UnrealEngine-4.24.1-release源码

% Embree: High Performance Ray Tracing Kernels 2.14.0 % Intel Corporation Embree Overview =============== Embree is a collection of high-performance ray tracing kernels, developed at Intel. The target user of Embree are graphics application engineers that want to improve the performance of their application by leveraging the optimized ray tracing kernels of Embree. The kernels are optimized for photo-realistic rendering on the latest Intel® processors with support for SSE, AVX, AVX2, and AVX512. Embree supports runtime code selection to choose the traversal and build algorithms that best matches the instruction set of your CPU. We recommend using Embree through its API to get the highest benefit from future improvements. Embree is released as Open Source under the [Apache 2.0 license](http://www.apache.org/licenses/LICENSE-2.0). 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 leverages SSE, AVX, AVX2, and AVX512 without any code change. ISPC also supports runtime code selection, thus ISPC will select the best code path for your application, while Embree selects the optimal code path for the ray tracing algorithms. 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). For standard CPUs, the single-ray traversal kernels in Embree provide the best performance for incoherent workloads and are very easy to integrate into existing rendering applications. For AVX512 enabled machines, a renderer written in ISPC using the default hybrid ray/packet traversal algorithms have shown to perform best, but requires writing the renderer in ISPC. In general for coherent workloads, ISPC outperforms the single ray mode on each platform. Embree also supports dynamic scenes by implementing high performance two-level spatial index structure construction algorithms. In addition to the ray tracing kernels, Embree provides some tutorials to demonstrate how to use the [Embree API]. The example photorealistic renderer that was originally included in the Embree kernel package is now available in a separate GIT repository (see [Embree Example Renderer]). Supported Platforms ------------------- Embree supports Windows (32 bit and 64 bit), Linux (64 bit) and Mac OS X (64 bit). The code compiles with the Intel Compiler, GCC, Clang and the Microsoft Compiler. Using the Intel Compiler improves performance by approximately 10%. Performance also varies across different operating systems, with Linux typically performing best as it supports transparently transitioning to 2MB pages. Embree is optimized for Intel CPUs supporting SSE, AVX, AVX2, and AVX-512 instructions, and requires at least a CPU with support for SSE2. Contributing to Embree ---------------------- To contribute code to the Embree repository you need to sign a Contributor License Agreement (CLA). Individuals need to fill out the [Individual Contributor License Agreement (ICLA)]. Corporations need to fill out the [Corporate Contributor License Agreement (CCLA)] and each employee that wants to contribute has to fill out an [Individual Contributor License Agreement (ICLA)]. Please follow the instructions of the CLA forms to send them. Embree Support and Contact -------------------------- If you encounter bugs please report them via [Embree's GitHub Issue Tracker](https://github.com/embree/embree/issues). For questions please write us at <embree_support@intel.com>. To receive notifications of updates and new features of Embree please subscribe to the [Embree mailing list](https://groups.google.com/d/forum/embree/). Acknowledgements ---------------- This software is based in part on the work of the Independent JPEG Group. Installation of Embree ====================== Windows Installer ----------------- You can install the 64 bit version of the Embree library using the Windows installer application [embree-2.14.0-x64.exe](https://github.com/embree/embree/releases/download/v2.14.0/embree-2.14.0.x64.exe). This will install the 64 bit Embree version by default in `Program Files\Intel\Embree v2.14.0 x64`. To install the 32 bit Embree library use the [embree-2.14.0-win32.exe](https://github.com/embree/embree/releases/download/v2.14.0/embree-2.14.0.win32.exe) installer. This will install the 32 bit Embree version by default in `Program Files\Intel\Embree v2.14.0 win32` on 32 bit systems and `Program Files (x86)\Intel\Embree v2.14.0 win32` on 64 bit systems. You have to set the path to the `lib` folder manually to your `PATH` environment variable for applications to find Embree. To compile applications with Embree you also have to set the `Include Directories` path in Visual Studio to the `include` folder of the Embree installation. To uninstall Embree again open `Programs and Features` by clicking the `Start button`, clicking `Control Panel`, clicking `Programs`, and then clicking `Programs and Features`. Select `Embree 2.14.0` and uninstall it. Windows ZIP File ----------------- Embree is also delivered as a ZIP file for 64 bit [embree-2.14.0.x64.windows.zip](https://github.com/embree/embree/releases/download/v2.14.0/embree-2.14.0.x64.windows.zip) and 32 bit [embree-2.14.0.win32.windows.zip](https://github.com/embree/embree/releases/download/v2.14.0/embree-2.14.0.win32.windows.zip). After unpacking this ZIP file you should set the path to the `lib` folder manually to your `PATH` environment variable for applications to find Embree. To compile applications with Embree you also have to set the `Include Directories` path in Visual Studio to the `include` folder of the Embree installation. If you plan to ship Embree with your application, best use the Embree version from this ZIP file. Linux RPMs ---------- Uncompress the 'tar.gz' file [embree-2.14.0.x86_64.rpm.tar.gz](https://github.com/embree/embree/releases/download/v2.14.0/embree-2.14.0.x86_64.rpm.tar.gz) to obtain the individual RPM files: tar xzf embree-2.14.0.x86_64.rpm.tar.gz To install the Embree using the RPM packages on your Linux system type the following: sudo rpm --install embree-lib-2.14.0-1.x86_64.rpm sudo rpm --install embree-devel-2.14.0-1.x86_64.rpm sudo rpm --install embree-examples-2.14.0-1.x86_64.rpm You also have to install the Intel® Threading Building Blocks (TBB) using `yum`: sudo yum install tbb.x86_64 tbb-devel.x86_64 or via `apt-get`: sudo apt-get install libtbb-dev Alternatively you can download the latest TBB version from [https://www.threadingbuildingblocks.org/download](https://www.threadingbuildingblocks.org/download) and set the `LD_LIBRARY_PATH` environment variable to point to the TBB library. Note that the Embree RPMs are linked against the TBB version coming with CentOS. This older TBB version is missing some features required to get optimal build performance and does not support building of scenes lazily during rendering. To get a full featured Embree please install using the tar.gz files, which always ship with the latest TBB version. Under Linux Embree is installed by default in the `/usr/lib` and `/usr/include` directories. This way applications will find Embree automatically. The Embree tutorials are installed into the `/usr/bin/embree2` folder. Specify the full path to the tutorials to start them. To uninstall Embree again just execute the following: sudo rpm --erase embree-lib-2.14.0-1.x86_64 sudo rpm --erase embree-devel-2.14.0-1.x86_64 sudo rpm --erase embree-examples-2.14.0-1.x86_64 Linux tar.gz files ------------------ The Linux version of Embree is also delivered as a tar.gz file [embree-2.14.0.x86_64.linux.tar.gz](https://github.com/embree/embree/releases/download/v2.14.0/embree-2.14.0.x86_64.linux.tar.gz). Unpack this file using `tar` and sour