Make Godot native staging target-aware

docs/platform-portability.md

@@ -21,6 +21,11 @@ The VM and content pipeline are already mostly platform-neutral:
 - The Himegari Godot assembly embeds generated `build/opcodes.json` as profile runtime metadata. Exported
   builds never search for an `age-reimpl` repository ancestor; their automatic page-map diagnostics live
   under `user://diagnostics/page-maps`, while editor/development runs retain the workspace `build/` handoff.
+- `GodotTargetPlatform`, not the build host OS, selects the optional Windows GDI adapter. `AgeNativeRid`
+  follows an explicit export `RuntimeIdentifier` and otherwise supplies the current x64 development default;
+  mutually exclusive `win-x64` DLL and `linux-x64` shared-object groups stage to build and publish output.
+  The managed FFmpeg resolver derives reserved Windows, Linux, and macOS x64/arm64 RIDs from the actual
+  process and rejects unreserved architectures instead of silently looking in the wrong directory.
 
 The sole movie path now uses the project-owned FFmpeg C ABI rather than a Windows multimedia API, but only a
 Windows-x64 native bundle is built and staged today. The accepted DirectShow fallback was deleted after the

engine/Age.Engine.Tests/FfmpegMovieNativeTests.cs

@@ -0,0 +1,31 @@
+using System.Runtime.InteropServices;
+
+public class FfmpegMovieNativeTests
+{
+    [Theory]
+    [InlineData(true, false, Architecture.X64, "win-x64")]
+    [InlineData(true, false, Architecture.Arm64, "win-arm64")]
+    [InlineData(false, true, Architecture.X64, "osx-x64")]
+    [InlineData(false, true, Architecture.Arm64, "osx-arm64")]
+    [InlineData(false, false, Architecture.X64, "linux-x64")]
+    [InlineData(false, false, Architecture.Arm64, "linux-arm64")]
+    public void ResolverUsesOperatingSystemAndProcessArchitecture(
+        bool isWindows,
+        bool isMacOS,
+        Architecture architecture,
+        string expected)
+    {
+        Assert.Equal(
+            expected,
+            FfmpegMovieNative.RuntimeIdentifierFor(isWindows, isMacOS, architecture));
+    }
+
+    [Fact]
+    public void ResolverRejectsUnreservedArchitectures()
+    {
+        var error = Assert.Throws<PlatformNotSupportedException>(() =>
+            FfmpegMovieNative.RuntimeIdentifierFor(false, false, Architecture.Wasm));
+
+        Assert.Contains("Linux/Wasm", error.Message);
+    }
+}

godot/FfmpegMovieNative.cs

@@ -209,9 +209,10 @@ internal static class FfmpegMovieNative
             ? "age_movie_ffmpeg.dll"
             : OperatingSystem.IsMacOS() ? "libage_movie_ffmpeg.dylib" : "libage_movie_ffmpeg.so";
         string? configured = Environment.GetEnvironmentVariable("AGE_FFMPEG_NATIVE_DIR");
-        string rid = OperatingSystem.IsWindows() ? "win-x64"
-            : OperatingSystem.IsMacOS() ? (RuntimeInformation.ProcessArchitecture == Architecture.Arm64 ? "osx-arm64" : "osx-x64")
-            : "linux-x64";
+        string rid = RuntimeIdentifierFor(
+            OperatingSystem.IsWindows(),
+            OperatingSystem.IsMacOS(),
+            RuntimeInformation.ProcessArchitecture);
         string[] candidates =
         {
             configured == null ? "" : Path.Combine(configured, fileName),
@@ -225,6 +226,23 @@ internal static class FfmpegMovieNative
             $"{fileName} was not found; set AGE_FFMPEG_NATIVE_DIR or package runtimes/{rid}/native");
     }
 
+    internal static string RuntimeIdentifierFor(
+        bool isWindows,
+        bool isMacOS,
+        Architecture architecture)
+        => (isWindows, isMacOS, architecture) switch
+        {
+            (true, _, Architecture.X64) => "win-x64",
+            (true, _, Architecture.Arm64) => "win-arm64",
+            (false, true, Architecture.X64) => "osx-x64",
+            (false, true, Architecture.Arm64) => "osx-arm64",
+            (false, false, Architecture.X64) => "linux-x64",
+            (false, false, Architecture.Arm64) => "linux-arm64",
+            _ => throw new PlatformNotSupportedException(
+                $"The FFmpeg movie backend has no reserved RID for " +
+                $"{(isWindows ? "Windows" : isMacOS ? "macOS" : "Linux")}/{architecture}."),
+        };
+
     internal static string DecodeUtf8(byte[] buffer)
     {
         int length = Array.IndexOf(buffer, (byte)0);

godot/Himegari.csproj

@@ -3,8 +3,12 @@
     <TargetFramework>net8.0</TargetFramework>
     <EnableDynamicLoading>true</EnableDynamicLoading>
     <Nullable>enable</Nullable>
+    <AgeNativeRid Condition="'$(RuntimeIdentifier)' != ''">$(RuntimeIdentifier)</AgeNativeRid>
+    <AgeNativeRid Condition="'$(AgeNativeRid)' == '' and '$(GodotTargetPlatform)' == 'windows'">win-x64</AgeNativeRid>
+    <AgeNativeRid Condition="'$(AgeNativeRid)' == '' and '$(GodotTargetPlatform)' == 'linuxbsd'">linux-x64</AgeNativeRid>
+    <AgeNativeDirectory>..\build\native\$(AgeNativeRid)</AgeNativeDirectory>
   </PropertyGroup>
-  <PropertyGroup Condition="$([MSBuild]::IsOSPlatform('Windows'))">
+  <PropertyGroup Condition="'$(GodotTargetPlatform)' == 'windows'">
     <DefineConstants>$(DefineConstants);AGE_WINDOWS_GDI</DefineConstants>
   </PropertyGroup>
   <ItemGroup>
@@ -12,16 +16,28 @@
     <EmbeddedResource Include="..\build\opcodes.json"
                       LogicalName="Himegari.Runtime.opcodes.json" />
   </ItemGroup>
-  <ItemGroup Condition="$([MSBuild]::IsOSPlatform('Windows'))">
+  <ItemGroup Condition="'$(GodotTargetPlatform)' == 'windows'">
     <ProjectReference Include="..\engine\Age.Engine.Text.Windows\Age.Engine.Text.Windows.csproj" />
   </ItemGroup>
-  <ItemGroup Condition="Exists('..\build\native\win-x64\age_movie_ffmpeg.dll')">
-    <None Include="..\build\native\win-x64\*.dll"
+  <ItemGroup Condition="'$(AgeNativeRid)' == 'win-x64' and Exists('$(AgeNativeDirectory)\age_movie_ffmpeg.dll')">
+    <None Include="$(AgeNativeDirectory)\*.dll"
           Link="%(Filename)%(Extension)"
-          CopyToOutputDirectory="PreserveNewest" />
-    <None Include="..\build\native\win-x64\FFmpeg-LICENSE.txt"
+          CopyToOutputDirectory="PreserveNewest"
+          CopyToPublishDirectory="PreserveNewest" />
+    <None Include="$(AgeNativeDirectory)\FFmpeg-LICENSE.txt"
           Link="FFmpeg-LICENSE.txt"
-          CopyToOutputDirectory="PreserveNewest" />
+          CopyToOutputDirectory="PreserveNewest"
+          CopyToPublishDirectory="PreserveNewest" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(AgeNativeRid)' == 'linux-x64' and Exists('$(AgeNativeDirectory)\libage_movie_ffmpeg.so')">
+    <None Include="$(AgeNativeDirectory)\*.so*"
+          Link="%(Filename)%(Extension)"
+          CopyToOutputDirectory="PreserveNewest"
+          CopyToPublishDirectory="PreserveNewest" />
+    <None Include="$(AgeNativeDirectory)\FFmpeg-LICENSE.txt"
+          Link="FFmpeg-LICENSE.txt"
+          CopyToOutputDirectory="PreserveNewest"
+          CopyToPublishDirectory="PreserveNewest" />
   </ItemGroup>
   <Target Name="RequireGeneratedRuntimeMetadata" BeforeTargets="PrepareForBuild"
           Condition="!Exists('..\build\opcodes.json')">