Better support for OrthoStudio XP packages

src/OrthoStreamXP/Scenery/FileSystem/SceneryOverlay.cs

@@ -50,8 +50,9 @@ public SceneryOverlay(SceneryRoots roots, TextureScheduler? textures, bool lazyT
 
     /// <summary>
     /// What X-Plane gets for a path. A tile's terrain definition is made in memory. With streaming, a photo texture
-    /// is streamed level by level unless it is already complete in the cache or the package has its own copy (both
-    /// are served as they are); everything else, and every texture without streaming, is a backing file from
+    /// is streamed level by level unless it is already complete in the cache or the lazy store has a copy (both
+    /// are served as they are; the package's own photo copies are ignored); everything else, and every texture
+    /// without streaming, is a backing file from
     /// <see cref="Resolve(VirtualPath)"/>.
     /// </summary>
     public OverlayEntry Open(VirtualPath path)
@@ -188,25 +189,31 @@ private void ReportTextureRequest(VirtualPath path, RequestOutcome outcome, Time
 
     /// <summary>
     /// Merged listing of a directory: source entries, replaced by same-named cache entries. The textures
-    /// directory merges the source's textures\ and _textures\; _textures itself is not shown.
+    /// directory merges the source's textures\ and _textures\, without the package's own photo textures;
+    /// _textures itself is not shown.
     /// </summary>
     public IReadOnlyList<FileSystemInfo> List(VirtualPath directory)
     {
         if (_lazyTerrainListing && directory.Is("terrain"))
             return []; // DSF references terrain definitions by path; X-Plane opens them directly.
         var entries = new Dictionary<string, FileSystemInfo>(StringComparer.OrdinalIgnoreCase);
         // Lowest priority first, so later folders replace same-named entries.
-        foreach (string path in _roots.SourceFolders(directory).Reverse().Append(_roots.CachePath(directory)))
+        foreach (string path in _roots.SourceFolders(directory).Reverse())
+            AddEntries(entries, directory, path, fromSource: true);
+        AddEntries(entries, directory, _roots.CachePath(directory), fromSource: false);
+        return [.. entries.Values.OrderBy(e => e.Name, StringComparer.OrdinalIgnoreCase)];
+    }
+
+    private static void AddEntries(Dictionary<string, FileSystemInfo> entries, VirtualPath directory, string path, bool fromSource)
+    {
+        var folder = new DirectoryInfo(path);
+        if (!folder.Exists) return;
+        foreach (FileSystemInfo child in folder.EnumerateFileSystemInfos())
         {
-            var folder = new DirectoryInfo(path);
-            if (!folder.Exists) continue;
-            foreach (FileSystemInfo child in folder.EnumerateFileSystemInfos())
-            {
-                if (directory.IsRoot && HiddenRootEntries.Contains(child.Name, StringComparer.OrdinalIgnoreCase)) continue;
-                entries[child.Name] = child;
-            }
+            if (directory.IsRoot && HiddenRootEntries.Contains(child.Name, StringComparer.OrdinalIgnoreCase)) continue;
+            if (fromSource && SceneryRoots.IsPackagePhoto(directory.Child(child.Name))) continue;
+            entries[child.Name] = child;
         }
-        return [.. entries.Values.OrderBy(e => e.Name, StringComparer.OrdinalIgnoreCase)];
     }
 
     public (int Terrain, int Textures) RequestCounts()

src/OrthoStreamXP/Scenery/FileSystem/SceneryPaths.cs

@@ -100,9 +100,20 @@ public IEnumerable<string> SourceFolders(VirtualPath path) =>
             ? SourceTextureFolders.Select(folder => Path.Join(Source, folder, string.Join('\\', path.Parts[1..])))
             : [Path.Join(Source, string.Join('\\', path.Parts))];
 
-    /// <summary>The existing source file or directory behind a virtual path, looking in textures\ then _textures\.</summary>
+    /// <summary>
+    /// The existing source file or directory behind a virtual path, looking in textures\ then _textures\.
+    /// The package's own photo textures are never found (see <see cref="IsPackagePhoto"/>).
+    /// </summary>
     public string? FindInSource(VirtualPath path) =>
-        SourceFolders(path).FirstOrDefault(candidate => File.Exists(candidate) || Directory.Exists(candidate));
+        IsPackagePhoto(path) ? null
+        : SourceFolders(path).FirstOrDefault(candidate => File.Exists(candidate) || Directory.Exists(candidate));
+
+    /// <summary>
+    /// Whether a path names a photo texture (textures\21904_35824_BI16.dds). The package's own copies of these
+    /// (made by Ortho4XP or similar) are hidden and never served: photos are always streamed or downloaded,
+    /// while the package's masks (PNGs) and other files pass through as they are.
+    /// </summary>
+    public static bool IsPackagePhoto(VirtualPath path) => PhotoTexture(path) is not null;
 
     /// <summary>
     /// Where a virtual path is kept in the cache: a photo texture under its cache name (textures\87520_143440_BI18.dds
@@ -176,9 +187,10 @@ public bool DdsMatchesSize(VirtualPath path, string file)
     }
 
     /// <summary>
-    /// A file under textures/ that the package itself provides: from the source's textures\ or _textures\,
-    /// or from the lazy texture store (which holds a textures folder's contents). For a DDS this is the
-    /// local copy that can be served while, or instead of, a download.
+    /// A file under textures/ that the package itself provides: from the source's textures\ or _textures\
+    /// (never a photo texture, see <see cref="IsPackagePhoto"/>), or from the lazy texture store (which holds a
+    /// textures folder's contents). For a store DDS this is the local copy that can be served while, or instead
+    /// of, a download.
     /// </summary>
     public string? FindTexture(VirtualPath path)
     {

tests/OrthoStreamXP.Tests/SceneryOverlayTests.cs

@@ -65,6 +65,34 @@ public void Textures_merges_the_cache_textures_and_underscore_textures_and_hides
         Assert.Equal(["Earth nav data", "terrain", "textures"], overlay.List(VirtualPath.Parse(@"\")).Select(e => e.Name));
     }
 
+    [Theory]
+    [InlineData("textures")]
+    [InlineData("_textures")]
+    public void The_packages_own_photo_textures_are_hidden_and_never_served_but_its_pngs_are(string folder)
+    {
+        _tree.WriteText($"source/{folder}/21904_35824_BI16.dds", "Ortho4XP photo");
+        string mask = _tree.WritePngHeader($"source/{folder}/21904_35824_ZL16.png", 1024);
+        string transition = _tree.WritePngHeader($"source/{folder}/water_transition.png", 64);
+        string other = _tree.WriteText($"source/{folder}/custom.dds", "not a photo texture");
+        SceneryOverlay overlay = Overlay();
+
+        Assert.Equal(["21904_35824_ZL16.png", "custom.dds", "water_transition.png"],
+            overlay.List(VirtualPath.Of("textures")).Select(e => e.Name));
+        var notFound = Assert.Throws<NtStatusException>(() => overlay.Resolve(@"\textures\21904_35824_BI16.dds"));
+        Assert.Equal(NtStatus.ObjectNameNotFound, notFound.Status);
+        Assert.Equal(mask, overlay.Resolve(@"\textures\21904_35824_ZL16.png"));
+        Assert.Equal(transition, overlay.Resolve(@"\textures\water_transition.png"));
+        Assert.Equal(other, overlay.Resolve(@"\textures\custom.dds"));
+    }
+
+    [Fact]
+    public void A_downloaded_photo_texture_is_served_over_the_packages_own_copy()
+    {
+        _tree.WriteText("source/textures/87520_143440_BI18.dds", "Ortho4XP photo");
+        string cached = _tree.WriteText("cache/textures/10940_17930_PX15.dds", "DDS "); // Overlay() is at level -3
+        Assert.Equal(cached, Overlay().Resolve(@"\textures\87520_143440_BI18.dds"));
+    }
+
     [Fact]
     public void A_lazy_store_dds_is_served_in_place_without_copying()
     {