OSPRay

A Ray Tracing Based Rendering Engine for High-Fidelity Visualization

Interactive CPU Rendering

OSPRay features interactive CPU rendering capabilities geared towards Scientific Visualization applications. Advanced shading effects such as Ambient Occlusion, shadows, and transparency can be rendered interactively, enabling new insights into data exploration.

Global Illumination

OSPRay includes a path tracer capable of interactively rendering photorealistic global illumination.

Volume Rendering

OSPRay supports high-fidelity interactive direct volume rendering with a number of state of the art features.

MPI Distributed

Run on large scale distributed-memory systems with a high-performance MPI backend. Shown is a 450GB direct numerical simulation dataset running interactively at TACC’s Maverick cluster.

Display Walls

OSPRay parallel rendering on TACC’s “Stallion” display wall.

ParaView

OSPRay is directly integrated into ParaView 5.x. Implementations for VisIt, VMD, and other popular tools have also been developed.

Open Source

OSPRay is Open Sourced under the Apache 2.0 license.

OSPRay Overview

OSPRay is an open source, scalable, and portable ray tracing engine for high-performance, high-fidelity visualization on Intel® Architecture CPUs. OSPRay is released under the permissive Apache 2.0 license.

The purpose of OSPRay is to provide an open, powerful, and easy-to-use rendering library that allows one to easily build applications that use ray tracing based rendering for interactive applications (including both surface- and volume-based visualizations). OSPRay is completely CPU-based, and runs on anything from laptops, to workstations, to compute nodes in HPC systems.

OSPRay internally builds on top of Embree and ISPC (Intel® SPMD Program Compiler), and fully utilizes modern instruction sets like Intel® SSE4, AVX, AVX2, and AVX-512 to achieve high rendering performance, thus a CPU with support for at least SSE4.1 is required to run OSPRay.

OSPRay Support and Contact

OSPRay is under active development, and though we do our best to guarantee stable release versions a certain number of bugs, as-yet-missing features, inconsistencies, or any other issues are still possible. Should you find any such issues please report them immediately via OSPRay’s GitHub Issue Tracker (or, if you should happen to have a fix for it,you can also send us a pull request); for missing features please contact us via email at ospray@googlegroups.com.

For recent news, updates, and announcements, please see our complete news/updates page.

Join our mailing list to receive release announcements and major news regarding OSPRay.

Version History

Changes in v1.2.1:

Various bugfixes related to MPI distributed rendering, ISPC issues on Windows, and other build related issues.

Changes in v1.2.0:

Added support for volumes with voxelType short (16-bit signed integers). Applications need to recompile, because OSPDataType has been re-enumerated
Removed SciVis renderer parameter aoWeight, the intensity (and now color as well) of AO is controlled via “ambient” lights. If aoSamples is zero (the default) then ambient lights cause ambient illumination (without occlusion)
New SciVis renderer parameter aoTransparencyEnabled, controlling whether object transparency is respected when computing ambient occlusion (disabled by default, as it is considerable slower)
Implement normal mapping for SciVis renderer
Support of emissive (and illuminating) geometries in the path tracer via new material “Luminous”
Lights can optionally made invisible by using the new parameter isVisible (only relevant for path tracer)
OSPRay Devices are now extendable through modules and the SDK.
- Devices can be created and set current, creating an alternative method for initializing the API
- New API functions for committing parameters on Devices
Removed support for the first generation Intel® Xeon Phi™ coprocessor (codename Knights Corner)
Other minor improvements, updates, and bugfixes:
- Updated Embree required version to v2.13.0 for added features and performance
- New API function ospDeviceSetErrorMsgFunc() to specify a callback for handling message outputs from OSPRay
- Add ability to remove user set parameter values with new ospRemoveParam() API function
- The MPI device is now provided via a module, removing the need for having separately compiled versions of OSPRay with and without MPI
- OSPRay build dependencies now only get installed if OSPRAY_INSTALL_DEPENDENCIES CMake variable is enabled

Changes in v1.1.2:

Various bugfixes related to normalization, epsilons and debug messages

Changes in v1.1.1:

Fixed support of first generation Intel Xeon Phi coprocessor (codename Knights Corner) and the COI device
Fix normalization bug that caused rendering artifacts

Changes in v1.1.0:

New “scivis” renderer features
- Single sided lighting (enabled by default)
- Many new volume rendering specific features
  - Adaptive sampling to help improve the correctness of rendering high frequency volume data
  - Pre-integration of transfer function for higher fidelity images
  - Ambient occlusion
  - Volumes can cast shadows
  - Smooth shading in volumes
  - Single shading point option for accelerated shading
Added preliminary support for adaptive accumulation in the MPI device
Camera specific features
- Initial support for stereo rendering with the perspective camera
- Option architectural in perspective camera, rectifying vertical edges to appear parallel
- Rendering a subsection of the full view with imageStart/imageEnd supported by all cameras
This will be our last release supporting the first generation Intel Xeon Phi coprocessor (codename Knights Corner)
- Future major and minor releases will be upgraded to the latest version of Embree, which no longer supports Knights Corner
- Depending on user feedback, patch releases are still made to fix bugs
Enhanced output statistics in ospBenchmark application
Many fixes to the OSPRay SDK
- Improved CMake detection of compile-time enabled features
- Now distribute OSPRay configuration and ISPC CMake macros
- Improved SDK support on Windows
OSPRay library can now be compiled with -Wall and -Wextra enabled
- Tested with GCC v5.3.1 and Clang v3.8
- Sample applications and modules have not been fixed yet, thus applications which build OSPRay as a CMake subproject should disable them with -DOSPRAY_ENABLE_APPS=OFF and -DOSPRAY_ENABLE_MODULES=OFF
Minor bug fixes, improvements, and cleanups
- Regard shading normal when bump mapping
- Fix internal CMake naming inconsistencies in macros
- Fix missing API calls in C++ wrapper classes
- Fix crashes on MIC
- Fix thread count initialization bug with TBB
- CMake optimizations for faster configuration times
- Enhanced support for scripting in both ospGlutViewer and ospBenchmark applications

Changes in v1.0.0:

New OSPRay SDK
- OSPRay internal headers are now installed, enabling applications to extend OSPRay from a binary install
- CMake macros for OSPRay and ISPC configuration now a part of binary releases
  - CMake clients use them by calling include(${OSPRAY_USE_FILE}) in their CMake code after calling find_package(ospray)
- New OSPRay C++ wrapper classes
  - These act as a thin layer on top of OSPRay object handles, where multiple wrappers will share the same underlying handle when assigned, copied, or moved
  - New OSPRay objects are only created when a class instance is explicitly constructed
  - C++ users are encouraged to use these over the ospray.h API
Complete rework of sample applications
- New shared code for parsing the commandline
- Save/load of transfer functions now handled through a separate library which does not depend on Qt
- Added ospCvtParaViewTfcn utility, which enables ospVolumeViewer to load color maps from ParaView
- GLUT based sample viewer updates
  - Rename of ospModelViewer to ospGlutViewer
  - GLUT viewer now supports volume rendering
  - Command mode with preliminary scripting capabilities, enabled by pressing ‘:’ key (not available when using Intel C++ compiler (icc))
- Enhanced support of sample applications on Windows
New minimum ISPC version is 1.9.0
Support of Intel® AVX-512 for second generation Intel Xeon Phi processor (codename Knights Landing) is now a part of the OSPRAY_BUILD_ISA CMake build configuration
- Compiling AVX-512 requires icc to be enabled as a build option
Enhanced error messages when ospLoadModule() fails
Added OSP_FB_RGBA32F support in the DistributedFrameBuffer
Updated Glass shader in the path tracer
Many miscellaneous cleanups, bugfixes, and improvements

Changes in v0.10.1:

Fixed support of first generation Intel Xeon Phi coprocessor (codename Knights Corner)
Restored missing implementation of ospRemoveVolume()

Changes in v0.10.0:

Added new tasking options: Cilk, Internal, and Debug
- Provides more ways for OSPRay to interact with calling application tasking systems
  - Cilk: Use Intel® Cilk™ Plus language extensions (icc only)
  - Internal: Use hand written OSPRay tasking system
  - Debug: All tasks are run in serial (useful for debugging)
- In most cases, Intel Threading Building Blocks (Intel TBB) remains the fastest option
Added support for adaptive accumulation and stopping
- ospRenderFrame now returns an estimation of the variance in the rendered image if the framebuffer was created with the OSP_FB_VARIANCE channel
- If the renderer parameter varianceThreshold is set, progressive refinement concentrates on regions of the image with a variance higher than this threshold
Added support for volumes with voxelType ushort (16-bit unsigned integers)
OSPTexture2D now supports sRGB formats – actually most images are stored in sRGB. As a consequence the API call ospNewTexture2D() needed to change to accept the new OSPTextureFormat parameter
Similarly, OSPRay’s framebuffer types now also distinguishes between linear and sRGB 8-bit formats. The new types are OSP_FB_NONE, OSP_FB_RGBA8, OSP_FB_SRGBA, and OSP_FB_RGBA32F
Changed “scivis” renderer parameter defaults
- All shading (AO + shadows) must be explicitly enabled
OSPRay can now use a newer, pre-installed Embree enabled by the new OSPRAY_USE_EXTERNAL_EMBREE CMake option
New ospcommon library used to separately provide math types and OS abstractions for both OSPRay and sample applications
- Removes extra dependencies on internal Embree math types and utility functions
- ospray.h header is now C99 compatible
Removed loaders module, functionality remains inside of ospVolumeViewer
Many miscellaneous cleanups, bugfixes, and improvements:
- Fixed data distributed volume rendering bugs when using less blocks than workers
- Fixes to CMake find_package() config
- Fix bug in GhostBlockBrickVolume when using doubles
- Various robustness changes made in CMake to make it easier to compile OSPRay

Changes in v0.9.1:

Volume rendering now integrated into the “scivis” renderer
- Volumes are rendered in the same way the “dvr” volume renderer renders them
- Ambient occlusion works with implicit isosurfaces, with a known visual quality/performance trade-off
Intel Xeon Phi coprocessor (codename Knights Corner) COI device and build infrastructure restored (volume rendering is known to still be broken)
New support for CPack built OSPRay binary redistributable packages
Added support for HDRI lighting in path tracer
Added ospRemoveVolume() API call
Added ability to render a subsection of the full view into the entire framebuffer in the perspective camera
Many miscellaneous cleanups, bugfixes, and improvements:
- The depthbuffer is now correctly populated by in the “scivis” renderer
- Updated default renderer to be “ao1” in ospModelViewer
- Trianglemesh postIntersect shading is now 64-bit safe
- Texture2D has been reworked, with many improvements and bug fixes
- Fixed bug where MPI device would freeze while rendering frames with Intel TBB
- Updates to CMake with better error messages when Intel TBB is missing

Changes in v0.9.0:

The OSPRay v0.9.0 release adds significant new features as well as API changes.

Experimental support for data-distributed MPI-parallel volume rendering
New SciVis-focused renderer (“raytracer” or “scivis”) combining functionality of “obj” and “ao” renderers
- Ambient occlusion is quite flexible: dynamic number of samples, maximum ray distance, and weight
Updated Embree version to v2.7.1 with native support for Intel AVX-512 for triangle mesh surface rendering on the Intel Xeon Phi processor (codename Knights Landing)
OSPRay now uses C++11 features, requiring up to date compiler and standard library versions (GCC v4.8.0)
Optimization of volume sampling resulting in volume rendering speedups of up to 1.5x
Updates to path tracer
- Reworked material system
- Added texture transformations and colored transparency in OBJ material
- Support for alpha and depth components of framebuffer
Added thinlens camera, i.e. support for depth of field
Tasking system has been updated to use Intel Threading Building Blocks (Intel TBB)
The ospGet*() API calls have been deprecated and will be removed in a subsequent release

Changes in v0.8.3:

Enhancements and optimizations to path tracer
- Soft shadows (light sources: sphere, cone, extended spot, quad)
- Transparent shadows
- Normal mapping (OBJ material)
Volume rendering enhancements:
- Expanded material support
- Support for multiple lights
- Support for double precision volumes
- Added ospSampleVolume() API call to support limited probing of volume values
New features to support compositing externally rendered content with OSPRay-rendered content
- Renderers support early ray termination through a maximum depth parameter
- New OpenGL utility module to convert between OSPRay and OpenGL depth values
Added panoramic and orthographic camera types
Proper CMake-based installation of OSPRay and CMake find_package() support for use in external projects
Experimental Windows support
Deprecated ospNewTriangleMesh(); use ospNewGeometry("triangles") instead
Bug fixes and cleanups throughout the codebase

Changes in v0.8.2:

Initial support for Intel AVX-512 and the Intel Xeon Phi processor (codename Knights Landing)
Performance improvements to the volume renderer
Incorporated implicit slices and isosurfaces of volumes as core geometry types
Added support for multiple disjoint volumes to the volume renderer
Improved performance of ospSetRegion(), reducing volume load times
Improved large data handling for the shared_structured_volume and block_bricked_volume volume types
Added support for DDS horizon data to the seismic module
Initial support in the Qt viewer for volume rendering
Updated to ISPC 1.8.2
Various bug fixes, cleanups and documentation updates throughout the codebase

Changes in v0.8.1:

The volume renderer and volume viewer can now be run MPI parallel (data replicated) using the --osp:mpi command line option
Improved performance of volume grid accelerator generation, reducing load times for large volumes
The volume renderer and volume viewer now properly handle multiple isosurfaces
Added small example tutorial demonstrating how to use OSPRay
Several fixes to support older versions of GCC
Bug fixes to ospSetRegion() implementation for arbitrarily shaped regions and setting large volumes in a single call
Bug fix for geometries with invalid bounds; fixes streamline and sphere rendering in some scenes
Fixed bug in depth buffer generation

Changes in v0.8.0:

Incorporated early version of a new Qt-based viewer to eventually unify (and replace) the existing simpler GLUT-based viewers
Added new path tracing renderer (ospray/render/pathtracer),
roughly based on the Embree sample path tracer
Added new features to the volume renderer:
- Gradient shading (lighting)
- Implicit isosurfacing
- Progressive refinement
- Support for regular grids, specified with the gridOrigin and gridSpacing parameters
- New shared_structured_volume volume type that allows voxel data to be provided by applications through a shared data buffer
- New API call to set subregions of volume data (ospSetRegion())
Added a subsampling-mode, enabled with a negative spp parameter; the first frame after scene changes is rendered with reduced resolution, increasing interactivity
Added multi-target ISA support: OSPRay will now select the appropriate ISA at run time
Added support for the Stanford SEP file format to the seismic module
Added --osp:numthreads <n> command line option to restrict the number of threads OSPRay creates
Various bug fixes, cleanups and documentation updates throughout the codebase

Changes in v0.7.2:

Build fixes for older versions of GCC and Clang
Fixed time series support in ospVolumeViewer
Corrected memory management for shared data buffers
Updated to ISPC 1.8.1
Resolved issue in XML parser