VRI

One explicit rendering API. Every backend, every platform.

Write your renderer once — VRI runs it on Vulkan, Direct3D 12, Metal, WebGPU, and OpenGL, on desktop, mobile/embedded, and the web. A C ABI core with a header-only C++23 wrapper, honest capability queries, one diagnostics sink, and shaders authored in Slang.

▶︎ Run the examples in your browser GitHub ↗

write once

An explicit, modern surface (command buffers, descriptor sets, explicit synchronization) — à la Vulkan/D3D12 — that maps onto each platform's native graphics API.

// C ABI core, or a std::expected-based RAII layer in C++23:
auto device    = vri::Device::Create({ .graphicsAPI = VriGraphicsAPI_Auto });
auto swapchain = device->CreateSwapchain({ .window = window });
auto pipeline  = device->CreateGraphicsPipeline({ .shaders = { vs, fs }, ... });

cmd.BeginRendering({ .colors = { backbuffer } });
cmd.SetPipeline(*pipeline);
cmd.Draw({ .vertexNum = 3 });   // same image on every backend
cmd.EndRendering();

run everywhere

The desktop application requests Auto and VRI picks the best backend. On the web VRI runs through WebGPU and WebGL 2, both via Emscripten. A software (CPU) fallback renders with no GPU at all.

Backend	Platforms
Vulkan	Windows, Linux (and macOS via MoltenVK)
Direct3D 12	Windows
Metal	macOS (Apple Silicon)
WebGPU	Windows, Linux, macOS, Web
OpenGL	Windows, Linux (and macOS, capped at 4.1)
WebGL 2	Web
OpenGL ES	Linux / embedded (e.g. Raspberry Pi)
Software (CPU)	Windows, Linux, macOS — anywhere with a software Vulkan ICD

feature support

Every optional feature is queryable. If a backend can't do something, it tells you — it never silently no-ops.

✅ native · 🟡 emulated / simulated · ⬜ planned · ❌ unsupported by the API

Feature	Vulkan	D3D12	Metal	WebGPU	OpenGL	WebGL 2	GL ES
Core rendering & swapchain	✅	✅	✅	✅	✅	✅	✅
Depth / stencil, blending, MRT	✅	✅	✅	✅	✅	✅	✅
MSAA + resolve	✅	✅	✅	✅	✅	✅	✅
Mipmaps, instancing, cubemaps	✅	✅	✅	✅	✅	✅	✅
Compute shaders	✅	✅	✅	✅	✅	❌	❌
Push constants	✅	✅	✅	🟡	🟡	🟡	🟡
Bindless / descriptor indexing	✅	✅	🟡	🟡	🟡	🟡	🟡
Geometry shaders	✅	✅	❌	❌	✅	❌	❌
Tessellation	✅	✅	❌	❌	✅	❌	❌
Mesh shaders	✅	✅	✅	❌	❌	❌	❌
Ray tracing	✅	✅	✅	🟡	🟡	❌	❌
Opacity micromaps	✅	✅	❌	❌	❌	❌	❌
Variable rate shading	✅	✅	❌	❌	❌	❌	❌
Conservative rasterization	✅	✅	❌	❌	❌	❌	❌
Fragment-shader barycentrics	✅	✅	⬜	❌	❌	❌	❌
Custom sampler border color	✅	✅	❌	❌	❌	❌	❌
Subgroup / wave operations	✅	✅	⬜	❌	❌	❌	❌
Multiview (single-pass stereo)	✅	✅	✅	❌	✅	❌	✅
External memory / interop (CUDA)	✅	✅	❌	❌	❌	❌	❌
GPU timestamp queries	✅	✅	✅	🟡	🟡	❌	❌
Occlusion queries	✅	✅	✅	❌	✅	❌	❌
Pipeline-statistics queries	✅	✅	❌	❌	✅	❌	❌
Calibrated GPU+CPU timestamps	✅	✅	✅	❌	❌	❌	❌
Pipeline cache	✅	✅	✅	❌	✅	❌	❌
Indirect draw count (GPU-driven)	✅	✅	❌	❌	✅	❌	❌
Video memory budget	✅	✅	✅	❌	❌	❌	❌
Clear storage buffer / texture	✅	✅	❌	❌	✅	❌	❌
Built-in Dear ImGui renderer	✅	✅	✅	✅	✅	✅	✅

Per-backend implementation notes — fallbacks, caveats, and the native extension each feature uses — are in DETAIL.md.