Previously B-Bone deformation mapped every vertex to just one
B-Bone segment. This results in abrupt transformation differences
between the sides of each threshold plane, reducing the quality
of B-Bone deformation and making the use of shape keys impractical.
This commit replaces this approach with a linear blend between
the two closest segment transformations, effectively representing
the B-Bone as two weight-blended plain bones for each vertex.
In order to distribute the interpolation more evenly along the
bone, segment matrices for deformation are now computed at points
between the segments and at the ends of the B-Bone. The computation
also uses the true tangents of the Bezier curve for the orientation.
The nodes at the end of the bone require some special handling to
deal with zero-length Bezier handles caused by a zero ease value.
The Copy Transforms constraint now also smoothly interpolates
rotation and scaling along the bone shape when enabled.
The initial version of the patch was submitted by @Sam200.
Differential Revision: https://developer.blender.org/D4635
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This is often invalid, outdated or misleading
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See P901 for script to perform these edits.
- Remove 'rotate_m2', unlike 'rotate_m4' it created a new matrix
duplicating 'angle_to_mat2' - now used instead.
(better avoid matching functions having different behavior).
- Add 'axis_angle_to_mat4_single',
convenience wrapper for 'axis_angle_to_mat3_single'.
- Replace 'unit_m4(), rotate_m4()' with a single call to 'axis_angle_to_mat4_single'.
mul_m4_m4m4(R, A, B) gives us R = AB in general. Existing code assumed the worst, that A and B both alias the output R. For safety it makes internal copies of A and B before calculating & writing R.
This is the least common case. Usually all 3 matrices differ. Often we see M = AM or M = MB, but never M = MM.
With this revision mul_m4_m4m4 is called in exactly the same way but copies inputs only when needed. If you know the inputs are independent of the output use the "uniq" variant to skip the saftety checks.
mat3_polar_decompose gives the right polar decomposition of given matrix,
as a pair (U, P) of matrices.
interp_m3_m3m3 uses that polar decomposition to perform a correct matrix interpolation,
even with non-uniformly scaled ones (where blend_m3_m3m3 would fail).
interp_m4_m4m4 just adds translation interpolation to the _m3 variant.
`BLI_space_transform_from_matrices()` defines a 'global-invariant' transform
(same point in global space, two different coordinates in local and target spaces).
New `BLI_space_transform_global_from_matrices()` is kind of opposite, it defines
a 'local-invariant' transform (two different points in global space, same coordinates in local and target spaces).
Useful to 'match' meshes.
It still warns the user that there may be an error, but the baking goes
on. Also using the new is_uniform_scaled_m4() instead of float comparison.
Reported and fix suggested by Campbell Barton as a concern over 2bfc3deb
Issue was caused by inverting a degenerate matrix when
evaluating drivers.
Solved by using tweaked inverse code (same as used in Cycles).
Should have no affect on cases when matrix is not degenerate.
