Aras Pranckevicius
b32cb0266c
The new 3.1 OBJ exporter code had incorrect code to determine which vertex group a polygon belongs to -- for each vertex, it was only looking at the first vertex group it has, and not using the group weight either. This 99% fixes T96824, but not 100% on the user's submitted mesh -- exactly two faces from that mesh get assigned a different group compared to the old exporter. Either choice is "correct" given that on these two faces there are two vertex groups with equal contribution. The old Python exporter was picking the group based on internal python group name map order, whereas the new C++ exporter is picking the group with the lowest index, in case of ties. I'm not sure if it's possible to fix this TBH, will have to wait until the importer is also C++. While at it, the new vertex group calculation code was doing a lot of redundant work for each and every face (traversing group lists several times, allocating & freeing memory), so I fixed that. Exporting a 6-level subdivided Monkey mesh with 30 vertex groups was taking 810ms, now takes 330ms. Reviewed By: Howard Trickey Differential Revision: https://developer.blender.org/D14500