Embree¶
Embree is a collection of high-performance ray tracing kernels. The Embree target users are graphics application engineers who want to improve the performance of their photo-realistic rendering application by leveraging Embree’s performance-optimized ray tracing kernels. Embree supports runtime code selection to choose the traversal and build algorithms that best matches the instruction set of your CPU.
Embree supports applications written with the Intel® SPMD Program Compiler (ISPC, https://ispc.github.io/) by also providing an ISPC interface to the core ray tracing algorithms. This makes it possible to write a renderer in ISPC that automatically vectorizes and leverages SSE, AVX, AVX2, and AVX-512 instructions. ISPC also supports runtime code selection, thus ISPC will select the best code path for your application.
Embree contains algorithms optimized for incoherent workloads (e.g. Monte Carlo ray tracing algorithms) and coherent workloads (e.g. primary visibility and hard shadow rays).
The single-ray traversal kernels of Embree provide high performance for incoherent workloads and are very easy to integrate into existing rendering applications. Using the stream kernels, even higher performance for incoherent rays is possible, but integration might require significant code changes to the application to use the stream paradigm. In general for coherent workloads, the stream mode with coherent flag set gives the best performance.
Embree also supports dynamic scenes by implementing high-performance two-level spatial index structure construction algorithms.