One API to Rule Them All? Meet orhi, a Cross-Platform Graphics Interface

Navigating the modern graphics API landscape can feel like a full-time job. You've got Vulkan for Linux and Android, DirectX 12 for Windows, and Metal for Apple's ecosystem. Each one is powerful, but writing and maintaining separate rendering backends is a massive time sink. What if you could write your graphics code once and have it run efficiently across all of them?

Enter orhi, a developer's experiment to build a clean, unified abstraction layer over Vulkan, D3D12, and Metal. It’s not another heavyweight game engine, but a focused library that gives you direct access to modern GPU features without the platform lock-in.

What It Does

In short, orhi (Object-oriented Rendering Hardware Interface) provides a single C++ API that translates your calls down to the native graphics API of your target platform. You write your pipeline setups, descriptor bindings, and command submissions using orhi's structures, and it handles the translation to Vulkan structures, D3D12 commands, or Metal objects under the hood.

It targets the explicit, low-overhead design philosophy of these modern APIs. You're still managing memory, synchronization, and pipeline states—this isn't a return to OpenGL's global state machine. But you do it through one consistent interface.

Why It's Cool

The clever part is in its design. Instead of forcing a lowest-common-denominator approach, orhi seems to embrace the strengths of each backend while providing a unified workflow. It abstracts the verbose boilerplate (like the miles of struct setup in Vulkan) but keeps you close to the metal where it counts.

For developers working on tools, research renderers, or medium-sized cross-platform projects, this is a huge win. You can prototype a new rendering technique on your Windows machine with D3D12, then test it on a Mac with Metal and a Linux machine with Vulkan, all without rewriting your core graphics logic. It significantly reduces the "platform tax" for supporting all major desktop and mobile ecosystems.

It's also a fantastic codebase to study if you're interested in how these different APIs map to each other conceptually. The source is a practical guide to the similarities and differences between the big three.

How to Try It

Ready to take it for a spin? The project is hosted on GitHub.

1. Clone the repo:

   git clone https://github.com/adriengivry/orhi
   cd orhi
   

2. Check the requirements: You'll need CMake and the platform-specific SDKs (Vulkan SDK, Xcode with Metal, or Windows 10/11 SDK for D3D12).

3. Build it: The repository uses CMake. Generate the project files for your preferred IDE or build system. The examples are a great place to start seeing the API in action.

Head over to the orhi GitHub repository for detailed build instructions, a look at the growing examples, and the full source code to explore.

Final Thoughts

orhi is a promising and pragmatic tool for a specific problem. It won't replace your need to understand concepts like descriptor sets or command queues, but it will free you from rewriting them three times. If you're building a new graphics-heavy application that needs to be everywhere, or even if you're just tired of maintaining multiple backends, this library is absolutely worth a weekend of experimentation. It represents the kind of infrastructure work that lets developers focus on what they actually want to build: cool graphics.

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