bgfx — Cross-Platform Graphics API Agnostic Rendering Library

Introduction

bgfx is a cross-platform rendering library that abstracts over modern and legacy graphics APIs. It allows developers to write rendering code once and target Direct3D 9/11/12, Metal, OpenGL, Vulkan, and WebGPU without changing application logic.

What bgfx Does

• Provides a single C99/C++ API that compiles to 9 different graphics backends
• Handles shader cross-compilation from a unified BGFX shader language
• Manages GPU resource lifetimes, state sorting, and draw call batching
• Ships debug tools including real-time graphics debugger and profiler
• Supports compute shaders, instancing, occlusion queries, and multi-threaded submission

Architecture Overview

bgfx uses a submit-and-forget rendering model. The application thread records draw calls into a frame buffer which is swapped with the render thread each frame. The render thread sorts by state to minimize GPU pipeline changes, then dispatches to the platform-specific backend. This two-thread design keeps the API lock-free and predictable.

Self-Hosting & Configuration

• Build with GENie (bundled) or CMake; supports MSVC, GCC, Clang, and Emscripten
• Include bx (base library) and bimg (image processing) as sibling directories
• Select backend at runtime or compile-time via renderer type enum
• Shader compilation uses the bundled shaderc tool targeting GLSL, HLSL, MSL, or SPIR-V
• Integrates with any windowing library (SDL, GLFW, native) via platform data struct

Key Features

• Minimal API surface: fewer than 100 functions cover the entire rendering pipeline
• Frame-based resource management eliminates manual fence tracking
• Texture and buffer updates are safe from any thread
• Built-in debug text overlay and geometry rendering for rapid prototyping
• Used in production by commercial game engines and tools

Comparison with Similar Tools

• sokol_gfx — even smaller single-header approach; bgfx offers more backends and tooling
• LLGL — C++ focused multi-backend; bgfx has broader platform coverage and C API
• Diligent Engine — higher-level with scene graph; bgfx stays closer to GPU metal
• wgpu — Rust-first WebGPU implementation; bgfx is C/C++ and predates WebGPU
• Raw Vulkan/D3D12 — maximum control but requires per-platform code; bgfx abstracts this

FAQ

Q: What games or engines use bgfx? A: Notably used by the Torque3D engine, the MAME arcade emulator, and several commercial studios for cross-platform shipping.

Q: Can I mix bgfx with an existing engine? A: Yes. bgfx does not own the window or main loop; it only needs a native window handle to initialize.

Q: Does bgfx support ray tracing? A: Not currently. It focuses on rasterization pipelines across the widest range of hardware.

Q: How does shader authoring work? A: Write shaders in a GLSL-like dialect with bgfx macros, then compile with shaderc to target each backend.

Sources

• https://github.com/bkaradzic/bgfx
• https://bkaradzic.github.io/bgfx/overview.html