This repository contains low-level bindings for Embree used in Evergine. This binding is generated from the Embree release: https://github.com/RenderKit/embree/releases/tag/v4.4.1
Embree is Intel's high-performance ray tracing kernel library. It builds acceleration structures (BVHs) over triangles, quads, curves, subdivision surfaces, points, grids and user-defined primitives, and traverses them with hand-tuned SIMD kernels for SSE, AVX2, AVX-512 and NEON. It is the traversal backend behind most CPU renderers.
These bindings expose the full C API (rtcore.h) to .NET so Evergine can use Embree for
CPU ray tracing, lightmap baking, ambient occlusion and general geometric queries.
- Devices, scenes and geometry — the complete
rtcNewDevice/rtcNewScene/rtcNewGeometrylifecycle, with type-safe handle structs (Device,Scene,Geometry,Buffer,BVH,Traversable). - Ray queries —
Intersect1/4/8/16andOccluded1/4/8/16, plus theTraversableandForwardvariants used from instancing callbacks. - All geometry types — triangles, quads, grids, subdivision surfaces, every curve basis, points, instances, instance arrays and user geometry.
- Callbacks — filter, intersect, occluded, bounds, displacement, error, memory monitor
and progress monitor, exposed both as
delegate* unmanaged[Cdecl]parameters and as[UnmanagedFunctionPointer]delegates. - Point queries — closest-point search with the full context/transform stack.
- BVH builder API —
rtcBuildBVHwith user-supplied node/leaf allocation callbacks. - Hand-written helpers for the header's
RTC_FORCEINLINEfunctions, which have no exported symbol:InitIntersectArguments,InitRayQueryContext,DefaultBuildArguments, the quaternion decomposition setters,Interpolate0/1/2and the SoARayN_*/HitN_*packet accessors.
- Windows x64, ARM64
- Linux x64, ARM64
- MacOS ARM64
Ray structures must be aligned. RTCRay and RTCRayHit require 16-byte alignment,
RTCRay8 requires 32 and RTCRay16 requires 64 — Embree's kernels use aligned SIMD loads.
A C# local or array element carries no such guarantee, so taking the address of a stack local
crashes on some code paths and appears to work on others. Allocate ray structures with
NativeMemory.AlignedAlloc:
RayHit* rayhit = (RayHit*)NativeMemory.AlignedAlloc((nuint)sizeof(RayHit), 64);The C alignment of every generated struct is recorded in a comment above its declaration in
Evergine.Bindings.Embree/Generated/Structs.cs. See HelloEmbree/Program.cs for a complete
example.
C bool maps to byte. Functions such as PointQuery return byte (0 or 1) rather
than bool, because the default .NET marshalling of bool is the 4-byte Win32 BOOL, not
the 1-byte C _Bool.
EmbreeGen/ Generator console app (CppAst); vendored headers in Headers/
Evergine.Bindings.Embree/ The NuGet package: Generated/ bindings + runtimes/ natives
HelloEmbree/ Sample: CPU ray tracer drawn with the Evergine low-level API
HelloEmbree traces a small scene on the CPU with
rtcIntersect1/rtcOccluded1, uploads the result to a texture every frame and blits it to a
DX11 swapchain hosted in a Windows Forms window. It also has a --bench mode that reports the
cost of each stage. Being a WinForms + DX11 app it only runs on Windows, even though the binding
itself targets every supported RID.
Regenerate the bindings after changing a header with:
dotnet run --project EmbreeGen/EmbreeGen.csprojThe native binaries are produced by the manually dispatched
Build Embree Libraries workflow, which builds Embree
with EMBREE_TASKING_SYSTEM=INTERNAL so each library is self-contained (no TBB dependency).
Its artifacts include the generated rtcore_config.h, which must be vendored into
EmbreeGen/Headers/embree4/ alongside the binaries: it determines the layout of several
public structs. HelloEmbree asserts the resulting struct sizes at startup so a mismatch
fails loudly instead of corrupting memory.
- WebGPU.NET — Bindings for WebGPU
- Meshoptimizer.NET — Bindings for meshoptimizer
- RenderDoc.NET — Bindings for RenderDoc
- XAtlas.NET — Bindings for xatlas