diff --git a/src/AcDream.App/Rendering/Shaders/sky.frag b/src/AcDream.App/Rendering/Shaders/sky.frag
index e492f6e..c704467 100644
--- a/src/AcDream.App/Rendering/Shaders/sky.frag
+++ b/src/AcDream.App/Rendering/Shaders/sky.frag
@@ -3,7 +3,9 @@
 // D3D fixed-function:
 //
 //   fragment.rgb = texture.rgb × vTint + lightning_flash
-//   fragment.a   = texture.a   × (1 - uTransparency) × (1 - uSurfTranslucency)
+//   fragment.a   = texture.a   × (1 - uTransparency) × uSurfTranslucency
+//                 (uSurfTranslucency is OPACITY directly per retail's
+//                  D3DPolyRender::SetSurface at 0x59c7a6, NOT 1-x)
 //
 // vTint arrives from the vertex shader with retail's per-vertex
 // lighting formula baked in (Emissive + lightAmbient + lightDiffuse ×
diff --git a/src/AcDream.App/Rendering/Sky/SkyRenderer.cs b/src/AcDream.App/Rendering/Sky/SkyRenderer.cs
index 1aa9550..c593950 100644
--- a/src/AcDream.App/Rendering/Sky/SkyRenderer.cs
+++ b/src/AcDream.App/Rendering/Sky/SkyRenderer.cs
@@ -186,6 +186,14 @@ public sealed unsafe class SkyRenderer : IDisposable
         // Save + override GL state.
         _gl.DepthMask(false);
         _gl.Disable(EnableCap.DepthTest);
+        // Save + disable CullFace for the sky pass; restore at the end.
+        // Mirrors TextRenderer.cs's save/restore pattern. Without this the
+        // sky pass left CullFace disabled regardless of its prior state,
+        // which is benign today (the global convention in this codebase is
+        // off and subsequent renderers manage their own CullFace) but
+        // would break the moment any future caller assumes back-face
+        // culling stays on across the sky pass.
+        bool wasCullFace = _gl.IsEnabled(EnableCap.CullFace);
         _gl.Disable(EnableCap.CullFace);
         _gl.Enable(EnableCap.Blend);
         // Default blend — overridden per-submesh inside the inner loop.
@@ -406,6 +414,7 @@ public sealed unsafe class SkyRenderer : IDisposable
         _gl.Disable(EnableCap.Blend);
         _gl.DepthMask(true);
         _gl.Enable(EnableCap.DepthTest);
+        if (wasCullFace) _gl.Enable(EnableCap.CullFace);
         _gl.BindVertexArray(0);
     }
 
@@ -737,12 +746,14 @@ public sealed unsafe class SkyRenderer : IDisposable
         /// <summary>
         /// <c>Surface.Translucency</c> float (0..1) carried through from
         /// <see cref="GfxObjSubMesh.SurfTranslucency"/>. Passed to the
-        /// sky fragment shader as <c>uSurfTranslucency</c>; the shader
-        /// multiplies output alpha by <c>(1 - x)</c>. For the rain
-        /// surface 0x080000C5 this is 0.5 → opacity 0.5 → rain streaks
-        /// contribute at half intensity under the additive blend, matching
-        /// retail's <c>curr_alpha</c> derivation in
-        /// <c>D3DPolyRender::SetSurface</c> at <c>0x59c767</c>.
+        /// sky fragment shader as <c>uSurfTranslucency</c> and used
+        /// DIRECTLY as opacity (NOT <c>1 - x</c>). Retail's
+        /// <c>D3DPolyRender::SetSurface</c> at <c>0x59c7a6</c>
+        /// (decomp lines 425255-425260) computes
+        /// <c>curr_alpha = _ftol2(translucency × 255)</c> and writes that
+        /// as vertex.color.alpha — i.e. translucency is opacity directly.
+        /// For non-Translucent surfaces the GfxObjMesh.Build() path keeps
+        /// this at 1.0 so they stay fully opaque.
         /// </summary>
         public float SurfTranslucency;
     }