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The current code for computing tangents is not exactly fast. This has been a long-standing issue, and recently came up again with T97378. The main bottleneck is fetching the mesh data, since it's handled through a callback system and each vertex might have its data queried dozens of times. I've tried a lot of things to optimize `mikktspace.c`, but unfortunately most weren't that useful: - Vectorizing SVec3 gives a ~5% speedup, but I'm not sure if the additional ~70 lines of code are worth it - Keeping an internal copy of the data instead of re-querying all the time helps a lot (~50-60% time reduction), but requires a lot of extra memory (~100 byte per face) - Going C++ and replacing the internal quicksort with std::sort shows no difference - Restructuring the entire file to be a header-only library so that the callbacks can be inlined gives ~10% reduction, but is a major change and deviation from the original library In the end, two simple fixes that actually help remain: - Don't re-query the number of faces in each loop iteration - Don't bother looking for identical vertices if there's only one vertex with that hash With this, time for the test case in T97378 goes from 6.64sec to 4.92sec. It's something I guess. I feel like completely refactoring this library would not be a bad idea at some point, but for now it does the job... Differential Revision: https://developer.blender.org/D14675
.. Keep this document short & concise, linking to external resources instead of including content in-line. See 'release/text/readme.html' for the end user read-me. Blender ======= Blender is the free and open source 3D creation suite. It supports the entirety of the 3D pipeline-modeling, rigging, animation, simulation, rendering, compositing, motion tracking and video editing. .. figure:: https://code.blender.org/wp-content/uploads/2018/12/springrg.jpg :scale: 50 % :align: center Project Pages ------------- - `Main Website <http://www.blender.org>`__ - `Reference Manual <https://docs.blender.org/manual/en/latest/index.html>`__ - `User Community <https://www.blender.org/community/>`__ Development ----------- - `Build Instructions <https://wiki.blender.org/wiki/Building_Blender>`__ - `Code Review & Bug Tracker <https://developer.blender.org>`__ - `Developer Forum <https://devtalk.blender.org>`__ - `Developer Documentation <https://wiki.blender.org>`__ License ------- Blender as a whole is licensed under the GNU General Public License, Version 3. Individual files may have a different, but compatible license. See `blender.org/about/license <https://www.blender.org/about/license>`__ for details.