ObjViewer

A lightweight, cross-platform .OBJ 3D model viewer built in C# with Silk.NET and OpenGL. Load any Wavefront .obj file, rotate, pan, and zoom around it with simple mouse controls — no external 3D engine, no Unity, just raw OpenGL through .NET.

Features

• 📦 Custom OBJ parser — reads vertices, normals, and faces directly, with fan-triangulation support for quads and n-gons
• 🖱️ Interactive camera — orbit, pan, and zoom with the mouse
• 💡 Phong-style lighting — a simple, real-time specular/diffuse shader for clear shading on any mesh
• 🗂️ Open files at runtime — press O to bring up a native file picker (Windows, macOS, and Linux) and load a new model without restarting
• 📐 Auto-centering & normalization — models are automatically centered and scaled to fit the view, regardless of their original size
• 🧊 Built-in fallback cube — if no model.obj is found, a sample cube is shown so the viewer always has something to render

Controls

Input	Action
Left click + drag	Rotate the model
Right click + drag	Pan the camera
Scroll wheel	Zoom in / out
O	Open an .obj file
R	Reset camera
Esc	Quit

Requirements

• .NET 10 SDK
• A GPU/driver with OpenGL 3.3+ support

Getting Started

git clone https://github.com/BenyVK/cs-object.git
cd FolderNames Project
dotnet run

By default, the viewer looks for a model.obj (and optional model.mtl) file in the working directory. If none is found, it falls back to a sample cube. You can also press O at any time to open a different .obj file through your OS's native file dialog.

How It Works

• Windowing & input are handled by Silk.NET.Windowing and Silk.NET.Input.
• Rendering uses raw Silk.NET.OpenGL calls — a single VAO/VBO holds interleaved position + normal data, drawn with a minimal GLSL vertex/fragment shader pair.
• OBJ parsing is hand-written (no external mesh-loading library): it reads v, vn, and f lines, triangulates polygonal faces, and computes a flat fallback normal for faces missing normal data.
• File dialogs use a tiered approach — it tries NativeFileDialogSharp if present, falls back to a native Win32 GetOpenFileName call on Windows, osascript/zenity on macOS/Linux, and finally a console prompt if nothing else is available.

Dependencies

Package	Purpose
Silk.NET	Core windowing/input/OpenGL bindings
Silk.NET.Windowing	Cross-platform window creation
Silk.NET.OpenGL	OpenGL bindings
Silk.NET.Input	Mouse/keyboard input

License

This project is open source. Feel free to use, modify, and share it.

Author

Made by BenyVK