a361e61f23
The `VelocityGeometryData::pos_buf_get()` is returning `nullptr` because the batch it not yet ready during the sync phase. But it is after the first viewport has been drawn. The fix is to have a different function that return true if the data will be available. Candidate for 4.5 LTS backport. Pull Request: https://projects.blender.org/blender/blender/pulls/142238