feat(render): implement Campaign AR and terrain fidelity

src/AcDream.Core/Rendering/TranslucencyFadeManager.cs

@@ -53,6 +53,15 @@ public sealed class TranslucencyFadeManager
     // frames keep reading the settled value.
     private readonly Dictionary<uint, Dictionary<uint, float>> _committed = new();
 
+    private ulong _revision = 1;
+
+    /// <summary>
+    /// Advances whenever the committed per-part opacity topology changes.
+    /// Render products may use this to retain classification while no fade
+    /// state changes, and to rebuild exact caster membership when it does.
+    /// </summary>
+    public ulong Revision => _revision;
+
     /// <summary>
     /// Start (or replace) a translucency ramp for one Setup part of one
     /// entity. Mirrors <c>CPhysicsObj::SetPartTranslucency</c>: a
@@ -151,8 +160,10 @@ public sealed class TranslucencyFadeManager
     /// <summary>Drop all fade state for an entity (despawn / unload).</summary>
     public void ClearEntity(uint entityId)
     {
-        _activeFades.Remove(entityId);
-        _committed.Remove(entityId);
+        bool changed = _activeFades.Remove(entityId);
+        changed |= _committed.Remove(entityId);
+        if (changed)
+            AdvanceRevision();
     }
 
     private void Commit(uint entityId, uint partIndex, float value)
@@ -162,6 +173,26 @@ public sealed class TranslucencyFadeManager
             parts = new Dictionary<uint, float>();
             _committed[entityId] = parts;
         }
+
+        if (parts.TryGetValue(partIndex, out float prior)
+            && BitConverter.SingleToInt32Bits(prior)
+                == BitConverter.SingleToInt32Bits(value))
+        {
+            return;
+        }
+
         parts[partIndex] = value;
+        AdvanceRevision();
+    }
+
+    private void AdvanceRevision()
+    {
+        if (_revision == ulong.MaxValue)
+        {
+            throw new InvalidOperationException(
+                "Translucency fade revision space was exhausted.");
+        }
+
+        _revision++;
     }
 }