test2/extern/fast_float/README.blender

Project: fast_float
URL: https://github.com/fastfloat/fast_float
License: SPDX:MIT
Upstream version: 5.0.0 (f5a3e77, 2023 May 25)
Copyright: "Copyright 2023 The Wuffs Authors; Copyright (c) 2021 The fast_float authors"
Local modifications:

- Took only the fast_float.h header and the license/readme files
OBJ: further optimize, cleanup and harden the new C++ importer Continued improvements to the new C++ based OBJ importer. Performance: about 2x faster. - Rungholt.obj (several meshes, 263MB file): Windows 12.7s -> 5.9s, Mac 7.7s -> 3.1s. - Blender 3.0 splash (24k meshes, 2.4GB file): Windows 97.3s -> 53.6s, Mac 137.3s -> 80.0s. - "Windows" is VS2022, AMD Ryzen 5950X (32 threads), "Mac" is Xcode/clang 13, M1Max (10 threads). - Slightly reduced memory usage during import as well. The performance gains are a combination of several things: - Replacing `std::stof` / `std::stoi` with C++17 `from_chars`. - Stop reading input file char-by-char using `std::getline`, and instead read in 64kb chunks, and parse from there (taking care of possibly handling lines split mid-way due to chunk boundaries). - Removing abstractions for splitting a line by some char, - Avoid tiny memory allocations: instead of storing a vector of polygon corners in each face, store all the corners in one big array, and per-face only store indices "where do corners start, and how many". Likewise, don't store full string names of material/group names for each face; only store indices into overall material/group names arrays. - Stop always doing mesh validation, which is slow. Do it just like the Alembic importer does: only do validation if found some invalid faces during import, or if requested by the user via an import setting checkbox (which defaults to off). - Stop doing "collection sync" for each object being added; instead do the collection sync right after creating all the objects. Cleanup / Robustness: This reworking of parser (see "removing abstractions" point above) means that all the functions that were in `parser_string_utils` file are gone, and replaced with different set of functions. However they are not OBJ specific, so as pointed out during review of the previous differential, they are now in `source/blender/io/common` library. Added gtest coverage for said functions as well; something that was only indirectly covered by obj tests previously. Rework of some bits of parsing made the parser actually better able to deal with invalid syntax. E.g. previously, if a face corner were a `/123` string, it would have incorrectly treated that as a vertex index (since it would get "hey that's one number" after splitting a string by a slash), instead of properly marking it as invalid syntax. Added gtest coverage for .mtl parsing; something that was not covered by any tests at all previously. Reviewed By: Howard Trickey Differential Revision: https://developer.blender.org/D14586 2022-04-17 22:07:43 +03:00			`Project: fast_float`
			`URL: https://github.com/fastfloat/fast_float`
Add license and copyright information for external dependencies This is being added straight to 4.2, prior to the `make license` command which will use this to generate a more complete license file. Licenses information and ambiguities worked with Dalai Felinto. Part of !129018. 2024-10-18 16:06:05 +02:00			`License: SPDX:MIT`
Externals: update fast_float to latest version (5.0.0) to fix some compile warnings The library is used by OBJ/STL/PLY importers 2023-05-30 10:01:48 +03:00			`Upstream version: 5.0.0 (f5a3e77, 2023 May 25)`
Add license and copyright information for external dependencies This is being added straight to 4.2, prior to the `make license` command which will use this to generate a more complete license file. Licenses information and ambiguities worked with Dalai Felinto. Part of !129018. 2024-10-18 16:06:05 +02:00			`Copyright: "Copyright 2023 The Wuffs Authors; Copyright (c) 2021 The fast_float authors"`
OBJ: further optimize, cleanup and harden the new C++ importer Continued improvements to the new C++ based OBJ importer. Performance: about 2x faster. - Rungholt.obj (several meshes, 263MB file): Windows 12.7s -> 5.9s, Mac 7.7s -> 3.1s. - Blender 3.0 splash (24k meshes, 2.4GB file): Windows 97.3s -> 53.6s, Mac 137.3s -> 80.0s. - "Windows" is VS2022, AMD Ryzen 5950X (32 threads), "Mac" is Xcode/clang 13, M1Max (10 threads). - Slightly reduced memory usage during import as well. The performance gains are a combination of several things: - Replacing `std::stof` / `std::stoi` with C++17 `from_chars`. - Stop reading input file char-by-char using `std::getline`, and instead read in 64kb chunks, and parse from there (taking care of possibly handling lines split mid-way due to chunk boundaries). - Removing abstractions for splitting a line by some char, - Avoid tiny memory allocations: instead of storing a vector of polygon corners in each face, store all the corners in one big array, and per-face only store indices "where do corners start, and how many". Likewise, don't store full string names of material/group names for each face; only store indices into overall material/group names arrays. - Stop always doing mesh validation, which is slow. Do it just like the Alembic importer does: only do validation if found some invalid faces during import, or if requested by the user via an import setting checkbox (which defaults to off). - Stop doing "collection sync" for each object being added; instead do the collection sync right after creating all the objects. Cleanup / Robustness: This reworking of parser (see "removing abstractions" point above) means that all the functions that were in `parser_string_utils` file are gone, and replaced with different set of functions. However they are not OBJ specific, so as pointed out during review of the previous differential, they are now in `source/blender/io/common` library. Added gtest coverage for said functions as well; something that was only indirectly covered by obj tests previously. Rework of some bits of parsing made the parser actually better able to deal with invalid syntax. E.g. previously, if a face corner were a `/123` string, it would have incorrectly treated that as a vertex index (since it would get "hey that's one number" after splitting a string by a slash), instead of properly marking it as invalid syntax. Added gtest coverage for .mtl parsing; something that was not covered by any tests at all previously. Reviewed By: Howard Trickey Differential Revision: https://developer.blender.org/D14586 2022-04-17 22:07:43 +03:00			`Local modifications:`

			`- Took only the fast_float.h header and the license/readme files`