Structure.Gantt allows you to configure how progress for individual tasks and groups is calculated.
By default, it is depends on Work Estimates settings, i.e. it will use Time Tracking or Story Points or even both, but you can specify any Custom Field of numeric type or even Formula for progress calculation.
While using Time Tracking tasks with non empty resolution are treated as 100% complete.
Formula should return values from 0 to 1 (all values higher than 1 will be treated as 1)