Blender Git Loki

Remove nonnull attribute, NULL arg is valid here.

SCons: Weirdly enough at some point scons became broken in OpenSubdiv branch

OpenSubdiv: Commit of OpenSubdiv integration into Blender

This commit contains all the remained parts needed for initial integration of
OpenSubdiv into Blender's subdivision surface code. Includes both GPU and CPU
backends which works in the following way:

- When SubSurf modifier is the last in the modifiers stack then GPU pipeline
of OpenSubdiv is used, making viewport performance as fast as possible.

This also requires graphscard with GLSL 1.5 support. If this requirement is
not met, then no GPU pipeline is used at all.

- If SubSurf is not a last modifier or if DerivesMesh is being evaluated for
rendering then CPU limit evaluation API from OpenSubdiv is used. This only
replaces the legacy evaluation code from CCGSubSurf_legacy, but keeps CCG
structures exactly the same as they used to be for ages now.

This integration is fully covered with ifdef and not enabled by default
because there are several TODOs to be solved first:

- Face varying data interpolation is not really cleanly implemented for GPU
in OpenSubdiv 3.0. It is also not implemented for limit evaluation API.

This basically means we'll have really hard time supporting UVs.

- Limit evaluation only works with adaptivly subdivided meshes so far, which
basically means all the points of CCG are pushed to the limit. This gives
different result from old code.

- There are some serious optimizations possible on the topology refiner
creation, which would speed up initial OpenSubdiv mesh creation.

- There are some hardcoded asumptions in the GPU and DerivedMesh areas which
could be generalized.

That's something where Antony and Campbell can help, making it so the code
is structured in a way which is reusable by all planned viewport projects.

- There are also some workarounds in the dependency graph to make sure OpenGL
buffers are only freed from the main thread.

Those who'll be wanting to make experiments with this code should grab dev
branch (NOT master) from

https://github.com/Nazg-Gul/OpenSubdiv/tree/dev

There are some patches applied in there which we're working on on getting
into upstream.

OpenSubdiv: Add OpenSubdiv files which are related on the CCGSubSurf and GPU

Those files are still not in use (SCons will tyr to compile new CCGSubSurf files
but no code will be in use at all because those new files are fully wrapped by
ifdef WITH_OPENSUBDIV check).

OpenSubdiv: Add new OpenSubdiv related files

This includes C-API bindings in intern/opensubdiv and CMAke module
which finds the OpenSubdiv library. This filea are not in use so
far, making it a separate commit to make actual integration commit
more clear.

CCGSubSurf: Split file into several smaller ones

This is a preparation commit for having OpenSubdiv integrated into Blender
and new layout is the following:

- CCGSubSurf.c contains implementation of common functions used by both
legacy subdivisions code and by the new code in the future.

- CCGSubSurf_inline.h contains internal functions which are to be inlined
due to the performance reasons. Those functions are only ment to be used
bu CCGSubSurf* files.

- CCGSubSurf_intern.h contains declarations of private functions and data
structures used by CCGSubSurf module.

- CCGSubSurf_legacy.c contains legacy implementation of subdivision algorithm.

- CCHSubSurf_util.c contains utility functions which are not directly related
on the subdivision code (i.e. debug functions, hash implementation etc).

There should be no functional changes so far.

Usual UI messages fixes.

Minor optimization in CustomData_update_typemap().

Fix (unreported) broken MixWeight modifier in debug builds.

defvert_find_index() & co now assert when '-1' invalid vgroup index is passed.
We used to rely on NULL value returned in this case, but with the assert...

The assert completely stalls blender actually (repeated for every vertex!).
So much better to not call that func when vgroup index is invalid.

Fix (unreported) potential serious bug in CustomData_merge().

It was always only using the flags from the first source layer of a given type, not from
the layer actually being handled.

This was (probably) more or less harmless for the CD_FLAG_NOCOPY test,
but could be really bad when checking CD_FLAG_NOFREE, and when
copying the flags over to new copied data!

Fix recent own stupidity with indexed sculpt drawing.

Fix/Workaround for CMake buildinfo error

Correcting the paths for buildinfo to point to the real header,
ended up breaking buildinfo (by not running every build).

It turns out we relied on the output _never_ existing,
so CMake generates a new buildinfo each time.
This is quite bad, but I didn't see a way for CMake to do this,
so explicitly point to a missing file and comment whats going on.

Ugly hack to avoid GLEW context error printing when initializing GLX.

Filter the debug callback to only report errors unless debug value is
20.

stderr was getting flooded with too many error messages, most of which
were not really relevant.

Resolve compiler warning for clang

Fix T45218: Crash when trying to open System in the User preferences
Fix T45381: Crash Blender 2.75 in Win7 x64 AMD card

The issue is basically caused by graphics card driver which crashes when
querying OpenCL platforms. This isn't something we can really solve from
the CLEW side, because opencl.dll does exist in old driver and even has
all the needed symbols, but first ever call to clGetPlatformIDs crashes.

While rest of the blender works fine with those older ATI/AMD cards it's
really needed to solve crashes of OpenCL device enumeration.

Solution here is to force disable OpenCL platforms if we've detected that
display card is using old ATI/AMD driver. It's not really proper solution
so it's done in the python side where it's easy to do tweaks. Reasoning
behind this change is:

- If one uses really old driver it's likely because it's the latest one
he/she can ever to install (because of discontinued support from AMD).

- If old card is used it's likely to not have dedicated GPUs for rendering.

- Even if there's a dedicated GPU device enumeration is likely to crash
because of attempt to query OpenCL from the old card.

There are still some tweaks needed likely, but this commit should make
some of the configurations to work.

Fix broken GLEW initialization. Initialize GLEW twice, once to get GLX
extensions, once to get final context extensions.

Not so nice because we get a warning on startup from GLEW, but at least
it GL extensions should work now.

Dyntopo should be supported on systems without VBOs now.

Use abstraction to unbind buffers, should avoid crashes in systems that
don't support VBOs.

Exposed by initialization error in GLEW, which should be fixed
seperately.

Pixel format selection now favours a format with a number of samples
closer to the one requested on Windows.

Patch D1384 by Benoit Bolsee.