fix(rendering): repair EnvCell retail CLIP state

Exclude deferred EnvCell subsets from the opaque turn, preserve exact CLIP/ALPHA fixed-state groups through leaf replay, and use retail's row-3 override, blend, depth, and texture-class alpha references. Keep the existing building-detail sentinel distinct from the two CLIP references.

Bound rejected source payload, replace no-op allocation proofs with actual EnvCell and particle RHI paths, rebuild checked-in SPIR-V, and correct AP-238/AP-240 plus the S4-c2 evidence record.

Gates: Release 0W/0E; hermetic 16735/0/0; InstalledDat 255 pass/10 known fail/1 skip; shaders 32/32; focused 239/239; allocation 2/2 at 0 B. The evidence/comment repair re-ran Release 0W/0E, shaders 32/32, affected 37/37, and allocation 2/2; mesh_detail.vert.spv remained byte-identical at SHA-256 5346247ab7d606046943e19b28888c814e08dc6cb27cd9750096ac055457eb57.

Mutation proof, with each mutation restored after its named first failure:

1. Restoring the opaque predicate to !IsAdditive fails WholeLeaf_MixedCellDrawsOpaqueAtTurnThenClipAndAlphaAtDrain first at draw count: expected 1, actual 3.
2. Selecting _alphaPipeline for CLIP fails WholeLeaf_ClipDrainBindsExactStateAndTextureClassReference first at the bind sequence: expected [envcell-clip], actual [envcell-alpha].
3. Disabling CLIP depth write fails that production Theory first at Assert.True(clipPipeline.Depth.Write): expected true, actual false.
4. Swapping palette/DDS references fails the DDS row first: expected 0.784313738, actual 0.392156869; the palette row reports the inverse.
5. Mutating mesh_modern.frag from < to <= fails ClipShaders_UseGreaterEqualForThePerRangeReference first at Assert.Contains("if (color.a < alphaCutoff) discard;"): the required source spelling is absent.
6. Restoring row-3 OverrideClipmap=true fails the real-interface clip Theory first at Assert.False: expected false, actual true.
7. Deleting failed-append rollback fails the flush/end/abort rejection-storm rows first at the bounded pending-count assertion: expected 0, actual 9000.
8. Selecting _transparentDetailPipeline for a ClipMap detail contribution fails the leaf detail pin first at the bind sequence: expected second bind envcell-retail-detail-clip, actual envcell-retail-detail-alpha.
9. Resetting detail ParamB to zero fails the same detail pin first at the second pushed reference: expected 0.784313738, actual 0.
10. Classifying CLIP with exact mask equality excludes legal 0x09 and fails WholeLeaf_PositiveStippleClipMaskUsesClipPipelineAndDdsReference first at pipeline: expected envcell-clip, actual envcell-alpha.
11. Mapping the new blend to SRC_ALPHA/INVSRCALPHA fails AllRetailBlendModesAreRepresentable first at the tuple: expected (One, OneMinusSrcAlpha), actual (SrcAlpha, OneMinusSrcAlpha).
12. Restoring mesh_detail.vert's uParamB > 0.5 category predicate fails ClipShaders_UseGreaterEqualForThePerRangeReference first because vDetailCategory = uParamB == 1.0 is absent.
13. Treating every positive detail uParamB as a cutoff fails that source pin first because isRetailClipReference(uParamB) ? uParamB : 0.05 is absent.
14. Adding arbitrary 0.5 as an accepted reference to either mesh_modern.frag or mesh_detail.frag fails that source pin first at Assert.DoesNotContain("value - 0.5"); both mutations were run and reversed independently.

Retail: D3DPolyRender::SetSurface @ 0x0059c4d0; paired binary @ 0x0059c72a, 0x0059c747/0x0059c74f, 0x0059c821, 0x0059c838, 0x0059c866.

src/AcDream.App/Rendering/Gpu/GpuEnums.cs

@@ -121,6 +121,14 @@ internal enum GpuBlendMode
     /// <summary>Straight alpha: <c>SrcAlpha, OneMinusSrcAlpha</c>.</summary>
     StraightAlpha,
 
+    /// <summary>
+    /// Premultiplied/source-over: <c>One, OneMinusSrcAlpha</c>. Retail pure
+    /// Base1ClipMap surfaces select exactly this pair in
+    /// <c>D3DPolyRender::SetSurface</c> @0x0059c72a when the per-entry
+    /// override-clipmap byte is clear.
+    /// </summary>
+    PremultipliedAlpha,
+
     /// <summary>Additive: <c>SrcAlpha, One</c>.</summary>
     Additive,
 

src/AcDream.App/Rendering/Gpu/Vk/VulkanViewportMapping.cs

@@ -174,6 +174,7 @@ internal static class VulkanViewportMapping
     internal static (BlendFactor Source, BlendFactor Destination) BlendFactorsOf(GpuBlendMode blend) => blend switch
     {
         GpuBlendMode.StraightAlpha => (BlendFactor.SrcAlpha, BlendFactor.OneMinusSrcAlpha),
+        GpuBlendMode.PremultipliedAlpha => (BlendFactor.One, BlendFactor.OneMinusSrcAlpha),
         GpuBlendMode.Additive => (BlendFactor.SrcAlpha, BlendFactor.One),
         // Retail's third mode, found at slice V4c in WbDrawDispatcher.ApplyRetailBlend.
         GpuBlendMode.InverseAlpha => (BlendFactor.OneMinusSrcAlpha, BlendFactor.SrcAlpha),

src/AcDream.App/Rendering/ParticleRenderer.Rhi.cs

@@ -131,7 +131,7 @@ public sealed unsafe partial class ParticleRenderer
 
     /// <summary>
     /// The RHI arm's constructor. No GL context, no <c>Shader</c>, no
-    /// <c>BindlessSupport</c>: the five pipelines compile <c>particle</c> and
+    /// <c>BindlessSupport</c>: the six pipelines compile <c>particle</c> and
     /// <c>particle_mesh</c> from the committed SPIR-V, and both texture sources
     /// already hand out the device's own <c>GpuTextureSlot</c> (V4t).
     /// </summary>
@@ -267,9 +267,11 @@ public sealed unsafe partial class ParticleRenderer
         });
 
     /// <summary>
-    /// One mesh-particle pipeline. Same depth bracket as the billboards (see
-    /// <see cref="AcDream.App.Rendering.WorldDepthContract"/> for the world
-    /// <c>GL_LESS</c> citation); the winding is CW because
+    /// One mesh-particle pipeline. Every variant uses retail's world
+    /// <c>GL_LESS</c> compare; delayed alpha variants match the billboard
+    /// no-write bracket, while row 5's opaque variant depth-writes. See
+    /// <see cref="AcDream.App.Rendering.WorldDepthContract"/> for the compare
+    /// citation. The winding is CW because
     /// <c>PrepareMeshPipeline</c> sets <c>glFrontFace(GL_CW)</c>, and the cull
     /// mode stays DYNAMIC because it is resolved per sub-batch from the DAT's
     /// own <c>CullMode</c>.

src/AcDream.App/Rendering/RetailPViewPassExecutor.cs

@@ -263,13 +263,31 @@ internal sealed partial class RetailPViewPassExecutor : IEnvCellImmediateDrawSin
         if ((routes & EnvCellTransparentRoute.Clip) != 0)
         {
             int token = clipSource.AddPendingCellId(cellId);
-            queue.TryAppend(RetailAlphaList.Clip, clipSource, token, overrideClipmap: true);
+            // This fixed source is ordinary DrawMesh row 3: pure ClipMap,
+            // multipass false, therefore CLIP with overrideClipmap=false.
+            // If the queue drops at 3,000, retain no source-owned payload;
+            // TryAppend has already registered the source for exact reset.
+            if (!queue.TryAppend(
+                    RetailAlphaList.Clip,
+                    clipSource,
+                    token,
+                    overrideClipmap: false))
+            {
+                clipSource.RollbackPendingCellId(token);
+            }
         }
 
         if ((routes & EnvCellTransparentRoute.Alpha) != 0)
         {
             int token = alphaSource.AddPendingCellId(cellId);
-            queue.TryAppend(RetailAlphaList.Alpha, alphaSource, token, overrideClipmap: false);
+            if (!queue.TryAppend(
+                    RetailAlphaList.Alpha,
+                    alphaSource,
+                    token,
+                    overrideClipmap: false))
+            {
+                alphaSource.RollbackPendingCellId(token);
+            }
         }
     }
 
@@ -297,13 +315,27 @@ internal sealed partial class RetailPViewPassExecutor : IEnvCellImmediateDrawSin
         if ((routes & EnvCellTransparentRoute.Clip) != 0)
         {
             int token = clipSource.AddPendingCellId(cellId);
-            queue.TryAppend(RetailAlphaList.Clip, clipSource, token, overrideClipmap: true);
+            if (!queue.TryAppend(
+                    RetailAlphaList.Clip,
+                    clipSource,
+                    token,
+                    overrideClipmap: false))
+            {
+                clipSource.RollbackPendingCellId(token);
+            }
         }
 
         if ((routes & EnvCellTransparentRoute.Alpha) != 0)
         {
             int token = alphaSource.AddPendingCellId(cellId);
-            queue.TryAppend(RetailAlphaList.Alpha, alphaSource, token, overrideClipmap: false);
+            if (!queue.TryAppend(
+                    RetailAlphaList.Alpha,
+                    alphaSource,
+                    token,
+                    overrideClipmap: false))
+            {
+                alphaSource.RollbackPendingCellId(token);
+            }
         }
     }
 
@@ -327,15 +359,26 @@ internal sealed partial class RetailPViewPassExecutor : IEnvCellImmediateDrawSin
         EnvCellTransparentRoute route,
         bool detailSurfaceActive);
 
-    internal sealed class EnvCellAlphaDrawSource(
-        RenderEnvCellsByRoute renderTransparentOrdered,
-        EnvCellTransparentRoute route)
-        : IRetailAlphaDrawSource
+    internal sealed class EnvCellAlphaDrawSource : IRetailAlphaDrawSource
     {
+        private readonly RenderEnvCellsByRoute _renderTransparentOrdered;
+        private readonly EnvCellTransparentRoute _route;
+        private readonly Action? _resetObserver;
         private readonly List<uint> _pendingCellIds = new();
         private readonly List<uint> _preparedCellIds = new();
         private readonly List<uint> _drawScratch = new();
 
+        internal EnvCellAlphaDrawSource(
+            RenderEnvCellsByRoute renderTransparentOrdered,
+            EnvCellTransparentRoute route,
+            Action? resetObserver = null)
+        {
+            _renderTransparentOrdered = renderTransparentOrdered
+                ?? throw new ArgumentNullException(nameof(renderTransparentOrdered));
+            _route = route;
+            _resetObserver = resetObserver;
+        }
+
         /// <summary>Returns this cell's token — its index into
         /// <see cref="_pendingCellIds"/> at the moment it was added.</summary>
         internal int AddPendingCellId(uint cellId)
@@ -345,6 +388,22 @@ internal sealed partial class RetailPViewPassExecutor : IEnvCellImmediateDrawSin
             return token;
         }
 
+        /// <summary>
+        /// Rolls back only the just-reserved tail token after queue rejection.
+        /// Accepted indices therefore never move, while a rejection storm can
+        /// neither grow the pending count nor force a second geometric growth
+        /// beyond the 3,000-entry list's warmed capacity.
+        /// </summary>
+        internal void RollbackPendingCellId(int token)
+        {
+            if (token != _pendingCellIds.Count - 1)
+            {
+                throw new InvalidOperationException(
+                    "Only the just-reserved EnvCell alpha token can be rolled back.");
+            }
+            _pendingCellIds.RemoveAt(token);
+        }
+
         public void PrepareAlphaDraws(ReadOnlySpan<int> tokens)
         {
             _preparedCellIds.Clear();
@@ -359,7 +418,10 @@ internal sealed partial class RetailPViewPassExecutor : IEnvCellImmediateDrawSin
             _drawScratch.Clear();
             for (int i = 0; i < drawCount; i++)
                 _drawScratch.Add(_preparedCellIds[firstPreparedDraw + i]);
-            renderTransparentOrdered(_drawScratch, route, detailSurfaceActive: false);
+            _renderTransparentOrdered(
+                _drawScratch,
+                _route,
+                detailSurfaceActive: false);
         }
 
         public void ResetAlphaSubmissions()
@@ -367,9 +429,13 @@ internal sealed partial class RetailPViewPassExecutor : IEnvCellImmediateDrawSin
             _pendingCellIds.Clear();
             _preparedCellIds.Clear();
             _drawScratch.Clear();
+            _resetObserver?.Invoke();
         }
 
         internal int PendingCount => _pendingCellIds.Count;
+        internal int PendingCapacity => _pendingCellIds.Capacity;
+        internal int PreparedCapacity => _preparedCellIds.Capacity;
+        internal int DrawCapacity => _drawScratch.Capacity;
     }
 
     /// <summary>

src/AcDream.App/Rendering/Shaders/mesh_detail.frag

@@ -11,6 +11,10 @@ in flat uint vBatchFlags;
 in flat uint vDetailCategory;
 
 uniform uint uTextureIndexA; // category detail texture, layer 0
+// S4-c2 F3: 100/255 or 200/255 for a pure ClipMap base/detail pair. Exact 1
+// remains mesh_detail.vert's existing building-category sentinel and must use
+// the ordinary empty-fragment cutoff. Zero is the ordinary EnvCell category.
+uniform float uParamB;
 
 // SceneLighting UBO — IDENTICAL layout to mesh_modern.frag binding=1 (same
 // std140 block, same struct, same binding). Declared here ONLY for fog
@@ -50,6 +54,11 @@ vec3 applyFog(vec3 lit, vec3 worldPos) {
 
 out vec4 FragColor;
 
+bool isRetailClipReference(float value) {
+    return abs(value - (100.0 / 255.0)) < 0.000001
+        || abs(value - (200.0 / 255.0)) < 0.000001;
+}
+
 // VM2 (2026-08-22, live cdb read on the PDB-paired retail client, GUID
 // 9e847e2f-777c-4bd9-886c-22256bb87f32): retail's RenderDevice reports
 // m_caps.bCanDoSinglePassDetailing = 1 and the file-static trysinglepass = 1,
@@ -100,7 +109,8 @@ void main() {
     vec4 base = ACDREAM_SAMPLE_ARRAY(
         vBaseTextureIndex,
         vec3(vBaseUv, float(vBaseTextureLayer)));
-    if (base.a < 0.05)
+    float alphaCutoff = isRetailClipReference(uParamB) ? uParamB : 0.05;
+    if (base.a < alphaCutoff)
         discard;
 
     vec4 detail = ACDREAM_SAMPLE_ARRAY(

src/AcDream.App/Rendering/Shaders/mesh_detail.vert

@@ -38,9 +38,9 @@ layout(std430, binding = 3) readonly buffer ClipSlotBuf {
     uint instanceClipSlot[];
 };
 
-// Object renderer only: 1 for a retail building shell, 0 for ordinary
-// scenery/creatures/players. EnvCellRenderer sets uParamB=0 and ignores the
-// value, but still binds one valid word because Vulkan sees this static use.
+// Exact uParamB=1 selects this per-instance building/object category. EnvCell
+// zero and its pure-ClipMap 100/255 or 200/255 references retain the bound
+// environment category; the fragment shader consumes those CLIP references.
 layout(std430, binding = 9) readonly buffer InstanceDetailCategoryBuf {
     uint instanceDetailCategory[];
 };
@@ -61,7 +61,10 @@ uniform mat4 uViewProjection;
 uniform int uDrawIDOffset;
 uniform uint uTextureIndexB; // absolute transform prefix in the shared pose arena
 uniform float uParamA; // detail UV tiling
-uniform float uParamB; // 1 = require building instance, 0 = EnvCell category
+// Exact 1 remains the existing "require building instance" sentinel. S4-c2
+// also passes 100/255 or 200/255 for an EnvCell ClipMap alpha reference; both
+// must retain the EnvCell category rather than taking the building branch.
+uniform float uParamB;
 
 out vec2 vBaseUv;
 out vec2 vDetailUv;
@@ -95,7 +98,7 @@ void main() {
     vBaseTextureIndex = batch.textureIndex;
     vBaseTextureLayer = batch.textureLayer;
     vBatchFlags = batch.flags;
-    vDetailCategory = uParamB > 0.5
+    vDetailCategory = uParamB == 1.0
         ? instanceDetailCategory[instanceIndex]
         : 1u;
 }

src/AcDream.App/Rendering/Shaders/mesh_modern.frag

@@ -22,6 +22,10 @@ in flat vec2  vSelectionLighting;   // x=luminosity, y=diffuse
 //                         transparent overdraw cost otherwise)
 uniform int uRenderPass;
 uniform int uLightDebug;   // #176 stripe hunt (see mesh_modern.vert) — mode 3 handled here
+// S4-c2 F3: only retail's exact pure-ClipMap alpha-test references are
+// recognized, supplied per MDI range from TextureKey.PaletteId (100/255
+// paletted, 200/255 DDS/non-paletted). Every other value keeps 0.05.
+uniform float uParamB;
 
 // SceneLighting UBO — IDENTICAL layout to mesh_instanced.frag binding=1.
 struct Light {
@@ -57,15 +61,23 @@ vec3 applyFog(vec3 lit, vec3 worldPos) {
 
 out vec4 FragColor;
 
+bool isRetailClipReference(float value) {
+    return abs(value - (100.0 / 255.0)) < 0.000001
+        || abs(value - (200.0 / 255.0)) < 0.000001;
+}
+
 void main() {
     vec4 color = ACDREAM_SAMPLE_ARRAY(vTextureIndex, vec3(vTexCoord, float(vTextureLayer)));
+    float alphaCutoff = isRetailClipReference(uParamB) ? uParamB : 0.05;
 
     // Two-pass alpha-test (N.5 Decision 2).
     // A.5 T20: opaque pass writes alpha as-sampled so GL_SAMPLE_ALPHA_TO_COVERAGE
     // derives the MSAA sample mask from it — ClipMap foliage edges become smooth.
     // Discard only fully-transparent (α < 0.05); the GPU handles coverage masking.
     if (uRenderPass == 0) {
-        if (color.a < 0.05) discard;        // opaque pass — kill truly empty only (A2C)
+        // '<' spells D3DCMP_GREATEREQUAL: equality passes. Retail loads
+        // 100 or 200 and func 7 at SetSurface 0x0059c73c..0x0059c838.
+        if (color.a < alphaCutoff) discard;
     } else {
         // Transparent pass.
         //
@@ -84,7 +96,7 @@ void main() {
         // Keep the α<0.05 short-circuit as a fragment-cost optimization
         // (skip fully-empty pixels — saves blend bandwidth on alpha-keyed
         // sprites with large transparent margins).
-        if (color.a < 0.05) discard;
+        if (color.a < alphaCutoff) discard;
     }
 
     // Per-vertex Gouraud lighting from the vertex shader (ambient + capped

src/AcDream.App/Rendering/Shaders/spv/shaders.manifest.json

@@ -231,12 +231,12 @@
       "stages": [
         {
           "stage": "vert",
-          "sourceSha256": "0c1eddb0fc892cb76ef4da47f727cec2516052d63247fa2682918bfd60b84fa8",
+          "sourceSha256": "2d8b5b42f053a2d42e1ff44db3e331d5bea2d3f7dd36e20d813b7ae22c033181",
           "compiled": true
         },
         {
           "stage": "frag",
-          "sourceSha256": "e037fd28cf71453792c17522c97c4c7797193823ed78ca629a4331b632f177b1",
+          "sourceSha256": "a5285c51e8d6a1fa91f403f8489819595fa5a20abaaaccc969f220ea2c4eb335",
           "compiled": true
         }
       ]
@@ -252,7 +252,7 @@
         },
         {
           "stage": "frag",
-          "sourceSha256": "12f2ceec9a8420bd273650e95251ca56c3bf3c3691fce1a539e4c5aea7abaabf",
+          "sourceSha256": "d6ae09de279e814b159e7c481d6b66f3cc37c741b3d8a249fbe2bc8156e52d4e",
           "compiled": true
         }
       ]

src/AcDream.App/Rendering/Wb/EnvCellRenderer.Rhi.cs

@@ -26,9 +26,11 @@ public sealed unsafe partial class EnvCellRenderer
     private readonly IWorldPassScope? _scope;
     private IGpuPipeline? _opaquePipeline;
     private IGpuPipeline? _alphaPipeline;
+    private IGpuPipeline? _clipPipeline;
     private IGpuPipeline? _additivePipeline;
     private IGpuPipeline? _detailPipeline;
     private IGpuPipeline? _transparentDetailPipeline;
+    private IGpuPipeline? _clipDetailPipeline;
     private readonly TerrainAtlas.RetailDetailTextureBinding _environmentDetail;
     private readonly Func<bool> _buildingDetailEnabled;
 
@@ -48,7 +50,7 @@ public sealed unsafe partial class EnvCellRenderer
 
     /// <summary>
     /// The RHI arm's constructor. It also completes <c>Initialize</c>'s job: the
-    /// five pipelines ARE this renderer's program, so there is no second step
+    /// seven pipelines ARE this renderer's program, so there is no second step
     /// and no <c>Shader</c> to hand in.
     /// </summary>
     internal EnvCellRenderer(
@@ -72,6 +74,12 @@ public sealed unsafe partial class EnvCellRenderer
             device, "envcell-opaque", GpuBlendMode.None, depthWrite: true, scope.SampleCount);
         _alphaPipeline = CreateShellPipeline(
             device, "envcell-alpha", GpuBlendMode.StraightAlpha, depthWrite: false, scope.SampleCount);
+        _clipPipeline = CreateShellPipeline(
+            device,
+            "envcell-clip",
+            GpuBlendMode.PremultipliedAlpha,
+            depthWrite: true,
+            scope.SampleCount);
         _additivePipeline = CreateShellPipeline(
             device, "envcell-additive", GpuBlendMode.Additive, depthWrite: false, scope.SampleCount);
         _detailPipeline = CreateShellPipeline(
@@ -92,6 +100,15 @@ public sealed unsafe partial class EnvCellRenderer
             shaderName: "mesh_detail",
             depthCompare: RetailDetailTextureContract.DetailDepthCompare(
                 transparent: true));
+        _clipDetailPipeline = CreateShellPipeline(
+            device,
+            "envcell-retail-detail-clip",
+            GpuBlendMode.RetailDetail,
+            depthWrite: true,
+            scope.SampleCount,
+            shaderName: "mesh_detail",
+            depthCompare: RetailDetailTextureContract.DetailDepthCompare(
+                transparent: false));
         _initialized = true;
     }
 
@@ -274,12 +291,18 @@ public sealed unsafe partial class EnvCellRenderer
             MdiDrawRange drawRange = _mdiDrawRanges[drawRangeIndex];
             int groupIndex = drawRange.GroupIndex;
             CullMode cullMode = ResolveRetailCellShellCullMode(
-                (CullMode)(groupIndex % 4));
+                (CullMode)(groupIndex % CullGroupCount));
 
-            bool isAdditive = groupIndex >= 4;
-            IGpuPipeline rangeBasePipeline = isAdditive
-                ? _additivePipeline!
-                : _alphaPipeline!;
+            bool isAdditive = renderPass == WbRenderPass.Transparent
+                && groupIndex >= AdditiveGroupBase
+                && groupIndex < ClipDdsGroupBase;
+            bool isClip = renderPass == WbRenderPass.Transparent
+                && groupIndex >= ClipDdsGroupBase;
+            IGpuPipeline rangeBasePipeline = isClip
+                ? _clipPipeline!
+                : isAdditive
+                    ? _additivePipeline!
+                    : _alphaPipeline!;
             if (renderPass == WbRenderPass.Transparent)
             {
                 // Blend state is the pipeline's; switching variants mid-pass has
@@ -298,6 +321,9 @@ public sealed unsafe partial class EnvCellRenderer
                 ? (int)renderPass | 0x100
                 : (int)renderPass;
             pushConstants.DrawIdOffset = drawRange.FirstCommand;
+            pushConstants.ParamB = isClip
+                ? groupIndex >= ClipPalettedGroupBase ? 100f / 255f : 200f / 255f
+                : 0f;
             encoder.SetPushConstants(in pushConstants);
 
             // Retail DrawMesh's two-pass fallback redraws each transparent
@@ -317,7 +343,9 @@ public sealed unsafe partial class EnvCellRenderer
                     pushConstants.DrawIdOffset = command;
                     pushConstants.TextureIndexA = 0;
                     pushConstants.ParamA = 0f;
-                    pushConstants.ParamB = 0f;
+                    pushConstants.ParamB = isClip
+                        ? groupIndex >= ClipPalettedGroupBase ? 100f / 255f : 200f / 255f
+                        : 0f;
                     encoder.SetPushConstants(in pushConstants);
                     encoder.MultiDrawIndexedIndirect(
                         commandBuffer,
@@ -325,12 +353,17 @@ public sealed unsafe partial class EnvCellRenderer
                         1,
                         (uint)sizeof(DrawElementsIndirectCommand));
 
-                    BindPipelineWithMesh(encoder, _transparentDetailPipeline!, mesh);
+                    BindPipelineWithMesh(
+                        encoder,
+                        isClip ? _clipDetailPipeline! : _transparentDetailPipeline!,
+                        mesh);
                     SetCullMode(encoder, cullMode);
                     pushConstants.DrawIdOffset = command;
                     pushConstants.TextureIndexA = _environmentDetail.TextureSlot.Index;
                     pushConstants.ParamA = _environmentDetail.Tiling;
-                    pushConstants.ParamB = 0f;
+                    pushConstants.ParamB = isClip
+                        ? groupIndex >= ClipPalettedGroupBase ? 100f / 255f : 200f / 255f
+                        : 0f;
                     encoder.SetPushConstants(in pushConstants);
                     encoder.MultiDrawIndexedIndirect(
                         commandBuffer,
@@ -348,9 +381,11 @@ public sealed unsafe partial class EnvCellRenderer
                 (uint)sizeof(DrawElementsIndirectCommand));
         }
 
-        // Retail DrawEnvCell category (2). Replay the already-filtered opaque
-        // shell commands, including ClipMap built-mesh subsets. No distance
-        // fade (VM1/VM2): retail's noFadeDetail gates get_alpha_for_z to the
+        // Retail DrawEnvCell category (2). Replay only the already-filtered
+        // opaque shell commands. Transparent ClipMap is excluded here: it
+        // takes the immediate/delayed CLIP path and, when detail is active,
+        // its own _clipDetailPipeline contribution. No distance fade
+        // (VM1/VM2): retail's noFadeDetail gates get_alpha_for_z to the
         // immediate-polygon path only, which built meshes never reach;
         // attenuation is the sampler's linear mip chain converging to the
         // texture mean. The existing "Building Detail Textures" option gates
@@ -368,7 +403,7 @@ public sealed unsafe partial class EnvCellRenderer
             {
                 MdiDrawRange drawRange = _mdiDrawRanges[drawRangeIndex];
                 CullMode cullMode = ResolveRetailCellShellCullMode(
-                    (CullMode)(drawRange.GroupIndex % 4));
+                    (CullMode)(drawRange.GroupIndex % CullGroupCount));
                 SetCullMode(encoder, cullMode);
                 pushConstants.DrawIdOffset = drawRange.FirstCommand;
                 encoder.SetPushConstants(in pushConstants);
@@ -468,9 +503,10 @@ public sealed unsafe partial class EnvCellRenderer
 
     /// <summary>
     /// Binds one category word for <c>mesh_detail.vert</c>'s statically used
-    /// binding 9. EnvCell draws select their renderer-wide category via
-    /// <c>uParamB=0</c>, so the value is semantically unused, but Vulkan still
-    /// requires the declared descriptor to be valid.
+    /// binding 9. The vertex shader treats only exact <c>uParamB=1</c> as the
+    /// object/building-category sentinel; ordinary EnvCell zero and the CLIP
+    /// references 100/255 and 200/255 therefore keep the environment category.
+    /// Vulkan still requires the declared descriptor to be valid.
     /// </summary>
     internal static void BindEnvironmentDetailCategory(
         IGpuPassEncoder encoder,
@@ -491,11 +527,15 @@ public sealed unsafe partial class EnvCellRenderer
         _opaquePipeline = null;
         _alphaPipeline?.Dispose();
         _alphaPipeline = null;
+        _clipPipeline?.Dispose();
+        _clipPipeline = null;
         _additivePipeline?.Dispose();
         _additivePipeline = null;
         _detailPipeline?.Dispose();
         _detailPipeline = null;
         _transparentDetailPipeline?.Dispose();
         _transparentDetailPipeline = null;
+        _clipDetailPipeline?.Dispose();
+        _clipDetailPipeline = null;
     }
 }

src/AcDream.App/Rendering/Wb/EnvCellRenderer.cs

@@ -142,8 +142,17 @@ public sealed partial class EnvCellRenderer :
     private readonly List<(ObjectRenderData renderData, ulong gfxObjId, int count, int offset)> _renderDrawCalls = new();
     private readonly Dictionary<ulong, List<InstanceData>> _filteredGroups = new();
     private readonly HashSet<List<InstanceData>> _filteredOwnedLists = new();
+    // S4-c2 F3: four cull modes for each fixed-state family. The original
+    // eight slots were non-additive/additive only; transparent replay also
+    // needs distinct pure-ClipMap DDS/paletted ranges because their alpha-test
+    // references differ and neither state may share an MDI call with ALPHA.
+    private const int CullGroupCount = 4;
+    private const int AdditiveGroupBase = 4;
+    private const int ClipDdsGroupBase = 8;
+    private const int ClipPalettedGroupBase = 12;
+    private const int BatchGroupCount = 16;
     private readonly List<(ObjectRenderBatch batch, int instanceCount, int instanceOffset)>[] _batchesByCullGroup =
-        Enumerable.Range(0, 8)
+        Enumerable.Range(0, BatchGroupCount)
             .Select(_ => new List<(ObjectRenderBatch, int, int)>())
             .ToArray();
     private readonly List<int> _activeCullGroups = new(8);
@@ -1214,17 +1223,8 @@ public sealed partial class EnvCellRenderer :
                 foreach (var batch in call.renderData.Batches)
                 {
                     // WB BaseObjectRenderManager.cs:723-731: pass-filter.
-                    if (renderPass != WbRenderPass.SinglePass)
-                    {
-                        if (batch.IsAdditive)
-                        {
-                            if (renderPass == WbRenderPass.Opaque) continue;
-                        }
-                        else if (!batch.IsTransparent)
-                        {
-                            if (renderPass == WbRenderPass.Transparent) continue;
-                        }
-                    }
+                    if (!BatchBelongsToPass(batch, renderPass))
+                        continue;
 
                     if (renderPass == WbRenderPass.Transparent
                         && transparentRoute != EnvCellTransparentRoute.All
@@ -1277,17 +1277,8 @@ public sealed partial class EnvCellRenderer :
                 var call = drawCalls[callIndex];
                 foreach (var batch in call.renderData.Batches)
                 {
-                    if (renderPass != WbRenderPass.SinglePass)
-                    {
-                        if (batch.IsAdditive)
-                        {
-                            if (renderPass == WbRenderPass.Opaque) continue;
-                        }
-                        else if (!batch.IsTransparent)
-                        {
-                            if (renderPass == WbRenderPass.Transparent) continue;
-                        }
-                    }
+                    if (!BatchBelongsToPass(batch, renderPass))
+                        continue;
 
                     if (renderPass == WbRenderPass.Transparent
                         && transparentRoute != EnvCellTransparentRoute.All
@@ -1296,7 +1287,9 @@ public sealed partial class EnvCellRenderer :
                         continue;
                     }
 
-                    int groupIndex = (int)batch.CullMode + (batch.IsAdditive ? 4 : 0);
+                    int groupIndex = ResolveBatchGroupIndex(
+                        batch,
+                        renderPass);
                     List<(ObjectRenderBatch batch, int instanceCount, int instanceOffset)> group =
                         _batchesByCullGroup[groupIndex];
                     if (group.Count == 0)
@@ -1357,6 +1350,50 @@ public sealed partial class EnvCellRenderer :
         SubmitRhi(allInstances, renderPass, totalDraws, uniqueInstanceCount);
     }
 
+    /// <summary>
+    /// Exact WB pass membership, with <see cref="WbRenderPass.SinglePass"/>
+    /// intentionally unchanged. A non-additive transparent batch is delayed
+    /// content and must never draw during the preceding opaque cell turn.
+    /// </summary>
+    internal static bool BatchBelongsToPass(
+        ObjectRenderBatch batch,
+        WbRenderPass renderPass) => renderPass switch
+        {
+            WbRenderPass.Opaque => !batch.IsAdditive && !batch.IsTransparent,
+            WbRenderPass.Transparent => batch.IsAdditive || batch.IsTransparent,
+            WbRenderPass.SinglePass => true,
+            _ => false,
+        };
+
+    private static int ResolveBatchGroupIndex(
+        ObjectRenderBatch batch,
+        WbRenderPass renderPass)
+    {
+        int cull = (int)batch.CullMode;
+        if ((uint)cull >= CullGroupCount)
+            throw new ArgumentOutOfRangeException(nameof(batch), batch.CullMode, "Unknown cell-shell cull mode.");
+
+        // Preserve the old SinglePass grouping exactly: non-additive 0..3,
+        // additive 4..7. Its submission path still keeps the opaque pipeline.
+        if (renderPass != WbRenderPass.Transparent)
+            return cull + (batch.IsAdditive ? AdditiveGroupBase : 0);
+
+        if (batch.IsAdditive)
+            return cull + AdditiveGroupBase;
+
+        // Fixed state follows ConstructMesh's retained per-subset class, not
+        // the DrawMesh row action. Detail-active row 1 is Immediate, but a
+        // mask-0x08 subset (including legal positive-stipple 0x09) still needs
+        // the CLIP base pipeline/reference. ConstructMesh's priority already
+        // excludes additive/alpha-family rows before retaining this class.
+        if ((batch.RetailSurfaceMask & RetailAlphaMeshRouter.MaskClipMap) == 0)
+            return cull;
+
+        return cull + (batch.Key.PaletteId != 0
+            ? ClipPalettedGroupBase
+            : ClipDdsGroupBase);
+    }
+
     internal static void AppendMdiDrawRange(
         List<MdiDrawRange> ranges,
         int groupIndex,