Version History
---------------

### Changes in v3.2.0:

-   Sampling improvements:
      - Better performance (lower rendering time and faster convergence)
      - More pleasing blue noise enabled when the total number of frames
        to be accumulated is known in advance and set as the
        `targetFrames` parameter at the framebuffer
      - Note a maximum of 64k samples is supported
-   Improved `denoiser` image operation:
      - User-controlled quality levels via parameter `quality`
      - Optionally denoise alpha channel as well, enabled via
        parameter `denoiseAlpha`
-   Support half-precision (16\ bit float) texture formats
    `OSP_TEXTURE_[RGBA16F|RGB16F|RA16F|R16F]` and two-channel 32\ bit
    float textures `OSP_TEXTURE_RA32F`
-   New parameter `limitIndirectLightSamples` for the `pathtracer` which
    limits the number of light samples after the first non-specular
    (i.e., diffuse and glossy) bounce to at most one
-   Implement MIP Mapping for better texture filtering. If the
    additional memory per texture needed cannot be spared, applications
    can disable the generation of MIP maps with device parameter
    `disableMipMapGeneration`
-   The backplate (background texture) is now always sampled at the pixel
    center and thus not blurred by the pixel filter anymore
-   Avoid color bleeding across eye-subimages when stereo rendering
-   Superbuild uses binary packages of Open VKL
-   Removed Intel ISPCRT dependency (ISPC compiler is still needed):
    -   oneAPI Level Zero Loader is no longer necessary
    -   `zeContext` and `zeDevice`device parameters are no longer supported
    -   `ispcrtContext` and `ispcrtDevice`device parameters are no longer
        supported
-   Clarify the size of `OSP_BOOL` to be 1 byte
-   Fix artifacts occasionally appearing with `gpu` device
-   The new minimum versions of dependencies:
    -    Embree v4.3.3 (better error reporting)
    -    Open Image Denoise v2.3 (better image quality with `HIGH`
         quality mode, added `FAST` quality mode)
    -    rkcommon v1.14.0

### Changes in v3.1.0:

-   Principled and Luminous materials support emissive textures
-   Add native support for disc and oriented disc geometry
-   Add support for mirror repeat and clamp to edge texture wrap modes
-   GPU device now also supports motion blur
-   Improve noise in reflections of ThinGlass
-   Improve adaptive accumulation: working with GPU, fix correlations
-   Fix indirectly seen albedo and normal buffer
-   Fix artifacts when using specular texture for Principled
-   Fixes for PixelFilter
    -   Parameter was ignored (always using the default Gaussian)
    -   Avoid a shift/misalignment within the pixel for first sample
-   Fix empty image on Windows when `focusDistance=0`
-   Fix missing SDK headers for `ISPCDevice*`
-   The new minimum versions of dependencies:
    -    Embree v4.3.1
    -    Open VKL v2.0.1
    -    Open Image Denoise v2.2 (better quality with fine details,
         support AArch64 CPU on Linux)
    -    ISPCRT v1.23.0 (uses environment variable `ISPCRT_GPU_DRIVER`
         to select GPU to run on when multiple (i)GPUs are present)
    -    rkcommon v1.13.0 (fixes crash using GPU and emissive geometry)

### Changes in v3.0.0:

-   Beta support for Intel Xe GPUs (Intel Arc™ GPUs a Intel Data Center
    GPU Flex and Max Series), exploiting ray tracing hardware support.
    Implementation is based on the [SYCL](https://www.khronos.org/sycl/)
    cross-platform programming language implemented by [Intel oneAPI
    Data Parallel C++
    (DPC++)](https://www.intel.com/content/www/us/en/developer/tools/oneapi/data-parallel-c-plus-plus.html).  
    Note that the following features are not implemented yet or are not
    working correctly on the new `gpu` device:
    -   Multiple volumes in the scene
    -   Clipping
    -   Motion blur
    -   Subdivision surfaces
    -   Progress reporting via `ospGetProgress` or canceling the frame
        via `ospCancel`
    -   Picking via `ospPick`
    -   Adaptive accumulation via `OSP_FB_VARIANCE` and
        `varianceThreshold`
    -   Framebuffer channels `OSP_FB_ID_*` (id buffers)
    -   Experimental support for shared device-only data, works only for
        `structuredRegular` volume
    -   Further known issues
        -   Some delay on start-up or when changing the scene, because
            kernel code is JIT compiled and specialized. JIT compilation
            can be cached by setting environment variable
            `SYCL_CACHE_PERSISTENT=1`, then consecutive starts or
            rendering the same scene configuration is without delay
        -   For some combination of compiler, GPU driver and scene the
            rendered images might show artifacts (e.g., vertical lines
            or small blocks)
        -   Multidevice does not support `OSPImageOperation`s for
            denoising or tone mapping
-   Add implicit indexing for `mesh` geometry
-   Add support for transferring ownership of temporary buffers:
    `ospNewSharedData` accepts an optional deleter callback
-   Optimizations for MPI module, supported by new integrated
    performance tracing framework
-   Optimize `scivis` gradient shading
-   Main thread does not set FTZ/DAZ anymore for denormals handling
-   Compute intersection epsilon for Mesh to avoid rendering artifacts
    due to self-intersection
-   Fix energy conservation of Pricipled material under certain
    parameter combinations
-   Fix `denoiser` to not wipe the alpha channel
-   Fix crash in HDRI light
-   Fix link order for Debug build on Windows
-   The new minimum versions of dependencies:
    -    Embree v4.3.0
    -    Open VKL v2.0.0
    -    Open Image Denoise v2.1.0
    -    ISPC v1.21.1
    -    rkcommon v1.12.0
-   Breaking API changes
    -   Renamed `OSP_TEXTURE_FILTER_BILINEAR` to
        `OSP_TEXTURE_FILTER_LINEAR ` and
        `OSP_VOLUME_FILTER_TRI[LINEAR|CUBIC]` to
        `OSP_VOLUME_FILTER_[LINEAR|CUBIC]`
    -   Most enums now use storage type `uint32`
    -   `gridSpacing` of spherical regular volume defaults to full
        sphere
    -   Remove deprecated parameters and API calls
        -   error callback signatures without user pointer
        -   first argument of `ospNewMaterial`
        -   module name `ispc`; use `cpu`
        -   `volume` texture and `isosurface` geometry:
            `volumetricModel`; use `OSPVolume volume`
        -   Transfer function `vec2f valueRange`; use `box1f value`
        -   `hdri` and `sun-sky` lights: `intensityQuantity`
            `OSP_INTENSITY_QUANTITY_RADIANCE`
        -   `spot` light with `intensityDistribution`:
            `intensityQuantity` other than
            `OSP_INTENSITY_QUANTITY_SCALE`


### Changes in v2.12.0:

-   Support denoising on the GPU with OIDN 2.0, which is the new minimum
    version. The `denoiser` now uses HDR mode
-   New parameter `maxScatteringEvents` for the `pathtracer` which
    limits the number of non-specular (i.e., diffuse and glossy) bounces
-   Optimized dynamic load balancing for MPI devices
-   Fix crash when using small image resolution and many MPI ranks
-   Fix crash in `pathtracer` when `lightSamples > 0` but there are
    lights in the scene
-   Fix transparent shadows with too high `minContribution` setting
-   The new minimum version for ISPC is v1.20.0
-   Release binaries on Linux are built on Rocky 8

### Changes in v2.11.0:

-   Support single ISPC target on Windows
-   OSPRay's superbuild can now be provided a CMake toolchain file for
    cross-compilation
-   Add support for double pumped NEON instruction on ARM64
-   Reduce the memory overhead of the `mpiOffload` device and resolve
    memory and `MPI_Comm` handle leaks
-   Support for volume rendering (and thus the dependency to Open VKL)
    can now be compile-time controlled via CMake variable
    `OSPRAY_ENABLE_VOLUMES`
-   OSPRay's MPI modules have been split up and renamed, the `mpiOffload`
    device is now in the `mpi_offload` module, while the `mpiDistributed`
    device is now in the `mpi_distributed_cpu` module
-   Add native support for spheres via Embree, which requires the
    positions and radius of the spheres to be interleaved in memory; if
    this is not the case, OSPRay will internally create a copy of the
    data
-   Fix `dynamicScene` flag on World and Group to influence BVH quality
    again: default is now "high", which should improve rendering
    performance, depending on the scene; and "low" when `dynamicScene`
    is enabled (improving BVH build performance)
-   Fix a crash in `pathtracer` when there are no lights
-   Fix a data corruption bug when setting string parameters for objects
    in the `mpiOffload` device
-   Various documentation fixes
-   OSPRay now has a new dependency, which is ISPC Run Time (ISPCRT) in
    minimum 1.19.0 version
-   Adapt to Embree v4.0.0 API changes, which is thus the new minimum
    version; additionally, the new minimum version for Open VKL is
    v1.3.2 and for ISPC v1.19.0
-   Removed support of MSVC14.0 (Visual Studio 2015) and the second
    generation Intel Xeon Phi processor (codename Knights Landing)

### Changes in v2.10.0:

-   Add support for primitive, object, and instance ID buffers as
    framebuffer channels
-   Support face-varying attributes for Mesh and Subdivision geometry
-   Replace CMake variable `OSPRAY_PIXELS_PER_JOB` by
    `OSPRAY_RENDER_TASK_SIZE`; variance tracking for adaptive
    accumulation is now per task instead of per tile, allowing for more
    granular adaptation
-   OSPRay now requires minimum Open VKL v1.3.0 to bring the following
    improvements:
    -   VDB volumes added support for contiguous data layouts, which can
        provide improved performance (`nodesPackedDense`,
        `nodesPackedTile` parameters)
    -   Particle volumes are more memory efficiency and improved
        performance
-   OSPRay now requires minimum ISPC v1.18.0 for Open VKL and to include
    a fix for parallel dispatch of uniform function pointers
-   MPI Offload: resolve object life time tracking issue that would
    result in framebuffer and data info being release too early, leading
    to a crash
-   Fix crash with OpenMPI due to argument handling
-   Fix clipping when rays are parallel to clipping planes
-   Fix missing SDK headers from CPU and MPI module
-   Deprecated the `vec2f valueRange` parameter of the `piecewiseLinear`
    transfer function, use `box1f value` instead

### Changes in v2.9.0:

-   Add support for multi-segment deformation motion blur for `mesh`
    geometry
-   OSPRay now requires minimum Open VKL v1.2.0 to bring the following
    improvements:
    -   Structured regular volumes support for cell-centered data via
        the `cellCentered` parameter (vertex-centered remains the
        default)
    -   Particle volumes ignore particles with zero radius
-   Add support for dynamic load balancing in MPI Offload device 
-   Support for photometric lights (e.g., IES or EULUMDAT) also for
    `sphere` and `quad` lights. When setting `intensityDistribution`,
    other values for `intensityQuantity` than
    `OSP_INTENSITY_QUANTITY_SCALE` are deprecated
-   Changed CMake variables for enabling app categories:
    -   `OSPRAY_ENABLE_APPS_BENCHMARK` replaces `OSPRAY_APPS_BENCHMARK`
    -   `OSPRAY_ENABLE_APPS_EXAMPLES` replaces `OSPRAY_APPS_EXAMPLES`
    -   `OSPRAY_ENABLE_APPS_TUTORIALS` replaces `OSPRAY_APPS_TUTORIALS`
    -   `OSPRAY_ENABLE_APPS_TESTING` replaces `OSPRAY_APPS_TESTING`
-   Improve sampling of quad lights in the `pathtracer` (solid angle
    instead of area)
-   Instances can now have the group object rebound via a parameter
-   Fix leaking framebuffers in the MPI Offload device
-   Resolve possible race condition in assigning IDs to distributed
    objects in the MPI device
-   Move ISPC module to `modules/` folder and renamed the module to
    `cpu`
-   Minimum version of rkcommon is 1.9.0, which brings the following
    improvements:
    -   Add detection of Intel oneAPI DPC++/C++ compiler
    -   Fix memory leak

### Changes in v2.8.0:

-   Lights can be now part of `OSPGroup` and thus instanced like
    geometries and volumes and thus lights also support motion blur
    (with the path tracer)
-   Add cylinder light (with solid area sampling)
-   Add support for rolling shutter of cameras
-   Add support for quaternion motion blur for instance and camera to
    allow for smoothly interpolated rotations
-   Fix illumination from emissive quad meshes

### Changes in v2.7.1:

-   Use Open VKL v1.0.1 to fix sporadic slowdowns when rendering
    structured regular and VDB volumes with the SciVis renderer
-   Fix CMake variables and logic
-   Fix crash when `transferfunction.opacity = 0`
-   Fix bug in MPI data-parallel rendering that caused rendering to hang
-   Workaround dynamic linking issue on Windows in MPI distributed
    rendering
-   Correctly initialize `renderFrame` progress
-   Improved performance of data-parallel rendering for scenes with a
    large number of regions
-   Expanded camera model support of the data-parallel renderer,
    data-parallel rendering can now use all the camera models supported
    by the SciVis renderer
-   Clarify documentation and error messages

### Changes in v2.7.0:

-   Add support for transformation and camera motion blur (with the path
    tracer) via `shutter` parameter of the camera and `motion.transform`
    array and `time` parameter of the instance and camera
-   OSPRay can now be built for ARM64 CPUs with NEON (e.g., Apple M1)
    using the superbuild. Thus, new minimum versions are for ISPC
    1.16.0, for Embree 3.13.1 and for rkcommon 1.7.0
-   OSPRay now requires minimum Open VKL v1.0.0 to bring the following
    improvements:
    -   Configurable `background` values for all volume types (default
        `NaN`), defining region outside the volume domain
    -   Better default sampling rate for scaled VDB volumes, improved
        robustness
    -   Structured regular volumes now support tricubic filtering and
        more accurate gradient computations as well as more robust
        isosurfaces
-   The multidevice module contains a new OSPRay device implementation
    that delegates work to any number of subdevices. This is an
    experimental feature in this release but we invite feedback
-   SciVis Renderer now ignores normal/albedo/depth hits on surfaces
    that are fully transmissive (material `d = 0`)
-   Changed the behavior of background rendering in SciVis renderer to
    more closely reflect that of the path tracer: Background hits are
    rendered in background color in the albedo buffer and black in the
    normal buffer
-   The SciVis renderer does not compute depth of field (DoF) anymore,
    as this effect does not align with the SciVis renderer definition
    and exposed artifacts
-   Fixed crash on exit when using the MPI device
-   Fixed rendering of depth buffer in the example application
-   The first argument to material constructor `ospNewMaterial`, i.e.,
    `renderer_type`, is now deprecated and will be removed in a future
    release. AO and SciVis renderers still assume "obj" like behavior
    for all material types
-   Deprecated the `xfm` parameter of the instance, use `transform`
    instead
-   Dependencies Google Benchmark, GoggleTest, and Snappy moved
    out-of-source to superbuild ExternalProjects

### Changes in v2.6.0:

-   Added new `intensityQuantity` type `OSP_INTENSITY_QUANTITY_SCALE`
    for the `hdri` and `sunSky` light source. For the future this is the
    only supported quantity for these lights, the value
    `OSP_INTENSITY_QUANTITY_RADIANCE` is deprecated. When
    `OSP_INTENSITY_QUANTITY_SCALE` is used for `sunSky` the default
    value of `intensity` is `0.025` to match the old behavior
-   The MPI module is included in the releases packages. An
    [MPICH-ABI](https://www.mpich.org/abi/) compatible build is provided
    for Linux that can be run with the Intel oneAPI HPC Toolki, MPICH,
    and other MPICH-ABI compatible MPI distributions. The Windows
    release is built against MPI provided in the Intel oneAPI HPC
    Toolkit
-   OSPRay now requires minimum Open VKL v0.13.0 to bring the following
    improvements:
    -   Support half precision float (fp16) voxel data in structured
        volumes (regular and spherical) and VDB volume
    -   Supporting tricubic filtering via `VKL_FILTER_TRICUBIC` filter
        for VDB volume
    -   Fixed artifacts for isosurfaces of unstructured volumes
    -   Performance improvements for isosurfaces when multiple isovalues
        are selected 
    -   Better, adaptive sampling of AMR volumes
-   The `mpiOffload` and `mpiDistributed` devices now support picking.
    Picking in the distributed device will return the globally closest
    object on the rank that owns that object. Other ranks will report no
    hit
-   Messages issued from ISPC code use the same reporting path as the
    C++ code, thus now the whole OSPRay console output can be
    consistently filtered with log levels
-   Open VKL and Embree internal errors are now correctly mapped to
    their corresponding OSPRay errors
-   Fix behavior of committing the framebuffer in distributed rendering
    to match that of local rendering

### Changes in v2.5.0:

-   Add native support for cones or cylinders with curves geometry of
    type `OSP_DISJOINT`, requiring minimum version 3.12.0 of Embree
-   Replaced OSPRay's internal implementation of round linear curves by
    Embree's native implementation. Internal surfaces at joints are now
    correctly removed, leading to higher quality renderings with
    transparency, at the cost of intersection performance
-   SciVis renderer improvements:
    -   Colored transparency, colored shadows
    -   Light sources are visible including HDRI Light environment map
-   The MPI module is now distributed as part of OSPRay in the modules
    directory
    -   The socket-based communication layer has been removed
-   Add `intensityQuantity` parameter to light sources to control the
    interpretation and conversion of the `intensity` into a radiative
    quantity
-   OSPRay now requires minimum Open VKL v0.12.0 to bring the following
    improvements: 
    -   Better default sampling rate for scaled volumes, improving
        performance
    -   Higher robustness for axis-aligned rays
-   Removed limit on the number of volumes (both overlapped and separate)
    that a ray can intersect while rendering. Now it is limited by
    available memory only.
-   Move to OIDN v1.3.0 to bring the following improvements:
    -   Improved denoising quality (sharpness of fine details, fewer
        noisy artifacts)
    -   Slightly improved performance and lower memory consumption
-   Both geometric and volumetric models can now have their child
    geometry/volume objects rebound using an object parameter
-   Fix light leaking artifacts at poles of HDRI (and Sun-Sky) light
-   Add sRGB conversion to `ospExamples` such that the color of the
    widget for `backgroundColor` actually matches 
-   Dropping support for MSVC14, new minimum compiler on Windows is
    MSVC15 (Visual Studio 2017)

### Changes in v2.4.0:

-   The `pathtracer` optionally allows for alpha blending even if the
    background is seen through refractive objects like glass, by
    enabling `backgroundRefraction`
-   OSPRay now requires minimum Open VKL v0.11.0 to bring the following
    improvements: 
    -   Improved rendering performance of VDB volumes
    -   Added support for configurable iterator depth via the
        `maxIteratorDepth` parameters for unstructured and particle
        volumes, improved performance
    -   Added support for filter modes for structured volumes (regular
        and spherical)
-   Expose parameter `horizonExtension` of Sun-sky light, which extends
    the sky dome by stretching the horizon over the lower hemisphere
-   Optimize handling of geometry lights by the `pathtracer`
-   The optional `denoiser` image operation now respects frame
    cancellation, requiring Intel® Open Image Denoise with minimum
    version 1.2.3
-   Fixed normals of (transformed) isosurfaces
-   Robust calculation of normals of `boxes` geometry
-   Clipping geometry is now working correctly with `map_maxDepth`
    renderer parameter
-   Using materials in a renderer with a mismatched `renderer_type` no
    longer causes crashes while rendering
-   Significant improvements have been made to loading performance in
    the MPI Offload device. Applications which make large numbers of API
    calls or create many smaller geometries or volumes should see
    substantial load time improvements.
-   MPI module compacts strided data arrays on the app rank before
    sending

### Changes in v2.3.0:

-   Re-add SciVis renderer features (the previous version is still
    available as `ao` renderer)
    -   Lights are regarded, and thus the OBJ material terms `ks` and
        `ns` have effect again
    -   Hard shadows are enabled via the `shadows` parameter
    -   The control of ambient occlusion changed:
        -   The `aoIntensity` parameter is replaced by the combined
            intensity of ambient lights in the `World`
        -   The effect range is controlled via `aoDistance`
-   Added support for data arrays with a stride between voxels in
    volumes
-   Application thread waiting for finished image via `ospWait`
    participates in rendering, increasing CPU utilization; via
    rkcommon v1.5.0
-   Added `ospray_cpp` compatibility headers for C++ wrappers to
    understand rkcommon and glm short vector types
    -   For rkcommon, include `ospray/ospray_cpp/ext/rkcommon.h`
    -   For glm, include `ospray/ospray_cpp/ext/glm.h`
    -   Note in debug builds some compilers will not optimize out type
        trait definitions. This will require users to manually
        instantiate the glm definitions in one translation unit within
        the application using `#define OSPRAY_GLM_DEFINITIONS` before
        including `ext/glm.h`: see `ospTutorialGLM` as an example
-   Changed parameters to `volume` texture: it now directly accepts the
    `volume` and the `transferFunction`
-   Fixed many memory leaks
-   Handle `NaN` during volume sampling, which led to bounding boxes
    being visible for some volumes and settings
-   Depth is now "accumulated" as well, using the minimum
-   Fix shading for multiple modes of the `debug` renderer
-   New minimum ISPC version is 1.14.1

### Changes in v2.2.0:

-   Support for texture transformation in SciVis OBJ material
-   Add transformations for volume textures; volume texture lookups are
    now with local object coordinates (not world coordinates anymore)
-   Changed behavior: if solely a texture is given, then the default
    value of the corresponding parameter is *not* multiplied
-   Support for better antialiasing using a set of different pixel
    filters (e.g, box, Gaussian, ...). The size of the pixel filter is
    defined by the used filter type. Previously OSPRay implicitly used a
    box filter with a size of 1, for better results the default filter
    is now `OSP_PIXELFILTER_GAUSS`
-   Support stereo3d mode for panoramic camera
-   Add new camera `stereoMode` `OSP_STEREO_TOP_BOTTOM` (with left eye
    at top half of the image)
-   Added support for random light sampling to the `pathtracer`, the
    number of sampled light sources per path vertex is defined by the
    `lightSamples` parameter
-   Support ring light by extending spot with `innerRadius`
-   Fixed nonphysical behavior of the `spot` and `sphere` light sources
    -   for area lights (when `radius > 0`) surfaces close to the light
        will be darker
    -   the `spot` now has an angular falloff, such that a disk light is
        a proper lambertian area light, which leads to darker regions
        perpendicular to its direction (thus barely visible with a
        typically small `openingAngle`)
-   Support for Open VKL v0.10.0 and its new sampler object API, thus
    this is now the required minimum version
-   Added support for particle and VDB volumes
-   Move from `ospcommon` to `rkcommon` v1.4.2
-   New minimum ISPC version is 1.10.0
-   Status and error callbacks now support a user pointer
-   Enabled C++ wrappers (`ospray_cpp`) to work with non-rkcommon math
    types
    -   Note that while the C API remains the same, the C++ wrappers
        will require some application updates to account for these
        changes
-   MPI module improved parallelism of framebuffer compression &
    decompression when collecting the final framebuffer to the head
    rank. This provides a substantial performance improvement when using
    just a few ranks or large framebuffers (both in pixel count or
    channel count).
-   The MPI module will now default to setting thread affinity off, if
    no option is selected. This improves thread usage and core
    assignment of threads in most cases, where no specific options are
    provided to the MPI runtime.
-   Fix bug where `ospGetCurrentDevice` would crash if used before
    `ospInit`
-   Allow `NULL` handles to be passed to `ospDeviceRetain` and
    `ospDeviceRelease`
-   ISPC generated headers containing the exported functions for
    OSPRay's ISPC types and functions are now distributed with the SDK
-   Add CarPaint `flakeColor` parameter, defaults to current Aluminium
-   Fixed Debug build (which were producing different images)
-   The path tracer now also regards the renderer materialist when
    creating geometry lights
-   Fix bug where OSPObject handles where not translated to worker-local
    pointers when committing an OSPData in the MPIOffloadDevice.
-   MPI module: Fix handling of `OSP_STRING` parameters

### Changes in v2.1.1:

-   CarPaint material obeys `coat` weight parameter
-   Correct depth buffer values with SciVis renderer
-   Adaptions to Embree v3.10.0
-   The Linux binary release finds `ospcommon` again

### Changes in v2.1.0:

-   New clipping geometries feature that allows clipping any scene
    (geometry and volumes); all OSPRay geometry types can by used as
    clipping geometry
    -   Inverted clipping is supported via new `invertNormals` parameter
        of `GeometricModel`
    -   Currently there is a fixed upper limit (64) of how many clipping
        geometries can be nested
    -   When clipping with curves geometry (any basis except linear)
        some rendering artifacts may appear
-   New plane geometry defined via plane equation and optional bounding
    box
-   Sun-sky light based on physical model of Hošek-Wilkie
-   Support for photometric lights (e.g., IES or EULUMDAT)
-   Add new `ospGetTaskDuration` API call to query execution time of
    asynchronous tasks
-   Support for 16bit (unsigned short) textures
-   Add static `cpp::Device::current` method as a C++ wrapper equivalent
    to `ospGetCurrentDevice`
-   Generalized `cpp::Device` parameter setting to match other handle
    types
-   Passing `NULL` to `ospRelease` is not reported as error anymore
-   Fix computation of strides for `OSPData`
-   Fix transparency in `scivis` renderer
-   Add missing C++ wrapper for `ospGetVariance`
-   Proper demonstration of `ospGetVariance` in `ospTutorialAsync`
-   Fix handling of `--osp:device-params` to process and set all passed
    arguments first before committing the device, to ensure it is
    committed in a valid state
-   Object factory functions are now registered during module
    initialization via the appropriate `registerType` function
-   MPI module: Use flush bcasts to allow us to use non-owning views for
    data transfer. Note that shared `ospData` with strides is currently
    transmitted as whole
-   Fix issue with OSPRay ignoring tasking system thread count settings
-   Fix issue where OSPRay always loaded the ISPC module, even if not
    required
-   Fixes for MPI module
    - Fix member variable type for bcast
    - Fix incorrect data size computation in `offload` device
    - Fix large data chunking support for MPI Bcast
-   OSPRay now requires minimum Open VKL v0.9.0

### Changes in v2.0.1:

-   Fix bug where Embree user-defined geometries were not indexed
    correctly in the scene, which now requires Embree v3.8.0+
-   Fix crash when the path tracer encounters geometric models that do
    not have a material
-   Fix crash when some path tracer materials generated `NULL` bsdfs
-   Fix bug where `ospGetBounds` returned incorrect values
-   Fix missing symbol in denoiser module
-   Fix missing symbol exports on Windows for all OSPRay built modules
-   Add the option to specify a single color for geometric models
-   The `scivis` renderer now respects the opacity component of `color`
    on geometric models
-   Fix various inconsistent handling of framebuffer alpha between
    renderers
-   `ospGetCurrentDevice` now increments the ref count of the returned
    `OSPDevice` handle, so applications will need to release the handle
    when finished by using `ospDeviceRelease` accordingly
-   Added denoiser to `ospExamples` app
-   Added `module_mpi` to superbuild (disabled by default)
-   The superbuild now will emit a CMake error when using any 32-bit
    CMake generator, as 32-bit builds are not supported

### Changes in v2.0.0:

-   New major revision of OSPRay brings API breaking improvements over
    v1.x. See [doc/ospray2_porting_guide.md] for a deeper description of
    migrating from v1.x to v2.0 and the latest
    [API documentation](README.md#ospray-api)
    -   `ospRenderFrame` now takes all participating objects as
        function parameters instead of setting some as renderer params
    -   `ospRenderFrame` is now asynchronous, where the task is managed
        through a returned `OSPFuture` handle
    -   The hierarchy of objects in a scene are now more granular to
        aid in scene construction flexibility and reduce potential
        object duplication
    -   Type-specific parameter setting functions have been consolidated
        into a single `ospSetParam` API call
    -   C++ wrappers found in `ospray_cpp.h` now automatically track
        handle lifetimes, therefore applications using them do not need
        to use `ospRelease` (or the new `ospRetain`) with them: see
        usage example in `apps/tutorials/ospTutorial.cpp`
    -   Unused parameters are reported as status messages when
        `logLevel` is at least `warning` (most easily set by enabling
        OSPRay debug on initialization)
-   New utility library which adds functions to help with new API
    migration and reduction of boilerplate code
    -   Use `ospray_util.h` to access these additional functions
    -   All utility functions are implemented in terms of the core API
        found in `ospray.h`, therefore they are compatible with any
        device backend
-   Introduction of new Intel® Open Volume Kernel Library (Open VKL)
    for greatly enhanced volume sampling and rendering features and
    performance
-   Added direct support for Intel® Open Image Denoise as an optional
    module, which adds a `denoiser` type to `ospNewImageOperation`
-   OSPRay now requires minimum Embree v3.7.0
-   New CMake superbuild available to build both OSPRay's dependencies
    and OSPRay itself
    -   Found in `scripts/superbuild`
    -   See documentation for more details and example usage
-   The `ospcommon` library now lives as a stand alone repository and
    is required to build OSPRay
-   The MPI module is now a separate repository, which also contains all
    MPI distributed rendering documentation
-   Log levels are now controlled with enums and named strings (where
    applicable)
    -   A new flag was also introduced which turns all `OSP_LOG_WARNING`
        messages into errors, which are submitted to the error callback
        instead of the message callback
    -   Any unused parameters an object ignores now emit a warning
        message
-   New support for volumes in the `pathtracer`
    -   Several parameters are available for performance/quality
        trade-offs for both photorealistic and scientific visualization
        use cases
-   Simplification of the SciVis renderer
    -   Fixed AO lighting and simple ray marched volume rendering for
        ease of use and performance
-   Overlapping volumes are now supported in both the `pathtracer` and
    `scivis` renderers
-   New API call for querying the bounds of objects (`OSPWorld`,
    `OSPInstance`, and `OSPGroup`)
-   Lights now exist as a parameter to the world instead of the renderer
-   Removal of `slices` geometry. Instead, any geometry with volume
    texture can be used for slicing
-   Introduction of new `boxes` geometry type
-   Expansion of information returned by `ospPick`
-   Addition of API to query version information at runtime
-   Curves now supports both, per vertex varying radii as in `vec4f[]
    vertex.position_radius` and constant radius for the geometry with
    `float radius`. It uses `OSP_ROUND` type and `OSP_LINEAR` basis by
    default to create the connected segments of constant radius. For per
    vertex varying radii curves it uses Embree curves.
-   Add new Embree curve type `OSP_CATMULL_ROM` for curves
-   Minimum required Embree version is now 3.7.0
-   Removal of `cylinders` and `streamlines` geometry, use `curves`
    instead
-   Triangle mesh and Quad mesh are superseded by the `mesh` geometry
-   Applications need to use the various error reporting methods to
    check whether the creation (via `ospNew...`) of objects failed; a
    returned `NULL` is not a special handle anymore to signify an error
-   Changed module init methods to facilitate version checking:
    `extern "C" OSPError ospray_module_init_<name>(int16_t versionMajor, int16_t versionMinor, int16_t versionPatch)`
-   The `map_backplate` texture is supported in all renderers and does
    not hide lights in infinity (like the HDRI light) anymore;
    explicitly make lights in`visible` if this is needed
-   Changed the computation of variance for adaptive accumulation to be
    independent of `TILE_SIZE`, thus `varianceThreshold` needs to be
    adapted if using a different `TILE_SIZE` than default 64
-   `OSPGeometricModel` now has the option to index a renderer-global
    material list that lives on the renderer, allowing scenes to avoid
    renderer-specific materials
-   Object type names and parameters all now follow the camel-case
    convention
-   New `ospExamples` app which consolidates previous interactive apps
    into one
-   New `ospBenchmark` app which implements a runnable benchmark suite
-   Known issues:
    -   ISPC v1.11.0 and Embree v3.6.0 are both incompatible with OSPRay
        and should be avoided (OSPRay should catch this during CMake
        configure)
-   MPI module
    -   The MPI module is now provided separately from the main OSPRay
        repository
    -   Users can now extend OSPRay with custom distributed renderers
        and compositing operations, by extending
        `ospray::mpi::DistributedRenderer` and the
        `ospray::mpi::TileOperation`, respectively. See the
        `ospray::mpi::DistributedRaycastRenderer` for an example to
        start from.
    -   The MPI Offload device can now communicate over sockets, allowing
        for remote rendering on clusters in the listen/connect mode
    -   Data and commands are now sent asynchronously to the MPI workers
        in the Offload device, overlapping better with application work.
        The number of data copies performed has also been significantly
        reduced, and should improve load times
    -   The MPI Distributed device will now infer the rank's local data
        bounds based on the volumes and geometry specified if no bounding
        boxes are specified
    -   When specifying custom bounds on each rank IDs are no longer
        required, and ranks sharing data will be determined by finding
        any specifying the same bounding boxes. This will also be done
        if no bounds are specified, allowing automatic image and hybrid
        parallel rendering.
    -   The MPI Distributed device can now be used for image-parallel
        rendering (e.g., same as offload), where now each application
        can load data in parallel. See the
        `ospMPIDistributedTutorialReplicatedData` for an example.

### Changes in v1.8.5:

-   Fix float precision cornercase (`NaN`s) in sphere light sampling
-   Fix CMake bug that assumed `.git` was a directory, which is not true
    when using OSPRay as a git submodule
-   Fix CMake warning
-   Fix `DLL_EXPORT` issue with `ospray_testing` helper library on
    Windows

### Changes in v1.8.4:

-   Add location of `libospray` to paths searched to find modules

### Changes in v1.8.3:

-   Fix bug where parameters set by `ospSet1b()` were being ignored
-   Fix bug in box intersection tests possibly creating `NaN`s
-   Fix issue with client applications calling `find_package(ospray)`
    more than once
-   Fix bug in cylinder intersection when ray and cylinder are
    perpendicular
-   Fix rare crash in path tracer / MultiBSDF

### Changes in v1.8.2:

-   CMake bug fix where external users of OSPRay needed CMake newer than
    version 3.1
-   Fix incorrect propagation of tasking system flags from an OSPRay
    install
-   Fix inconsistency between supported environment variables and
    command line parameters passed to `ospInit()`
    -   Missing variables were `OSPRAY_LOAD_MODULES` and
        `OSPRAY_DEFAULT_DEVICE`

### Changes in v1.8.1:

-   CMake bug fix to remove full paths to dependencies in packages

### Changes in v1.8.0:

-   This will be the last minor revision of OSPRay. Future development
    effort in the `devel` branch will be dedicated to v2.0 API changes
    and may break existing v1.x applications.
    -   This will also be the last version of OSPRay to include
        `ospray_sg` and the Example Viewer. Users which depend on these
        should instead use the separate OSPRay Studio project, where
        `ospray_sg` will be migrated.
    -   We will continue to support patch releases of v1.8.x in case of
        any reported bugs
-   Refactored CMake to use newer CMake concepts
    -   All targets are now exported in OSPRay installs and can be
        consumed by client projects with associated includes, libraries,
        and definitions
    -   OSPRay now requires CMake v3.1 to build
    -   See documentation for more details
-   Added new minimal tutorial apps to replace the more complex Example
    Viewer
-   Added new "`subdivision`" geometry type to support subdivision
    surfaces
-   Added support for texture formats `L8`, `LA8` (gamma-encoded
    luminance), and `RA8` (linear two component). Note that the enum
    `OSP_TEXTURE_FORMAT_INVALID` changed its value, thus recompilation
    may be necessary.
-   Automatic epsilon handling, which removes the "`epsilon`" parameter
    on all renderers
-   Normals in framebuffer channel `OSP_FB_NORMAL` are now in
    world-space
-   Added support for Intel® Open Image Denoise to the Example Viewer
    -   This same integration will soon be ported to OSPRay Studio
-   Fixed artifacts for scaled instances of spheres, cylinders and
    streamlines
-   Improvements to precision of intersections with cylinders and
    streamlines
-   Fixed Quadlight: the emitting side is now indeed in direction
    `edge1`×`edge2`

### Changes in v1.7.3:

-   Make sure a "`default`" device can always be created
-   Fixed `ospNewTexture2D` (completely implementing old behavior)
-   Cleanup any shared object handles from the OS created from
    `ospLoadModule()`

### Changes in v1.7.2:

-   Fixed issue in `mpi_offload` device where `ospRelease` would
    sometimes not correctly free objects
-   Fixed issue in `ospray_sg` where structured volumes would not
    properly release the underlying OSPRay object handles

### Changes in v1.7.1:

-   Fixed issue where the `Principled` material would sometimes show up
    incorrectly as black
-   Fixed issue where some headers were missing from install packages

### Changes in v1.7.0:

-   Generalized texture interface to support more than classic 2D image
    textures, thus `OSPTexture2D` and `ospNewTexture2D` are now
    deprecated, use the new API call `ospNewTexture("texture2d")`
    instead
    -   Added new `volume` texture type to visualize volume data on
        arbitrary geometry placed inside the volume
-   Added new framebuffer channels `OSP_FB_NORMAL` and `OSP_FB_ALBEDO`
-   Applications can get information about the progress of rendering the
    current frame, and optionally cancel it, by registering a callback
    function via `ospSetProgressFunc()`
-   Lights are not tied to the renderer type, so a new function
    `ospNewLight3()` was introduced to implement this. Please convert
    all uses of `ospNewLight()` and/or `ospNewLight2()` to
    `ospNewLight3()`
-   Added sheenTint parameter to Principled material
-   Added baseNormal parameter to Principled material
-   Added low-discrepancy sampling to path tracer
-   The `spp` parameter on the renderer no longer supports values less
    than 1, instead applications should render to a separate, lower
    resolution framebuffer during interaction to achieve the same
    behavior

### Changes in v1.6.1:

-   Many bug fixes
    -   Quad mesh interpolation and sampling
    -   Normal mapping in path tracer materials
    -   Memory corruption with partly emitting mesh lights
    -   Logic for setting thread affinity

### Changes in v1.6.0:

-   Updated ispc device to use Embree3 (minimum required Embree
    version is 3.1)
-   Added new `ospShutdown()` API function to aid in correctness and
    determinism of OSPRay API cleanup
-   Added "`Principled`" and "`CarPaint"` materials to the path tracer
-   Improved flexibility of the tone mapper
-   Improvements to unstructured volume
    -   Support for wedges (in addition to tets and hexes)
    -   Support for implicit isosurface geometry
    -   Support for cell-centered data (as an alternative to per-vertex
        data)
    -   Added an option to precompute normals, providing a
        memory/performance trade-off for applications
-   Implemented "`quads`" geometry type to handle quads directly
-   Implemented the ability to set "void" cell values in all volume
    types: when `NaN` is present as a volume's cell value the volume
    sample will be ignored by the SciVis renderer
-   Fixed support for color strides which were not multiples of
    `sizeof(float)`
-   Added support for RGBA8 color format to spheres, which can be set by
    specifying the "`color_format`" parameter as `OSP_UCHAR4`, or
    passing the "`color`" array through an `OSPData` of type
    `OSP_UCHAR4`.
-   Added ability to configure Embree scene flags via `OSPModel`
    parameters
-   `ospFreeFrameBuffer()` has been deprecated in favor of using
    `ospRelease()` to free framebuffer handles
-   Fixed memory leak caused by incorrect parameter reference counts in
    ispc device
-   Fixed occasional crashes in the `mpi_offload` device on shutdown
-   Various improvements to sample apps and `ospray_sg`
    -   Added new `generator` nodes, allowing the ability to inject
        programmatically generated scene data (only C++ for now)
    -   Bug fixes and improvements to enhance stability and usability

### Changes in v1.5.0:

-   Unstructured tetrahedral volume now generalized to also support
    hexahedral data, now called `unstructured_volume`
-   New function for creating materials (`ospNewMaterial2()`) which
    takes the renderer type string, not a renderer instance (the old
    version is now deprecated)
-   New `tonemapper` PixelOp for tone mapping final frames
-   Streamlines now support per-vertex radii and smooth interpolation
-   `ospray_sg` headers are now installed alongside the SDK
-   Core OSPRay ispc device now implemented as a module
    -   Devices which implement the public API are no longer required to
        link the dependencies to core OSPRay (e.g., Embree v2.x)
    -   By default, `ospInit()` will load the ispc module if a device
        was not created via `--osp:mpi` or `--osp:device:[name]`
-   MPI devices can now accept an existing world communicator instead of
    always creating their own
-   Added ability to control ISPC specific optimization flags via CMake
    options. See the various `ISPC_FLAGS_*` variables to control which
    flags get used
-   Enhancements to sample applications
    -   `ospray_sg` (and thus `ospExampleViewer`/`ospBenchmark`) can now
        be extended with new scene data importers via modules or the SDK
    -   Updated `ospTutorial` examples to properly call `ospRelease()`
    -   New options in the `ospExampleViewer` GUI to showcase new
        features (sRGB framebuffers, tone mapping, etc.)
-   General bug fixes
    -   Fixes to geometries with multiple emissive materials
    -   Improvements to precision of ray-sphere intersections

### Changes in v1.4.3:

-   Several bug fixes
    -   Fixed potential issue with static initialization order
    -   Correct compiler flags for `Debug` config
    -   Spheres `postIntersect` shading is now 64-bit safer

### Changes in v1.4.2:

-   Several cleanups and bug fixes
    -   Fixed memory leak where the Embree BVH was never released when
        an `OSPModel` was released
    -   Fixed a crash when API logging was enabled in certain situations
    -   Fixed a crash in MPI mode when creating lights without a
        renderer
    -   Fixed an issue with camera lens samples not initialized when
        `spp` <= 0
    -   Fixed an issue in `ospExampleViewer` when specifying multiple data
        files
-   The C99 tutorial is now indicated as the default; the C++ wrappers
    do not change the semantics of the API (memory management) so the
    C99 version should be considered first when learning the API

### Changes in v1.4.1:

-   Several cleanups and bug fixes
    -   Improved precision of ray intersection with streamlines,
        spheres, and cylinder geometries
    -   Fixed address overflow in framebuffer, in practice image size is
        now limited only by available memory
    -   Fixed several deadlocks and race conditions
    -   Fix shadow computation in SciVis renderer, objects behind light
        sources do not occlude anymore
    -   No more image jittering with MPI rendering when no accumulation
        buffer is used
-   Improved path tracer materials
    -   Additionally support RGB `eta`/`k` for Metal
    -   Added Alloy material, a "metal" with textured color
-   Minimum required Embree version is now v2.15

### Changes in v1.4.0:

-   New adaptive mesh refinement (AMR) and unstructured tetrahedral
    volume types
-   Dynamic load balancing is now implemented for the `mpi_offload`
    device
-   Many improvements and fixes to the available path tracer materials
    -   Specular lobe of OBJMaterial uses Blinn-Phong for more realistic
        highlights
    -   Metal accepts spectral samples of complex refraction index
    -   ThinGlass behaves consistent to Glass and can texture
        attenuation color
-   Added Russian roulette termination to path tracer
-   SciVis OBJMaterial accepts texture coordinate transformations
-   Applications can now access depth information in MPI distributed
    uses of OSPRay (both `mpi_offload` and `mpi_distributed` devices)
-   Many robustness fixes for both the `mpi_offload` and
    `mpi_distributed` devices through improvements to the `mpi_common`
    and `mpi_maml` infrastructure libraries
-   Major sample app cleanups
    -   `ospray_sg` library is the new basis for building apps, which is
        a scene graph implementation
    -   Old (unused) libraries have been removed: miniSG, command line,
        importer, loaders, and scripting
    -   Some removed functionality (such as scripting) may be
        reintroduced in the new infrastructure later, though most
        features have remained and have been improved
    -   Optional improved texture loading has been transitioned from
        ImageMagick to OpenImageIO
-   Many cleanups, bug fixes, and improvements to `ospray_common` and
    other support libraries
-   This will be the last release in which we support MSVC12 (Visual
    Studio 2013). Future releases will require VS2015 or newer

### Changes in v1.3.1:

-   Improved robustness of OSPRay CMake `find_package` config
    -   Fixed bugs related to CMake configuration when using the OSPRay
        SDK from an install
-   Fixed issue with Embree library when installing with
    `OSPRAY_INSTALL_DEPENDENCIES` enabled

### Changes in v1.3.0:

-   New MPI distributed device to support MPI distributed applications
    using OSPRay collectively for "in-situ" rendering (currently in
    "alpha")
    -   Enabled via new `mpi_distributed` device type
    -   Currently only supports `raycast` renderer, other renderers will
        be supported in the future
    -   All API calls are expected to be exactly replicated (object
        instances and parameters) except scene data (geometries and
        volumes)
    -   The original MPI device is now called the `mpi_offload` device
        to differentiate between the two implementations
-   Support of Intel® AVX-512 for next generation Intel® Xeon® processor
    (codename Skylake), thus new minimum ISPC version is 1.9.1
-   Thread affinity of OSPRay's tasking system can now be controlled via
    either device parameter `setAffinity`, or command line parameter
    `osp:setaffinity`, or environment variable `OSPRAY_SET_AFFINITY`
-   Changed behavior of the background color in the SciVis renderer:
    `bgColor` now includes alpha and is always blended (no
    `backgroundEnabled` anymore). To disable the background do not set
    `bgColor`, or set it to transparent black (0, 0, 0, 0)
-   Geometries "`spheres`" and "`cylinders`" now support texture
    coordinates
-   The GLUT- and Qt-based demo viewer applications have been replaced
    by an example viewer with minimal dependencies
    -   Building the sample applications now requires GCC 4.9
        (previously 4.8) for features used in the C++ standard library;
        OSPRay itself can still be built with GCC 4.8
    -   The new example viewer based on `ospray::sg` (called
        `ospExampleViewerSg`) is the single application we are
        consolidating to, `ospExampleViewer` will remain only as a
        deprecated viewer for compatibility with the old `ospGlutViewer`
        application
-   Deprecated `ospCreateDevice()`; use `ospNewDevice()` instead
-   Improved error handling
    -   Various API functions now return an `OSPError` value
    -   `ospDeviceSetStatusFunc()` replaces the deprecated
        `ospDeviceSetErrorMsgFunc()`
    -   New API functions to query the last error
        (`ospDeviceGetLastErrorCode()` and `ospDeviceGetLastErrorMsg()`)
        or to register an error callback with `ospDeviceSetErrorFunc()`
    -   Fixed bug where exceptions could leak to C applications

### Changes in v1.2.1:

-   Various bug fixes 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 bug fixes
    -   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
    -   Added 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 bug fixes 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, bug fixes, 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, bug fixes, 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 `double`s
    -   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, bug fixes, 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 1.5×
-   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 (sub-)regions 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 runtime
-   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