Implement native-backed SC0000 SFX lifecycle

engine/Age.Engine.Tests/SfxOpsTests.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using Age.Engine.Model;
+using Age.Engine.Sys4;
+using Age.Engine.Vm;
+using Xunit;
+
+public class SfxOpsTests
+{
+    [Fact]
+    public void Sc0000SfxLifecycleAndBgmFadeReachHost()
+    {
+        var table = OpcodeTableJson.Load(Paths.OpcodesJson);
+        var script = ScriptAssembler.Assemble(table, "SFX",
+            new List<(int, Operand[])>
+            {
+                (0xb4, new[] { new Operand(0, 0x28), new Operand(0, 0) }),
+                (0xb5, new[] { new Operand(0, 0) }),
+                (0xb6, new[] { new Operand(0, 0) }),
+                (0xc2, new[] { new Operand(0, 25), new Operand(0, 3000) }),
+                (0xd9, Array.Empty<Operand>()),
+                (0x2, Array.Empty<Operand>()),
+            }, Array.Empty<string>());
+        var host = new RecordingHost();
+        var vm = new VirtualMachine(script, table, host);
+
+        vm.Run();
+
+        Assert.Equal("exit", vm.HaltReason);
+        Assert.Equal((0x28L, 0), Assert.Single(host.SfxLoads));
+        Assert.Equal(0, Assert.Single(host.SfxStarts));
+        Assert.Equal(0, Assert.Single(host.SfxReleases));
+        Assert.Equal((25, 3000L), Assert.Single(host.BgmFades));
+    }
+}

engine/Age.Engine.Tests/TestSupport.cs

@@ -17,6 +17,10 @@ internal sealed class RecordingHost : IHost
     public readonly List<(int Slot, int X, int Y)> TextCursors = new();
     public readonly List<(int Surface, int X, int Y, string Text)> SurfaceStrings = new();
     public readonly List<long> SleptDurations = new();
+    public readonly List<(long Resource, int Channel)> SfxLoads = new();
+    public readonly List<int> SfxStarts = new();
+    public readonly List<int> SfxReleases = new();
+    public readonly List<(int Target, long Duration)> BgmFades = new();
     public void ShowText(int offset, string text) => Lines.Add((offset, text));
     public void SetAdvTextCursor(int layoutSlot, int x, int y) => TextCursors.Add((layoutSlot, x, y));
     public void DrawStringToSurface(int surfaceSlot, int x, int y, string text)
@@ -44,6 +48,10 @@ internal sealed class RecordingHost : IHost
     public (int Width, int Height) GetTextureSize(int slot) => (0, 0);
     public void PlayBgm(long id) { }
     public void PlayVoice(long id) { }
+    public void LoadSoundEffect(long resourceId, int channel) => SfxLoads.Add((resourceId, channel));
+    public void StartSoundEffect(int channel) => SfxStarts.Add(channel);
+    public void ReleaseSoundEffect(int channel) => SfxReleases.Add(channel);
+    public void FadeBgm(int targetPercent, long durationMs) => BgmFades.Add((targetPercent, durationMs));
 }
 
 internal sealed class MapProvider : IScriptProvider