExporter.cs

@@ -30,11 +30,11 @@ namespace SplashEdit.RuntimeCode
         public float GTEScaling = 100.0f;
         public LuaFile SceneLuaFile;
         
-        [Header("Fog Configuration")]
+        [Header("Fog & Background")]
-        [Tooltip("Enable distance fog. Fog color is also used as the GPU clear color.")]
+        [Tooltip("Background clear color. Also used as the fog blend target when fog is enabled.")]
-        public bool FogEnabled = false;
-        [Tooltip("Fog color (RGB). Also used as the sky/clear color.")]
         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
+        // Phase 4: Nav regions
-        private PSXCollisionExporter _collisionExporter;
         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.