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Release 1.9 -- ?? 2017 (compared to 1.8)

Dependency and standards changes:

  • C++11 required: OSL 1.9 requires a minimum standard of C++11. It should also build against C++14 (and we intend to make it C++-17-safe, as soon as it is ratified.
  • LLVM 3.9 / 4.0: Support for LLVM 3.4 has already been removed, and support for LLVM 3.5 will be removed as soon as we address some performance issues with the JIT in 3.9+.
  • OpenImageIO 1.7+: This release of OSL should build properly against OIIO 1.7 or newer. You may find that 1.6 is still ok, but we are not doing any work to ensure that.
  • CMake >= 3.2.2
  • Boost >= 1.55

Language features:

Standard library additions/changes:

API changes, new options, new ShadingSystem features (for renderer writers):

  • ShadingSystem API changes:
  • ShadingSystem attribute additions/changes:
  • Shader group attribute additions/changes:
  • RendererServices:

Performance improvements:

Bug fixes and other improvements:

Build & test system improvements and developer goodies:

Documentation:

Release 1.8 [1.8.3] -- 20 Feb 2017 (compared to 1.7)

Dependency and standards changes:

  • OSL now builds properly against LLVM 3.9 and 4.0 (in addition to 3.5 and 3.4). Please note that for 3.9 or 4.0 (which use MCJIT), the JIT overhead time is about twice as much as when using LLVM 3.4/3.5 ("old" JIT), but the resulting code runs a bit faster. You may see fast, low-quality, interactive renders slow down, but long complex renders speed up. We are working to address the JIT overhead. In the mean time, if you are especially sensitive to interactive compile speed, just keep using LLVM 3.5 (or 3.4) while we work to address the problem. OSL 1.8 will be the last branch that supports LLVM 3.4 and 3.5.
  • C++ standard: OSL 1.8 should build againt C++03, C++11, or C++14. OSL 1.8 is the last release that will build against C++03. Future major releases will require C++11 as a minimum.
  • OpenImageIO: This release of OSL should build properly against OIIO 1.6 or newer.

New library: liboslnoise and header oslnoise.h expose OSL's noise functions to C++ apps. Currently, only signed and unsigned perlin, and cellnoise, are exposed, but other varieties and options may be added if desired. #669 (1.8.2)

Language features:

  • Function return values are now allowed to be structs. (#636)
  • oslc now will warn when assigning the result of a "comma operator", which almost always is a programming error where the shader writer omitted the type name when attempting to construct a vector or matrix. (#635) (1.8.0/1.7.3)
  • Nested structs (structs containing other structs) are now functional as shader parameters, with initialization working as expected with nested { {...}, {...} }. #640 (1.8.0)
  • oslc (and liboslcomp) now supports UTF-8 filenames, including on Windows. #643 (1.8.0)
  • osl now accepts hexidecimal integer constants (such as 0x01ff). #653 (1.8.1)

Standard library additions/changes:

  • pow(triple,triple) is now part of the standard library. (1.8.2)
  • New getattribute() tokens: "shader:shadername", "shader:layername", and "shader:groupname" lets the shader retrieve the shader, layer, and group names. This is intended primarily for helpful error messages generated by the shader. #673 (1.8.2)
  • The texture(), texture3d(), and environment() functions now accept an optional "errormessage" parameter (followed by a string variable reference). A failure in the texture lookup will result in an error message being placed in this variable, but will not have any error message passed to the renderer (leaving error handling and reporting entirely up to the shader). #686 (1.8.2)
  • select(a,b,cond) is similar to mix, but without interpolation -- if cond is 0, returns a, else return b (per comonent). #696 (1.8.3)

API changes, new options, new ShadingSystem features (for renderer writers):

  • ShadingSystem API changes:
    • Long-deprecated ShadingAttribState type has been removed (now called ShaderGroup).
    • ShadingSystem::create() and destroy() are no longer necessary and have been removed.
    • A new Shadingsystem::optimize_group() method takes bit fields describing which ray types are known to be true or false, allowing specialized versions of the shader to be optimized for certain ray types (such as for shadow rays only, or displacement shades only). #668 (1.8.2)
  • ShadingSystem attribute additions/changes:
    • Attribute "userdata_isconnected", if set to a nonzero integer, causes a shader call to isconnected(param) to return 1 if the parameter is potentially connected to userdata (that is, if lockgeom=0 for that parameter). This if for particular renderer needs, and the default remains for isconnected() to return 1 only if there is an actual connection. #629 (1.8.0/1.7.3)
    • Attribute "no_noise" will replace all noise calls with an inexpensive function that returns 0 (for signed noise) or 0.5 (for unsigned noise). This can be helpful in understanding how much render time is due to noise calls. #642 (1.8.0)
    • Attribute "no_pointcloud" will short-circuit all pointcloud lookups. This can be helpful in understanding how much render time is due to pointcloud queries. #642 (1.8.0)
    • When the attribute "profile" is set, the statistics report will include a count of the total number of noise calls. #642 (1.8.0)
    • ShadingSystem and shader group attribute "exec_repeat" (int; default is
      1. can artifically manipulate how many times the shader is executed. This can sometimes be handy for tricky benchmarks. #659 (1.8.2)
    • Attribute "force_derivs" can force derivatives to be computed everywhere. (Mostly good for debugging or benchmarking derivatives, not intended for users.) #667 (1.8.2)
    • Attribute "llvm_debug_ops" adds a printf before running each op. This is mostly for debugging OSL itself, not for users. (1.8.3)

Performance improvements:

  • New runtime optimization: better at understanding the initial values of output parameters and what optimizations can be done based on that. #657 (1.8.1)
  • Better runtime optimization of certain matrix constructors. #676 (1.8.2)
  • Improved alias analyis for parameters with simple initialization ops. #679 (1.8.2)
  • Runtime optimizer now constant-folds bitwise &, |, ^, ~ operators. #682 (1.8.2)
  • Improved runtime constant folding of triple(space,const,const,const) when the space name is known to be equivalent to "common". #685 (1.8.2)

Bug fixes and other improvements:

  • oslc bug: getmatrix() failed to note that the matrix argument was written. #618 (1.8.0/1.7.2)
  • Fix oslc incorrectly emitting init ops for constructor color(float). #637 (1.8.0/1.7.3)
  • Fix subtle bug in runtime optimizer that could seg fault. #651 (1.8.0)
  • Fixed incorrect instance merging when unspecified-length arrays differed. #656 (1.8.1/1.7.4)
  • Fix oslc crash/assertion when indexing into a closure type. #663
  • A version of spline() where the knots were colors without derivs and the abscissa was a float with derivs, computed its result derivatives incorrectly. #666
  • Fix incorrect dropping of certain optional texture() arguments. #671 (1.8.2/1.7.5)
  • Fix: matrix parameters initialized with matrix(space,1) did not initialize properly. #675 (1.8.2/1.7.5)
  • Bug fix: matrix parameters initialized with matrix(space,1) did not initialize properly. #675 (1.8.2/1.7.5)
  • oslc: better error reporting for use of non-function symbol as a function. #684 (1.8.2/1.7.5)

Build & test system improvements and developer goodies:

  • Default build is now C++11! Currently, the project will still build as C++03, but to do so you must explicitly 'make USE_CPP11=0'. #615 (1.8.0)
  • Build: better handling of multiple USE_SIMD options. #617 (1.8.0/1.7.2)
  • CMake FindOpenEXR.cmake totally rewritten, much simpler and better. #621 (1.8.0/1.7.2)
  • 'make CODECOV=1' on a gcc/clang system will run the testsuite and generate a code coverage report in build/$PLATFORM/cov/index.html #624 (1.8.0)
  • Remove support for LLVM 3.2 or 3.3. Now the minimum supported version is LLVM 3.4. #627 (1.8.0)
  • Changed the CMake variable OSL_BUILD_CPP11 to simply USE_CPP11 (matching the name used for the Makefile wrapper). #634 (1.8.0)
  • Clear up inconsistencies with USE_LIBCPLUSPLUS vs OSL_BUILD_USECPLUSPLUS #639 (1.8.0)
  • Windows build improvements: Fixed build breaks #643 (1.8.0); fix problems with lexer #646 (1.8.0/1.7.3).
  • Improvements in finding OpenEXR installations. #645 (1.8.0)
  • Travis tests now include gcc 6 tests. #647 (1.8.0)
  • Fixes for build breaks and warnings for gcc6. #647 (1.8.0/1.7.3)
  • Fix build breaks for certain older versions of OIIO.
  • Failed to properly propagate the C++ standard flags (e.g. -std=c++11) when turning llvm_ops.cpp into LLVM bitcode. #674 (1.8.2/1.7.5)
  • Suppress compile warnings when using clang 3.9. #683 (1.8.2/1.7.5)
  • Improve search for Partio. #689 (1.8.3)
  • More robust finding of LLVM components. (1.8.3)
  • OSL now builds properly with LLVM 3.9 and 4.0. #693 (1.8.3)

Documentation:

  • Various typos fixed.
  • Explain rules for connections.
  • Explain that getattribute retrieves userdata.
  • Document that #once works in shader source code.
  • The CHANGES and INSTALL files have been changed from plain text to Markdown.

Release 1.7.5 -- 1 Nov 2016 (compared to 1.7.4)

  • Fix oslc crash/assertion when indexing into a closure type. #663
  • A version of spline() where the knots were colors without derivs and the abscissa was a float with derivs, computed its result derivatives incorrectly. #666
  • Incorrect dropping of certain optional texture arguments. #671
  • Bug fix: matrix parameters initialized with matrix(space,1) did not initialize properly. #675
  • Suppress warnings when compiling with clang 3.9. #683
  • oslc: better error reporting for use of non-function symbol as a function. #684
  • Filed to properly propagate the C++ standard flags (e.g. -std=c++11) when turning llvm_ops.cpp into LLVM bitcode. #674

Release 1.7.4 -- 1 Aug 2016 (compared to 1.7.3)

  • Bug fix: incorrect instance merging when unspecified-length arrays differed. (#656)
  • Make oslc understand hex integer constants (like 0x01fc). #653

Release 1.7.3 -- 1 Jul 2016 (compared to 1.7.2)

  • ShadingSystem attribute "userdata_isconnected", if set to a nonzero integer, causes a shader call to isconnected(param) to return 1 if the parameter is potentially connected to userdata (that is, if lockgeom=0 for that parameter). This if for particular renderer needs, and the default remains for isconnected() to return 1 only if there is an actual connection. #629 (1.8.0/1.7.3)
  • oslc now will warn when assigning the result of a "comma operator", which almost always is a programming error where the shader writer omitted the type name when attempting to construct a vector or matrix. #635 (1.8.0/1.7.3)
  • Fix oslc incorrectly emitting init ops for constructor color(float). #637 (1.8.0/1.7.3)
  • Bug fix: don't test or set the "layer ran bits" on the last layer of the group. #626 (1.8.0/1.7.3)
  • Windows fixes: build breaks #643; fixes for lexer #646.
  • Fixes for clean compile with gcc 6.x. #647

Release 1.7.2 -- 1 Mar 2016 (compared to 1.7.1)

  • Build: better handling of multiple USE_SIMD options. #617
  • oslc bug: getmatrix() failed to note that the matrix argument was written. #618
  • CMake FindOpenEXR.cmake totally rewritten, much simpler and better. #621

Release 1.7 [1.7.1] -- 29 Jan 2016 (compared to 1.6)

Language, standard libary, and compiler changes (for shader writers):

  • Language features:
    • Support for closure arrays in shader inputs. #544 (1.7.0)
    • Disallow quote strings from spanning lines (just like you can't in C). This was never intended, but was accidentally allowed by the oslc lexer. #613 (1.7.1)
  • Standard library additions/changes:
    • linearstep() and smooth_linearstep() functions. #566 (1.7.0)
    • isconstant(expr) returns 1 if the expression can be turned into a constant at runtime (with full knowledge of the shader group's parameter values and connections). This is helpful mostly for advanced shader writers to verify their assuptions about which expressions can end up being fully constant-folded by the runtime optimizer. #578 (1.7.1)
    • New behavior of isconnected(parmaname): return 1 if the parameter is connected to an upstream layer, 2 if connected to a downstream layer, 3 if both, 0 of neither. #589 (1.7.1)
    • int hash(string) returns an integer hash of a string. #605 (1.7.1)
    • int getchar(string s,int i) returns the integer character code of the i-th character in string s. #589 (1.7.1)
  • Removed from stdosl.h all closure function declarations that were not documented in the spec and not implemented in testrender. (1.7.0)
  • osutil.h changes:
    • New draw_string() rasterizes a string! #606 (1.7.1)

API changes, new options, new ShadingSystem features (for renderer writers):

  • shade_image() utility runs a shader to generate every pixel of an ImageBuf. (1.7.0)
  • ShaingSystem::optimize_group() is a new method that lets you force a shader group to optimize/JIT (without executing it). (1.7.0)
  • Remove deprecated ShadingSystem::state() method. #551 (1.7.0)
  • Changed logic of lazy shader layer evaluation: "unconnected" layers are now lazy. That means that shaders that appear to have no connected outputs, and don't set globals or set renderer outputs, are no longer run unconditionally. #560 (1.7.0)
  • ShadingSystem attribute additions/changes:
    • ShadingSystem attribute "lockgeom" default changed to 1. (1.7.0)
    • SS::getattribute new attributes "num_attributes_needed", "attributes_needed", "attribute_scopes", and "unknown_attributes_needed" can be used to query for a shader group what OSL getattribute queries it might make. #537 (1.7.0)
    • "llvm_debug_layers" controls debug printfs for layer enter/exit (strictly for our debugging of the system; not intended for users). (1.7.0)
    • "opt_passes" controls the number of optimization passes over each instance (default: 10). This is mainly for developer debugging, you should not need to change or expost this. #576 (1.7.1)
    • "connection_error" controls whether a bad connection is considered a true error (or is just ignored). #583 (1.7.1)
  • Shader group attribute additions/changes:
    • Group attribute "entry_layers" can explicitly provide a list of which layers within the group (specified by layer names) are "entry points", and then new ShadingSystem methods execute_init(), execute_layer(), and execute_cleanup() can be used to call them individually in any order. The old execute(), which executes starting with the "root" and lazily evaluating any upstream nodes needed, still works and is still the usual way to run shaders for most purposes. #553 (1.7.0)
  • RendererServices:
    • Remove has_userdata() method, which was unused. #603 (1.7.1)
  • osl.imageio.so -- an OIIO image reader plugin that runs OSL shaders to generate pixels in an image (or texture). #531 (1.7.0)

Performance improvements:

  • Much faster (10x or more, for large shaders) parsing of oso files (and .osl source as well). #511 (1.7.0)
  • Optimize away unused optional arguments to noise functions. #548 (1.7.0)
  • Improved runtime optimization via better tracking of variable aliasing across certain basic block boundaries. #585,588 (1.7.1)

Bug fixes and other improvements:

  • oslinfo now has a "--runstats" flag to report how much time it takes to OSLQuery the shaders. (Mostly used for benchmarking the speed of OSLQuery internals.) #510 (1.7.0)
  • Improved "debug_uninit" mode eliminates certain false alarms, and when uninitialized values are found, the error messages is more clear about which shader group and layer were involved (in addition to the previous reporting of the OSL source file ane line number). #512 (1.7.0)
  • Bug fix serializing shader groups with "unsized arrays." #539 (1.7.0)
  • Make sure OSL works fine with LLVM 3.5. #542 (1.7.0)
  • Bug fix with unconditional running of earlier layers. (1.7.0)
  • Improved error message for range errors and uninitialized variable errors (when using "range_checking" and "debug_uninit", respectively). #540 (1.7.0)
  • Fixed oslc bug where shader parameters that were structs and whose values were initialized by copying another struct whole, generated incorrect initialization code. (1.7.0)
  • Better tracking of layers that are the unused duplicates after an instance merge. This allows us to be sure those layers are skipped, and avoid situations where they look like they should run unconditionally. #506 (1.7.0)
  • Record oslc options in a comment at the start of the oso file. #575 (1.7.1)
  • Better error messages when an closure is used that is unknown to the renderer. #576 (1.7.1)
  • Fix potential SIGFPE from divide-by-zero in shaders. #596 (1.7.1)
  • Improve optimizer logic behind lifetime analysis inside loops, fixing some subtle optimizer bugs. #598 (1.7.1)

Build & test system improvements and developer goodies:

  • Allow testshade to test OSL snippets without whole full shaders. #564 (1.7.0)
  • Much less verbose builds, when not using VERBOSE=1. (1.7.0)
  • New build-time options:
    • USE_NINJA=1 will use Ninja rather than Make (faster!). #546 (1.7.0)
    • USE_fPIC=1 will build with -fPIC. (1.7.0)
    • OSL_BUILD_TESTS=0 will cause it to not build unit tests, testshade, or testrender. (1.7.0)
    • OSL_NO_DEFAULT_TEXTURESYSTEM=1 will cause the ShadingSystem to not create a raw OIIO::TextureSystem, and instead hit an assertion if a TextureSystem is not passed to the ShadingSystem constructor. Use this when building OSL to embed in renderers that supply their own TextureSystem class rather than using OIIO's. (1.7.0)
  • Fixes when building for VS2012. #543 (1.7.0)
  • Add --path to testshade and testrender to allow setting search path to find oso files. #549 (1.7.0)
  • Testsuite: the presence of a file called "OPTIMIZEONLY" in a test directory will cause that test to run only in optimized mode. (1.7.0)
  • Better detection of clang version. #559 (1.7.0)
  • testshade --offsetst and --scalest let you make custom st ranges for the image being sampled (not restricted to 0-1 defaults). #565 (1.7.0)
  • C++11 compatibility. #573 (1.7.1)
  • Ensure proper build on Apple Clang 6.1. #580 (1.7.1)
  • CMake build option OSL_BUILD_PLUGINS, if set to OFF, will disable building of any OSL plugins (such as the osl.imageio.so). #587 (1.7.1)
  • CMake build option OSL_BUILD_TESTS, if set to OFF, will disable building of standalone test programs. #587 (1.7.1)
  • We now use Travis-CI to do continuous integration and testing of every checkin and PR for a variety of platform / compiler / option combinations. #592,595,600 (1.7.1)
  • Get rid of the "make doxygen" targer, which did nothing. (1.7.1)
  • Build scripts automatically use ccache if available and in an obvious location. This can be forcefully disabled by setting USE_CCACHE=0. #595,597 (1.7.1)
  • Use deprecation attribute for the methods that are considered deprecated. #602,607,608 (1.7.1)
  • Testsuite organization overhaul now avoids copying test source to build. #612 (1.7.1)
  • New macro OSL_CPLUSPLUS_VERSION (set to 03, 11, 14, etc) rather than using OSL_USING_CPP11. #581 (1.7.1)

Documentation:

Release 1.6 -- 26 May 2015 (compared to 1.5)

Language, standard libary, and compiler changes (for shader writers):

  • It is now supported to have shader parameters that are arrays of unspecified length (like 'float foo[] = {...}'). Their length will be fixed when they are assigned an instance value of fixed length, or when connected to another layer's output parameter of fixed length. If there is no instance value nor a connection, the length will be fixed to the number of elements given in the default initializer. #481 #497 (1.6.4)
  • The "comma operator" now works in the way you would expect in other C-like languages. #451 (1.6.2)
  • The "and", "or", and "not" keywords are synonyms for the &&, ||, and ! operators, respectively. (If this seems strange, note that this is true of C++ as well.) #446 (1.6.2)
  • oslc will now silently ignore trailing commas in function or shader parameter lists and metadata lists. #447 (1.6.2)
  • The "gabor" varieties of noise were found to have a serious mathematical bug, which after fixing results in a change to the pattern. We are hoping that they were rarely used, but beware a change in appearance. (1.6.1)
  • We have clarified that shader metadata may be arrays (still not structs or closures) and fixed the implementation to support this (in addition to several other ways that metadata was brittle). (1.6.2)
  • Spec clarification: emission() has units of radiance, so a surface directly seen by the camera will directly reproduce the closure weight in the final pixel, regardless of it being a surface or volume. Thus, you don't need to weight it by PI. #427 (1.6.2)
  • oslc bug fixed in variable declaration + assignment of nested structs. #453 (1.6.2)

API changes, new options, new ShadingSystem features (for renderer writers):

  • New ShadingSystem attribute int "profile", if set to 1, will include in the runtime statistics output a measure of how much total time was spent executing shaders, as well as the identities and times of the 5 shader groups that spent the most time executing. Note that this option is 0 (off) by default, since turning it on can add significantly to total runtime for some scenes. #418 (1.6.2)
  • New per-ShaderGroup attributes:
    • You can retrieve information about all closures that an optimized group might create using new queries "num_closures_needed", "closures_needed", "unknown_closures_needed". This could be useful for renderers by, for example, noticing that a material can't possibly call the "transparent" closure, and thus concluding that it must be opaque everywhere and thus shadow rays need not execute shaders to determine opacity. (#400) (1.6.0)
    • You can retrieve information about all "globals" (P, N, etc.) that an optimized group needs using new queries "num_globals_needed" and "globals_needed". This could be useful for renderers for which computing those globals is very expensive; examining which are truly needed and only computing those. (#401) (1.6.0)
  • It is now possible to specify per-group "renderer_outputs" in the form "layername.paramname", thus designating a parameter of a specific layer as a render output that should be preserved, but excluding identically named output variables in other layers. #430 (1.6.2)
  • New ShadingSystem runtime option int "lazy_userdata", when set to nonzero, causes userdata to be interpolated lazily (on demand) rather than at the beginning of a shader that needs it. For some renderer implementations, this may be a performance improvement. #441 (1.6.2)
  • New OSLCompiler::compile_buffer() method compiles OSL source in a string into oso stored in a string. When combined with ShadingSystem:: LoadMemoryCompiledShader, this allows an application to go straight from osl source code to executing shader without writing disk file or launching a shell to invoke oslc. #444 (1.6.2)
  • OSLQuery: in the OSLQuery::Parameter structure, the 'validdefault' field now reliably is true for a valid default value, false if no default value could be statically determined (for example, if the param default is the result of code that must run at runtime). (1.6.2)
  • Extend ShadingSystem::get_symbol() to retrieve the symbol from a particular named layer (rather than always getting it from the last layer in which the name is found). #458 (1.6.2)
  • New SS option "opt_merge_instances_with_userdata", which if set to 0 will prevent instance merging for instances that access userdata. If you don't know why you'd want this turned off, you don't want it turned off! #459 (1.6.2)
  • New RendererServices::supports() function allows for future expansion of querying (by the ShadingSystem) of features supported by a particular renderer. #470 (1.6.2)
  • New ShadingSystem::execute() variety that takes a ShadingContext* rather than a ShadingContext&. If you pass NULL for the context pointer, the SS will automatically allocate (and eventually release) a context for you. #471 (1.6.2)
  • New RendererServices API methods added that supply a handle-based version of texture(), texture3d(), environment(), and get_texture_info(), in addition to the existing name-based versions. Renderer implementations will need to add these, if they overload the name-based ones. #472 (1.6.2)
  • RendererServices API methods for texture have been revised again, now each variety takes a filename (will always be passed) and also a TextureHandle* and TexturePerthread* (which may be NULL). Renderers may use the name only if that's easiest, but also may use the handle when supplied. #478 (1.6.3)
  • New ShadingSystem methods: find_symbol() and symbol_address() tease apart the functionality of the (now deprecated) get_symbol(). The fairly expensive name lookup is in find_symbol(), and it can be done once per shader group (and reused for the lifetime of the group), while the relatively inexpensive symbol_address() can be cheaply done after each shader execution. If your renderer is currently using get_symbol() to retrieve the shader output values after each shade, we strongly recommend changing to the find_symbol() [once up front] and symbol_address() [once per execution] combination for improved performance. #495 (1.6.4)

Performance improvements:

  • Many noise() varieties have been sped up significantly on architectures with SIMD vector instructions (such as SSE). Higher speedups when returning vectors rather than scalars; higher speedups when supplying derivatives as well, higher speedups the higher the dimensionality of the domain. We're seeing 2x-3x improvement for noise(point), depending on the specific variety, 3x-4x speedup for 4D noise varieties. #415 #422 #423 (1.6.1, 1.6.2)
  • Change many transcendental functions (sin, cos, exp, etc) to use approximations that are must faster than the 100% correct versions in libm. The new ones may differ from the old in the last decimal place, which is probably undesirable if programming ICBM guidance systems, but seems fine for rendering when the result is many times faster to evaluate those functions. You can turn it back to the fully precise and slow way by building with OSL_FAST_MATH=0. #413 (1.6.0)
  • New runtime optimization of mix(a,a,x) -> a (even if none of them are constant). #438 (1.6.2)
  • Fix performance regression: avoid incrementing profile-related stats on every execution if profiling is disabled. (1.6.2)
  • When the runtime optimizer can figure out which textures are being called, it will retrieve the handle once and generate code for handle-based RendererServices callbacks, rather than name-based ones. This speeds up texture-heavy shading by 5-10% by eliminating the need for the name-to-handle lookups for every texture call. #472 (1.6.2)
  • New runtime optimization: constant folding of sincos(). #486 (1.6.4)
  • New runtime optimization: constant folding of matrix construction from 16 floats. #486 (1.6.4)
  • Improved optimizations -- caught some additional places where assignments could be found to be useless and eliminated. #403 (1.6.4)
  • Improved speed of runtime optimization for large shaders. #499 (1.6.5)
  • Improved threading performance by not locking during pointcloud_search and pointcloud. (1.6.5)
  • Dramatic speedup of runtime optimization of large shaders (5x for big shaders (1.6.5)
  • Speed up loading of large shaders from disk (1.6.5).

Bug fixes and other improvements:

  • oslinfo --param lets you ask for information on just one parameter of a shader. #397 (1.6.0)
  • oslc now properly catches and issues error messages if you define a struct with duplicate field names. #398 (1.6.0)
  • Some math speedups (especially those involving sqrt). (1.6.0)
  • Improved detection of shader groups that optimize away to nothing. (1.6.2)
  • Fix of possible (but never reported) bug with instancing merging. #431 (1.6.2)
  • Fix incorrect oslc code generation when assigining an element of an array-of-structs to another element of array-of-structs. #432 (1.6.2)
  • Bug fix in code generation of constant folding of getmatrix() calls (never reported symptomatic). #440 (1.6.2)
  • Fixes to constuction of temporary filename used for group serialization archive. (1.6.2)
  • Internals fix: logb() incorrectly declaring derivative functions (it has no derivs). #437 (1.5.12/1.6.2)
  • Catch serialization errors resulting from failed system() calls to zip/tar the archive. #436 (1.5.12/1.6.2)
  • Bug fix: Delay instance merging from ShaderGroupEnd until optimize time, it messed with the serialization. #426 (1.5.12/1.6.2)
  • Fix OSLQuery crash when reading .oso file of a compiled shader that had local variables but no parameters. #435 (1.5.12/1.6.2)
  • Shader-wide metadata is now correctly output by oslc, and correctly read by OSLQuery. #455 (1.6.2)
  • Only merge instances when optimize level >= 1. #456 (1.6.2)
  • Bug fix: runtime optimizer should not consider a layer unused if its outputs are renderer outputs. Also fix subtle bug in detecting whether an output param is a renderer output. #457 (1.6.2)
  • Clear derivatives properly in the implementaiton of gettextureinfo. #463 (1.6.2)
  • Correct handling of point-like shader parameters defined with default values that use the constructors that provide "space" names. #465 (1.6.2)
  • Fixed some subtle runtime optimizer bugs. #485 #491 (1.6.4)
  • Using "debugnan" mode now also checks for NaNs in the results of interpolated userdata. #490 (1.6.4)
  • Fixed bug in generating code for closure optional keyword parameters. #492 (1.6.4)
  • Fixed bug where instances were incorrectly merged if they had a parameter that was never used in the shader, but was connected downstream, and each of the two instances had a difference instance value for that parameter. #493 (1.6.4)
  • Fix critical bug that in very particular circumstances could result in shader layers not executing when they should. (1.6.5)

Under the hood:

  • Change a couple long-deprecated OIIO calls to modern versions. #448 (1.5.12/1.6.2)
  • Change runtime code generation, putting TextureOptions, NoiseParams, TraceOptions in the ShadingContext, which avoided a dynamic alloca which was tickling an LLVM code generation bug. #442 (1.5.12/1.6.2)
  • Allow memory-aligned closure component classes. (1.6.2)
  • Lots of internal refactoring of llvm_ops.cpp in order to better and more performantly support MCJIT and newer LLVM releases. #468 (1.6.4)

Build & test system improvements and developer goodies:

  • Windows build fix for compiling shaders finding the right oslc.exe. #399 (1.6.0/1.5.11)
  • Fix thread contention issue in testshade that was making benchmarks inaccurate. $407 (1.6.0)
  • Build scripts better help messages. (1.6.0)
  • Changes to build correctly against LLVM 3.5, though please note that using LLVM 3.5 seems to require C++11. If you have C++98 toolchain, then please continue using LLVM 3.4. #412 (1.6.0)
  • testrender improvements: update the microfacet models to the latest improved visible normal sampling technique of d'Eon & Heitz, stratified sampling, simplification of Oren-Nayar, and speed improvements. #425 (1.6.2)
  • Build fixes for recent OIIO changes. (1.5.12/1.6.2)
  • testshade -group now accepts the name of a file containing the serialized group. #439 (1.6.2)
  • Various fixes for Windows and Visual Studio 2010. #461 #462 #464 (1.6.2)
  • testshade -param can now specify arrays. (1.6.4)
  • Remove the USE_MCJIT build flag. Now we ALWAYS compile with ability to use MCJIT any time we are using LLVM that's new enough to have it, and a renderer can select MCJIT at runtime by setting the SS attribute "mcjit" to nonzero (the default, 0, will use old JIT). When compiling against LLVM 3.6 or newer, which has removed MCJIT, OSL will always use MCJIT. #487 #488 (1.6.4)
  • Fixes to work with LLVM 3.5 and 3.6, though 3.6 especially has not yet been very thoroughly tested for OSL. #487 (1.6.4)
  • C++11 support: the preprocessor symbol OSL_BUILD_CPP11 is set to 1 if OSL was built with C++11 (or higher) support, and the separate OSL_USING_CPP11 is set to 1 if C++11 is detected right now. (These can be different from the point of view of an app using OSL headers.) #508 (1.6.6RC1)

Documentation:

  • Short chapter added to spec describing the syntax of our serialization protocol.
  • Documentation fix: surfacearea() should return float, not int. (1.5.12)
  • Clarified that the way to use gettextureinfo() to retrieve matrices from textures created from rendered images (or shadow maps) is with the tags "worldtocamera" (for the world-to-3D-camera) and "worldtoscreen" (for the world-to-2D-projection that runs -1 to +1 in x and y).
  • Clarified documentation on gettxtureinfo(file,"exists"). (1.6.2)
  • Improved the comments in shaderglobals.h to explain in detail the meaning and use of all the fields. #489 (1.6.4)

Release 1.5.12 -- 26 Dec 2014 (compared to 1.5.11)

  • Build fixes for 32 bit machines.
  • Documentation fix: surfacearea() should return float, not int.
  • Bug fix: Delay instance merging from ShaderGroupEnd until optimize time, it messed with the serialization.
  • Build fixes for recent OIIO changes.
  • Fix OSLQuery crash when reading .oso file of a compiled shader that had local variables but no parameters.
  • Catch serialization errors resulting from failed system() calls to zip/tar the archive.
  • Fix logb() incorrectly declaring derivative functions (it has no derivs).
  • Change a couple long-deprecated OIIO calls to modern versions.

Release 1.5.11 -- 22 Sep 2014 (compared to 1.5.10)

  • Windows compilations fixes for very MSVC 2013.
  • Windows build fix for compiling shaders finding the right oslc.exe. #399
  • Speedup from telling gcc/clang to ignore the fact that math functions can set errno (helps code generation of sqrtf in particular.
  • Fix thread contention issue in testshade which could make it hard to use testshade as a benchmark with many threads.
  • Make it build properly with LLVM 3.5.
  • Fix compiler warnings about signed/unsigned comparisons.

Release 1.5 (1.5.10) -- July 30, 2014 (compared to 1.4)

Language, standard libary, and compiler changes (for shader writers):

  • New closure function for microfacet BSDFs: closure color microfacet (string distribution, normal N, float alpha, float eta, int refract) closure color microfacet (string distribution, normal N, vector U, float xalpha, float yalpha, float eta, int refract) These replace the growing zoo of microfacet_blah functions (using different distribution values such as "beckmann" or "ggx", as well as selecting refraction when refract!=0). The old varieties are now considered deprecated and will eventually be removed (but will alow back-compatibility of compiled oso files).
  • Remove documentation about unimplemented hash() function -- it was never implemented, and we can't figure out what it's good for. (#359) (1.5.7)
  • Documented the specific names that should be used with getattribute() to retrieve common camera parameters. We should expect these to be the same for all renderers (though individual renderers may also support additional attribute queries). #393 (1.5.9)

API changes, new options, new ShadingSystem features (for renderer writers):

  • ShadingSystem API changes:
    • ShadingSystem::Parameter() has a new variety that can set lockgeom=0 for a particular parameter at runtime, even if it was not declared this way in the shader's metadata. This allows an app to effectively say "I intend to vary this shader's parameter value, don't optimize as if it were a a constant." (1.5.1)
    • New ShadingSystem::ReParameter() lets you change the instance value of a shader parameter after the shader group has already been declared (but only if the shader has not yet been optimized, OR if the parameter was declared with lockgeom=0). This, in combination with the new SS::Parameter() variety, lets an app select a parameter for variation, compile the shader network, and then continuously modify the value and re-render without needing to redeclare and recompile the shader group (though at a slightly higher execution cost than if the parameter were fully optimized. (1.5.1)
    • ShadingAttribState has been simlified and replaced with ShaderGroup. And ShadingAttribStateRef replaced by ShaderGroupRef. (1.5.1)
    • ShaderGroupBegin returns the ShaderGroupRef for the group, there is no need to call state() to get the group reference. (1.5.1)
    • New ShadingSystem::getattribute() and attribute() varieties that takes a ShaderGroup* as a first argument, allows setting and retrieval of attributes pertaining to a specific shader group. (#362, #368) (1.5.8) SEE SECTION BELOW ON GROUP-SPECIFIC ATTRIBUTES
    • New ShaderGroupBegin() variant takes a text description of a shader group. (3.5.8) (#379) For example: ShaderGroupBegin ("groupname", "surface", "param float fin 3.14; " /concatenate string/ "shader a alayer;" "shader b blayer;" "connect alayer.f_out blayer.f_in;");
    • ShadingSystem methods renderer() and texturesys() retrieve the RendererServices and TextureSystem, respectively. (1.5.8)
    • ShadingSystem statistics output now prints the version and major runtime options. (1.5.8) (#369)
  • New/changed ShadingSystem global attributes:
    • Attributes "archive_groupname" and "archive_filename", when set, will cause the named group to be fully archived into a .tar, .tar.gz, or .zip file containing the serialized description of the group, and all .oso files needed to reconstruct it. This is great for shipping debugging or performance benchmark cases to the developers! It's also a good way to "extract" a shader network from the midst of a complex renderer and then be able to reconstitute it inside a debugging test harness like testshade. (1.5.8) (#381) For more detail and explanation, please see AcademySoftwareFoundation#381
  • New per-ShaderGroup attributes:
    • ShadingSystem::getattribute(group,...) allows queries that retrieve all the names and types of userdata the compiled group may need ("num_userdata", "userdata_names", "userdata_types"), as well as the names of all textures it might access and whether it's possible that it will try to acccess textures whose names are not known without executing the shader ("num_textures_needed", "textures_needed", "unknown_textures_needed"). (#362) (1.5.8)
    • Retrieving the group attribute "pickle" (as a string) gives you the serialized description of the shader group in the same format that is accepted by ShaderGroupBegin(). (1.5.8) (#381)
    • Group-wise attribute "renderer_outputs" (array of strings) lets you specify different renderer outputs for each shader group in addition to the ShadingSystem-wide "renderer_outputs" that apply to all groups. Remember that naming the renderer outputs prevents those from being optimized away if they are not connected to downstream shaders. (1.5.8) (#386)
    • New group attribute queries: "groupname", "num_layers", "layer_names" allow you to ask for the name of the group, how many layers there are, and the names of all the layers.
  • ShaderGlobals changes:
    • Added a RendererServices pointer to ShaderGlobals, to eliminate a bunch of pointless indirection during shader execution. (1.5.2)
    • Split the definition of ShaderGlobals into its own header file, shaderglobals.h. (1.5.1)
  • RendererServices changes:
    • RendererServices::get_texture_info method parameters have changed, now includes an additional ShaderGlobals* parameter (as did all the other texture functions already). (1.5.5)
    • Split RendererServices definition into separate rendererservices.h. (1.5.6)
    • Add RendererServices::texturesys() that returns a pointer to the RS's TextureSystem. (1.5.6)
    • Add a ShaderGlobals* parameter to the various get_matrix and get_inverse_matrix methods. This makes it easier for renderers that might need the ShaderGlobals (or access to the void* renderstate contained therein) to look up matrices, especially if the renderer supports different per-primitive transformation name bindings. #396 (1.5.10)
    • Change the last 4 RenderServices methods that took a void* renderstate to instead take a ShaderGlobals *. It's more general, since the SG does itself contain the renderstate pointer, and some implementations or features might need the other contents of the SG. #396 (1.5.10)
  • OSLQuery changes:
    • OSLQuery::Parameter has a new 'structname' field, that for struct parameters reveals the name of the structure type. The oslinfo utility has also been updated to print this information. (1.5.4)
    • OSLQuery now may be initialized by a ShaderGroup*, which allows an app with a live shading system to query information about shaders much more efficiently than reloading and parsing the .oso file from disk. #387 (1.5.8)
    • OSLQuery API has replaced most of its std::string parameters and members with string_view and ustring, to speed it up and eliminate lots of small allocations. This may introduce some small source incompatibilities with the old OSLQuery, but they should be very easy to fix in your code. #387 (1.5.8)
  • Miscellaneous/general:
    • Use OIIO's new string_view for many public API input parameters that previously took a std::string& or a const char*. (1.5.7) (#361)
    • De-virtualized OSLCompiler and ShadingSystem classes -- it is now safe to construct them in the usual way, the create() and destroy() functions for them are optional/deprecated. (#363) (1.5.8)

Performance improvements:

  • Dramatically speed up LLVM optimization & JIT of small shaders -- reducing the per-shader-network compile overhead of small shaders from 0.1-0.2s to less than 0.01s per shader group. (1.5.1)
  • Runtime constant folding of substr(). (1.5.6)
  • Improved code generation for texture calls, removing redundant setting of optional texture parameters when they don't change from the default values. (1.5.6)
  • Remove lock from RendererServices texture calls that would create a big thread botteneck (but only for renderers that used the RS base class texture calls; those that overrode them would not notice). (1.5.6)
  • Constant folding of certain assignments to individual components or array elements. (#356) (1.5.7)
  • Much more complete constant-folding of format(). (1.5.8) (#366)
  • Enhanced simplification of component and array assignment, when multiple assignments actually fill out the entire array or aggregate. For example: 'color C; C[0] = 3.14; C[1] = 0; C[2] = 42.0;' Now it recognizes that all components are assigned and will replace the whole thing (and subsequent uses of C) with a constant color. (1.5.8) (#367)
  • Eliminate redundant retrieval of userdata within a shading network. (1.5.8) (#373)

Bug fixes:

  • testshade/testrender timer didn't properly break out execution time from setup time. (1.4.1/1.5.1)
  • Guard matrix*point transformations against possible division by zero. (1.4.1/1.5.1)
  • Fix subtle bug with splines taking arrays, where the number of knots passed was less than the full length of the array, and the knots had derivatives -- the derivatives would be looked up from the wrong spot in the array (and could read uninitialized portions of the array). (1.4.1/1.5.3)
  • Fix incorrect function declarations for the no-bitcode case (only affected Windows or if a site purposely built without precompiled bitcode for llvm_ops.cpp). (1.4.1/1.5.3)
  • When using Boost Wave for oslc's preprocessor, fixed it so that variadic macros work. (1.5.4)
  • Ensure that isconnected() works for struct parameters. (1.5.4)
  • Fix incorrect data layout in heap for certain array parameters. (1.5.5/1.4.2)
  • oslc -D and -U did not work properly when OSL was built against Boost Wave as the C preprocessor. (1.5.5/1.4.2)
  • oslc bug fix for innitializing array elements inside a parameter that's a struct. (1.5.6)
  • Implementation of the luminance() function has been improved to guarantee that all the components sum to exactly 1.0. (1.5.6)
  • OSLQuery: for array parameters whose source code only specify default values for partially initializing the array, nonetheless make the default vectors be the correct length for the array (with zeroes for array elements without explicit initialization). (1.5.6)
  • oslc: negating closures resulted in hitting an assertion. (1.5.6)
  • ShadingSystem - bug fix when Parameter() sets the same parameter twice for the same instance, the second time back to the default value. (1.5.8) (#370)
  • Fix debug printing crash when group name was not set. (1.5.7)
  • Bug fix with runtime optimization instance merging -- differing "lockgeom" status of parameters should invalidate the merge. (1.5.8) (#378)
  • Runtime optimizer bug fix: output parameter assignment elision was overly aggressive when the output parameter in question was a renderer output (and therefore should not be elided). (1.5.8) (#378)
  • Fix printf("%f",whole_float_array) to work properly. (1.5.8) (#382)
  • oslc improperly allowed ONE too many initializers for arrays. (1.5.8) (#383)

Under the hood:

  • Internals refactor that separates the runtime optimization from the LLVM generation and JIT. (1.5.1)
  • Removed legacy built-in closures that weren't actually used. (1.5.1)
  • Split all the direct calls to LLVM API into a separate LLVM_Util class, which has no other OSL dependencies and may be used from other apps to simpilfy use of LLVM to JIT code dynamically. (1.5.1)
  • Stop using deprecated TypeDesc #defines. (1.5.4)
  • A shader's printf, warning, and error output is now buffered so that all the "console" output from a shader invocation will appear contiguous in a log, rather than possibly line-by-line interspersed with the output of another shader invocation running concurrently in a different thread (1.5.5).
  • By de-virtualizing OSLCompiler and ShadingSystem classes, we make it much easier in the future to change both these classes (at least, adding new methods) and changing the Impl internals, without breaking link compatibility within release branches. (#363) (1.5.8)
  • Eliminate the need for a special dlopen when using OSL from within a DSO/DLL plugin of another app. (1.5.8) (#374, #384)

Build & test system improvements and developer goodies:

  • Make OSL work with LLVM 3.4 (1.5.4)
  • New llvm_util.h contains an LLVM_Util standalone utility class that can be used from any app as a simplified wrapper for LLVM code generation and JIT. (1.5.1)
  • testshade consolidates --iparam, --fparam, --vparam, --sparam into just --param that figures out the types (or could be explicitly told. (1.5.1)
  • More robust detection of clang, for older cmake versions. (1.4.1/1.5.1)
  • Handle 3-part version numbers for LLVM installations. (1.4.1/1.5.1)
  • Fix USE_EXTERNAL_PUGIXML versus USING_OIIO_PUGI issue. (1.4.1/1.5.3)
  • Remove all ehader include guards, switch to '#pragma once' (1.5.2)
  • Adjust build to account for new library names in OpenEXR 2.1. (1.5.3)
  • Make sure we include all OpenEXR and Ilmbase headers with <OpenEXR/foo.h> and remove the addition of OpenEXR sub-folder from system search paths. (1.5.1)
  • Better detection of LLVM version number from the LLVM installation. (1.5.1)
  • Support for using LLVM's "MCJIT" instead of "old JIT" (controlled by using the optional 'make USE_MCJIT=1'). This is mostly experimental, and not recommended since performance of old JIT is still much better than MCJIT. (1.5.6) Fixes in (1.5.8) (#385)
  • Moved the source of all public header files to src/include/OSL, to more closely mimic the install file layout. (1.5.6)
  • Fixes for compilation warnings with newer gcc. (1.5.7) (#351)
  • Fixes for IlmBase 2.1 build breakages. (#354) (1.5.7)
  • Make testshade multithreaded, so it's always exercising the thread safety of the shading system. (1.5.8) (#365)
  • Compatibility with cmake 3.0. (1.5.8) (#377)
  • Fix warnings with some gcc versions. (1.5.8)
  • Make testrender accept the new shadergroup syntax. (1.5.9)
  • Make testrender & testshade support all the standard camera getattribute queries. (1.5.9)
  • testshade/testrender: have get_attribute fall back on get_userdata, and have get_userdata bind "s" and "t" to make it easy to test shader that rely on userdata. #395 (1.5.10)
  • Fixes for Boost 1.55 + Linux combination, where it needed -lrt on the link line. #394 (1.5.10)
  • Windows build fix for compiling shaders finding the right oslc.exe. #399 (1.5.11)

Documentation:

  • Clarified docs about floor(). (1.5.8)
  • Clarified that oren_nayar() is the name of the function, not orennayar (it was not consistent). (1.5.8) (#375)
  • backfacing() was previously left out of the docs. (1.5.8) (#376)
  • Documented the specific names that should be used with getattribute() to retrieve common camera parameters. We should expect these to be the same for all renderers (though individual renderers may also support additional attribute queries). #393 (1.5.9)
  • Clarify that we intend for getattribute() to be able to retrieve "userdata" (aka primitive variables) if no attribute is found with the matching name. #395 (1.5.10)

Release 1.4.1 - 19 Dec 2013 (compared to 1.4.0)

  • Guard matrix*point transformations against possible division by zero.
  • Fix subtle bug with splines taking arrays, where the number of knots passed was less than the full length of the array, and the knots had derivatives -- the derivatives would be looked up from the wrong spot in the array (and could read uninitialized portions of the array).
  • testshade/testrender - Fix timer call that wasn't correctly reporting execution time versus total time.
  • Fix incorrect function declarations for the no-bitcode case (only affected Windows or if a site purposely built without precompiled bitcode for llvm_ops.cpp).
  • Build: more robust detection of clang, for older cmake versions.
  • Build: handle 3-part version numbers for LLVM installations.
  • Build: Fix USE_EXTERNAL_PUGIXML versus USING_OIIO_PUGI issue.

Release 1.4.0 - 12 November 2013 (compared to 1.3)

Language, standard libary, and compiler changes (for shader writers):

  • Simplex noise: new noise varieties "simplex" and "usimplex" are faster than Perlin noise (and MUCH faster for the 4-D variety), but has a somewhat different appearance. Judge for yourself, use whichever noise suits your purpose.
  • oslc now catches mismatches between the format string and the types of arguments to format(), printf(), fprintf(), warning(), and error().
  • oslc now gives a compile error when trying to use a function as if it were an ordinary variable. (1.3.2)
  • Improvement to oslc function type checking -- allow more nuanced matching of polymorphism based on return types. First we check for identical return types, then we test allowing non-identical spatial triples to match, then finally we allow any return type to match.
  • New ShadingSystem attribute "debug_uninit", which when set to nonzero tries to detect use of uninitialized variables at runtime. (Off by default because it's very expensive, just use if you are debugging.)
  • Implemented the OSL aastep() function, which was always described in the docs but never implemented.
  • The texture lookup functions all take new optional parameters, "missingtexture", (color), "missingalpha", (float), which when supplied will substitute that color and alpha for missing or broken textures, rather than treating it as an error condition.
  • New gettextureinfo() queries: "datawindow", "displaywindow" (both take an int[4] as destination argument).

ShadingSystem API changes and new options (for renderer writers):

  • New ShadingSystem attribute "renderer_outputs" enumerates the renderer outputs (AOVs) explicitly, so that elision of unused outputs can be done with full understanding of which params will or will not be sued. Beware: if you enable "opt_elide_unconnected_outputs", you MUST pass "renderer_outputs" or your AOVs may be eliminated!

Performance improvements:

  • "Middleman" optimization notices when you have 3 layers A,B,C with connections A.Aout -> B.Bin and B.Bout -> C.Cin, an Bout is simply copied unconditionally from Bin. In this case, Aout is connected directly to Cin, potentially leading to further optimizations, including layer B getting culled entirely.
  • Layer-to-layer global propagation: Notice cases where an upstream output is guaranteed to be aassigned a global variable (such as N or u) and then alias the downstream parameter to that global (eliminating the connection and possibly culling the upstream layer entirely).
  • Improve constant propagation from layer to layer (it used to do so only if the output of the earlier layer was never used in the upstream layer; but actually it's ok for it to be read, as long as it's not rewritten).
  • Runtime constant-folding of cellnoise() calls.
  • Local variables that are arrays initialized with float, int, or string constants have been greatly optimized. If that's the only time anything is written into the array, it will be turned into a true static constant with no per-shader-invocation initialization or allocation costs. Thus, it is no longer expensive to use a large array of constants as a table... it may look like a per-shade cost to set up the array, but by the time the optimizer gets done with it, it is not.
  • Improved runtime constant-folding of max/min (now works for the integer case, as well as previously working for the float-based types).
  • Runtime constant-folding of cos, sin, acos, asin, normalize, inversesqrt, exp, exp2, expm1, log, log2, log10, logb, erf, erfc, radians, degrees.
  • Optimization that speeds up certain closure manipulations and can cut overhead especially for relatively simple shaders.
  • New peephole optimizations for two common patterns: (1) add A B C ; sub D A C => [add A B C;] assign D B and the same if the order of add & sub are switched. (2) OP A B... ; assign A C => OP C B... as long as A is not subsequently used and OP fully overwrites A and writes to no other variables.
  • Constant folding of Dx, Dy, Dz, area, and filterwidth, when passed a constant (the deriv will be 0 in that case).
  • Substantial multithread speedups by eliminating testing of some shared variables.
  • Constant folding of add & sub for the mixed float/triple cases.
  • Speed up closure construction by combining the closure primitive with its (nearly inevitable) multiplication by weight, into a single internal operation.
  • The OSLQuery library has been sped up by 20x when querying the parameters of large shaders.

Bug fixes:

  • Fix 'debugnan' tendency to give false positives for certain assignments to arrays and multi-component variables (colors, points, etc.).
  • The integer versions of min(), max(), and clamp() were not working properly. (1.3.1)
  • fmod(triple,triple,float) was not working properly in Windows. (1.3.2)
  • Avoid incorrect heap addressing when retrieving a symbol's address. (1.3.2)
  • Fix for a bug where an early 'return' from a shader could lead to output parameters not being properly copied to the inputs of their downstream connections. (1.3.2)
  • Fix bug where filterwidth() didn't properly mark itself as needing derivatives of its argument. (1.3.2)
  • Bug fix: Was not properly initializing the default values of output params if they were written but never subsequently read.
  • Better error handling for missing pointclouds.
  • Fixed improper initialization of arrays of closures.
  • Fixed constant folding bug for the split() function.
  • Fixed constant folding bug for pow(x,2.0).

Under the hood:

  • Eliminate use of custom DEBUG preprocessor symbol in favor of the more standard NDEBUG (beware: its sense is reversed).
  • All references to and vestiges of TBB have been removed.

Build & test system improvements and developer goodies:

  • testshade: --options lets you set arbitrary options to the ShadingSystem for test runs.
  • Added CMake option 'ENABLERTTI' that enables use of RTTI for sites that must link against an RTTI-enabled LLVM (the default is to assume LLVM is built without RTTI, so we don't use it either). (1.3.1)
  • Fix some ambiguity about which variety of shared_ptr we are using -- this could produce problems in apps that include the OSL headers but also use different shared_ptr varieties.
  • Fix a variety of build issues and warnings under Windows.
  • Work around CMake bug where on some platforms, CMake doesn't define the 'NDEBUG' when making the 'RelWithDebInfo' target (which is sometimes used for profiling). (1.3.1)
  • Add Make/CMake option 'USE_EXTERNAL_PUGIXML' which if set to nonzero will find and use a system-installed PugiXML rather than assuming that it's included in libOpenImageIO. When used, it will also use the environment variable PUGIXML_HOME (if set) as a hint for where to find it, in case it's not in a usual system library directory. (1.3.1)
  • Nicer debug printing (for developers) when an op doesn't have an associated source line. (1.3.2)
  • Reorder include directories for building LLVM bitcode so that the openimageio, ilmbase and boost directories are ahead of any system directories given by llvm-config --cxxflags. This avoids the LLVM bitcode getting compiled against different library versions than the rest of the code if multiple versions are installed.
  • Have debug_groupname and debug_layername apply to LLVM debugging info as well.
  • Support for LLVM 3.3.
  • Fix compiler warnings for clang 3.3 and libc++.
  • CMake files now more carefully quote assembled file paths to more gracefully handle paths with spaces in them.
  • CMakeLists.txt has been moved to the top level (not in src/) to conform to the usual CMake conventions.

Documentation:

  • Eliminate references to OSL random() function; it was never implemented and nobody seemed to miss it or have a compelling use case. (1.3.1)

Release 1.3.3 - 11 July 2013 (compared to 1.3.2)

  • Fix bug in the implementation of filterwidth() when passed a constant (for which no derivative could be taken).
  • Changes to support LLVM 3.3.

Release 1.3.2 - 19 Jun 2013 (compared to 1.3.1)

  • fmod(triple,triple,float) was not working properly in Windows.
  • Nicer debug printing (for developers) when an op doesn't have an associated source line.
  • Avoid incorrect heap addressing when retrieving a symbol's address.
  • oslc new gives a compile error when trying to use a function as if it were an ordinary variable.
  • Fix for a bug where an early 'return' from a shader could lead to output parameters not being properly copied to the inputs of their downstream connections.
  • Fix bug where filterwidth() didn't properly mark itself as needing derivatives of its argument.

Release 1.3.1 - 15 May 2013 (compared to 1.3.0)

  • The integer versions of min(), max(), and clamp() were not working properly.
  • Added CMake option 'ENABLERTTI' that enables use of RTTI for sites that must link against an RTTI-enabled LLVM (the default is to assume LLVM is built without RTTI, so we don't use it either).
  • Work around CMake bug where on some platforms, CMake doesn't define the 'NDEBUG' when making the 'RelWithDebInfo' target (which is sometimes used for profiling).
  • Docs: Eliminated discussion of random(), which was never implemented and we can't think of a good use case.
  • Add Make/CMake option 'USE_EXTERNAL_PUGIXML' which if set to nonzero will find and use a system-installed PugiXML rather than assuming that it's included in libOpenImageIO. When used, it will also use the environment variable PUGIXML_HOME (if set) as a hint for where to find it, in case it's not in a usual system library directory.

Release 1.3.0 - 14 Feb 2013 (compared to 1.2)

Language, standard libary, and compiler changes (for shader writers):

  • pointcloud_write() allows shaders to write data and save it as a point cloud.
  • spline now accepts a "constant" interpolation type, which interpolates with discrete steps.
  • isconnected(var) returns true if var is a shader parameter and is connected to an earlier layer. This is helpful in having shader logic that can discern between a connected parameter versus a default.
  • Whole-array assignment is now supported. That is, if A and B are arrays of the same type and length(A) >= length(B), it is legal to write A=B without needing to write a loop to copy each element separately.
  • stoi() and stof() convert strings to int or float types, respectively (just like the identically-named functions in C++11). These do properly constant-fold during runtime optimization if their inputs can be deduced.
  • split() splits a string into tokens and stores them in the elements of an array of strings (and does constant-fold!).
  • distance(point A, point B, point Q) gives the distance from Q to the line segment joining A and B. This was described by the OSL spec all along, but somehow was not properly implemented.

ShadingSystem API changes and new options (for renderer writers):

  • Default implementation of all the pointcloud_*() functions in RendererServices, if Partio is found at build time.
  • ShadingSystem attribute "compile_report" controls whether information should be sent to the renderer for each shading group as it compiles. (The default is now to be more silent, set this to nonzero if you want to see the old per-group status messages.)
  • ShadingSystem attribute "countlayerexecs" adds debugging code to count the total number of shader layer executions (off by default; it slows shader execution down slightly, is only meant for debugging).
  • Add a parameter to OSLCompiler::compile to specify the path to the stdosl.h file.
  • New call: ShadingSystem::LoadMemoryCompiledShader() loads a shader with OSO data from a memory buffer, rather than from a file.

Performance improvements:

  • Reduce instance symbol memory use, lowering OSL-related memory by 1/2-2/3 for large scenes.
  • Identical shader instances within a shader group are automatically merged -- this can have substiantial performance and memory improvements for very complex shader groups that may (inadvertently, for convenience, or as an artifact of certain lookdev tools) have multiple instances with identical input parameters and connections. We have seen some shots that render up to 20% faster with this change.
  • Better constant-folding for pointcloud_get (if indices are known).
  • Speed up implementation of exp() for some Linux platform (works around a known glibc issue).
  • Speed up of mix() by making it a built-in function (rather than defined in stdosl.h) and doing aggressive constant folding on it. Also some special cases to try to avoid having mix() unnecessarily trigger execution of earlier layers when one or both of its arguments is a connected shader param and the mix value turns out to be 0 or 1.
  • Runtime optimization now includes constant-folding of getattribute() calls, for those attributes which are scene-wide (such as renderer options that apply to the whole frame).
  • Improvements in the algorithm that tracks which symbols need to carry derivatives around results in MUCH faster compile times for extremely complex shaders.
  • Improve bad performance for shaders that call warning() prolifically, by imposing a maximum number of shader warnings that are echoed back to the renderer (controlled by ShadingSystem attribute "max_warnings_per_thread", which defaults to 100; 0 means that there is no maximum).

Bug fixes and minor improvements:

  • Fix incorrect oso output of matrix parameter initialization. (This did not affect shader execution, but could result in oslquery/oslinfo not reporting default matrix parameter values correctly.)
  • Bug fix: oslinfo didn't print int metadata values properly.
  • oslc better error checking when calling a variable as if it were a function.
  • Parsing of oso files was broken for compiled shaders that had string metadata whose metadata value contained the '}' character.
  • Pointcloud function bug fixes: now robust to being passed empty filenames, or calling pointcloud_get when count=0.
  • Fix crash with C preprocessor when #include fails or no shader function is defined.
  • Improve error reporting when parsing oso, especially in improving the error messages when an old renderer tries to load a .oso file created by a "newer" oslc, and the oso contains new instruction opcodes that the older renderer didn't know about.
  • oslc now gives a helpful error message, rather than hitting an assertion, if you try to index into a non-array or non-component type.
  • Broken "XYZ" color space transformations because of confusion between "xyz" and "XYZ" names.
  • oslc: correctly catch errors with integer literals that overflow.
  • oslc: proper error, rather than assertion, for 'closure color * closure color'.
  • oslc: proper handling of preprocessor errors when stdosl.h is in a path containing spaces.
  • Fix bugs in the OSL exit() function.
  • Don't error/warn if metadata name masks a global scope name.

Under the hood:

  • Simplify code generation of binary ops involving closures.

Build & test system improvements and developer goodies:

  • Many, many fixes to enable building and correct running of OSL on Windows. Too many to list individually, let's just say that OSL 1.3 builds and runs pretty robustly on Windows, older versions did not.
  • Remove unused OpenGL and GLEW searching from CMake files.
  • Fix a variety of compiler warnings, particularly on newer compilers, 32 bit platforms, and Windows.
  • Find LLVM correctly even when using "svn" LLVM versions.
  • Adjust failure threshold on some tests to account for minor platform differences.
  • New minimum OIIO version: 1.1.
  • CMake fixes: Simplify searching for and using IlmBase, and remove unneeded search for OpenEXR.
  • Find Partio (automatically, or using 'make PARTIO_HOME=...'), and if found, use it to provide default RendererServices implementations of all the pointcloud-related functions.
  • Make/CMake STOP_ON_WARNING flag (set to 0 or 1) controls whether the build will stop upon any compiler warning (default) or if it should keep going (=0).
  • Fixed bad interaction between weave preprocessor, OIIO::Strutil::format, and gcc 4.7.2.
  • Fixes for static linkage of liboslcomp.
  • Addressed compilation errors on g++ 4.7.2.
  • Improved logic and error reporting for finding OpenImageIO at build time.
  • Add support for linking to static LLVM libraries, and for specifying a particular LLVM version to be used.
  • New BUILDSTATIC option for CMake/Make allows building of static OSL libraries.
  • Fixes to allow OSL to use LLVM 3.2.
  • Fixes to allow OSL to be compiled by clang 3.2.
  • Fixes to allow building on Windows with MinGW.
  • Fix for building from a chroot where the host may be, e.g., 64 bit, but the target is 32 bit.
  • Minimize cmake output clutter for things that aren't errors, unless VERBOSE=1.
  • Various fixes to get OSL building and running on FreeBSD.
  • Cmake/make option USE_LLVM_BITCODE to be able to force LLVM bitcode compilation on or off (defaults to on for Windows, off for Unix/Linux).

Documentation:

  • Clarify that documentation is licensed under Creative Commons 3.0 BY.
  • Clean up OSL Spec discussion of built-in material closures.
  • Overhaul the suggested metadata conventions in the OSL spec (now conforms to the conventions used by Katana).

Release 1.2.1 - 6 Nov, 2012 (compared to 1.2.0)

  • Fix incorrect oso output of matrix parameter initialization. (This did not affect shader execution, but could result in oslquery/oslinfo not reporting default matrix parameter values correctly.)
  • Build: remove unused OpenGL and GLEW searching from CMake files.
  • Build: Fix a variety of compiler warnings, particularly on newer compilers, 32 bit platforms, and Windows.
  • Build: Find LLVM correctly even when using "svn" LLVM versions.
  • Bug fix: oslinfo didn't print int metadata values properly.

Release 1.2.0 - Aug 30, 2012 (compared to 1.1)

Note: this is more or less the production-hardened version of OSL that was used to complete Men in Black 3, The Amazing Spider-Man, and Hotel Transylvania.

New tools/utilities:

  • New program "testrender" is a tiny ray-tracing renderer that uses OSL for shading. Features are very minimal (only spheres are permitted at this time) and there has been no attention to performance, but it demonstrates how the OSL libraries may be integrated into a working renderer, what interfaces the renderer needs to supply, and how the BSDFs/radiance closures should be evaluated and integrated (including with multiple importance sampling).
  • shaders/ubersurface.osl is an example of a general purpose surface shader.

Language, standard libary, and compiler changes:

  • texture()/texture3d() support for subimage/face selection by name as well as by numeric index.
  • getattribute() performs automatic type conversions that mostly correspond to the kind of automatic type casting you would get from ordinary assignments in OSL. For example, getattribute("attrib",mycolor) used to fail if "attrib" turned out to be a float rather than a color; but now it succeeds and copies the float value to all three channels of mycolor.

ShadingSystem API changes and new options:

  • Remove unused 'size' parameter from the register_closure API.

Optimization improvements:

  • Constant-fold pointcloud_search calls when the position is a constant if the search returns few enough results, by doing the query at optimization time and putting the results into new constant arrays.
  • Matrix parameters initialized by m=matrix(constA,constB,...) now statically initialize, and no longer need to run initialization code each time the shader executes.

Bug fixes and minor improvements:

  • Fix pointcloud_search to optionally take a 'sort' parameter, as originally documented.
  • Unit tests weren't properly run as part of the testsuite.
  • Track local+temp memory usage of optimized shaders and consider it an error if a shader needs more than a maximum amount at runtime, set with the "max_local_mem_KB" attribute.
  • Add pointcloud statistics.
  • Fix derivative error for sincos() when the inputs have no derivatives but the outputs do.
  • Bug fix to vector-returning Gabor noise (it could previously generate different values for different platforms).
  • printf() of closures built from other closures allows for proper recursive printing of the closure tree.

Build & test system improvements and developer goodies:

  • Simplify the namespace scheme.
  • Remove support for certain old dependencies: OIIO versions < 0.10, LLVM < 3.0, and Boost < 1.40.
  • Lots of little fixes to solve compiler warnings on various compilers.
  • Support for newer OSX releases, particularly if /usr/bin/cpp-4.2 is not found.
  • Better support for Boost::wave (portable C preprocessor replacement). Build with 'make USE_BOOST_WAVE=1' to force Wave use instead of system cpp.
  • You can select a custom LLVM namespace with 'make LLVM_NAMESPACE=...'.
  • Symbols that are not part of the OSL public APIs are now hidden from the linker in Linux/OSX if the CMake variable HIDE_SYMBOLS is on.
  • New Makefile/CMake option LLVM_STATIC can be used to use static LLVM libraries rather than the default dynamic libraries.
  • Support for LLVM 3.1.
  • Support for building with Clang 3.1 (lots of warning fixes).
  • Makefile/CMake variable EXTRA_CPP_DEFINITIONS allows you to inject additional compiler flags that you may need to customize the build for your site or a choice of unusual compiler.
  • Add support for 'PROFILE=1' builds that are appropriate for use with a profile.

Release 1.1.0 - Mar 14, 2012 (compared to 1.0.0)

Language, standard libary, and compiler changes:

  • Allow closures as parameters to closures.
  • New constants: M_2PI, M_4PI
  • Generic noise: noise("noisetype",coords,...)
  • Gabor noise (anisotropic, automatically antialiased) via noise("gabor").
  • Fix mod/fmod discrepancy: fmod() now matches C, mod() always returns a positive result like in RSL.
  • Allow "if (closure): and "if (!closure)" to test if a closure is empty or not.
  • New optional parameter to trace(): "traceset" allows you to specify a named geometry set for tracing.

ShadingSystem API changes and new options:

  • New "greedyjit" option will optimize & JIT all shader groups up front, concurrently, without locking.
  • Add a way to name shader groups.
  • attribute("options",...) lets you set a bunch of options at once.
  • Options to enable/disable individual optimizations (mostly useful for debugging)

Optimization improvements:

  • Allow block alias tracking on non-constants when it's safe.
  • Track "stale" values to eliminate pointless assignments.
  • Eliminate redundant "useparam" ops.
  • Assignments to output parameters that are not connected to any downstream layers are now eliminated.
  • More aggressive elision of ops that only write to symbols that won't be subsequently used.
  • More careful identification and removal of parameters (input and output) that are both unused in the shader and not connected downstream.

Bug fixes and minor improvements:

  • Minor blackbody fixes.
  • Bug fix: don't mark constants as having their derivatives taken.
  • Clamp splineinverse() for out-of-knot-range x input.
  • Bug fix: the optimization of "a=b; a=c" was incorrect if c was an alias for a (it incorrectly eliminated the first assignment).
  • Bug fix: work around LLVM thread safety issues during JIT.
  • Bug fix: symbol_data() wasn't returning the right address for non-heap parameters.
  • Bug fix: optimization errors related to break, continue, and return not properly marking the next instruction as a new basic block.
  • Bug fix: luminance() with derivatives didn't work.
  • Bug fix: in code generation of structure initializers.
  • Improved error messages from ConnectShaders.
  • Bug fix: type checking bug could case non-exactly-matching polymorphic functions to coerce a return value even when that was not intended.
  • Type checking improvements: Make sure point-point is a vector expression, and point+vector & point-vector are point expressions.

Build & test system improvements and developer goodies:

  • testsuite overhauls:
    • run each test both optimized and not
    • generate all tests in build, not directly in ./testsuite
    • greatly simplify the run.py scripts
  • Much more detailed debugging logs of the optimization process.
  • Upgrade to clang/llvm 3.0.
  • Lots of infrastructure to make debugging the optimizer easier. Including new options debug_groupname, debug_layername, only_groupname.
  • Improved the build system's LLVM-finding logic.
  • Fix warnings from gcc 4.6.

Release 1.0.0 - Oct 12, 2011

  • Modified testshade (and the underlying SimpleRender class) to handle several standard named coordinate systems such as "camera", "screen", "NDC", "raster."
  • blackbody() and wavelength_color().
  • New ShadingSystem configuration attribute: "colorspace" lets you explain to OSL what RGB really means (e.g., "Rec709", "sRGB", "NTSC", etc.). The luminance(), blackbody(), wavelength_color, and conversion to/from XYZ now takes this into account correctly.
  • rotate() (always in spec, never implemented)

Release 0.6.2 - Sept 29, 2011

  • Statistics overhaul -- added optimization stats, eliminated unused ones.
  • Allow a shader parameter to mask a global built-in function with only a warning, and improve scope conflict errors by pointing out the file and line of the previous definition.
  • Altered the RendererServices API to add transform_points() method, which allows renderers to support nonlinear transformations (i.e., those that are not expressible as a 4x4 matrix).
  • Issue a renderer error when unknown coordinate system names are used (can be turned of by setting the new ShadingSystem attribute "unknown_coordsys_error" to false).
  • New OSL built-in function: splineinverse().

Release 0.6.1 - Sept 20, 2011

  • Be more aggressive in freeing shader instance memory that's no longer needed after optimization and LLVM JIT. This greatly reduces OSL-related memory consumption for scenes with large numbers of very complicated shading networks.
  • Add Dz() which is helpful for apps that use OSL to shade volumes. At present, we only correctly compute Dz(P), all other Dz() queries return 0.
  • Additional statistics on how many instances and groups compile, and how many are empty after all optimizations are performed.
  • Make sure all the relevant statistics can be queried via ShadingSystem::getattribute.

Release 0.6.0 - Sept 9, 2011

  • ShadeExec API overhaul -- an app using it no longer needs ShadingSystemImpl internal knowledge.
  • Thread-parallel runtime optimization and LLVM JIT of different shader groups.
  • Optimizations: runtime constant folding of arraylength and regex_search, new instruction 'arraycopy' will copy an entire array at once.
  • Renamed patterns.h to oslutil.h.
  • Do not generate unnecessary code when optional texture parameters are set to their default values.
  • Restore long-lost ability for layers to run unconditionally (not lazily) if they were marked as "non-lazy" (for example, if they write to globals.
  • Make the "debugnan" attribute work again -- when turned on, code will be inserted after every op to be sure that no NaN or Inf values are generated, and also verify that shader inputs (globals) don't have NaN or Inf values passed in by the renderer. A similar facility existed a long time ago, but we lost that functionality when we switched from the interpreter to LLVM.
  • Looks for release versions of LLVM-2.9 (allows using a Macports LLVM installation).

Release 0.5.4 - Jul 21, 2011

  • Several fixes related to arrays of structs, and structs containing other structs.
  • Fixed arrays of closures.
  • Removed support for old LLVM 2.7, nobody seemed to be using it any more.
  • Changed the definition of dict_find() to return -1 for an invalid dictionary, to distinguish it from 0 meaning that the query failed but the dictionary itself was valid.
  • Make array parameters safe to convert to constants during runtime optimization.
  • Support derivatives in pointcloud searches.
  • Fixed several runtime optimizer bugs.
  • Fixed a bug where environment() calls with an optional "alpha" parameter that has derivatives was overwriting memory.
  • Fixed code generation bug for a*=b and a/=b.
  • Automatically initialize all local string variables to NULL, to avoid bad pointers for uninitialized strings.
  • Bug fix: dict_value() wasn't properly marking its argument as writable.
  • Automatic range checking of array and component access.
  • Fix uninitialized derivatives for pointcloud().
  • Speed up getattribute() calls by caching information about failed getattribute queries in the ShadingContext.
  • Fix to constant folding of gettextureinfo: a failed lookup should not fold, because we want the error to occur in shader execution, not during optimization.
  • Refactor, clean up, and comment testshade.
  • oslc now gives an error on non-void functions that fail to return a value.
  • Fixed implementation of area() that could generate an assertion.
  • Fix escape sequences in string literals: we were handling it correctly for printf-like format strings, but not other string literals.
  • break and continue now work properly (just like in C/C++).
  • You can now return from anywhere in a user function (multiple times if you want), just like C/C++, and are no longer restricted to the only return statement being the last statement of the function.
  • New include file for shaders: patterns.h. Now, it only includes a handy 'wireframe()' function, but will expand for other useful things.
  • New function: int getmatrix(from,to,M) is like the matrix(from,to) constructor, but returns a success value so a shader can tell if the named coordinate systems failed to be found by the renderer.

Release 0.5.3 - Apr 19, 2011

  • Fix missing derivatives for sign() function.
  • Fix closure color type size (crashes).
  • Fix bug with environment() when passed "alpha" pointers with derivatives.
  • Improve error messages for getmessage/setmessage to catch the most common sources of non-deterministic behavior.
  • Bug fix when constant-folding gettextureinfo().
  • Fix mismatched prototype for subsurface() closure.
  • Texture errors encountered in shader constant folding are now properly reported to the renderer.
  • Allow functions to have array parameters of unspecified length.
  • Fix subtle bug related to lifetime analysis of variables in loops (led to incorrect optimizations).

Release 0.5.2 - Mar 14, 2011

  • Windows: use boost::wave instead of external cpp; various other Windows compilation fixes.
  • texture & environment now take an optional "interp" parameter that overrides the interpolation/filtering method (valid arguments: "smartcubic", "cubic", "linear", "closest").
  • Bug fixes to getmessage() and its handling of derivatives, which includes a slight RendererServices API change.