perf(vfx): port retail particle visibility degradation

Resolve DAT-authored particle ranges from the hardware GfxObj, apply retail distance and completed-cell visibility gates, and preserve the exact finite/infinite off-view update semantics. This removes dense-world simulation work without shortening terrain, entity, fog, or streaming distance.

Publish doorway-clipped outdoor cells through a focused frame controller, retain effect cell identity for outdoor statics, reject hidden emitters before particle-slot scans, and offer an explicit opt-in Extended particle range.

Release build succeeds and all 5,857 tests pass with five intentional skips. Retail-conformance, architecture, and adversarial review cycles are clean; connected Aerlinthe visual/performance gate pending.

Co-authored-by: OpenAI Codex <codex@openai.com>

src/AcDream.UI.Abstractions/Panels/Settings/DisplaySettings.cs

@@ -3,6 +3,17 @@ using AcDream.UI.Abstractions.Settings;
 
 namespace AcDream.UI.Abstractions.Panels.Settings;
 
+/// <summary>
+/// Particle visibility distance policy. Retail uses the GfxObj-authored
+/// distance exactly; Extended is an explicit acdream adaptation for players
+/// who prefer longer-lived distant effects with the corresponding CPU cost.
+/// </summary>
+public enum ParticleRange
+{
+    Retail = 0,
+    Extended = 1,
+}
+
 /// <summary>
 /// Display-related preferences persisted to <c>settings.json</c>.
 /// Modern addition (no retail equivalent for FOV / vsync etc) — replaces
@@ -22,7 +33,8 @@ public sealed record DisplaySettings(
     float FieldOfView,
     float Gamma,
     bool ShowFps,
-    QualityPreset Quality)
+    QualityPreset Quality,
+    ParticleRange ParticleRange)
 {
     /// <summary>Values used on first launch / when settings.json is absent.
     /// Geometry/render defaults preserve the pre-L.0 runtime state — Resolution
@@ -36,7 +48,8 @@ public sealed record DisplaySettings(
         FieldOfView:  60f,
         Gamma:        1.0f,
         ShowFps:      false,
-        Quality:      QualityPreset.High);
+        Quality:      QualityPreset.High,
+        ParticleRange: ParticleRange.Retail);
 
     /// <summary>16:9 resolution presets offered in the dropdown.</summary>
     public static IReadOnlyList<string> AvailableResolutions { get; } = new[]

src/AcDream.UI.Abstractions/Panels/Settings/SettingsPanel.cs

@@ -236,12 +236,20 @@ public sealed class SettingsPanel : IPanel
         if (renderer.Combo("Quality", ref qIdx, presets))
             _vm.SetDisplay(d with { Quality = (QualityPreset)qIdx });
 
+        int particleRangeIndex = (int)d.ParticleRange;
+        if (particleRangeIndex < 0 || particleRangeIndex >= s_particleRangeNames.Length)
+            particleRangeIndex = (int)ParticleRange.Retail;
+        if (renderer.Combo("Particle Range", ref particleRangeIndex, s_particleRangeNames))
+            _vm.SetDisplay(d with { ParticleRange = (ParticleRange)particleRangeIndex });
+
         renderer.Spacing();
         renderer.TextWrapped(
             "Resolution / Fullscreen / V-Sync apply on Save. FOV + Gamma "
             + "preview live as you drag; Cancel reverts to the saved value. "
             + "Quality preset applies streaming radius, anisotropic, and A2C "
-            + "immediately on Save; MSAA sample count requires a restart.");
+            + "immediately on Save; MSAA sample count requires a restart. "
+            + "Particle Range defaults to retail-authored distances; Extended "
+            + "doubles effect range and costs additional CPU time.");
     }
 
     /// <summary>
@@ -474,6 +482,9 @@ public sealed class SettingsPanel : IPanel
     private static readonly string[] s_qualityPresetNames =
         { "Low", "Medium", "High", "Ultra" };
 
+    private static readonly string[] s_particleRangeNames =
+        { "Retail", "Extended" };
+
     private void RenderSection(IPanelRenderer renderer, string label, InputAction[] actions)
     {
         // Movement defaults open; other sections collapsed for first-run UX.

src/AcDream.UI.Abstractions/Panels/Settings/SettingsStore.cs

@@ -73,7 +73,9 @@ public sealed class SettingsStore
                 FieldOfView: ReadFloat       (disp, "fieldOfView", d.FieldOfView),
                 Gamma:       ReadFloat       (disp, "gamma",       d.Gamma),
                 ShowFps:     ReadBool        (disp, "showFps",     d.ShowFps),
-                Quality:     ReadQuality     (disp, "quality",     d.Quality));
+                Quality:     ReadQuality     (disp, "quality",     d.Quality),
+                ParticleRange: ReadParticleRange(
+                    disp, "particleRange", d.ParticleRange));
         }
         catch (Exception ex)
         {
@@ -569,6 +571,7 @@ public sealed class SettingsStore
             ["fieldOfView"] = d.FieldOfView,
             ["fullscreen"]  = d.Fullscreen,
             ["gamma"]       = d.Gamma,
+            ["particleRange"] = d.ParticleRange.ToString(),
             ["quality"]     = d.Quality.ToString(),
             ["resolution"]  = d.Resolution,
             ["showFps"]     = d.ShowFps,
@@ -656,4 +659,18 @@ public sealed class SettingsStore
         var s = el.GetString();
         return Enum.TryParse<QualityPreset>(s, ignoreCase: true, out var v) ? v : fallback;
     }
+
+    private static ParticleRange ReadParticleRange(
+        JsonElement obj,
+        string name,
+        ParticleRange fallback)
+    {
+        if (!obj.TryGetProperty(name, out var el) || el.ValueKind != JsonValueKind.String)
+            return fallback;
+        var value = el.GetString();
+        return Enum.TryParse(value, ignoreCase: true, out ParticleRange parsed)
+               && Enum.IsDefined(parsed)
+            ? parsed
+            : fallback;
+    }
 }