diff --git a/Makefile b/Makefile
index c54ab3c..6601abd 100644
--- a/Makefile
+++ b/Makefile
@@ -37,5 +37,10 @@ ifeq ($(MEMOVERLAY),1)
 CPPFLAGS += -DPSXSPLASH_MEMOVERLAY
 endif
 
+# FPSOVERLAY=1  → Enable runtime FPS overlay
+ifeq ($(FPSOVERLAY), 1)
+CPPFLAGS += -DPSXSPLASH_FPSOVERLAY
+endif
+
 include third_party/nugget/psyqo-lua/psyqo-lua.mk
 include third_party/nugget/psyqo/psyqo.mk
diff --git a/src/main.cpp b/src/main.cpp
index b924a0e..3aa9195 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -119,8 +119,10 @@ void MainScene::frame() {
     
     m_sceneManager.GameTick(gpu());
 
+    #if defined(PSXSPLASH_FPSOVERLAY)
     app.m_font.chainprintf(gpu(), {{.x = 2, .y = 2}}, {{.r = 0xff, .g = 0xff, .b = 0xff}}, "FPS: %i",
                            gpu().getRefreshRate() / deltaTime);
+    #endif
 
     gpu().pumpCallbacks();
 }
diff --git a/src/renderer.cpp b/src/renderer.cpp
index 603bb33..2f8b8d7 100644
--- a/src/renderer.cpp
+++ b/src/renderer.cpp
@@ -45,14 +45,14 @@ void psxsplash::Renderer::SetCamera(psxsplash::Camera& camera) { m_currentCamera
 
 void psxsplash::Renderer::SetFog(const FogConfig& fog) {
     m_fog = fog;
+    // Always use fog color as the GPU clear/back color
+    m_clearcolor = fog.color;
     if (fog.enabled) {
-        m_clearcolor = fog.color;
         write<Register::RFC, Unsafe>(static_cast<uint32_t>(fog.color.r) << 4);
         write<Register::GFC, Unsafe>(static_cast<uint32_t>(fog.color.g) << 4);
         write<Register::BFC, Safe>(static_cast<uint32_t>(fog.color.b) << 4);
         m_fog.fogFarSZ = 8000 / fog.density;
     } else {
-        m_clearcolor = {.r = 0, .g = 0, .b = 0};
         m_fog.fogFarSZ = 0;
     }
 }
@@ -135,9 +135,8 @@ void psxsplash::Renderer::processTriangle(
     int32_t fogIR[3] = {0, 0, 0};
     if (fogFarSZ > 0) {
         int32_t fogNear = fogFarSZ / 4;
-        int32_t range4 = (fogFarSZ - fogNear) >> 4;
-        if (range4 < 1) range4 = 1;
-        int32_t scale = 4096 / range4;
+        int32_t range = fogFarSZ - fogNear;
+        if (range < 1) range = 1;
         int32_t szArr[3] = {sz0, sz1, sz2};
         for (int vi = 0; vi < 3; vi++) {
             int32_t ir;
@@ -146,11 +145,10 @@ void psxsplash::Renderer::processTriangle(
             } else if (szArr[vi] >= fogFarSZ) {
                 ir = 4096;
             } else {
-                ir = ((szArr[vi] - fogNear) * scale) >> 4;
-                if (ir > 4096) ir = 4096;
-                int32_t inv = 4096 - ir;
-                ir = 4096 - ((inv >> 2) * (inv >> 2) >> 8);
-                if (ir < 0) ir = 0;
+                // Linear 0..4096 over [fogNear, fogFarSZ]
+                int32_t t = ((szArr[vi] - fogNear) * 4096) / range;
+                // Quadratic ease-in: t^2 / 4096
+                ir = (t * t) >> 12;
             }
             fogIR[vi] = ir;
         }
diff --git a/src/scenemanager.cpp b/src/scenemanager.cpp
index 13fc356..0fbf70a 100644
--- a/src/scenemanager.cpp
+++ b/src/scenemanager.cpp
@@ -69,17 +69,13 @@ void psxsplash::SceneManager::InitializeScene(uint8_t* splashpackData, LoadingSc
     m_roomTriRefs = sceneSetup.roomTriRefs;
     m_roomTriRefCount = sceneSetup.roomTriRefCount;
 
-    // Configure fog from splashpack data (v11+)
-    if (sceneSetup.fogEnabled) {
+    // Configure fog and back color from splashpack data (v11+)
+    {
         psxsplash::FogConfig fogCfg;
-        fogCfg.enabled = true;
+        fogCfg.enabled = sceneSetup.fogEnabled;
         fogCfg.color = {.r = sceneSetup.fogR, .g = sceneSetup.fogG, .b = sceneSetup.fogB};
         fogCfg.density = sceneSetup.fogDensity;
         Renderer::GetInstance().SetFog(fogCfg);
-    } else {
-        psxsplash::FogConfig fogCfg;
-        fogCfg.enabled = false;
-        Renderer::GetInstance().SetFog(fogCfg);
     }    
     // Copy component arrays
     m_interactables = std::move(sceneSetup.interactables);