While verbose, this is a more flexible way to construct shaders.
Libs & defines can be optionally included for each shader type
which was previously done with inline string creation.
Not only were those often making doublons with already existing
BLI_math's stuff, but they were also used to hide implicit type
conversions...
As usual this adds some more exotic inlined vector functions (one of
the rare cases where I really miss C++ and its templates... ;) ).
Will document the new options in release notes, then in manual.
Still a bit of work to do on the bulging shape that appears
on cube corners if using arc inner miters, but will do that later.
Also need to do something smarter in clamp overlap.
Reported by @pepeland.
Adding missing events on the first point was breaking the guide behaviour.
Also, updated Ckey so it always defaults to Circular mode when guides are off.
Instead of doing manual ray-plane intersection we use normalized positions
of the grid mesh and apply scaling after interpolation so that we keep
good precision even at really far distances.
Precision is now two order of magnitude better and does not produce the
same kind of artifact at lower clip start values.
This commit also cleanup the implementation.
Fixes T58918 Grid not appearing correctly at low clip start in 2.8
Memfile undo isn't compatible with sculpt or edit-mode.
This didn't work in 2.7x, so best disable memfile undo for now in
situations where it's going to loose data or crash.
Before that only normal component was averaged, which is not
really correct.
Unfortunately, the new code is somewhat slower due to more
involved math to deal properly with non-quad faces, but the
plan is to move averaging from runtime to edit time, This
means, that mdisps will always be continuous around the edges
and no averaging on every frame change of animated character
will be needed.
Avoids nasty code all over where such math is required, and
compilers can easily deal with such situation.
Don't prefer questionable micro-optimization which comes with
a cost of nasty actual logic code.
The idea is to run reshaping for every boundary vertex
of a grid rather than trying to copy boundary grid
elements.
While this is somewhat slower, this avoids all this
tangent flipping magic, which tempts to be rather tricky
and fragile.
The boundary copy code was not dealing correct with flipping
tangent vectors, hence causing discontinuity in the final
positions.
Now we only copy boundaries for quads, where we know how to
deal with tangent vectors and where we know that this is
needed.
More clear solution could be to change the code in a way that
handles handles displacement grids of quads in the same way
as it's done for non-quad faces.
