Campbell Barton
0e172e9732
Calculate a tangent per loop, apply the transformation in multiple spaces and accumulate the result weighting by the loop-angle. Note that previously only the tangents Z axis (normal) was properly accumulated, the X and Y axes only contained the values from a single loop (the last one written to), meaning only two edges contributed to the result. Now the transformation from all loops are taken into account. In practice the difference between both methods is minimal, only for more extreme bending it can be noticed which is often when the previous method didn't work as well.