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.
Yep, at last it's here!
There are a few minor issues remaining but development can go on in
master after discussion at blender institute.
For full list of features see:
http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.72/Painting
Thanks to Sergey and Campbell for the extensive review and to the
countless artists that have given their input and reported issues during
development.
to support more than 2 UV maps. This code indirectly depended on the order of
OpenGL attribute ID's assigned by the OpenGL driver being the same as the
attributes being declared in the GLSL shader code, which is not always the case.
* Cleaning up the conversion code to avoid a per-face material conversion. Materials are now stored in buckets and only converted if a new material is found. This replaces some of Campbell's earlier work on the subject. His work wasn't as thorough, but it was much safer for a release.
* Shaders are only compiled for LibLoaded materials once. Before they could be compiled twice, which could really slow things down.
* Refactoring the rasterizer code to use a strategy design pattern to handle different geometry rendering methods such as immediate mode, vertex arrays and vertex buffer objects. VBOs are added, but they will be disabled in a following commit since they are still slower than vertex arrays with display lists. However, VBOs are still useful for mobile, so it's good to keep them around.
* Better multi-uv support. The BGE should now be able to handle more than two UV layers, which should help it better match the viewport.
