Combobulate 0.2.0

Combobulate

A XAML controls library for UWP and WinUI 3 / Windows App SDK that renders 3D .obj files made of quads using the Windows Composition visual layer — no D3D, no SwapChainPanel, no shaders.

combobulate (humorous) — to compose (oneself); to compose, organize, design, or arrange; to reverse the effect of discombobulation. (Wiktionary)

Each quad becomes a SpriteVisual placed in 3D by a perspective TransformMatrix, with back-face culling and a topology-aware painter's algorithm to get the draw order right without a depth buffer.

Packages

NuGet: Combobulate

Targets

• UWP — uap10.0.19041
• WinUI 3 / Windows App SDK — net10.0-windows10.0.19041.0

Repo Layout

src/
  Combobulate/                 UWP class library (canonical source)
  Combobulate.WinAppSdk/       WinUI 3 head — links sources from Combobulate
  Combobulate.Sample.Uwp/      UWP sample app
  Combobulate.Sample.WinUI3/   WinUI 3 sample app
samples/
  book.obj                     Example quad-based model

Getting Started

1. Add the Combobulate NuGet package to your UWP or WinUI 3 app.

2. Place a Combobulate control in your XAML:

   <Page xmlns:c="using:Combobulate">
       <c:Combobulate x:Name="Viewer"
                      ModelScale="200"
                      RotationX="-30"
                      RotationY="40"
                      RotationZ="0" />
   </Page>
   

3. Parse an .obj file and assign the resulting model:

   using Combobulate.Parsing;
   
   var text = await FileIO.ReadTextAsync(
       await StorageFile.GetFileFromPathAsync(@"C:\path\to\book.obj"));
   var result = ObjParser.Parse(text);
   Viewer.Model = result.Model;        // partial model on parse error
   foreach (var err in result.Errors)  // optional: inspect parse diagnostics
       System.Diagnostics.Debug.WriteLine(err);
   

That's it — the control rebuilds its visual tree whenever Model, ModelScale, or any rotation property changes.

Supported .obj subset

• v x y z — vertex positions
• f a b c d — quad faces (4 indices, 1-based, positive or negative)
• Vertex normals/UVs in f entries (a/b/c) are accepted but ignored

Faces must be quads (triangles and n-gons are reported as parse errors). Wind each face so that (V1 - V0) × (V3 - V0) points outward — that's the direction the renderer treats as front-facing for back-face culling.

See samples/book.obj for a worked example.

Control properties

Releasing

Push a tag of the form vX.Y.Z to trigger the GitHub Actions workflow that builds both targets, packs Combobulate.nuspec, publishes to NuGet.org, and creates a GitHub Release.